Unusual V6 Airplane Engine Makes Boxer 6 OBSOLETE?
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- เผยแพร่เมื่อ 18 พ.ย. 2023
- We look at a new V6 light airplane engine and compare it to the legacy air-cooled horizontally opposed 6 cylinder engines. I cover the technical pro's and con's of each layout and explain the problem with the legacy boxer six airplane engines., and why the new v6 potentially solves the problem of the boxer 6.
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Image credits:
Conti IO520-Author Eric Friedebach (creativecommons.org/licenses/...) no changes
IO520 Explode view 1-Author Eric Friedebach (creativecommons.org/licenses/...) zoomed in, cropped, rotated
Lycoming GO-480-Author Nimbus227 (creativecommons.org/licenses/...) no changes
Boxer amination-Author Gabriel h 011 (creativecommons.org/licenses/...) no changes
Maule M7-Author Aleksander Markin (creativecommons.org/licenses/...) no changes
Cessna 210-Author Eddie Maloney (creativecommons.org/licenses/...) no changes
Drawn O-435-Author OstojA10 (creativecommons.org/licenses/...) old film effect added
RV10-Author Sniper Zeta (creativecommons.org/licenses/...) no changes
Beech Bonanza-Author Bill Larkins (creativecommons.org/licenses/...) no changes
Navion-Author FlugKerl2 (creativecommons.org/licenses/...) no changes
Extra300-Author Tomás Del Coro (creativecommons.org/licenses/...) no changes
C310-Author Rami Mizrahi on Jetphotos (creativecommons.org/licenses/...) no changes
Pitts S1-Author David Smith (creativecommons.org/licenses/...) no changes
ZlinZ50-Author Christian Jansky (creativecommons.org/licenses/...) no changes
Aerostar-Author Aaryana8 (creativecommons.org/licenses/...) no changes
Turbo-Author Panoha (creativecommons.org/licenses/...) no changes
TSIOF-550-D-Author FlugKerl2 (creativecommons.org/licenses/...) no changes
Lycoming TEO-540-AuthorFlugKerl2 (creativecommons.org/licenses/...) no changes
Continental IO-520-Source Stahlkocher (creativecommons.org/licenses/...) no changes
CessnaP210-Author Bob Adams (creativecommons.org/licenses/...) no changes
LancairIV-Author Tomás Del Coro (creativecommons.org/licenses/...) no changes
SR22T-Author Maxime (creativecommons.org/licenses/...) no changes
MalibuMirage-Author Aleksandr Markin (creativecommons.org/licenses/...) no changes
4 Valves-Author Tennen-Gas (creativecommons.org/licenses/...) no changes
Valve drawing-Author Graham.Fountain (creativecommons.org/licenses/...) no changes
DOHC head-Author Stahlkocher (creativecommons.org/licenses/...) overlay arrows
Pushrod-Author IJB TA (creativecommons.org/licenses/...) no changes
Merlin OHC-Author Les Chatfield (creativecommons.org/licenses/...) no chanes
McLaren Artura-Author Calreyn88 (creativecommons.org/licenses/...) no changes
Ferrari 296-Author Alexander Migl (creativecommons.org/licenses/...) no changes
Jaguar V6-Author Jaguar MENA (creativecommons.org/licenses/...) no change
Piston animation-Author Zephyris (creativecommons.org/licenses/...) no change
Inline 3 animation-Author MichaelFrey (creativecommons.org/licenses/...) cropped
Hype Cycle-Author Rosenfeld Media (creativecommons.org/licenses/...) no changes
Adept+prop-Author FlugKerl2 (creativecommons.org/licenses/... changes
Lycoming LTIO-540 YSSYguy (creativecommons.org/licenses/...) no changes
Valves are vital-Author Owen Allen (creativecommons.org/licenses/...) cropped
Napier Lion DOHC-Author Andy Dingley (creativecommons.org/licenses/...) no changes
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.
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.
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.
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.
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.
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.
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.
The Inline 6 Airplane Engine : th-cam.com/video/Su9WN0Pi04s/w-d-xo.html
Boxer 4 vs Inline 4 airplane engines : th-cam.com/video/0wWpSVTHQTI/w-d-xo.html
Boxer Twin vs Inline twin vs V-twin airplane engines : th-cam.com/video/jtS9tkD3M4c/w-d-xo.html
Hi Thats our Engine,Thanks for featuring it. Lets get in touch ?
Hi, that would be great! Please contact me on letsgoaviate at protonmail dot com. My email is also on the "about" tab of the channel (on PC). Else please leave an address where I can contact you.
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.
Excellent show mate,well explained and informative,thank you.
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
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.
all points were covered and well explained. Thanks!
30% better all around, that's impressive. Very well done and EZ to understand, great job.
A very excellent and informative presentation. Thank you very much!
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!
Respect for the Recap. Cheers
Excellent Eloquent Explanation thanks
Very nice presentation! I would be interested on a close-up of the Higgs engine too.
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
Well delivered, and knowledgeable talk, thanks
Incredibly interesting and well presented!
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.
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.
Great review. Always like your videos.....
I love tech! grate way of explaining it. Thank you
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.
Good luck, Adept. I hope you do well.
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.
Excellent analysis 👍
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…
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.
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.
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.
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.
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 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.
Good luck with that! You'll need it.
Crazy how 8.5:1 is considered high compression in an aircraft engine.
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.
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.
Perfectly explained
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 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.
Mabey they are Using a weighted crankshaft. Extra weight is added to parts of the shaft that are 180 degrees out of faze, and then drilled out to match the weight of the piston, connecting rod and wrist pin. Another possibility is using part of the gear reduction as a harmonic balancer. Say weighting the first output gear on in the gear box to further counter the phase vibration.
But im just speculating from what I remember of engine theory.
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.
Very interesting!
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
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.
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!
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.
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.
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.
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.
additionally, increasing displacement also runs counter to increasing rpm; phsyical limits to piston speed and inertia
EXCELLENT!!!
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?
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.
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)
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
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.
Expertly explained and very well done! I'm not in aviation, but you had my attention the entire time.
Thank you!
Is it going to leak Oil like the 2 stroke Detroit Diesel engines in trucks and boats? How do you counter engine run away when the turbo seals fail?
It's a petrol engine not diesel, it has a throttle valve. Turbo and engines have improved greatly since Detroit engines were made.
Timing belt vs pushrod IFR Single pilot at night - which do you choose?
Timing gears
Good engineering! Great explanation that a non-engineer found easy to understand. Lovely accent... from where do you hail?
Thanks, you're too kind. South Africa
I came across this engine in its development stage in the 1990's. Its origins are South african and a university engineering department. One issue was the opposition from established operators. I seem to remember that it had a bolt on supercharger at one end of the crank which fitted snugly into the 120 degree V. @@LetsGoAviate I was involved in business development then. I would love to see this engine become a successful venture.
@@JohnLear-nu8hl Nice! It's come a long way, would like to see it being successful as well.
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.
what do you think off the spanish INN 1 stroke engine, 500cc, 120 hp, 35 kg , can doubble,tripple ect conectet
I like innovation so it seems like a great concept, potentially having a use case for light sport aircraft, but I have not done enough research on it yet to give a meaningful opinion.
like a modern and better wankel concept, you can add unit after unit behind
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.
What’s the TBO? How much will it cost?
And how much fuel does it burn?
How would the balance be should this be a Y9?
i always thought the boxer 6 had a shared crank pin, would it work?
it would work. but it's no longer a boxer but a 180deg V6
My bet is that a modern 4 valve car engine would be more reliable than those ancient aero specific engines. Engine science has advanced considerably since then, it should be made use of with new but proven designs.
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?
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.
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
Personally I would have gone with a 90 degree v4. Or possibly like the Taunus Ford 60 degree v4 engines used in Saab Sonnet race cars. We could pull naturally asperated 200 hp out of those Taunus engines easily, and they came with a $50 (Fifty dollars) "life time warranty" !!
But I digress, Oil Dry sump with an efficient high pressure oil pump should help solve oil "windage" by only injecting the oil it needs rather than dump a bunch in the oil pan and let everything splash around. Along with a crankshaft-scrapper system that dumps into a side container and back to the pump. You don't have to make oil pans deeper, you can make them wider instead. And of course louvered windage tray baffles. Additionally doing a "knife edge" treatment to the leading and trailing edges of the crank lobes (in effect turning them into small wings to guide oil flow and reduce the aerosol effect). You can't avoid or change much the air flow inside the crank case (windage), but you can control the oil flow to help keep it from becoming an aerosol. Oil mixed in air cannot shed heat as well as liquid oil.
Believe it or not, we have all these same windage problems with old Flat Head motorcycle engines like the Indian Chiefs. However there we could tap off some of the crank case pressure and oil spray with a one way check valve and let it simply dump on the rear chain of the bike to help oil the chain !
...my only real concern with this engine is .....TWENTY FOUR VALVES !!!......woof. Better get that deluxe valve grinder out of the shed....
Have you ever seen the front crank bearing in a lyc or continental?
Yes, they're massive and long! Problems facing a geared drive system are the gyro forces of the propeller when moving the engine out of its normal operating plane; e.g.normal or aerobatic maneuvers. if the gear case is part of the engine casting, then there are fewer problems. But trying to bolt the case to the front of a motor not designed for it will cause problems and failures.
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.
@LetsGoAviate >>> Great video...👍
I like V6s. In cars. I'm also a pilot. I don't see the advantage of a 120 degree engine over a 180 degree engine in an airplane.
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…
Adding a Turbo does NOT increase the compression ratio. It does increase cylinder filling, thus, better performance, more HP, torque etc., but has no effect on ratio.
Agreed. It does not increase compression ratio, I said it increases compression. I.e. it forces more air in, which compresses it more.
@@LetsGoAviatecompression also means decompression and the work done in the work stroke. Context! Outside of engine mechanics you are correct.
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.
Anyone notice the reduction gear box on the front of the engine? The old school engines will often run direct drive to the prop due to the low RPM power curve.
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.
The air-cooled flat is plain simple and that makes em sexy. Fuel injection is sophisticated enough. If V-engine then put the heads down and the crank up and get clearance for a bigger prop. Use a planetary gear and rev up if necessary.
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.
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.
How about water injection that would allow a leaner fuel mixture?
The main problem with a V6 / V8 engine (when mounted at the front of the airplane) is the fact the drive shaft is at the bottom, while the preferred location of the shaft driving the propeller would be to have it at the TOP of the engine (so that the propeller has more ground clearance). The solution to this is to either have a gearbox that raises the output shaft higher, or to use the engine in a 'PUSHER' configuration, where the engine itself is mounted way up high in the airstream above the body of the airplane itself.
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.
If it turned out to be the best engine ever built the FAA would take another 20 years to certify it. Plus I have flown behind Lycoming engines my entire life and they are super reliable!
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
Those specs need to be independently verified rather than rely on the manufacturer.
Another geared aviation engine, except this one will be reliable and cost effective to maintain.
Hmm, if only there was a company known for helping out others with engine development that also has decades of experience with boxer-6s and has worked with airplanes before🤔
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.
the DOHC v engine in aircraft has been around for 79 years. Your display engine has a Reduction gearbox (extra weight and maintenance) along with DOHC which is more moving parts and maintenance. The v6 engine was ran at the Reno Air Race in the "Ponds Special", a Twin engine TSIGO DOHC v6 which failed in a turn causing a turn into the dead engine at 400mph 300 feet off the deck. Diesel is the future for fuel efficiency in light aircraft (The germans were flying a twin Bomber diesel in ww2).
The primary purpose of a PSRU is to improve the power to weight ratio of an engine.
Sorry but that Boxer Engine Animation at the start was funny.
They way they were connected to the crank from different ends :D
They have normal conrods and dont share a crank pin like in the animation or like V8's