Took apart a 55 year old 2000 hour Lycoming out of a Cessna. Not only did the crankshaft pass inspection after grinding but I have been able to find every part needed to reassemble it with brand new camshaft kit, oil pump kit, 4 brand new cylinder kits with pistons, rings, valves, springs. Should be good for another 50 years.
2000hrs is 1/4 the hrs a mechanical device should last without major replacement. 5000 hrs on rental construction equipment. So in comparison air planes are a waste of effort. Like the electric scam!
@@congerthomas1812 Completely different designs. Camshaft in aircraft engines turn in a bored aluminum case. So many things are optimized for weight rather than longevity. Construction equipment engines are all cast iron blocks, water cooled, and mostly sleeved. I have a 3 cylinder diesel that weighs as much as an O-200 and produces 34 hp.
It's awesome when a company like this actually tries to make a vast improvement to their product; instead of doing just enough to say it's different. Some still use carburetors, in 2023. I hope this new engine is excellent, and it challenges other aircraft engine makers to improve; instead of riding on their, it's good enough, ways.
All it will do is make it even more expensive to fly. I've had a dream of flying for 50 years. At 58, I still can't afford it. Price just keeps going up out of my paying ability. My time is running out.
It does make things easier a bit. Not that it was an overwhelming problem in aero use of course but it does help with the design of heads, returns, and then how much oil you need to have in total etc
@@driverjamescopeland There are a lot of options for oil windage that can minimize it to a large effect in any engine. I posted a few of them at the top of this list.
The V6 only requires a harmonic balancer like is used widely in the auto industry. In the case of car engines this is incorporated into the front-mounted crank pulley or on the rear-mounted flywheel. I suspect since a reduction box is required regardless of the motor configuration that the harmonic balancer is likely part of that gearset and incurs no additional weight penalty.
@@ArneChristianRosenfeldt The Inline-4 balance 'problem' is secondary imbalance related, not primary. If a v6 has a 90 degree inclined angle, it can be made with perfect primary balance, but secondary balance suffers. It will also have unequal phase from bank to bank.
@@robertrobinson3861 120° V6 has even firing and primary and secondary imbalance. 90° V6 is composed of 3 Ducati engines. Their primary rocking imbalance is balanced overall. Secondary, I dunno. I just concur. Uneven firing order which leads to uneven kinetic energy. Torque vibration. To make a six cylinder engine smooth, you need 6 throws (cranks). V8 only needs 4. So you get away with a lighter crankshaft and narrow bearings and less friction on a V8. It is more stiff. Only problem is that optimization seems to favour additional bays for counter weights. You can place the valve train there for DOHC. Pumps on the other end. Without this additional length you need very heavy counterweights which reduce the first resonance frequency of the crankshaft and defines your redline.
Car V6 engines using 6 throws (cranks), not 3, like this. Harmonic balancer is a different topic, this 120° V6 may not need it because of shorter crankshaft due to only 3 throws. Harmonic balancer is very important in case of inline 6 engines.
The glider club that I'm flying at has a Pawnee with an ls1 in it as it's tug plane, and the advantages of the ls1 compared to the original 540 are absolutely ridiculous! It has got a similar hourly fuel consumption as the 540, but with a higher power output and more torque. The ls1 is "de-tuned" to max out at around 400hp at 5000-5200 rpm, with a torque of about 1000nm on the prop and therefore has a much higher BSFC. But the biggest performance increase as a tug comes down to the water cooling and the gearbox for the prop. Since there is no risk of shock-cooling the cylinders after a pull, so the throttle can be pulled right of. Then the gearbox for the propeller makes it much harder for the air to windmill the engine, and therefore the rate of descent that can be achieved reassembles that of the Ju-87. It can pull a fully loaded 2 seater to 1000m/3000ft and then go down to land in around 6-7 minutes!
15:30 I agree with that statement, but at the same time, it is pretty darn amazing it took 65-odd years to achieve! Shows just how good those designs from the 1950s really were.
@PistonAvatarGuy And what is Rotax? A 912 has the same power and the same weight as an O-200 whose basic design is from the 30s.. but they added four more failure modes (gearbox, dog clutch, coolant leak, and extra throttle cable). It’s a textbook example of why specific power (something Europeans obsess about) is meaningless in aviation.
@@Bartonovich52 The Rotax 912ULS weighs about 50 pounds (30%) less than the O-200 and burns about half as much fuel, which proves that the Europeans know what they're doing. The EFI engines burn 30% less than the carbureted engines! The Rotax engines are also capable of supporting turbocharging and making significantly more power than the 0-200. Americans seem to use specific power as a strawman, trying to claim that it's all that the Europeans and Japanese care about, and while the Americans build their strawmen, they're being left further and further behind with the passing of each decade.
@@Bartonovich52 Here's what I suggest, look at the fuel consumption graphs in the operator's manual for the O-200, then read an article by Paul Bertorelli for The Aviation Consumer which is titled _Rotax 912 iS Efficiency: Better than Claimed_ (Published:July 17, 2013)
Zundapp was using a 170° V-4 in motorcycles starting in 1939. It gave better ground clearance while retaining most of the benefits of the flat engines used by BMW.
V4 is the current most winning configuration in highest level of motorcycle racing....your Ducatis Aprillias KTMS and Hondas...I recon the only hold out left now in motogp is Yamaha which I expect to also finally go V4 due to 2027 new discplacement of 850cc ....which means a reset with all new motors for all the factories....V4 maybe better for weight distribution? And narrower width compared to inlines Although just prior to pulling out of motogp Suzuki starting kicking some V4 butt with their old inline tech
I have been thinking about a 120 degree V-6 for years, and I always came up with the problem that it has primary imbalance unless there is a balance shaft, so what this video discuses at the end makes sense.
For a rocking motion the balance shaft needs to be long. For low weight the weights needs to fly along a large circle. Why are there no vehicle engines which give me this space? Replace a V8 of the same displacement. Thin shim under the clutch bell. Why would a reduction gear have a gear running counter to the crank, but with the same RPM?
I like your description, but have a comment on balance. A 3-cylinder engine has a primary rocking couple. Put two of these together with a 90-degree bank angle and the two couples combine into a rotating couple that can be balance with a crankshaft counterweight at each end of the engine. For a 120-degree bank angle, these rocking couples add together into a rotating couple that could best be described as elliptical. two crankshaft counterweights can then balance out all but about 13%. The marketing people could then describe the balance as "excellent!" Actually, the remaining unbalance is probably acceptable. I picked this engine configuration for my senior design project in school, a long time ago.
Thanks for the comment. Great info here. I came to the same conclusion but stopped short of how excellent balance was achieved. Those two crankshaft counterweights you mention would then be 2 additional to the standard 3, one at the front and one at the back where the combined rocking couple moment can be cancelled to some extent? And would an unbalanced flywheel be able to futher reduce the inbalance?
Having a much shorter compact engine also is an advantage for the center of gravity for aviation. When you're agent hangs way over your wings that you have to put weight in the back end the ballast the center of gravity. Having a much more compact engine package means you don't need to have that much added weight for balance which gives you more cargo weight capacity for your plane. It's not just as much as saving weight but also just shortening your fulcrum is a huge advantage to have good control of the aircraft
Honda use F6 on GoldWing... Fix dual spark plug to tick the box for certification and here you go... Smaller, stronger, more reliable, out of the box!! Add Turbo and you can replace most of low-mid power F4 and F6 in the fleet. For bigger planes consider modern L6 diesel units!
Fascinating information. We have 3 Chevy Corvairs in the collection and the owner is a pilot. Never knew how popular those engines were in small experimental aircraft Thanks for the excellent video.
A couple of little points here. The inefficiencies mentioned at the beginning all relate to other areas of obsolete design, not the fact that the engines are horrizontaly opposed. Imagine comparing a late model Subaru engine to a 1950s VW engine: Both are flat fours. Also, if the engine has twin cam heads, and you 'swing' the cylinders up, the lower cams may still come out to a wider position (wider ove all). A simpler idea would be for the manufacturer to run two cams side by side in the crankcase, with each cam serving that side, and shortening up the push rod lengths, while still running four valve heads if needed. Yes, yes, I realise that this complicates the cam drive a little, but it's not that big of a problem. Just an idea.
You don't need twin cams to have 4 valves per cylinder. It's how it is often done but not needed. There have been many single cam 4 valve engines. Heck, in the case of pushrod engines, you don't even need to double the number of pushrods. You can actuate two valves off of a single pushrod. Many inline 4 motorcycle engines have 16 valves and a single overhead cam.
This is the same hurdle Japanese vertical motorcycle engines had versus Harley V twin engines. I believe the vertical engines have won on all fronts except engine “growl”.
I dont think that Japanese 4 is going to run very long across the desert in the summer without coolant, unlike a harley v twin. To compare the two is more like comparing apples to oranges. They are from two entirely different set of values. Air cooled simplicity for ease of mechanics. Vs an effort to overt any necessity for mechanics.
"growl" ia subjective but if you ask me? NOTHING beats the growl of a crossplane I4 of Yamaha R1 /MT-10 Whatever coolness one derives from Harley is just made IRRELVANT in light of the THRILL an R1 provides....again IMHO....you must experience it to understand
1] A 120 degree V-6 would be great in a Honda Gold Wing. 2] In a legacy flat 6, having two cams in the block, one above, and one below could facilitate 4 valve cylinders. 3] I find it hare to believe the 30 percent improvement in specific fuel consumption as lower rpm motors generally have better fuel efficiency, at the expense of weight.
I have been flying powered A/C since 1976. The IO-520 and the PT-6 Turbine are examples of engines that will run for 50 plus years. But what the future of aviation needs is an inexpensive (less then $150K) and simple gas turbine engine in the 300 to 400 SHP power range that can burn any liquid fuel and can even be retrofitted to existing airframes.
An unfortunate property of turbines is that small ones are inefficient. For example, a 180 HP turbine would have on the order of 50% higher GPH compared to an equivalent HP Lycoming. Then there is the expense…
Porsche has been making and refining boxer 6's for quite a while and as far as I'm aware, they have also been increasing power and efficiency at the same time. Not much discussion about that.
Porsche & BMW Motorcycles maintain those Boxers and evolve them to maintain brand identity and retain loyal customers, not necessarily because it's the pinnacle of Engineering.
On the air-cooled flat sixes, one can decrease weight while improving cooling is to replace the steel cylinder barrels or linings by using nikasil coated alloy cylinder barrels. Also as both use 2 pushrods per cylinder, use the technic Honda used with the CX motorcycle & Moto Guzzi used with Daytona to get 4 valves per cylinder from 2 pushrods for cylinder
@@SuperYellowsubmarin even diesels profit from multivalving. Sure aero engines run on low speed torque, well unless the prop is geared down, like Naipers & Rotax, but an added efficiency of 10 to 15 % is nothing to squeeze at. Especially without the added weight, complexity & unreliability of DOHC engines. Go do a image search of Honda CX or MG Daytona heads to see how simply they operate 4 valves per cylinder off 2 pushrods per cylinder. Plus there are many UTube channels where they tear down blown motors. (After blown bearings) the 2nd most common reasons engines blow are from hydraulic OHC cam chain tensioners breaking a part & bits going everywhere in the engine. This does not happen with old fashioned pushrods.
Nikasils worked well in Porsche 911s but I think aircraft grade nikasils would be prohibitively expensive. I have seen specially made nikasils used in VW engines modified for motogliders, and they seemed to work well in that application, but they were very expensive. I liked they way they could be weld repaired and recoated.
@@mickvonbornemann3824 most DOHC related engine failures are because they haven't been adequately serviced, something that isn't usually an issue with aircraft since they just wouldn't be allowed to fly.
Boxers won't go obsolete just because of a new engine design. When jet engines were introduced some also thought this would make piston engines obsolete but they were wrong. Boxers will be around for a long time to come.
the problem is that those engines havent been improved in decades, Even worse is that they use older tech than some WWII piston fighter airplanes (like Fw190 with its commandoGërat). current automotive tech is decades ahead of those old engines. it's way about time for a proper efficient piston engine for airplanes.
The German company Zoche had a four cylinder radial two stroke diesel. It was light powerful very efficient and did away with many parts needed on conventional engines. The company failed of course. Homologation of new engines (even simple ones) is ridiculously slow and expensive.
I saw the Zoche engine built in an Extra 230 airplane when I visited Extra aircraft about 25 years ago. They were very angry about Zoche because he didn´t try to get the test permission to flying the engine and Walter Extra, the boss of the company wouldn´t have tried the thing illegally. On the test bench the engine made only a few ours before failing. The piston part is in fact very simpel. However there is a gear box with transmission ratio 1:42 to start the engine and to deliver compustion air to the cylinders. This gear box is rather complicated.
The fact that they are still allowed to use leaded fuel, and to rebuild these engines for LL still in 2024 is absolutely mindblowing. I know private aviation is a very minor aspect when it comes to ones to emissions. But just because they are allowed to still be extremely dirty and inefficient means we don’t get better engine with much less fuel consumption, lighter and much more environmental friendly while also not making you breath in these toxins. Yes they are reliable but they are also relicts. Time for some chance. And by law, otherwise nothing will change.
And their reliability is also way overrated. But like with everything - if it's properly driven and taken care of it may last a long time. But this is very much down to the human factor. Many flightschools (or most) seem to have the wrong idea about fuel mixture, which is manually controlled when using a carb engine.
@@terjehansen0101 it’s a engine design that is several decades old. It’s inefficient, requires a lot of knowledge and should long be replaced but there are hardly any new ones especially certified ones
DK, laws and regulations, thousands of pages of laws and regulations are precisely why alternatives do not exist. Regulation is the enemy of innovation
There are plenty of improvements to be made on the old engines. Add in squish pads for improved fuel homogeneousation, or completely redesign the combustion chamber to modern 2 valve standards like the LS engine's to improve thermal efficiency.
Without liquid cooling, you're not going to see any significant gains in efficiency, air-cooled engines literally rely on ridiculously rich fuel mixtures in order to stay cool at high power settings. Significantly improving reliability without liquid-cooling is also not going to happen.
@@CreeperOnYourHouse Name an air-cooled engine (aircraft, or otherwise) that this has ever been done with, while also resulting in the engine being able to match the low BSFC of a similar liquid-cooled engine at full power.
@@PistonAvatarGuy Bristol Hercules, DB-601. Literally any other WW2 liquid cooled engine, actually. Please cite your sources. Combustion chamber design works on any engine, liquid cooled or air cooled. A move away from the traditionally used semi-hemispherical combustion chambers currently used on lycoming/Continental, or the unfeatured wedge shaped ones on Jabiru and another one I can't remember, to a properly shaped combustion chamber with strategically placed spark plugs to optimise the propogation of the flame front would massively increase efficiency of the engines.
@@CreeperOnYourHouse I was talking about modern engines. You'd have to start reading some books to get some official sources, but you can find some knowledgeable people on TH-cam, like rv6ejguy who will confirm what I said about air-cooled engines needing to use fuel for cooling at high power settings. See: Vid #93. Diesel vs. Spark Ignition Aero Engines by rv6ejguy You'll see a 10:1, EFI Lycoming in that video that puts up some pretty impressive numbers, but it needs 100 octane fuel to make that possible. EFI Rotax engines are currently able to get to a BSFC of around 0.36 at cruise, but they're also able to run on 91 octane unleaded mogas Really, anyone who wants to modernize light aircraft engines understands that they should be liquid-cooled. Honda (they built what was basically a liquid-cooled IO-360 with 4 valves/cylinder about 20 years ago), Red Aircraft, EPS (Graflight), Continental with their Voyager engines (which did have more modern combustion chambers and were quite efficient), Liquid Cooled Air Power (which used modern combustion chambers on a Lycoming and also saw a very significant improvement in efficiency... on 100LL), Austro Engine, Deltahawk, etc. Basically every engine manufacturer in the world has moved away from air cooling, as liquid-cooled engines are more reliable, lighter and more efficient.
Interesting video. I have it on good authority that Prodrive is also building an engine with similar parameters. High efficiency, high HP and lower weight. Unfortunately as some others have said..all but impossible to get into GA unless its for experimental AC.
Very nice presentation for the non aviation and non-engine designers. However - - -The one overriding parameter that has not been addressed is OTE, overall thermal efficiency. OK, sure, valve timing, expansion ratio, compression ratio, friction reduction gas dynamics all can be optimized for this engine but . . . . does it burn less fuel? That was not addressed, or I missed it. Yes you can push RPM, meet weight, meet the cal envelope BUT fuel burn (Efficiency) It is THE most important factor for business GA, and even hobbyists, when the fuel cost is high and the gal/hr or liters/hour are considered. My RV7 IO360 gets 20-25 MPG at 200 mph. but is all airframe efficiency. Most GA get 7-12 mpg. At 17 gallons per hour for the power needed, that is a very high cost and bites the customer every time fuel is purchased. From the dawn of time, if a replacement "thing" does not meet ALL the needs of the original AND offer something (or many) better, then it is a failure. Better, faster, cheaper. The iPhone is one good example. Camera, palm pilot, music storage, on and on - -all in one device. I was in this business (engine design) for 40 yrs and part of that for aircraft. A Rotax is very unreliable by comparison to a Lycoming. Nobody, nobody can spend the required $300-500M to design, develop, tool and make a better engine for 2000 units per year. Many have tried, and many have gone broke/quit when the proper parameters were not improved or ROI was not in sight.
Some very valid points, thanks! Yes you've hit the nail on the head with your first sentence. I'm not making videos for engine designers, I couldn't possibly teach them anything. I'm not trying to go too in-depth either. I'm not sitting with the engine data, I only have what I can find on the net so I'm elaborating on what I can find in my research. I often hear people saying that Rotax is less reliable than the Lyco/Conti. I've come accross few statistics analysis showing that simply is not true. The latest one I saw recently was by Kitplanes. I can't share links in comments, go to kitplanes dot com and search for the article "Accidents: Passing the Engine Baton" for an eye opening read if you are interested.
Air-cooled engines have historically had high fuel consumption due to the piston clearance. They simply lose too much fuel-air alongside the pistons, which must then be vented out of the crankcase. My memory is that the rule of thumb was 8-12% better sfc for a similarly designed water cooled engine. That’s why the Voyager had one in the aft position.
@russbell6418 Actually, the air-cooled engines are pretty good compared to liquid cooled, brethren, some actually much better than most, and in the '80s were competitive with diesels. Mostly because they run at WOT most of the time, but are certainly challenged by the lower compression ratios which yield much less expansion ratio of the combustion charge. Liquid cooled allows lower combustion metal temps, allowing higher Cr yet not detonating. The prime voyager engine was pushing much higher Cr due to a special combustion chamber design and allowed much greater LOP operation than production air-cooled engines. I think that model EFI, with better A/F control and management of swirl, tumble, and optimized valve events could do much better on SCF. Typical gasoline engines were in the 25% overall thermal efficiency, but today pushing 35% and F1 engines are over 50% OTE - of course limited to seconds at full power vs 2000 hours on an aircraft engine.
Hello, very good video, an tried to make very clear explanations, but, There are many pushrod engines that are efficient and reliable by modern standards, modern GM small blocks and Chrysler Hemi engines come to mind. The Hemi even has 2 spark plugs per cylinder, so it is an ideal candidate for dual ignintion systems. The air cooled heads presents the most limitations to working with higher compression and more efficient designs. Rotax has solved the issue with water cooled heads.
Hemi isn't very reliable. Lifter and camshaft failures all day long because they oil the valvetrain in the dumbest way I've seen since the Ford Y block. The cam bearings get oiled the typical way, but the lifters, pushrods and rockers... Oil comes up into the rocker shaft, then it goes into the rocker arms, where hits a T intersection - one side is very short and goes to the where the rocker and valve stem meet, the other goes to the pushrod, then down the pushrod, then into the lifter, then, what little actually makes it TO the lifter can bleed out and fall straight down and away from the cam lobe (and lifter roller bearing, where the failure happens) because the cam is so high in the block, the pushrods and lifters are nearly if not horizontal. Despite what the fanboys say, the 6.4 lifters also fail. One solution I've seen is to use modified pistol oil squirters to shoot oil at the cam lobes (and lifter rollers) instead, but I'm not a fan of that because then the pistons can get hotter than they should. About the best way to keep a Hemi alive is to avoid idling it any more than necessary. To save fuel, there's next to no oil flow at idle, meaning little splash lubrication from the crankshaft and basically no "overflow" from the lifters themselves. And to preempt the Hemi fanboys again; yes, Chevy LS series lifters do fail. Sometimes. But nowhere NEAR the rate of Hemi lifters. Because the Hemi is not a good design.
The world of experimental and light aviation in general is really frustrating when it comes to power units. It's impossible to find a 100-150hp, light, relatively affordable engine. This has forced me to look at BMW's R1200GS conversions. With conversions come reliability question marks. I plan on blowing at least two of these engines in ground simulators to see where they stand and how far they can be taken. At the moment, in the design stage, it looks like the solution that I've been looking for, but only time will tell. The S1000RR engine was a great candidate on paper. However, its TBO would've been way too short. Still interesting for purely aerobatic and short recreational flights.
@@JoshRiolu No, they do not. There are two main problems with rotaries. One is that their lightness and compactness will be offset by the extra weight and extra volume of the extra fuel which they demand. Second, the TBO of wankel engines will inevitably by a short one. They need to spend a lot of time at high revs during TO and climbs. It can be done, it has been done, but these are the main reasons why we do not see them very often.
Many bike engine repurposed for use in cars have had oiling issues during sustained lateral Gs. I would be concerned about this in an aviation application.
The Yamaha Genesis 998 Turbo 3 cylinder is a reliable and quite powerful engine. 300 hp are readily available with the original turbo and a good engine tune. The engine weighs about the same as the Rotax 4 cylinder engine. The Yamaha engine is originally used in a snowmobile and can be had as a crate engine for something like $6000. You have to count an additional $12000 to $16000 to make it aircraft worthy.
Um nah. Like Richard VanGrunsven said the best auto engine conversion is take it down to the junk yard and convert it into a $50 deposit in a new lycoming
Your description of the balance situation is the best that I have ever seen; excellent and very understandable graphics. I am an engine balancing "nut" and you are the best at this rather difficult topic. Thank you.
This engine looks like it"s not air cooled, the more power an engine produces the more heat, If it needs a cooling system that's going to add weight and drag. Enjoyed the video.
Again a very good video ! I didn´t know about this engine. The advantages seemed to give a chance to have success. However, it is more than 10 years ago, the made it. If the breakthrough does not come after two to three years, the thing will be over normally. So, the question about the balance shaft : I studied the images available in the internet and I am afraid the engine hasn´t got any balace shaft. For an engine of this configuration a balance shaft is needed like a three cylinder inliner has, compensation a circulating torque 90° to the crankshaft by turning in the opposite direction with the speed 1:1. It is easy to achieve but to make it light weighted it should be minimum as long as the crankshaft is or longer if possibel. This reduces the balance weight masses of the balance shaft. The position of the shaft can be chosen whereever the designer wants. It coudl be below the crankshaft, where I cannot see any space for that nor a gear transmission. It could be above the crankshaft and fill the space between the V-Cylinders but again, there ist nothing to see like this. The space is filled by the oil pump, the transmission gear for the prop and the generator. If the balance shaft were on top or beside the engine, any transmission would have leaded to it. So as a result I expect lots of vibrations of this design. Interestingly: the starter is acting on the prop shaft which is unusual and requires a powerfull starter.
You may very well be correct. I studied available material as you have and couldn't see where a balance shaft could be positioned (but not visible), but thought the available imagery maybe isn't all-revealing. Since they state it's a very smooth running engine my conclusion was it has to use a balance shaft, since the chosen configuration can't achieve extremely smooth running without it.
The starter is on a large ring gear at the back of the engine, which is bolted to the crankshaft (like all GA engines), and not on the prop shaft which turns slower and therefore would necessitate more torque from the starter.
Porsche tried a new aircraft engine, so did Bombardier. Diamond has been using turbo diesels successfully. Rotax has many liquid cooled engines out there too.
all i believe, I have never seen one Diamond sells many but i am not sure how many Astros are out there, Tielerts are now Continentals and i hope they have truly solved the Reduction drive problems, Early DA-42s were more costly to operate than PT6 over the Life cycle ( Fuel included) when they could fly, and, i do hate the single electronic fuel system, had a few DA-42 in the early years Land on Takeoff , gear half way retracted and engines shut down due to Low voltage when electric Hydraulic pumps shut everything down. New world tries to take away redundancy when there are still only three places an aircraft can be at any time, On the ground, In the Air or the Unfortunate In the Ground! Lets hope these guys understand good practices!
@brucecurtis4465 I think five Mooney M20Ls still have the PFM3200 engine. It was great to fly, but a practical and maintenance nightmare. A Mooney M20J was faster, had better useful load, better support, and considerably less expensive maintenance. What finally killed any future interest in the PFM3200 was the Airworthiness Directive that mandated replacing valve springs every 500 hrs. That's what happens when a sports car engine sits and runs at a steady 4,500-5,000 rpm for several hours at a time. It was never a suitable aircraft powerplant. An engine designed around modern automotive technology will never be a top choice for aircraft.
They tried Subaru engine but same issue with rpm for HP. I feel they should work better but car engines are not made for high continuous output. Orenda tried but it never went anywhere, I made some cowling parts for otter conversions back in the day. But in theory they should be better.
@MrAerocomp The best car engine conversions are probably VW engines. They were initially based on a 1912 aircraft engine design. Being a shorter stroke than bore, they could make use of different camshafts to great advantage. Also, being air-cooled, they lent themselves well to motorgliders and small homebuilt aircraft use. Water cooled aircraft engines are definitely not to be favored, and I don't know why so many people love the idea. Water cooling is one more point of failure that is completely eliminated in an air-cooled engine. Yes, I know all about Mustangs and Spitfires and, yes, their liquid cooling systems were huge liabilities that air-cooled Thunderbolts never had. In an aircraft, safety and reliability must trump all other factors, even efficiency. Seems like most people want airplanes to have car engines. They don't realize that cars are cars and airplanes are airplanes. Airplane engines are more like hotrod tractor engines, making all their power down at a lower rpm. Car engines have to geared up to make that kind of power. There is the problem. Cars don't use all their power all the time. In fact, cars almost never use more than half their power. Airplanes do all the time. The car cruising down the highway might be using 18% of its power to maintain speed. An airplane needs about 55% of its power just to hold altitude in slow flight. Economy cruise is about 65-70% power all the time. Airplane engines are designed and built to be such.
120deg V6 does not exhibit secondary balance. It is almost as bad as I3 in terms of primary and secondary balance, with end-to-end rocking motion for both. The only even-firing V6 with some inherent balance (akin to the crossplane V8) is the 60deg with 60deg offset crankpins. The primary vibrations become rotational, to be compensated with crankshaft counterweights. Secondary vibrations go (counter)rotational too, possible to compensate with a single balancing shaft, rotating 2x the crankshaft in opposite direction, so the gear coupling is the easiest possible, although most engine makers dampen these vibrations in the engine mounts.
The secondary imbalance of this engine configuration is not even enough of an issue to warrant the use of a balance shaft in the current 120 degree V6s from Ferrari.
Most gearboxes also need to maintain a minimum torque to avoid gear chatter and failure. This is part of the reason why geared lycoming/continental have lower tbo's
No balance shaft needed in this configuration... Inline 3s have a rocking couple that can be balanced by putting extra weights at both ends of the crank... This is a dual inline 3 configuration....
@@WaltDesine : Hmmmm.... In looking at the cutaway view of the V6 at 7:55 it seems that the reduction gear has a shaft that extends into the engine block. Couldn't this also be used as a balance shaft?
@@InquisitiveSearcher That's a torsion shaft to absorb the shock of a prop strike and prevent damage to the gearbox. You couldn't actually have a balance shaft connected to the PSRU, the available gear ratios would make that impossible. Ferrari doesn't use a balance shaft in their 120 degree V6, so I can't imagine why this engine would need one.
@@InquisitiveSearcher depend on secondary vibration. The chef would have to move her twice, the engine speed… The shaft on the V rotates at approximately half the engine speed… So now this cannot be utilized as a balancing shaft.
I think so too, that no balance shaft is necessary because it is perfectly balanced in primary and secondary. It's the same situation as the v8 engine which has perfect balance with no balance shafts, because 720/90 degree bank angle is 8 pistons, and in this v6 720/120 degree bank angle is 6 pistons.
Many legacy high performance aircraft engines have propeller reduction gearing, so that's happening already, just like forced induction. Also like forced induction, it is reserved for the high performance, high-cost segment, for the reasons you said.
As far as pushrod engines go if you wanted to make the engine rev higher you attach the prop to the cam gear for a 2-1 gear reduction. Its also not very hard to make them rev high either as long as the pushrods hold up you can put 1.5-1 ratio roller rockers in the head.
You may want to rethink that. Crankshafts are massive; camshafts can be lightweight or even hollow. If you want a set of massive gears to drive a massive camshaft with a massive propeller bearing , then maybe this engine belongs in a very large truck!
@@captronrv7 well the camshaft and propeller would just be connected to the same gear. The gear would be over kill for the camshaft that's attached to it but perfect for the propeller on the other side
It's not the camshaft or pushrods that are the ultimate weakness, it is piston mass. An io390 piston weighs about 3kg while an aver 1.5l 4 cylinders piston weighs about 300g both making similar power at similar piston speed. Those big engines are under a lot of stress.
What is the fuel burn? No mention of this anywhere, and what is the BSFC at a cruising altitude with around 70% power? Most IO540 / IO550 and other similar engines run a BSFC of 0.39-0.395. So 30 % more efficient than what?
1. Engine efficiency increases rapidly with compression ratio up to 6.5. Then the rate of improvement slows so the gain between 10. and 12 may be only 3%. On the other hand engine weight to contain the pressure is theoretically linear. 2. In auto engines, For a given power pushrod engines weigh less than OHC, even though the pushrod displaces more. 3. Air cooling fins spread the cylinder centers making for a longer block and crank. Add in sloppy air cooled (AC) tolerances, Continentals and Lycomings (C&L) squirm and as a result wear out. 4. The logic behind AC engines is simplicity makes for reliability. This was true in 1935. Liquid cooling (LC) has come a ways since. Nowdays, LC is arguably MORE reliable because it makes for stiffer, evenly cooled engine. As bonuses, a LC installation has lower drag than AC, the engine CR can be increased, and the engine is smaller. 5. The power pulses in a four stroke engine don’t overlap until it’s an 8 cylinder. When the pulses don’t overlap, the engine drives the prop then the prop drives the engine. In the PSRU, the teeth - which need clearance- are slammed back and forth. C&L built geared engines which were headaches. Rotax 912 coupling works fine..is it scalable? 6. Likely the lightest, simplest aviation engine would be: 90DV4, two stroke, wet sump, Schnuerle ported, FADEC direct injected, LC, blower scavenged, sleeved aluminum block, oil cooled pistons, and PSRU. Think a Deltahawk diesel, but running on gasoline. 7. The engine block, heads, and crank would be designed to be machined from billets instead of cast or forged. Also designed to use auto parts. The idea is scratch build when ordered, minimum inventory, minimum staff. 8. Schnuerle ported engines can be turbocharged. Will it be done? Could it please the FAA magnetoheads? Cheers
#2 is not true when you're talking about high performance engines. No pushrod engine, for example, can match the power to weight ratio of the engines in the following cars: Aston Martin Valkyrie, Porsche 918, Gordon Murray Automotive T.50, Lamborghini Aventador, Ferrari Enzo, Porsche Carrera GT, Ferrari F50. When it comes to racing engines, there's just absolutely no contest. A 3.0 liter Formula One V10 can weigh as little as 203 pounds (their required minimum weight) but make as much as 965 hp.
@@PistonAvatarGuywhich of these engines will likely come with a warranty or make large production numbers in an auto or aircraft? It might be interesting to see, now that most cars and light trucks have tiny engines.
@@davidbaldwin1591 All of the road car engines that I listed come/came with warranties. All of these engines are produced in relatively small numbers. It's interesting to note, though, that the pushrod engine that competes most closely with the other road car engines listed in my comment had some pretty significant reliability issues.
@@PistonAvatarGuy My information came from the Wall Street Journal’s auto columnist, Dan Neil. He compared a Corvette C7 V8 OHV to a Ferrari V8 DOHC of the same power. The Vette engine though it displaced more, was lighter. You can take up your arguments with the WSJ. It’s the only apples to apples I know on this question. For any reasonable engine candidate for an aircraft engine - which is what we are talking about, not an F1 DOHC screamer- this is going to be true. OHV has better specific power. For a plane engine there up to ~3100 RPM a LC Side Valve engine is adequate (if LC), up to ~5500 OHV is OK, above 5500 DOHC four valve. The specific power decreases from left to right. Cheers D
@@PistonAvatarGuy In the world of high performance engines, nothing comes close to a pushrod top fuel dragster. These guys make North of 3000 hp out of 500cid or there about. In the world of affordable production engines available to humans, the Rotax ETec snowmobile engine makes 180hp from 800cc. Cheers
I suggest you give the Delta-hawk a look. It’s been certified by the FAA for new certified aircraft, retrofit legacy certified aircraft, and of course it’s good for experimental. It uses jet fuel which is more available in airports outside the US. It is however expensive…
A turbo-charger usually doesn't increase the efficiency of a gas engine (well in contrast to most Diesels). For traditional aircraft use, turbo-chargers are (mostly) used to maintain power up to higher altitudes. Fuel efficiency of the engines suffer, but a turbo-charger often allows to fly a more efficient pattern.
You can also get mire takeoff power with "turbo juice" then keeping the chamber pressure in the preferred zone at altitude should keep everything more efficient than a larger NA engine to make equivalent power in both areas.
Yeah, turbo chargers increase the weight of air ingested per one intake stroke, allowing more fuel to be burned. The actual compression ratio is limited by engine knock. In aircraft engines turbos are mostly used for turbo normalization. Car engines actually reduce the cylinder compression ratio to allow for use of turbos at sea level without knock.
GA is just too expensive to bother with for most of us. I can afford it, but recently came to the conclusion its just not worth it. What ever happened to Honda's new motor?
I’m the same way. I had a C 150 for 20 years and agree. Too many hassles not to mention ancient designs with well known deficiencies yet you are stuck with them thanks to Big Brother. Then there is the fuel prices and tie down rates👎🏻. I knew they were nuts when I saw them come out with those new monstrously priced electronic magnetos. Parts were drying up for the old styles and going crazy with pricing. I showed an illustration to my AI buddy asking what in he)) is safer or better about these things because everything that can fail is still mechanical there and heavy. He totally agreed.
The "golden age" of aviation, attainable by the common working man is possible. It will be less safe, and many foolish, daring, adventurous people would die, but more people would realize their dream of free flight. IMHO, totally worth it. I'm thankful for part 103, without it, I'm grounded. Vivek Ramaswamy claims all laws, and regulations, not expressly granted by Congress are null and void as soon as he's sworn in. Along with a 75% headcount reduction for federal employees, he's got my vote. Should he win, I'll be cruising in my LS3 powered Helio Stallion in no time. Tail number- Nun-ya.
Every time someone talks about increasing compression ratio in aviation engines, they bring up the fallacy that high compression engines aren't possible without being unreliable. All other engines in the industry has reliably increased to 9.5:1 minimum, with automotive engines going as high as 13:1 while reliably running on 87 octane that has gone stale. The big key is to build the engine around having high compression, not just slapping domed pistons and calling it a day. Small and Big Block Chevy guys has been doing this for decades by installing a modern style cylinder head with a small chamber volume, high compression pistons, a camshaft designed for high compression use, and an ignition controller to automatically adjust ignition timing based on load and RPM. Yes, that's a big list, but they are able to easily modernize a 70 year old engine design, improving efficiency while still running on regular pump gas. Yes, you can still keep your carburetor to make people feel happy. No, this does not require water cooling, as people has done this same work on air cooled Porsches for years.
I'm sorry, but please stop trying to apply automotive thinking to aircraft. Automobile engines cruise down the highway at 12-18% power while aircraft engines run at 65-100% power all the time. An aircraft engine has to be designed and built from the ground up to fly. Automotive technology like 13:1 compression ratios will not work in aviation. The best aircraft engines actually function more like lightweight air cooled tractor engines.
@rescue270 and this is my problem with many aircraft enthusiasts. They are stuck in the mindset that "this is not possible", or "it can't be reliable". They automatically assume that anything remotely modern, even if it's 1980s technology, is automatically not reliable. As I said, it's possible to improve efficiency with aircraft engines while also improving reliability. The thing is you can't just slap high compression pistons and call it a day. Different camshafts, cylinder heads, and ignition system is required, but can easily be done reliably.
@patx35 I am not an "aviation enthusiast." I am an aviation professional. A&P, I.A., CPL. I have worked on and flown airplanes for 42 years. I have learned that much of what has been purported to be new and improved is almost always more expensive, more complex, and more trouble with little improvement. I am speaking from experience. Sealed recombinant gas batteries are a definite improvement. The Castlegar Trust engine baffle STC is another great improvement. An old Bonanza with that installed will run so cool you'd think the CHT gauge is broken. Composite propellers are not. Expensive to buy and expensive to repair. Nicks that can be easily filed out of aluminum blades have to be repaired by a specially rated propeller shop. Electronic ignition and injection systems require electric power sources and backup power supplies that are not even needed with magnetos that generate their own power in a very compact and very simple unit. To me, the efficiency gained is not worth all the added complexity and subsequent maintenance. Don't even get me started on glass panel displays. We had so damned much trouble with those at the flight school. The old "steam gauge" (I hate that term) instruments were much more reliiable. A car with 13:1 compression will use that power for short bursts and cruise at speed using about 12-18% power, but an airplane has to sustain 60-75% all the time in cruise. A gasoline engine with compression that high will wear quickly. Ask anyone with a 220 hp Franklin engine that has 10:1 compression how long their cylinders last. You have to very diligently manage power in one of those. Liquid cooling was fine for WWII fighters that were constantly maintained, but in general aviation it is another critical system that requires scrutiny because it could fail. Airplanes are air cooled for a reason, as the Thunderbolt proved against the Mustang. Diesels are also a subject of my criticism due to the fact that they cannot make enough power to hold altitude if the turbocharger fails. Too many eggs in one basket for me. Couple that with the fact that they are very expensive and I don't think any of them are authorized to be overhauled. They have life limits and must be replaced. I am all for new innovation but I strongly and obviously feel that general aviation research and development is going in the wrong directions. Working toward complexity only begets more points of failure.
I saw much more compression with direct injection engines. BMW aims at a bowl in the piston. This would really work well with long stroke, high torque flat-6. (BMW uses it for inline-6 with their small bore)
Great video! Pushrod engines can rev to 11000 rpm as Mercedes Benz once did with their racing pushrod engine, using the advantage in the rules allowing higher compression, more boost and larger displacement to increase performance. Chevy V8 tuners spin their motors to 9000 rpm. GM estimates they save $400 per engine with the pushrod design and they are more compact, lighter and easier to work on. On a purpose built aircraft engine the camshaft drive could be designed to work as the Propeller Reduction drive and with Camshaft above the crank would also raise the prop centerline. My 2 cents
You said it yourself though: "racing engines". An aircraft piston engine has to be in a far lower state of tune, and probably even a lower state of tune then a production automotive engine, because high reliability is an absolute requirement. When pushrod engines are used in racing, it's usually because the series rules make it advantageous to do so (or require it). Engineers are making these engines run fast _despite_ using pushrods. All that extra reciprocating mass and friction will always have a performance penalty at higher RPMs, and pushrods also make it much more difficult (though certainly not impossible) to have more than two valves per cylinder, which will always negatively effect high RPM breathing. You can work around that with bigger valves, higher lift, forced induction, etc. but all of those have downsides. With more valves, you can simply make much easier compromises.
That is how some old stationary engines worked. To get more power from a smaller engine, they had the crankshaft run faster and had the output pulley on the camshaft. So you still have 500 RPM at the pulley while allowing the engine to run faster.
@@TonboIV thanks for your reply. My point was simply that 5000 rpm is not considered to be too high for a pushrod engine if they handle 9000+ rpm reliably. Some of these motors push out 5000hp. See Steve Morris videos. The lower costs, lighter and smaller size of pushrod engines make OHC/DOHC unnecessary when we consider that their advantages are more theoretical than practical.
Yes, that’s the problem. Automobile engines run at full throttle only a fraction of the time and mostly loaf around at partial throttle settings, generating a small fraction of their maximum power. Aero engines on the other hand hav to run at maximum power for long periods of time during takeoff and climb and then typically cruise between 2/3 and 3/4 of full power for most of the flight. Asking a motorcycle engine or an auto engine to do the work of an aero engine without significant re-engineering is asking for trouble.
Not good at all. This engine has been surrounded by BS for some time now. It was funded by the South African taxpayer, with the intent of producing a local engine for us, to avoid the high dollar exchange rate. Sadly, the engine is offered in the States, but not here. There is more money in the overseas market, but not the local one, which generates less in financial value. Try buy one, and suddenly all the banners disappear, and the worms come out. It has left a bitter taste with local aviators, and now languishes in the class of bar-room BS.
@@tonyforrester9570 There's no proof of anything that you say. I'd like to see the engine tested by an unbiased third party. Bombardier built a very similar engine, and by all accounts, it was absolutely worlds better than the current standard. The observed (as in, pilots actually flew it and reported on how efficient it was) efficiency was absolutely incredible.
@@tonyforrester9570 Also, there are several US buyers who were able to purchase engines. One was being installed in a Velocity, while another was being installed in a Lancair (there are pictures of this installation on the internet).
With plateau honing becoming more and more the norm and now piston dimpling, development has not stopped. I am sure both will carry over to the aviation industry.
i doubt it has a balance shaft,the only V6 i know of is the 90 degree buick engine which has a 90-150 degree separation between firing cyl cos they didnt want to produce a split crankpin crank,the 60 degree V6 is also a 120deg between firing cyl engine and does not require a balance shaft either,the 120 degree V6 was used in volvos,renaults and delorians,steve knott ran a modified volvo V6 in a karmann ghia he won australian off road championship with some years ago
Manufacturers used to produce 90 degree split crankpin V6s without balance shafts and six throw crankshaft 60 degree V6's without balance shafts but they have gone away from that entirely. I don't think there are any V6's currently in production without balance shafts.
I have an engine in one of my cars with a compression ratio of 12 and it runs regular 87 octane gas because it wasn’t designed in the 40s. Direct injection is a thing. So why are companies in the US allowed to sell engines that can only run on leaded Avgas. Its crazy I mean i would understand if you are flying like a antique ww2 museum piece. new airplane engines should Only run unleaded by now. kids live near airports.
You can reduce the displacement and increase RPM to get the HP increase, Rotax did it that way, but Rotax is a big company, with lots of overhead and share holders to pay off, so they did the flying public no favors in lower prices. Every car on the road have a gear box and liquid cooling, and I think aircraft should be the same, what ever weight increase for liquid sure did not bothered many WW2 airplanes. The cam shaft can be made much stronger to be the engine output shaft and most engine, the cam is at a 50% RPM. Please do not have direct injection only in airplanes, There is already enough trouble in cars with dirty intake valves. A new engine give opportunity to add stuff like knock sensors and computers on to it, I like the individual coil packs and then you can dump the magnetos, I hate the 500 hour TBO. Turbo should be manual operation , with some automation by computer so over boost will not happen. but turbo is a high maintenance item. The main reason why airplane engines are so behind the times is because of FAA regulations discouraging anything new. The approval process is time consuming and expensive. There is also politics involved. such as the Eagle unleaded fuel initiative, which been bogged down again. They been messing with that for over 2 decades now. In contrast, automotive industry, about 100 time larger than general aviation, when they need to change fuel, it took a mere 4 years to change everything from the early 70s.
WOW!! What a great idea !!to take output power from the camshaft!!!! Just would need heavy duty gears on the Crankshaft and Camshaft!!! and heavy camshaft bearings and bearing saddles with a thrust bearing inside the engine.The front of the camshaft would have to be similar size to the front of the crankshaft. I hated the 500 hour magneto overhaul also. And sometimes they would not make the 500 hours! In my VW beetle engine, the gear driven point ignition takes minimal maintenance, will go 100,000 miles with only couple contact points replacement . and costs around 5 cents/hour to maintain and is super reliable, much more reliable than aircraft magnetos. I calculated once that my aircraft magneto's costs were approx $5.00/hour just for ignition.
I wonder if it's possible that they figured out how to use the integrated gear box/large final driven gear/oil pump shaft assembly to offset any engine imbalance instead of using a separate balance shaft.
Yeah wow. Every time I said to myself yeah but what about… you went on to address the topic. Very good video! Surprised though aviation hasn’t borrowed from the automotive industry like with the diesel counterparts (Astro engines now continental). Suppose weight is still the issue.
There certainly will be a market for this engine but it will not replace the old Cessna engine. There are turbo prop style engines that fit into that space also and those are vary simple and reliable and powerful. So new is good and there will be plenty of vary expensive planes that will take advantage but not the old Cessna that sells for much less then 100k and is what many people will own and fly because that is the level they can afford to operate. Don't forget all the aircraft mechanics that will need to certify to touch this new engine further reducing its spread thought he aircraft industry. Like I said high end use only. Kinda like asking a Cessna mechanic to fix a jet engine.... say what? um no. but, don't let that stop you with the new better and stratospheric expensive endeavors like this. Plenty of $$ out there in the aircraft industry. Kinda like my wife just HAD TO HAVE that new RAV4 um.. because it gets 45mpg. Me... really. um ok so you save 100 bucks a month in gas cost but what about the 900.00 payment per month? She would not let facts get in her way so we bought it.
Hi, you made a typo in your title. You left out the “r” in airplane. I really appreciate your explanations of engine technology! I have learned a great deal from watching your channel Thank you!
Converting the old engines to lead-free is actually pretty simple, just like it was for automotive engines 50 years ago. Install hardened valve seats and MAYBE tweak the spark advance and you're done. The FAA is probably to blame for leaded fuel holding on for so long in aviation, because they're so reluctant to make any changes unless someone gets killed... immediately. The slow death tetraethyl lead can cause is just a "eh" to them. Turbochargers also add a lot of heat, which is a huge problem for air-cooled engines. Bumping compression ratios on a low-RPM engine can (will) lead to high piston and cylinder head temperatures, detonation, etc. Overhead cams and multi-valve engines could be a huge step. I'd argue they don't really reduce complexity over pushrod engines. One upgrade that should be simple would be manufacturing cross-flow cylinder heads. You get more room for larger ports and more efficient port designs, since they're on opposite sides of the head, and you get less heat into the intake port. There is so much of the 1930s stuck in these engines and it honestly wouldn't be too hard to engineer it out. But, again, FAA doesn't like change so they make any little tweaks prohibitively expensive. Oh, crap. This wide vee is going to be odd-fire? Yikes. One of the other huge advantages to boxer engines is that they're very smooth. Odd-fire V6s have serious NVH issues, which is why the automotive world quit using them, again, decades ago.
Why would it be odd-firing? The firing interval of a straight three is 240 degrees, and a 120 degree bank angle is smack in the middle of that interval.
1000% agree. GM manufactures it's large displacement diesel engines for it's trucks at a fraction of the production cost of a new io540 and it does so at a lower volume... which is totally counter-intuitive. Those diesels contain highly complex computer systems and even higher tolerance parts than GA requires. In some cases, they are even using materials that are MORE EXOTIC than anything in the lycoming. The issue has never been profitability for the companies involved. It's liablity and the INSANE amount of regulatory hoops required to bring a GA product to market. Modern development cycles are almost prohibited because it can take two years or more to get a major design change certified. Companies want to be able to iterate on their products very rapidly and current certification regulations make that almost impossible. You almost can't bring a product to market unless it's perfect and ready to stay the way it is for decades. That said, if GM got involved, they'd sick their lobbyists on congress and probably get themselves an exception somehow. God I wish they'd do it. lol.
They'd have to charge more than that to pay off all of the shysters who'd be suing them for imaged faults. Out legal system is one of the biggest obstacles to offering any product in the U.S.
Lovely engineering but completely useless in the real world of manifacturing scale, aviation insurance and the need for STCs for each and every retrofit application. In my 43 years of flying, building and maintaining aircraft I have seen at least a dozen similar efforts that have never come to fruition. When I started building my Velocity XL-5 RG, I was consumed with installing a high-tech, fuel injected V8 with a PSRU. A very wise friend and fellow builder suggested I contact a few insurance companies for quotes. Not a single one would provide hull coverage, only liability. The same friend said it was an excellent way to turn a $300k airplane into a $100k airplane and “you’re still going to need to convince a prospective buyer that it’s safe.” Rotax is the only company that’s made it work and none of their engines makes over 140HP. Sadly, this engine is the answer to a never asked question.
yep it's not an engineering problem at this point! The pure weight of regs, certification, maintenance procedures etc have already killed this initiative! Just look at the process to move off leaded fuel and that has proven negative ecological and health issues!
Maybe for now, but business as usual isn't going to be an option for all that much longer. Climate change, and the need to deal with it, is changing the world, and GA engines are going to have to change too. Maybe Continental and Lycoming can develop their existing designs to run on biofuel or whatever, and deal with whatever regulatory changes are coming, but everyone is going to have to make changes eventually, which will have costs, and that may allow new players to get into the market with more radical (or at least less stodgy) designs.
@@TonboIV Interesting that you worked those two painfully skeptical words, “climate change” into the mix. General aviation, as we historically know it, will soon be beyond the reach of our citizenry. Especially for the big-bore-engined models. A new Bonanza is well north of $1 million and insurance is the tail wagging the dog. In the very near future, GA will be a distant memory.
@@bwalker4194 Yes, I wrote "climate change" because it's a reality which we all have to deal with. General aviation is already beyond the reach of most people, at least as far as owning an airplane anyway. Smaller, more modern engines would likely be a positive change for accessibility of aviation, though far from transformative.
Well good luck, It has been tried many times and it never seemed to work as well as theory , But in concept it would be useful , most systems fail due to Insurance issues of Untried systems. I hope they work out but i have been in the field for many years and have seen most fail to be Viable! I had High hopes for Delta Hawk but if has been years to coming to General Aviation, It is finialy starting to come out. Once again Godd luck
Airplane piston engines live at full throttle the majority of their life and last 2000+ hours. A gold wing spends the majority of its life at less than 50% power. Big difference
Rotax seems to be doing pretty well with horizontally opposed engine design. Almost everything you discuss is related to modern engine design vs. 1930s engine design, not to engine configuration.
Personally I don't think this engine will ever go out of style. They've been around for a long time, The technology is understood by not just mechanics, but by most airplane owners. They'll be around, no matter their faults, for a very long time. If these new v engines take over the market, these older engines will become the cheap alternative, and people who want to get into flying a serious aircraft on the cheap, so to speak, will flock to these kinds of aircraft.
so as a guy who has wrenched on just about anything you can think of on land or sea I know there are things I don't know about plans although I seem to get the impression that it is a very long and expensive proses to do anything to different or new and even more if you want to get into some kind of production. I am a little surprised that I haven't heard much or anything really on electric or hybrid systems for small plains I could imagen using a couple axial flux motors one as a generator on the engine and one to drive the prop that would give a number of options. One option would be to use a small battery in sensitive take off and landing arias , could also use it like an electric gear box giving a near infit options for engine and prop speeds, then if things were kept in line could have a emergency physical link.
6:06 the perfectly vertical valves make me think it's a diesel, not that being so changes valve actuation, just not something I've seen on gas. are the power ratings continuous, or time limited? that's a very high specific output if it can be sustained. I'm surprised at billet crank/rods rather than forged, but I suppose for a relatively small production run it's exceedingly expensive to do forgings. If they were doing a large production run, forged would be the way to go. regarding the claim of 30% lighter, I wonder if that includes a cooling system - adding radiator(s) and coolant adds a good chunk of weight, and you need to figure out where to put it.
I'm not sure if that is max continuous. Higher rpm engines are usually 5 minutes max (using the Rotax as an example), but I don't have those facts. The source of the 30% lighter claim I found on a few different websites (not their own). One can't post website links in Youtuve comments but I'm adding it to the video description now.
That image isn't the Adept engine. It's a cutaway of a Rolls Royce Merlin, which did indeed have valves that were parallel to the cylinder axis. Early development versions used an experimental and unproven "ramp head" design, with a squared off combustion chamber, vertical exhaust valves, and intake valves canted outward at 45 degrees. The design didn't work and it was quickly abandoned, replaced by the parallel valve design.
13:28 Look at the mid cylinder compare it to the botton or the upper cylinder, they have a bigger distance between them and opposed forces in different direction, wouldn't it cause a worst rocking couple? And the opposite cylinder for having same direction of force it would result in bigger forces also? I think that boxer is more balance for this reason and it explains why someone would prefer a large engine for better balance. So if I'm wrong please explain it please.
A good technical analysis thank you, but the big issues to new entrants into the GA engine market are commercial: 1) the market for new engines is tiny and the replacement lifespan of engines is very long (5 times that of automotive engines) 2) the only realistic market for newly designed engines is a retrofit market (and so the new engine cost needs to compete with an overhaul engine cost). This is almost impossible in a small market where not only the core engine build, but all the development and approval costs have to be absorbed into an inevitably limited production run. 3) the product liability risk is significant when comparing a new engine compared with modification to existing engines. In USA (where most of the GA market is) the General Aviation Revitalization Act imposes an 18 year Statute of Response for lawsuits against aircraft and engine designs. So if an old design is modified it may be exempt from product liability claims should there be a defect in design, whereas new designs are not exempt.
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Took apart a 55 year old 2000 hour Lycoming out of a Cessna. Not only did the crankshaft pass inspection after grinding but I have been able to find every part needed to reassemble it with brand new camshaft kit, oil pump kit, 4 brand new cylinder kits with pistons, rings, valves, springs. Should be good for another 50 years.
2000hrs is 1/4 the hrs a mechanical device should last without major replacement. 5000 hrs on rental construction equipment. So in comparison air planes are a waste of effort. Like the electric scam!
@@congerthomas1812higher standards are expected from Aircraft power plants
@@congerthomas1812 Completely different designs. Camshaft in aircraft engines turn in a bored aluminum case. So many things are optimized for weight rather than longevity.
Construction equipment engines are all cast iron blocks, water cooled, and mostly sleeved. I have a 3 cylinder diesel that weighs as much as an O-200 and produces 34 hp.
@@congerthomas1812 aeroplanes are expensive but totally worth the effort to me.
@congerthomas1812 Depending on how the aircraft engine is operated ( for hire) mandatory tear downs are required.
It's awesome when a company like this actually tries to make a vast improvement to their product; instead of doing just enough to say it's different. Some still use carburetors, in 2023. I hope this new engine is excellent, and it challenges other aircraft engine makers to improve; instead of riding on their, it's good enough, ways.
If it aint broke dont fix it
@@bloodspartan300 ride a horse then 😉
Improving something and fixing something are two different things.
All it will do is make it even more expensive to fly. I've had a dream of flying for 50 years. At 58, I still can't afford it. Price just keeps going up out of my paying ability. My time is running out.
The 120 degree V6 allows oil to more easily drain to the oil pan (or scavenge pumps in a dry sump) than a flat 6 too.
Tell us you're not familiar with the term "windage", without telling us.
@@driverjamescopelandwhat about windage?
It does make things easier a bit. Not that it was an overwhelming problem in aero use of course but it does help with the design of heads, returns, and then how much oil you need to have in total etc
@@driverjamescopeland There are a lot of options for oil windage that can minimize it to a large effect in any engine. I posted a few of them at the top of this list.
Porsche has had some real issues over the years with their beloved boxer mills
The V6 only requires a harmonic balancer like is used widely in the auto industry. In the case of car engines this is incorporated into the front-mounted crank pulley or on the rear-mounted flywheel. I suspect since a reduction box is required regardless of the motor configuration that the harmonic balancer is likely part of that gearset and incurs no additional weight penalty.
I thought something similar, it made sense for it to be part of the reduction unit since it's integrated.
V6 balance shaft rotates at crankshaft RPM . Valve train uses a reduction gear. Inline-4 balance runs at twice rpm
@@ArneChristianRosenfeldt The Inline-4 balance 'problem' is secondary imbalance related, not primary. If a v6 has a 90 degree inclined angle, it can be made with perfect primary balance, but secondary balance suffers. It will also have unequal phase from bank to bank.
@@robertrobinson3861 120° V6 has even firing and primary and secondary imbalance. 90° V6 is composed of 3 Ducati engines. Their primary rocking imbalance is balanced overall. Secondary, I dunno. I just concur. Uneven firing order which leads to uneven kinetic energy. Torque vibration.
To make a six cylinder engine smooth, you need 6 throws (cranks). V8 only needs 4. So you get away with a lighter crankshaft and narrow bearings and less friction on a V8. It is more stiff. Only problem is that optimization seems to favour additional bays for counter weights. You can place the valve train there for DOHC. Pumps on the other end. Without this additional length you need very heavy counterweights which reduce the first resonance frequency of the crankshaft and defines your redline.
Car V6 engines using 6 throws (cranks), not 3, like this. Harmonic balancer is a different topic, this 120° V6 may not need it because of shorter crankshaft due to only 3 throws. Harmonic balancer is very important in case of inline 6 engines.
The glider club that I'm flying at has a Pawnee with an ls1 in it as it's tug plane, and the advantages of the ls1 compared to the original 540 are absolutely ridiculous!
It has got a similar hourly fuel consumption as the 540, but with a higher power output and more torque. The ls1 is "de-tuned" to max out at around 400hp at 5000-5200 rpm, with a torque of about 1000nm on the prop and therefore has a much higher BSFC.
But the biggest performance increase as a tug comes down to the water cooling and the gearbox for the prop.
Since there is no risk of shock-cooling the cylinders after a pull, so the throttle can be pulled right of.
Then the gearbox for the propeller makes it much harder for the air to windmill the engine, and therefore the rate of descent that can be achieved reassembles that of the Ju-87.
It can pull a fully loaded 2 seater to 1000m/3000ft and then go down to land in around 6-7 minutes!
Finally, I've want to see a 120* V6 widely use motor for decades.
You must like taking the wheels off to change your plugs.
Some 80s f1 turbo v6 engines were 120°. Ferrari now has one in the 296.
15:30 I agree with that statement, but at the same time, it is pretty darn amazing it took 65-odd years to achieve! Shows just how good those designs from the 1950s really were.
Introducing a new engine into general aviation is just about impossible given all the hurdles.
Rotax did it, so did Austro Engine. The problem seems to be Americans and their aversion to change.
@PistonAvatarGuy
And what is Rotax?
A 912 has the same power and the same weight as an O-200 whose basic design is from the 30s.. but they added four more failure modes (gearbox, dog clutch, coolant leak, and extra throttle cable).
It’s a textbook example of why specific power (something Europeans obsess about) is meaningless in aviation.
@@Bartonovich52 The Rotax 912ULS weighs about 50 pounds (30%) less than the O-200 and burns about half as much fuel, which proves that the Europeans know what they're doing. The EFI engines burn 30% less than the carbureted engines! The Rotax engines are also capable of supporting turbocharging and making significantly more power than the 0-200.
Americans seem to use specific power as a strawman, trying to claim that it's all that the Europeans and Japanese care about, and while the Americans build their strawmen, they're being left further and further behind with the passing of each decade.
@@Bartonovich52 Here's what I suggest, look at the fuel consumption graphs in the operator's manual for the O-200, then read an article by Paul Bertorelli for The Aviation Consumer which is titled _Rotax 912 iS Efficiency: Better than Claimed_ (Published:July 17, 2013)
Diamond did it. By simply converting a car engine. Very reliable and one of the safest in GA.
Zundapp was using a 170° V-4 in motorcycles starting in 1939. It gave better ground clearance while retaining most of the benefits of the flat engines used by BMW.
V4 is the current most winning configuration in highest level of motorcycle racing....your Ducatis Aprillias KTMS and Hondas...I recon the only hold out left now in motogp is Yamaha which I expect to also finally go V4 due to 2027 new discplacement of 850cc ....which means a reset with all new motors for all the factories....V4 maybe better for weight distribution? And narrower width compared to inlines Although just prior to pulling out of motogp Suzuki starting kicking some V4 butt with their old inline tech
170 degrees? I’ve pondered a near-boxer V. Close enough to build it like a boxer. Thanks for the info. I’m going to look them up
I’ve seldom seen such high-quality content on TH-cam. Thank you!
I have been thinking about a 120 degree V-6 for years, and I always came up with the problem that it has primary imbalance unless there is a balance shaft, so what this video discuses at the end makes sense.
For a rocking motion the balance shaft needs to be long. For low weight the weights needs to fly along a large circle. Why are there no vehicle engines which give me this space? Replace a V8 of the same displacement. Thin shim under the clutch bell. Why would a reduction gear have a gear running counter to the crank, but with the same RPM?
I like your description, but have a comment on balance. A 3-cylinder engine has a primary rocking couple. Put two of these together with a 90-degree bank angle and the two couples combine into a rotating couple that can be balance with a crankshaft counterweight at each end of the engine. For a 120-degree bank angle, these rocking couples add together into a rotating couple that could best be described as elliptical. two crankshaft counterweights can then balance out all but about 13%. The marketing people could then describe the balance as "excellent!" Actually, the remaining unbalance is probably acceptable. I picked this engine configuration for my senior design project in school, a long time ago.
Thanks for the comment. Great info here. I came to the same conclusion but stopped short of how excellent balance was achieved.
Those two crankshaft counterweights you mention would then be 2 additional to the standard 3, one at the front and one at the back where the combined rocking couple moment can be cancelled to some extent? And would an unbalanced flywheel be able to futher reduce the inbalance?
The FAA will be glad to take your money until you have none
Having a much shorter compact engine also is an advantage for the center of gravity for aviation. When you're agent hangs way over your wings that you have to put weight in the back end the ballast the center of gravity. Having a much more compact engine package means you don't need to have that much added weight for balance which gives you more cargo weight capacity for your plane. It's not just as much as saving weight but also just shortening your fulcrum is a huge advantage to have good control of the aircraft
Agreed, mentioned here 9:49
Honda use F6 on GoldWing... Fix dual spark plug to tick the box for certification and here you go... Smaller, stronger, more reliable, out of the box!!
Add Turbo and you can replace most of low-mid power F4 and F6 in the fleet.
For bigger planes consider modern L6 diesel units!
Fascinating information.
We have 3 Chevy Corvairs in the collection and the owner is a pilot. Never knew how popular those engines were in small experimental aircraft
Thanks for the excellent video.
Before then, many people used VW bug and microbus engines for similar reasons.
A couple of little points here. The inefficiencies mentioned at the beginning all relate to other areas of obsolete design, not the fact that the engines are horrizontaly opposed. Imagine comparing a late model Subaru engine to a 1950s VW engine: Both are flat fours. Also, if the engine has twin cam heads, and you 'swing' the cylinders up, the lower cams may still come out to a wider position (wider ove all). A simpler idea would be for the manufacturer to run two cams side by side in the crankcase, with each cam serving that side, and shortening up the push rod lengths, while still running four valve heads if needed. Yes, yes, I realise that this complicates the cam drive a little, but it's not that big of a problem. Just an idea.
You don't need twin cams to have 4 valves per cylinder. It's how it is often done but not needed. There have been many single cam 4 valve engines. Heck, in the case of pushrod engines, you don't even need to double the number of pushrods. You can actuate two valves off of a single pushrod. Many inline 4 motorcycle engines have 16 valves and a single overhead cam.
Loved the sound from the Bosbok at the beginning of the video. It brings back fond memories.
This is the same hurdle Japanese vertical motorcycle engines had versus Harley V twin engines. I believe the vertical engines have won on all fronts except engine “growl”.
I dont think that Japanese 4 is going to run very long across the desert in the summer without coolant, unlike a harley v twin. To compare the two is more like comparing apples to oranges. They are from two entirely different set of values. Air cooled simplicity for ease of mechanics. Vs an effort to overt any necessity for mechanics.
"growl" ia subjective but if you ask me? NOTHING beats the growl of a crossplane I4 of Yamaha R1 /MT-10 Whatever coolness one derives from Harley is just made IRRELVANT in light of the THRILL an R1 provides....again IMHO....you must experience it to understand
30% better all around, that's impressive. Very well done and EZ to understand, great job.
1] A 120 degree V-6 would be great in a Honda Gold Wing. 2] In a legacy flat 6, having two cams in the block, one above, and one below could facilitate 4 valve cylinders. 3] I find it hare to believe the 30 percent improvement in specific fuel consumption as lower rpm motors generally have better fuel efficiency, at the expense of weight.
My guess is that the "redrive shaft" doubles as a balanceshaft, thus keeping the losses down.
Intresting however, and I wish them good luck
I have been flying powered A/C since 1976. The IO-520 and the PT-6 Turbine are examples of engines that will run for 50 plus years.
But what the future of aviation needs is an inexpensive (less then $150K) and simple gas turbine engine in the 300 to 400 SHP power range that can burn any liquid fuel and can even be retrofitted to existing airframes.
An unfortunate property of turbines is that small ones are inefficient. For example, a 180 HP turbine would have on the order of 50% higher GPH compared to an equivalent HP Lycoming. Then there is the expense…
You can’t build an efficient sub 400hp gas turbine. The blades and their tolerances get too fine for economical manufacture.
in other words magic beans
Porsche has been making and refining boxer 6's for quite a while and as far as I'm aware, they have also been increasing power and efficiency at the same time. Not much discussion about that.
Porsche & BMW Motorcycles maintain those Boxers and evolve them to maintain brand identity and retain loyal customers, not necessarily because it's the pinnacle of Engineering.
Excellent show mate,well explained and informative,thank you.
On the air-cooled flat sixes, one can decrease weight while improving cooling is to replace the steel cylinder barrels or linings by using nikasil coated alloy cylinder barrels. Also as both use 2 pushrods per cylinder, use the technic Honda used with the CX motorcycle & Moto Guzzi used with Daytona to get 4 valves per cylinder from 2 pushrods for cylinder
That system was known to be complex and unreliable.
They don't need the additional flow provided by 4 valves because they turn slowly.
@@SuperYellowsubmarin even diesels profit from multivalving. Sure aero engines run on low speed torque, well unless the prop is geared down, like Naipers & Rotax, but an added efficiency of 10 to 15 % is nothing to squeeze at. Especially without the added weight, complexity & unreliability of DOHC engines. Go do a image search of Honda CX or MG Daytona heads to see how simply they operate 4 valves per cylinder off 2 pushrods per cylinder. Plus there are many UTube channels where they tear down blown motors. (After blown bearings) the 2nd most common reasons engines blow are from hydraulic OHC cam chain tensioners breaking a part & bits going everywhere in the engine. This does not happen with old fashioned pushrods.
Nikasils worked well in Porsche 911s but I think aircraft grade nikasils would be prohibitively expensive. I have seen specially made nikasils used in VW engines modified for motogliders, and they seemed to work well in that application, but they were very expensive. I liked they way they could be weld repaired and recoated.
@@mickvonbornemann3824 most DOHC related engine failures are because they haven't been adequately serviced, something that isn't usually an issue with aircraft since they just wouldn't be allowed to fly.
Boxers won't go obsolete just because of a new engine design. When jet engines were introduced some also thought this would make piston engines obsolete but they were wrong. Boxers will be around for a long time to come.
It all boils down to cost, that is it
the problem is that those engines havent been improved in decades, Even worse is that they use older tech than some WWII piston fighter airplanes (like Fw190 with its commandoGërat). current automotive tech is decades ahead of those old engines. it's way about time for a proper efficient piston engine for airplanes.
Very nice presentation! I would be interested on a close-up of the Higgs engine too.
The German company Zoche had a four cylinder radial two stroke diesel. It was light powerful very efficient and did away with many parts needed on conventional engines. The company failed of course. Homologation of new engines (even simple ones) is ridiculously slow and expensive.
Porsche tried and failed too.
I saw the Zoche engine built in an Extra 230 airplane when I visited Extra aircraft about 25 years ago. They were very angry about Zoche because he didn´t try to get the test permission to flying the engine and Walter Extra, the boss of the company wouldn´t have tried the thing illegally. On the test bench the engine made only a few ours before failing. The piston part is in fact very simpel. However there is a gear box with transmission ratio 1:42 to start the engine and to deliver compustion air to the cylinders. This gear box is rather complicated.
The fact that they are still allowed to use leaded fuel, and to rebuild these engines for LL still in 2024 is absolutely mindblowing. I know private aviation is a very minor aspect when it comes to ones to emissions. But just because they are allowed to still be extremely dirty and inefficient means we don’t get better engine with much less fuel consumption, lighter and much more environmental friendly while also not making you breath in these toxins.
Yes they are reliable but they are also relicts. Time for some chance. And by law, otherwise nothing will change.
And their reliability is also way overrated. But like with everything - if it's properly driven and taken care of it may last a long time. But this is very much down to the human factor. Many flightschools (or most) seem to have the wrong idea about fuel mixture, which is manually controlled when using a carb engine.
@@terjehansen0101 it’s a engine design that is several decades old. It’s inefficient, requires a lot of knowledge and should long be replaced but there are hardly any new ones especially certified ones
DK, laws and regulations, thousands of pages of laws and regulations are precisely why alternatives do not exist.
Regulation is the enemy of innovation
There are plenty of improvements to be made on the old engines. Add in squish pads for improved fuel homogeneousation, or completely redesign the combustion chamber to modern 2 valve standards like the LS engine's to improve thermal efficiency.
Without liquid cooling, you're not going to see any significant gains in efficiency, air-cooled engines literally rely on ridiculously rich fuel mixtures in order to stay cool at high power settings. Significantly improving reliability without liquid-cooling is also not going to happen.
@@PistonAvatarGuy Cite your sources for this being the case.
@@CreeperOnYourHouse Name an air-cooled engine (aircraft, or otherwise) that this has ever been done with, while also resulting in the engine being able to match the low BSFC of a similar liquid-cooled engine at full power.
@@PistonAvatarGuy Bristol Hercules, DB-601. Literally any other WW2 liquid cooled engine, actually.
Please cite your sources.
Combustion chamber design works on any engine, liquid cooled or air cooled. A move away from the traditionally used semi-hemispherical combustion chambers currently used on lycoming/Continental, or the unfeatured wedge shaped ones on Jabiru and another one I can't remember, to a properly shaped combustion chamber with strategically placed spark plugs to optimise the propogation of the flame front would massively increase efficiency of the engines.
@@CreeperOnYourHouse I was talking about modern engines. You'd have to start reading some books to get some official sources, but you can find some knowledgeable people on TH-cam, like rv6ejguy who will confirm what I said about air-cooled engines needing to use fuel for cooling at high power settings.
See: Vid #93. Diesel vs. Spark Ignition Aero Engines by rv6ejguy
You'll see a 10:1, EFI Lycoming in that video that puts up some pretty impressive numbers, but it needs 100 octane fuel to make that possible. EFI Rotax engines are currently able to get to a BSFC of around 0.36 at cruise, but they're also able to run on 91 octane unleaded mogas
Really, anyone who wants to modernize light aircraft engines understands that they should be liquid-cooled. Honda (they built what was basically a liquid-cooled IO-360 with 4 valves/cylinder about 20 years ago), Red Aircraft, EPS (Graflight), Continental with their Voyager engines (which did have more modern combustion chambers and were quite efficient), Liquid Cooled Air Power (which used modern combustion chambers on a Lycoming and also saw a very significant improvement in efficiency... on 100LL), Austro Engine, Deltahawk, etc. Basically every engine manufacturer in the world has moved away from air cooling, as liquid-cooled engines are more reliable, lighter and more efficient.
Interesting video. I have it on good authority that Prodrive is also building an engine with similar parameters. High efficiency, high HP and lower weight. Unfortunately as some others have said..all but impossible to get into GA unless its for experimental AC.
Very nice presentation for the non aviation and non-engine designers. However - - -The one overriding parameter that has not been addressed is OTE, overall thermal efficiency. OK, sure, valve timing, expansion ratio, compression ratio, friction reduction gas dynamics all can be optimized for this engine but . . . . does it burn less fuel? That was not addressed, or I missed it. Yes you can push RPM, meet weight, meet the cal envelope BUT fuel burn (Efficiency) It is THE most important factor for business GA, and even hobbyists, when the fuel cost is high and the gal/hr or liters/hour are considered. My RV7 IO360 gets 20-25 MPG at 200 mph. but is all airframe efficiency. Most GA get 7-12 mpg. At 17 gallons per hour for the power needed, that is a very high cost and bites the customer every time fuel is purchased. From the dawn of time, if a replacement "thing" does not meet ALL the needs of the original AND offer something (or many) better, then it is a failure. Better, faster, cheaper. The iPhone is one good example. Camera, palm pilot, music storage, on and on - -all in one device. I was in this business (engine design) for 40 yrs and part of that for aircraft. A Rotax is very unreliable by comparison to a Lycoming. Nobody, nobody can spend the required $300-500M to design, develop, tool and make a better engine for 2000 units per year.
Many have tried, and many have gone broke/quit when the proper parameters were not improved or ROI was not in sight.
Some very valid points, thanks! Yes you've hit the nail on the head with your first sentence. I'm not making videos for engine designers, I couldn't possibly teach them anything. I'm not trying to go too in-depth either. I'm not sitting with the engine data, I only have what I can find on the net so I'm elaborating on what I can find in my research.
I often hear people saying that Rotax is less reliable than the Lyco/Conti. I've come accross few statistics analysis showing that simply is not true. The latest one I saw recently was by Kitplanes. I can't share links in comments, go to kitplanes dot com and search for the article "Accidents: Passing the Engine Baton" for an eye opening read if you are interested.
Air-cooled engines have historically had high fuel consumption due to the piston clearance. They simply lose too much fuel-air alongside the pistons, which must then be vented out of the crankcase. My memory is that the rule of thumb was 8-12% better sfc for a similarly designed water cooled engine. That’s why the Voyager had one in the aft position.
@russbell6418 Actually, the air-cooled engines are pretty good compared to liquid cooled, brethren, some actually much better than most, and in the '80s were competitive with diesels. Mostly because they run at WOT most of the time, but are certainly challenged by the lower compression ratios which yield much less expansion ratio of the combustion charge. Liquid cooled allows lower combustion metal temps, allowing higher Cr yet not detonating. The prime voyager engine was pushing much higher Cr due to a special combustion chamber design and allowed much greater LOP operation than production air-cooled engines. I think that model EFI, with better A/F control and management of swirl, tumble, and optimized valve events could do much better on SCF. Typical gasoline engines were in the 25% overall thermal efficiency, but today pushing 35% and F1 engines are over 50% OTE - of course limited to seconds at full power vs 2000 hours on an aircraft engine.
Hello, very good video, an tried to make very clear explanations, but, There are many pushrod engines that are efficient and reliable by modern standards, modern GM small blocks and Chrysler Hemi engines come to mind. The Hemi even has 2 spark plugs per cylinder, so it is an ideal candidate for dual ignintion systems. The air cooled heads presents the most limitations to working with higher compression and more efficient designs. Rotax has solved the issue with water cooled heads.
Hemi isn't very reliable. Lifter and camshaft failures all day long because they oil the valvetrain in the dumbest way I've seen since the Ford Y block. The cam bearings get oiled the typical way, but the lifters, pushrods and rockers...
Oil comes up into the rocker shaft, then it goes into the rocker arms, where hits a T intersection - one side is very short and goes to the where the rocker and valve stem meet, the other goes to the pushrod, then down the pushrod, then into the lifter, then, what little actually makes it TO the lifter can bleed out and fall straight down and away from the cam lobe (and lifter roller bearing, where the failure happens) because the cam is so high in the block, the pushrods and lifters are nearly if not horizontal.
Despite what the fanboys say, the 6.4 lifters also fail.
One solution I've seen is to use modified pistol oil squirters to shoot oil at the cam lobes (and lifter rollers) instead, but I'm not a fan of that because then the pistons can get hotter than they should.
About the best way to keep a Hemi alive is to avoid idling it any more than necessary. To save fuel, there's next to no oil flow at idle, meaning little splash lubrication from the crankshaft and basically no "overflow" from the lifters themselves.
And to preempt the Hemi fanboys again; yes, Chevy LS series lifters do fail. Sometimes. But nowhere NEAR the rate of Hemi lifters.
Because the Hemi is not a good design.
The world of experimental and light aviation in general is really frustrating when it comes to power units. It's impossible to find a 100-150hp, light, relatively affordable engine.
This has forced me to look at BMW's R1200GS conversions. With conversions come reliability question marks. I plan on blowing at least two of these engines in ground simulators to see where they stand and how far they can be taken. At the moment, in the design stage, it looks like the solution that I've been looking for, but only time will tell.
The S1000RR engine was a great candidate on paper. However, its TBO would've been way too short. Still interesting for purely aerobatic and short recreational flights.
And mazda rotaries, especially ones that are turbocharged, don't tick those boxes?
@@JoshRiolu No, they do not. There are two main problems with rotaries.
One is that their lightness and compactness will be offset by the extra weight and extra volume of the extra fuel which they demand.
Second, the TBO of wankel engines will inevitably by a short one. They need to spend a lot of time at high revs during TO and climbs.
It can be done, it has been done, but these are the main reasons why we do not see them very often.
Many bike engine repurposed for use in cars have had oiling issues during sustained lateral Gs. I would be concerned about this in an aviation application.
@@LogicalQ The R1200 conversion will be designed with a dry sump system, partly to avoid oil starvation but mainly to reduce its frontal area.
The Yamaha Genesis 998 Turbo 3 cylinder is a reliable and quite powerful engine. 300 hp are readily available with the original turbo and a good engine tune.
The engine weighs about the same as the Rotax 4 cylinder engine.
The Yamaha engine is originally used in a snowmobile and can be had as a crate engine for something like $6000. You have to count an additional $12000 to $16000 to make it aircraft worthy.
It's about time something new and improved came into the aviation world......
Um nah. Like Richard VanGrunsven said the best auto engine conversion is take it down to the junk yard and convert it into a $50 deposit in a new lycoming
@@davefoord1259 This isn't an auto conversion.
Yeah i know i just wanted to use that line.😂😂
Time will tell if its any good
Your description of the balance situation is the best that I have ever seen; excellent and very understandable graphics. I am an engine balancing "nut" and you are the best at this rather difficult topic. Thank you.
This engine looks like it"s not air cooled, the more power an engine produces the more heat, If it needs a cooling system that's going to add weight and drag. Enjoyed the video.
Again a very good video ! I didn´t know about this engine. The advantages seemed to give a chance to have success. However, it is more than 10 years ago, the made it. If the breakthrough does not come after two to three years, the thing will be over normally.
So, the question about the balance shaft : I studied the images available in the internet and I am afraid the engine hasn´t got any balace shaft. For an engine of this configuration a balance shaft is needed like a three cylinder inliner has, compensation a circulating torque 90° to the crankshaft by turning in the opposite direction with the speed 1:1. It is easy to achieve but to make it light weighted it should be minimum as long as the crankshaft is or longer if possibel. This reduces the balance weight masses of the balance shaft. The position of the shaft can be chosen whereever the designer wants. It coudl be below the crankshaft, where I cannot see any space for that nor a gear transmission. It could be above the crankshaft and fill the space between the V-Cylinders but again, there ist nothing to see like this. The space is filled by the oil pump, the transmission gear for the prop and the generator. If the balance shaft were on top or beside the engine, any transmission would have leaded to it. So as a result I expect lots of vibrations of this design. Interestingly: the starter is acting on the prop shaft which is unusual and requires a powerfull starter.
You may very well be correct. I studied available material as you have and couldn't see where a balance shaft could be positioned (but not visible), but thought the available imagery maybe isn't all-revealing. Since they state it's a very smooth running engine my conclusion was it has to use a balance shaft, since the chosen configuration can't achieve extremely smooth running without it.
The starter is on a large ring gear at the back of the engine, which is bolted to the crankshaft (like all GA engines), and not on the prop shaft which turns slower and therefore would necessitate more torque from the starter.
It is possible the gear reduction system will act as a balance shaft.
The main improvement is the engine runs on automotive unleaded pump gas.
Porsche tried a new aircraft engine, so did Bombardier. Diamond has been using turbo diesels successfully. Rotax has many liquid cooled engines out there too.
And how many does Diamond sell per year? 15? 20? How many Porsche Mooneys have been converted to Lycoming power?
all i believe, I have never seen one Diamond sells many but i am not sure how many Astros are out there, Tielerts are now Continentals and i hope they have truly solved the Reduction drive problems, Early DA-42s were more costly to operate than PT6 over the Life cycle ( Fuel included) when they could fly, and, i do hate the single electronic fuel system, had a few DA-42 in the early years Land on Takeoff , gear half way retracted and engines shut down due to Low voltage when electric Hydraulic pumps shut everything down. New world tries to take away redundancy when there are still only three places an aircraft can be at any time, On the ground, In the Air or the Unfortunate In the Ground! Lets hope these guys understand good practices!
@brucecurtis4465
I think five Mooney M20Ls still have the PFM3200 engine. It was great to fly, but a practical and maintenance nightmare. A Mooney M20J was faster, had better useful load, better support, and considerably less expensive maintenance.
What finally killed any future interest in the PFM3200 was the Airworthiness Directive that mandated replacing valve springs every 500 hrs. That's what happens when a sports car engine sits and runs at a steady 4,500-5,000 rpm for several hours at a time. It was never a suitable aircraft powerplant. An engine designed around modern automotive technology will never be a top choice for aircraft.
They tried Subaru engine but same issue with rpm for HP. I feel they should work better but car engines are not made for high continuous output. Orenda tried but it never went anywhere, I made some cowling parts for otter conversions back in the day. But in theory they should be better.
@MrAerocomp
The best car engine conversions are probably VW engines. They were initially based on a 1912 aircraft engine design. Being a shorter stroke than bore, they could make use of different camshafts to great advantage. Also, being air-cooled, they lent themselves well to motorgliders and small homebuilt aircraft use.
Water cooled aircraft engines are definitely not to be favored, and I don't know why so many people love the idea. Water cooling is one more point of failure that is completely eliminated in an air-cooled engine. Yes, I know all about Mustangs and Spitfires and, yes, their liquid cooling systems were huge liabilities that air-cooled Thunderbolts never had.
In an aircraft, safety and reliability must trump all other factors, even efficiency. Seems like most people want airplanes to have car engines. They don't realize that cars are cars and airplanes are airplanes. Airplane engines are more like hotrod tractor engines, making all their power down at a lower rpm. Car engines have to geared up to make that kind of power. There is the problem. Cars don't use all their power all the time. In fact, cars almost never use more than half their power. Airplanes do all the time.
The car cruising down the highway might be using 18% of its power to maintain speed. An airplane needs about 55% of its power just to hold altitude in slow flight. Economy cruise is about 65-70% power all the time. Airplane engines are designed and built to be such.
120deg V6 does not exhibit secondary balance. It is almost as bad as I3 in terms of primary and secondary balance, with end-to-end rocking motion for both.
The only even-firing V6 with some inherent balance (akin to the crossplane V8) is the 60deg with 60deg offset crankpins. The primary vibrations become rotational, to be compensated with crankshaft counterweights. Secondary vibrations go (counter)rotational too, possible to compensate with a single balancing shaft, rotating 2x the crankshaft in opposite direction, so the gear coupling is the easiest possible, although most engine makers dampen these vibrations in the engine mounts.
The secondary imbalance of this engine configuration is not even enough of an issue to warrant the use of a balance shaft in the current 120 degree V6s from Ferrari.
A very excellent and informative presentation. Thank you very much!
Most gearboxes also need to maintain a minimum torque to avoid gear chatter and failure. This is part of the reason why geared lycoming/continental have lower tbo's
Awesome elaboration! Pls keep us updated on the balance shaft situation!!
No balance shaft needed in this configuration... Inline 3s have a rocking couple that can be balanced by putting extra weights at both ends of the crank... This is a dual inline 3 configuration....
@@WaltDesine : Hmmmm.... In looking at the cutaway view of the V6 at 7:55 it seems that the reduction gear has a shaft that extends into the engine block. Couldn't this also be used as a balance shaft?
@@InquisitiveSearcher That's a torsion shaft to absorb the shock of a prop strike and prevent damage to the gearbox. You couldn't actually have a balance shaft connected to the PSRU, the available gear ratios would make that impossible.
Ferrari doesn't use a balance shaft in their 120 degree V6, so I can't imagine why this engine would need one.
@@InquisitiveSearcher depend on secondary vibration. The chef would have to move her twice, the engine speed… The shaft on the V rotates at approximately half the engine speed… So now this cannot be utilized as a balancing shaft.
I think so too, that no balance shaft is necessary because it is perfectly balanced in primary and secondary. It's the same situation as the v8 engine which has perfect balance with no balance shafts, because 720/90 degree bank angle is 8 pistons, and in this v6 720/120 degree bank angle is 6 pistons.
Excellent Eloquent Explanation thanks
Incredibly interesting and well presented!
Many legacy high performance aircraft engines have propeller reduction gearing, so that's happening already, just like forced induction. Also like forced induction, it is reserved for the high performance, high-cost segment, for the reasons you said.
As far as pushrod engines go if you wanted to make the engine rev higher you attach the prop to the cam gear for a 2-1 gear reduction. Its also not very hard to make them rev high either as long as the pushrods hold up you can put 1.5-1 ratio roller rockers in the head.
You may want to rethink that. Crankshafts are massive; camshafts can be lightweight or even hollow. If you want a set of massive gears to drive a massive camshaft with a massive propeller bearing , then maybe this engine belongs in a very large truck!
@@captronrv7crankshaft is also hollow
@@captronrv7 well the camshaft and propeller would just be connected to the same gear. The gear would be over kill for the camshaft that's attached to it but perfect for the propeller on the other side
It's been done. Look up Continental Tiara
It's not the camshaft or pushrods that are the ultimate weakness, it is piston mass. An io390 piston weighs about 3kg while an aver 1.5l 4 cylinders piston weighs about 300g both making similar power at similar piston speed. Those big engines are under a lot of stress.
What is the fuel burn? No mention of this anywhere, and what is the BSFC at a cruising altitude with around 70% power? Most IO540 / IO550 and other similar engines run a BSFC of 0.39-0.395. So 30 % more efficient than what?
1. Engine efficiency increases rapidly with compression ratio up to 6.5. Then the rate of improvement slows so the gain between 10. and 12 may be only 3%. On the other hand engine weight to contain the pressure is theoretically linear.
2. In auto engines, For a given power pushrod engines weigh less than OHC, even though the pushrod displaces more.
3. Air cooling fins spread the cylinder centers making for a longer block and crank. Add in sloppy air cooled (AC) tolerances, Continentals and Lycomings (C&L) squirm and as a result wear out.
4. The logic behind AC engines is simplicity makes for reliability. This was true in 1935. Liquid cooling (LC) has come a ways since. Nowdays, LC is arguably MORE reliable because it makes for stiffer, evenly cooled engine. As bonuses, a LC installation has lower drag than AC, the engine CR can be increased, and the engine is smaller.
5. The power pulses in a four stroke engine don’t overlap until it’s an 8 cylinder. When the pulses don’t overlap, the engine drives the prop then the prop drives the engine. In the PSRU, the teeth - which need clearance- are slammed back and forth. C&L built geared engines which were headaches. Rotax 912 coupling works fine..is it scalable?
6. Likely the lightest, simplest aviation engine would be: 90DV4, two stroke, wet sump, Schnuerle ported, FADEC direct injected, LC, blower scavenged, sleeved aluminum block, oil cooled pistons, and PSRU. Think a Deltahawk diesel, but running on gasoline.
7. The engine block, heads, and crank would be designed to be machined from billets instead of cast or forged. Also designed to use auto parts. The idea is scratch build when ordered, minimum inventory, minimum staff.
8. Schnuerle ported engines can be turbocharged.
Will it be done? Could it please the FAA magnetoheads? Cheers
#2 is not true when you're talking about high performance engines. No pushrod engine, for example, can match the power to weight ratio of the engines in the following cars: Aston Martin Valkyrie, Porsche 918, Gordon Murray Automotive T.50, Lamborghini Aventador, Ferrari Enzo, Porsche Carrera GT, Ferrari F50. When it comes to racing engines, there's just absolutely no contest. A 3.0 liter Formula One V10 can weigh as little as 203 pounds (their required minimum weight) but make as much as 965 hp.
@@PistonAvatarGuywhich of these engines will likely come with a warranty or make large production numbers in an auto or aircraft? It might be interesting to see, now that most cars and light trucks have tiny engines.
@@davidbaldwin1591 All of the road car engines that I listed come/came with warranties. All of these engines are produced in relatively small numbers. It's interesting to note, though, that the pushrod engine that competes most closely with the other road car engines listed in my comment had some pretty significant reliability issues.
@@PistonAvatarGuy My information came from the Wall Street Journal’s auto columnist, Dan Neil. He compared a Corvette C7 V8 OHV to a Ferrari V8 DOHC of the same power. The Vette engine though it displaced more, was lighter. You can take up your arguments with the WSJ. It’s the only apples to apples I know on this question.
For any reasonable engine candidate for an aircraft engine - which is what we are talking about, not an F1 DOHC screamer- this is going to be true. OHV has better specific power.
For a plane engine there up to ~3100 RPM a LC Side Valve engine is adequate (if LC), up to ~5500 OHV is OK, above 5500 DOHC four valve. The specific power decreases from left to right. Cheers D
@@PistonAvatarGuy In the world of high performance engines, nothing comes close to a pushrod top fuel dragster. These guys make North of 3000 hp out of 500cid or there about.
In the world of affordable production engines available to humans, the Rotax ETec snowmobile engine makes 180hp from 800cc. Cheers
Timing belt vs pushrod IFR Single pilot at night - which do you choose?
Timing gears
I suggest you give the Delta-hawk a look. It’s been certified by the FAA for new certified aircraft, retrofit legacy certified aircraft, and of course it’s good for experimental. It uses jet fuel which is more available in airports outside the US. It is however expensive…
Respect for the Recap. Cheers
A turbo-charger usually doesn't increase the efficiency of a gas engine (well in contrast to most Diesels). For traditional aircraft use, turbo-chargers are (mostly) used to maintain power up to higher altitudes. Fuel efficiency of the engines suffer, but a turbo-charger often allows to fly a more efficient pattern.
Turbos are not for fuel efficiency in cars either
You can also get mire takeoff power with "turbo juice" then keeping the chamber pressure in the preferred zone at altitude should keep everything more efficient than a larger NA engine to make equivalent power in both areas.
Yeah, turbo chargers increase the weight of air ingested per one intake stroke, allowing more fuel to be burned. The actual compression ratio is limited by engine knock. In aircraft engines turbos are mostly used for turbo normalization. Car engines actually reduce the cylinder compression ratio to allow for use of turbos at sea level without knock.
@@gustavlicht9620that is why I don’t understand the downsizing trend. Toyota with 2.2 l inline-4 in the Prius is efficient.
Subaru turbo 2.0L or 2.5L, conversion kit, done. One of the best things I ever did.
You're still alive?? Or, you just rarely fly it?
I am so scared
What’s the TBO? How much will it cost?
And how much fuel does it burn?
all points were covered and well explained. Thanks!
GA is just too expensive to bother with for most of us. I can afford it, but recently came to the conclusion its just not worth it. What ever happened to Honda's new motor?
I’m the same way. I had a C 150 for 20 years and agree. Too many hassles not to mention ancient designs with well known deficiencies yet you are stuck with them thanks to Big Brother. Then there is the fuel prices and tie down rates👎🏻. I knew they were nuts when I saw them come out with those new monstrously priced electronic magnetos. Parts were drying up for the old styles and going crazy with pricing. I showed an illustration to my AI buddy asking what in he)) is safer or better about these things because everything that can fail is still mechanical there and heavy. He totally agreed.
I’m struggling with the cost of ADSB, annuals, and avionics inspection cost. 17k for a 70 year old airplane looks like the cheap part of the equation.
The "golden age" of aviation, attainable by the common working man is possible.
It will be less safe, and many foolish, daring, adventurous people would die, but more people would realize their dream of free flight. IMHO, totally worth it. I'm thankful for part 103, without it, I'm grounded.
Vivek Ramaswamy claims all laws, and regulations, not expressly granted by Congress are null and void as soon as he's sworn in. Along with a 75% headcount reduction for federal employees, he's got my vote. Should he win,
I'll be cruising in my LS3 powered Helio Stallion in no time. Tail number- Nun-ya.
Every time someone talks about increasing compression ratio in aviation engines, they bring up the fallacy that high compression engines aren't possible without being unreliable. All other engines in the industry has reliably increased to 9.5:1 minimum, with automotive engines going as high as 13:1 while reliably running on 87 octane that has gone stale. The big key is to build the engine around having high compression, not just slapping domed pistons and calling it a day. Small and Big Block Chevy guys has been doing this for decades by installing a modern style cylinder head with a small chamber volume, high compression pistons, a camshaft designed for high compression use, and an ignition controller to automatically adjust ignition timing based on load and RPM. Yes, that's a big list, but they are able to easily modernize a 70 year old engine design, improving efficiency while still running on regular pump gas. Yes, you can still keep your carburetor to make people feel happy. No, this does not require water cooling, as people has done this same work on air cooled Porsches for years.
I'm sorry, but please stop trying to apply automotive thinking to aircraft. Automobile engines cruise down the highway at 12-18% power while aircraft engines run at 65-100% power all the time. An aircraft engine has to be designed and built from the ground up to fly. Automotive technology like 13:1 compression ratios will not work in aviation. The best aircraft engines actually function more like lightweight air cooled tractor engines.
@rescue270 and this is my problem with many aircraft enthusiasts. They are stuck in the mindset that "this is not possible", or "it can't be reliable". They automatically assume that anything remotely modern, even if it's 1980s technology, is automatically not reliable.
As I said, it's possible to improve efficiency with aircraft engines while also improving reliability. The thing is you can't just slap high compression pistons and call it a day. Different camshafts, cylinder heads, and ignition system is required, but can easily be done reliably.
@patx35
I am not an "aviation enthusiast." I am an aviation professional. A&P, I.A., CPL. I have worked on and flown airplanes for 42 years. I have learned that much of what has been purported to be new and improved is almost always more expensive, more complex, and more trouble with little improvement. I am speaking from experience. Sealed recombinant gas batteries are a definite improvement. The Castlegar Trust engine baffle STC is another great improvement. An old Bonanza with that installed will run so cool you'd think the CHT gauge is broken. Composite propellers are not. Expensive to buy and expensive to repair. Nicks that can be easily filed out of aluminum blades have to be repaired by a specially rated propeller shop. Electronic ignition and injection systems require electric power sources and backup power supplies that are not even needed with magnetos that generate their own power in a very compact and very simple unit. To me, the efficiency gained is not worth all the added complexity and subsequent maintenance. Don't even get me started on glass panel displays. We had so damned much trouble with those at the flight school. The old "steam gauge" (I hate that term) instruments were much more reliiable.
A car with 13:1 compression will use that power for short bursts and cruise at speed using about 12-18% power, but an airplane has to sustain 60-75% all the time in cruise. A gasoline engine with compression that high will wear quickly. Ask anyone with a 220 hp Franklin engine that has 10:1 compression how long their cylinders last. You have to very diligently manage power in one of those.
Liquid cooling was fine for WWII fighters that were constantly maintained, but in general aviation it is another critical system that requires scrutiny because it could fail. Airplanes are air cooled for a reason, as the Thunderbolt proved against the Mustang.
Diesels are also a subject of my criticism due to the fact that they cannot make enough power to hold altitude if the turbocharger fails. Too many eggs in one basket for me. Couple that with the fact that they are very expensive and I don't think any of them are authorized to be overhauled. They have life limits and must be replaced.
I am all for new innovation but I strongly and obviously feel that general aviation research and development is going in the wrong directions. Working toward complexity only begets more points of failure.
I saw much more compression with direct injection engines. BMW aims at a bowl in the piston. This would really work well with long stroke, high torque flat-6. (BMW uses it for inline-6 with their small bore)
Great video! Pushrod engines can rev to 11000 rpm as Mercedes Benz once did with their racing pushrod engine, using the advantage in the rules allowing higher compression, more boost and larger displacement to increase performance. Chevy V8 tuners spin their motors to 9000 rpm. GM estimates they save $400 per engine with the pushrod design and they are more compact, lighter and easier to work on. On a purpose built aircraft engine the camshaft drive could be designed to work as the Propeller Reduction drive and with Camshaft above the crank would also raise the prop centerline. My 2 cents
You said it yourself though: "racing engines". An aircraft piston engine has to be in a far lower state of tune, and probably even a lower state of tune then a production automotive engine, because high reliability is an absolute requirement.
When pushrod engines are used in racing, it's usually because the series rules make it advantageous to do so (or require it). Engineers are making these engines run fast _despite_ using pushrods. All that extra reciprocating mass and friction will always have a performance penalty at higher RPMs, and pushrods also make it much more difficult (though certainly not impossible) to have more than two valves per cylinder, which will always negatively effect high RPM breathing. You can work around that with bigger valves, higher lift, forced induction, etc. but all of those have downsides. With more valves, you can simply make much easier compromises.
That is how some old stationary engines worked. To get more power from a smaller engine, they had the crankshaft run faster and had the output pulley on the camshaft. So you still have 500 RPM at the pulley while allowing the engine to run faster.
@@TonboIV thanks for your reply. My point was simply that 5000 rpm is not considered to be too high for a pushrod engine if they handle 9000+ rpm reliably. Some of these motors push out 5000hp. See Steve Morris videos.
The lower costs, lighter and smaller size of pushrod engines make OHC/DOHC unnecessary when we consider that their advantages are more theoretical than practical.
@@captarmour Did you even read ANYTHING that I wrote? You're just ignoring all of it and repeating yourself.
I'll read it again, sorry man didnt mean to offend you@@TonboIV
Porsche Flight Motor came out 30 years ago. Motor had to run at near max revs to make power. Constant 6,000 rpm running wore them out quickly.
Yes, that’s the problem. Automobile engines run at full throttle only a fraction of the time and mostly loaf around at partial throttle settings, generating a small fraction of their maximum power. Aero engines on the other hand hav to run at maximum power for long periods of time during takeoff and climb and then typically cruise between 2/3 and 3/4 of full power for most of the flight. Asking a motorcycle engine or an auto engine to do the work of an aero engine without significant re-engineering is asking for trouble.
Good video, it's good to see the Adept Airmotive engine get some positive exposure.
Not good at all. This engine has been surrounded by BS for some time now. It was funded by the South African taxpayer, with the intent of producing a local engine for us, to avoid the high dollar exchange rate. Sadly, the engine is offered in the States, but not here. There is more money in the overseas market, but not the local one, which generates less in financial value. Try buy one, and suddenly all the banners disappear, and the worms come out. It has left a bitter taste with local aviators, and now languishes in the class of bar-room BS.
@@tonyforrester9570 There's no proof of anything that you say. I'd like to see the engine tested by an unbiased third party. Bombardier built a very similar engine, and by all accounts, it was absolutely worlds better than the current standard. The observed (as in, pilots actually flew it and reported on how efficient it was) efficiency was absolutely incredible.
@@tonyforrester9570 Also, there are several US buyers who were able to purchase engines. One was being installed in a Velocity, while another was being installed in a Lancair (there are pictures of this installation on the internet).
@@tonyforrester9570 And if there wasn't some conspiracy going on here, you wouldn't need to delete my comments.
With plateau honing becoming more and more the norm and now piston dimpling, development has not stopped. I am sure both will carry over to the aviation industry.
i doubt it has a balance shaft,the only V6 i know of is the 90 degree buick engine which has a 90-150 degree separation between firing cyl cos they didnt want to produce a split crankpin crank,the 60 degree V6 is also a 120deg between firing cyl engine and does not require a balance shaft either,the 120 degree V6 was used in volvos,renaults and delorians,steve knott ran a modified volvo V6 in a karmann ghia he won australian off road championship with some years ago
Manufacturers used to produce 90 degree split crankpin V6s without balance shafts and six throw crankshaft 60 degree V6's without balance shafts but they have gone away from that entirely. I don't think there are any V6's currently in production without balance shafts.
I thought every Nissan V6 was a 60 degree V6 and had no balance shaft.
@@skylinefever yeah performance V6's dont use balance shafts
You have not mentioned Golf Ball Dimples on the piston dome that increases power 15.5% and lowers BSFC and emissions
I have an engine in one of my cars with a compression ratio of 12 and it runs regular 87 octane gas because it wasn’t designed in the 40s. Direct injection is a thing. So why are companies in the US allowed to sell engines that can only run on leaded Avgas. Its crazy I mean i would understand if you are flying like a antique ww2 museum piece. new airplane engines should Only run unleaded by now. kids live near airports.
It makes me think of how many people are building diesels to avoid leaded avgas.
It’s because of how costly certification is.
I'm not a pilot air plane mechanic or rarely a passenger but whatever engine is in a plane it dam well have a long reliably history.
You can reduce the displacement and increase RPM to get the HP increase, Rotax did it that way, but Rotax is a big company, with lots of overhead and share holders to pay off, so they did the flying public no favors in lower prices. Every car on the road have a gear box and liquid cooling, and I think aircraft should be the same, what ever weight increase for liquid sure did not bothered many WW2 airplanes. The cam shaft can be made much stronger to be the engine output shaft and most engine, the cam is at a 50% RPM. Please do not have direct injection only in airplanes, There is already enough trouble in cars with dirty intake valves. A new engine give opportunity to add stuff like knock sensors and computers on to it, I like the individual coil packs and then you can dump the magnetos, I hate the 500 hour TBO. Turbo should be manual operation , with some automation by computer so over boost will not happen. but turbo is a high maintenance item. The main reason why airplane engines are so behind the times is because of FAA regulations discouraging anything new. The approval process is time consuming and expensive. There is also politics involved. such as the Eagle unleaded fuel initiative, which been bogged down again. They been messing with that for over 2 decades now. In contrast, automotive industry, about 100 time larger than general aviation, when they need to change fuel, it took a mere 4 years to change everything from the early 70s.
WOW!! What a great idea !!to take output power from the camshaft!!!! Just would need heavy duty gears on the Crankshaft and Camshaft!!! and heavy camshaft bearings and bearing saddles with a thrust bearing inside the engine.The front of the camshaft would have to be similar size to the front of the crankshaft. I hated the 500 hour magneto overhaul also. And sometimes they would not make the 500 hours! In my VW beetle engine, the gear driven point ignition takes minimal maintenance, will go 100,000 miles with only couple contact points replacement . and costs around 5 cents/hour to maintain and is super reliable, much more reliable than aircraft magnetos. I calculated once that my aircraft magneto's costs were approx $5.00/hour just for ignition.
I wonder if it's possible that they figured out how to use the integrated gear box/large final driven gear/oil pump shaft assembly to offset any engine imbalance instead of using a separate balance shaft.
Just to be clear : all boxer engines are flat. But, not all flat engines are boxers.
Yeah wow. Every time I said to myself yeah but what about… you went on to address the topic. Very good video! Surprised though aviation hasn’t borrowed from the automotive industry like with the diesel counterparts (Astro engines now continental). Suppose weight is still the issue.
Expertly explained and very well done! I'm not in aviation, but you had my attention the entire time.
Thank you!
wouldn't the balance shaft be the shaft of the reducer? I was thinking that they liked the balance shafts to be 2:1 ratioed
Could very well be yes
There certainly will be a market for this engine but it will not replace the old Cessna engine. There are turbo prop style engines that fit into that space also and those are vary simple and reliable and powerful. So new is good and there will be plenty of vary expensive planes that will take advantage but not the old Cessna that sells for much less then 100k and is what many people will own and fly because that is the level they can afford to operate. Don't forget all the aircraft mechanics that will need to certify to touch this new engine further reducing its spread thought he aircraft industry. Like I said high end use only. Kinda like asking a Cessna mechanic to fix a jet engine.... say what? um no. but, don't let that stop you with the new better and stratospheric expensive endeavors like this. Plenty of $$ out there in the aircraft industry. Kinda like my wife just HAD TO HAVE that new RAV4 um.. because it gets 45mpg. Me... really. um ok so you save 100 bucks a month in gas cost but what about the 900.00 payment per month? She would not let facts get in her way so we bought it.
Hi, you made a typo in your title. You left out the “r” in airplane. I really appreciate your explanations of engine technology! I have learned a great deal from watching your channel Thank you!
Lol thanks for the heads-up about the typo 🤦🏻♂️
@@LetsGoAviate And……………….fixed! Take care!
Crazy how 8.5:1 is considered high compression in an aircraft engine.
Converting the old engines to lead-free is actually pretty simple, just like it was for automotive engines 50 years ago. Install hardened valve seats and MAYBE tweak the spark advance and you're done. The FAA is probably to blame for leaded fuel holding on for so long in aviation, because they're so reluctant to make any changes unless someone gets killed... immediately. The slow death tetraethyl lead can cause is just a "eh" to them.
Turbochargers also add a lot of heat, which is a huge problem for air-cooled engines.
Bumping compression ratios on a low-RPM engine can (will) lead to high piston and cylinder head temperatures, detonation, etc.
Overhead cams and multi-valve engines could be a huge step. I'd argue they don't really reduce complexity over pushrod engines. One upgrade that should be simple would be manufacturing cross-flow cylinder heads. You get more room for larger ports and more efficient port designs, since they're on opposite sides of the head, and you get less heat into the intake port.
There is so much of the 1930s stuck in these engines and it honestly wouldn't be too hard to engineer it out. But, again, FAA doesn't like change so they make any little tweaks prohibitively expensive.
Oh, crap. This wide vee is going to be odd-fire? Yikes. One of the other huge advantages to boxer engines is that they're very smooth. Odd-fire V6s have serious NVH issues, which is why the automotive world quit using them, again, decades ago.
Why would it be odd-firing? The firing interval of a straight three is 240 degrees, and a 120 degree bank angle is smack in the middle of that interval.
Honda or GM could modify one of their v6s and charge $100,000 for it.
1000% agree. GM manufactures it's large displacement diesel engines for it's trucks at a fraction of the production cost of a new io540 and it does so at a lower volume... which is totally counter-intuitive. Those diesels contain highly complex computer systems and even higher tolerance parts than GA requires. In some cases, they are even using materials that are MORE EXOTIC than anything in the lycoming.
The issue has never been profitability for the companies involved. It's liablity and the INSANE amount of regulatory hoops required to bring a GA product to market. Modern development cycles are almost prohibited because it can take two years or more to get a major design change certified. Companies want to be able to iterate on their products very rapidly and current certification regulations make that almost impossible. You almost can't bring a product to market unless it's perfect and ready to stay the way it is for decades.
That said, if GM got involved, they'd sick their lobbyists on congress and probably get themselves an exception somehow. God I wish they'd do it. lol.
They'd have to charge more than that to pay off all of the shysters who'd be suing them for imaged faults. Out legal system is one of the biggest obstacles to offering any product in the U.S.
Good luck, Adept. I hope you do well.
There is already a lighter and smaller engine available - the turboshaft engine!
Turboprop
Good luck with that! You'll need it.
Lovely engineering but completely useless in the real world of manifacturing scale, aviation insurance and the need for STCs for each and every retrofit application. In my 43 years of flying, building and maintaining aircraft I have seen at least a dozen similar efforts that have never come to fruition. When I started building my Velocity XL-5 RG, I was consumed with installing a high-tech, fuel injected V8 with a PSRU. A very wise friend and fellow builder suggested I contact a few insurance companies for quotes. Not a single one would provide hull coverage, only liability. The same friend said it was an excellent way to turn a $300k airplane into a $100k airplane and “you’re still going to need to convince a prospective buyer that it’s safe.” Rotax is the only company that’s made it work and none of their engines makes over 140HP. Sadly, this engine is the answer to a never asked question.
Too bad you can’t just ditch the system and go Experimental.
yep it's not an engineering problem at this point! The pure weight of regs, certification, maintenance procedures etc have already killed this initiative! Just look at the process to move off leaded fuel and that has proven negative ecological and health issues!
Maybe for now, but business as usual isn't going to be an option for all that much longer. Climate change, and the need to deal with it, is changing the world, and GA engines are going to have to change too. Maybe Continental and Lycoming can develop their existing designs to run on biofuel or whatever, and deal with whatever regulatory changes are coming, but everyone is going to have to make changes eventually, which will have costs, and that may allow new players to get into the market with more radical (or at least less stodgy) designs.
@@TonboIV Interesting that you worked those two painfully skeptical words, “climate change” into the mix. General aviation, as we historically know it, will soon be beyond the reach of our citizenry. Especially for the big-bore-engined models. A new Bonanza is well north of $1 million and insurance is the tail wagging the dog. In the very near future, GA will be a distant memory.
@@bwalker4194 Yes, I wrote "climate change" because it's a reality which we all have to deal with. General aviation is already beyond the reach of most people, at least as far as owning an airplane anyway. Smaller, more modern engines would likely be a positive change for accessibility of aviation, though far from transformative.
Well good luck, It has been tried many times and it never seemed to work as well as theory , But in concept it would be useful , most systems fail due to Insurance issues of Untried systems. I hope they work out but i have been in the field for many years and have seen most fail to be Viable! I had High hopes for Delta Hawk but if has been years to coming to General Aviation, It is finialy starting to come out. Once again Godd luck
my face when the goldwing and sports bikes have had reliable high output lightweight engines for 40 years
Airplane piston engines live at full throttle the majority of their life and last 2000+ hours. A gold wing spends the majority of its life at less than 50% power. Big difference
@@tomedgar4375 LOL. Full throttle is only 2000-2500rpm on an aircraft engine. Literally no different to cruising down the highway.
Great presentation, I could live without all the sound effects though.
Thanks, noted
Rotax seems to be doing pretty well with horizontally opposed engine design. Almost everything you discuss is related to modern engine design vs. 1930s engine design, not to engine configuration.
Yeah. Why there is leaded fuel still used on these engines. Talking about real chemtrails.
Personally I don't think this engine will ever go out of style. They've been around for a long time, The technology is understood by not just mechanics, but by most airplane owners.
They'll be around, no matter their faults, for a very long time. If these new v engines take over the market, these older engines will become the cheap alternative, and people who want to get into flying a serious aircraft on the cheap, so to speak, will flock to these kinds of aircraft.
Electric is a joke
Whatever happened to the Theilert diesel(jet A) engine. I thought it was to replace some of the piston aircraft engines.
so as a guy who has wrenched on just about anything you can think of on land or sea I know there are things I don't know about plans although I seem to get the impression that it is a very long and expensive proses to do anything to different or new and even more if you want to get into some kind of production. I am a little surprised that I haven't heard much or anything really on electric or hybrid systems for small plains I could imagen using a couple axial flux motors one as a generator on the engine and one to drive the prop that would give a number of options. One option would be to use a small battery in sensitive take off and landing arias , could also use it like an electric gear box giving a near infit options for engine and prop speeds, then if things were kept in line could have a emergency physical link.
additionally, increasing displacement also runs counter to increasing rpm; phsyical limits to piston speed and inertia
Did you confirm it has a balance shaft?
No, I've since come to believe it has an unbalanced flywheel that would remove much the imbalance. However just speculation, not confirmed.
Does the weight include the cooing system?
if not, that probably cancels out the 30% weight savings.
Probably. I still like my cylinders be as close as possible together and two exhaust valves. And no dead animals between cooling fins.
Great review. Always like your videos.....
6:06 the perfectly vertical valves make me think it's a diesel, not that being so changes valve actuation, just not something I've seen on gas.
are the power ratings continuous, or time limited? that's a very high specific output if it can be sustained.
I'm surprised at billet crank/rods rather than forged, but I suppose for a relatively small production run it's exceedingly expensive to do forgings. If they were doing a large production run, forged would be the way to go.
regarding the claim of 30% lighter, I wonder if that includes a cooling system - adding radiator(s) and coolant adds a good chunk of weight, and you need to figure out where to put it.
I'm not sure if that is max continuous. Higher rpm engines are usually 5 minutes max (using the Rotax as an example), but I don't have those facts.
The source of the 30% lighter claim I found on a few different websites (not their own). One can't post website links in Youtuve comments but I'm adding it to the video description now.
The engine at 6:06 would be a Rolls-Royce Merlin.
In the "Kitplanes" mag listing the weight they list includes radiator etc.
That image isn't the Adept engine. It's a cutaway of a Rolls Royce Merlin, which did indeed have valves that were parallel to the cylinder axis. Early development versions used an experimental and unproven "ramp head" design, with a squared off combustion chamber, vertical exhaust valves, and intake valves canted outward at 45 degrees. The design didn't work and it was quickly abandoned, replaced by the parallel valve design.
So why not inverted?
13:28 Look at the mid cylinder compare it to the botton or the upper cylinder, they have a bigger distance between them and opposed forces in different direction, wouldn't it cause a worst rocking couple?
And the opposite cylinder for having same direction of force it would result in bigger forces also?
I think that boxer is more balance for this reason and it explains why someone would prefer a large engine for better balance. So if I'm wrong please explain it please.
A good technical analysis thank you, but the big issues to new entrants into the GA engine market are commercial:
1) the market for new engines is tiny and the replacement lifespan of engines is very long (5 times that of automotive engines)
2) the only realistic market for newly designed engines is a retrofit market (and so the new engine cost needs to compete with an overhaul engine cost). This is almost impossible in a small market where not only the core engine build, but all the development and approval costs have to be absorbed into an inevitably limited production run.
3) the product liability risk is significant when comparing a new engine compared with modification to existing engines. In USA (where most of the GA market is) the General Aviation Revitalization Act imposes an 18 year Statute of Response for lawsuits against aircraft and engine designs. So if an old design is modified it may be exempt from product liability claims should there be a defect in design, whereas new designs are not exempt.
I was not aware of number 3, and has now piqued my curiosity. Thanks!