Turboprop or Turboshaft
ฝัง
- เผยแพร่เมื่อ 5 ก.ย. 2024
- What is the difference between a turboprop and a turboshaft engine?
It's all in the details.
Let's look at a few of them.To help out the channel, and get access to many more hands on videos, visit Patreon.com and look up AgentJayZ
Thanks!
You know you love your "work" when you hang out there on the weekends. You are blessed man. Thank you for the great material !
Hello again, AgentJayZ. I've just mentioned one of the last engines that I worked on at R-R, about which you may not be aware. However, I know that you're already aware that the Marine Tyne was one of the first. So just to clarify how the aero engine was turned into a marine engine with a free power turbine and a hot end drive, we didn't need to design a new power turbine. We were able to split the aero three-stage LP turbine into a single-stage turbine to drive the LP compressor, with the second and third stages forming a two-stage power turbine. Of course, that meant designing a new bearing housing arrangement and a new PT1 nozzle guide vane.
Again, I am overshadowed by your experience and knowledge!
@@AgentJayZ I was still a new boy in the design office at the time (around 1967-8), so they didn't let me anywhere near the turbomachinery. I was on the fuel systems section and my small contribution on the RM1A was a mounting bracket on the left-hand gearbox, carrying some sort of valve and a junction block. That might be an RM1C on test and I didn't get a glimpse of that area.
Thank you so much I was just going to ask this! It seemed odd to leave so much power turbine in the gas flow when it's only load is the LP compressor and was going to ask if you removed some before fitting the PT. It's really cool to see a solution like you've described. Is it much a coincidence that the LP turbine could be so neatly divided into LP and PT stages or are the stages designed in a modular fashion?
@@deSloleye No, as far as I'm aware,, there was no such intention when the aero Tyne was designed under the leadership of Lionel Haworth, with whom I once had a fascinating chat over lunch. In the aero engine, all three discs of the LP turbine are held together by a ring of through bolts. I think that it was a fortunate coincidence and, as I recall, it wasn't even necessary to restagger either the LP1 NGVs or the LP1 blade, to tweak the power split. Even if it had not been the case, it is probably all that would have been required.
A new LP2 NGV was required to become the PT1 NGV. However, this was not for any aerodynamic reason. A new, wide chord NGV was required because a new bearing was required behind the single-stage LP turbine and at the front of the two-stage free power turbine, in a new bearing housing arrangement, which the new NGV supported.
It is pretty cool that the powers that be let you make all these cool videos. I've been in lots of shops where the powers that be have major sticks up their asses. No fun is ever allowed, and general morale always somehow mysteriously seems to reflect that.
I am lucky. Also, we have no secrets, and everyone is proud of their work.
@@AgentJayZ That IS rare indeed
@@LateNightHacks
G'day,
Um, well, I may be wrong, but I doubt if a Civilian Gas-Turbine Engine Workshop catering to the Warbird, Racing Jetboat, and Industrial & Marine Generator Industries is ever likely to be dealing with anything which has been on any "Secret Lists" for 50 years.
And as far as Jay's Boss is likely to be concerned (always assuming that it isn't all his own personal Workshop & Business ?!), then every time Agent JayZ posts a Video that's FREE ADVERTISING, Globally, for Jet City - generating interest, increasing public awarwness & thereby perhaps attracting new customers... (?).
So, unless Agent JayZ drops a really serious "Clanger" and says something wildly erroneous..., or he posts a Video showing & explaining the innards of something which is STILL "Classified as 'Secret Squirrel Only !'...", then ; it's ALL Good (Publicity)...
Let's face it..., if one watched every Upload on this Channel 3 times that would not enable one to attempt to refurbish an Old Jet Engine, even if all the Required Tools & Spare Parts came with the Project.
An Apprenticeship is required, for all the critical Word-Of-Mouth tips, & the Monkey-See/Monkey Do (repetitious) bits of the Job to be installed within one's Worldview....
At least that's my impression.
Such is Life,
Have a good one...
Stay safe.
;-p
Ciao !
That is quite a Test Setup Jay. Thanks for the explanation and demonstration.
What great timing. Juan Brown on his Blancolirio channel just covered CalFire (California Forest Fire Fighters) are buying used C-130 aircraft to retrofit into water bombers. Juan gave us some quick basics, a turboshaft runs at 100% all the time and the speed is controlled by changing the pitch on the props. So it's really cool to see the under the hood details here.
Cal Fire C-130 Program Update and Aircraft Tour
th-cam.com/video/N4OPp3UwBys/w-d-xo.html
Nice. Will watch.
I've heard of dog clutches in machines but I never expected an actual dog to be an essential part of the oil system in an industrial gas turbine engine.
Hi AgentJayZ. I think that the top diagram is of a Nene, though the engine is before my time. The small centrifugal impeller that you point to at approx 6:30 is for cooling air supply to the turbine area - but not for blade cooling, of course, as there was none.
The diagram of the small turboshaft at the bottom of the page is of a R-R Gem, which powered the Lynx helicopter. The Gem was one of the last engines that I worked on at R-R - after my retirement. I was invited back part-time and the Gem was one of my projects. The Lynx was on the limit for power 'hot and high' in Afghanistan and some engines were marginal. It was found to be primarily down to the efficiency of the HP compressor impeller. I did a lot of work on the impeller vane profiles, using an optical 3D scanner system. To cut a long story short, impeller efficiency was very sensitive to the leading edge profile of the vanes, within the drawing tolerances. And yes, impellers have vanes, not blades, even though they rotate.
Thanks for sharing your valuable expertise. Just a query as you mentioned that vanes used to rotate.... Was it a hydraulic mechanism? To me it looks like as they acted as IGVs...
However, my question is about vane rotation...
Thanks for sparing your valuable time.
@@cck0728 It appears that I have misled you. The usual convention in gas turbine engines is that blades rotate and vanes are fixed. However, the projections on the face of a centrifugal compressor impeller are frequently described as vanes: it was this terminology to which I was referring.
@@grahamj9101 Thanks for your clarification. Please keep us educating with your valuable expertise.
There is one particular engine, the Turbomeca Astazou, which is a single-shaft engine but is sold as both a turboprop and a turboshaft. It powers many European helicopters and small turboprop aircraft.
There is a free-turbine version of the 501 called the 501-KF which is used in marine propulsion. It has enjoyed a very long history powering US Navy vessels.
"HMS Test-cell" looks amazing! THANK YOU AgentJayZ for touching on the turboprop/turboshaft subject. I honestly enjoyed it.
Guys at 33:32..
- Are you a sailor?
- I don't know, I never signed up for any of this naval shenanigans!
That is a hell of a dyno installation. Thanks for sharing.
Stumbled on your videos while researching going back to school for mechanical engineering and took a tangent on how a jet engine works. Love your videos.
despite not understanding everything in English. I am studying and every day I learn more. I love your videos. I watch everyone. thank you so much for sharing knowledge.
The 2nd Edition of the RR book has more detail on the engine diagrams. I'm not going to guess what the mystery turbine does though! Just read in Flypast magazine that S&S Turbines donated a J79 to the Dutch F104 project!
Got videos of it...
@@AgentJayZ Thought you had! From what I read, it was originally for static use then S&S did the refurb on it when it was decided to get the F-104 to flyable condition. But I only quickly read the piece.
I am leaving a comment to say to you I enjoy your presentation and your personality. It is a refreshing and interesting and informative show when I watch you explain everything and I have actually learned a lot and I am very appreciative for your time and effort. Thanks, You are alright in my book for being as nice as you are to explain all of this, I can tell you might even enjoy all of this.
29:08 -- "… right next to the … dog, and that's an essential part of the oiling system…" :-)
The test set, not to mention the setup, must have cost more than the rebuild. This is engineering at its finest. WOW. That is so cool. Thanks for the video.
Swung off a spanner a few times changing out components on the RM1C a few times. Normally the fuel pumps. The first indication of failure of those fuel pumps was the LP bleed valve (or as us Navy types called it, the blow off valve) failing to operate.
This is yet another example of the difference in terminologies between Derby and Bristol. Going back into history, the Avon and for every subsequent Derby engine that had such valves, they were known as a bleed valves. I worked on the Industrial/Marine Proteus (which was originally the Bristol Proteus turboprop) as a very young designer and that had blow-off valves (BOVs).
DANG. I can feel the whole building/ship-mounted Earth itself propelling forward! Awesome.
Love you agent JZ! Don't ever change brother!! Xx
Thank you for including the diagrams with discriptions. Very fascinating!
The Derwent was also centripetal (centrefugal) flow and used on the Meteor F9 of which 2 are still in use for test purposes (1 for ejector seats in the RAF). Earlier Meteors used the Nene (up to F8 or possibly F6 I think) RR is still using river names for it's turbojet and turbofan engines today (I live near the river Trent). Tay, Spey, Avon, and Conway are 4 more examples. The engines with other names are either developed with other companies or were developed by other companies that were bought by RR.
WOW !! Just when I thought this channel could not get any better you show us that test cell set up !
😎😎😎😎😎😎😎😎
Thank you for sharing
JayZ, I have a book called "gas turbines and jet propulsion for aircraft" published 1946. It has a diagram of a Derwent, a scaled down Nene, and the little fan in the middle is described as a bearing cooling fan. It sends air through a duct around the shaft to the rear bearing and the front face of the turbine, and then goes overboard.
Fascinating test cell you built there, amazing the cooling and quantity/flow of oil that the reduction gearbox needs
Very interesting, I imagine setting everything up, and aligning all the shafts takes a little time, even with the modern digital aligning equipment
Wow I love how you are so smart and tell everything about what working on and how to get parts I love to build a little jet motor as a project thanks you are a awesome teacher
This video taught me something New. thanks
So what's behind that weird optical illusion of the MC Escher'ish door and removed stairs at the beginning of the video? lol
Good evening Sir, the maritime patrol CP 140 Aurora's use the Allison like the CC 130 Hercule Sir. Great engine for sure👍😊 Great video Sir and have a great week Sir and Happy Canada Sir Cheers 👍😊
29:06 "... right next to the dog. ..."
34:33 Well, the end clarifies the mysterious turbine part, "dog"... just in case you looked away for a second.
The Dart was a wonderfully obnoxious turboprop. I can still hear the shrill ground idle whine to this day when I stop to think of one.
Centrifugal compressors make a totally different noise, as compared to axials.
The sound effect of that engine starting up was pure gold.
OMG😱..I was just watching your old videos ..and you uploaded new one
i have learned so much from you. thank you for being so generous with your knowledge.
Yeah I'm surprised that he hasn't shut down due to jealous people talking shit.
Loved it. Plus Philly Gear..... I used to live close to the plant.
I really enjoy the step by step videos on the Patreon page.
the difference then would be that one has a gearbox and spins everything together, like a manual gearbox and the other has a "free power turbine" that works separately from the rest of the set? as if it were a type of automatic clutch? talking about torque converter, but exhaust gas. if my analogy is correct.
Whether it's a single shaft engine, or uses a free power turbine, all turboprops have a reduction gearbox. It's not helpful to think of gas turbine engines in piston engine ways.
@@AgentJayZ really are totally different things, thanks for the clarification
Torque tubes more famously in the Porsche front engine rear gearbox/drive (928 ,944 ,924 ) or 4 wheel drive Raid type cars . They also came with a dog that required regular maintenance . Interesting stuff . I'm looking for suitable engines for a water speed record and looking at the Licence built RR Viper 633-47 which should be available in pairs from the twin engine IAR 93 Vultur in Romania .
When the world gets back together I shall take a wander around that neck of the woods .
@29:08 "I did all this work and that's how you acknowledge me????"
I just turned on notifications. Your videos weren't showing up in my feed and it looks like I missed a lot.
Congratulations on your success & thanks for sharing
Outstanding vid...yet again. Thank you.
4:12 Whats the purpose of the blades at the front of the igniter cans?
Those are called swirler vanes. They cause the air going through them to swirl like a little tornado, which helps to increase turbulence and help mixing with the atomized fuel being sprayed from the fuel nozzle.
@@AgentJayZ the three T's of combustion, temperature, turbulence and time.
I think it's crazy that the F135 engine is an afterburning turbofan that also spins a shaft to the front vertical fan
Was wondering if you could do a video on a PT-6 engine? It’s interesting to me because it’s a hybrid axial and centrifugal flow. Also I’d love to see someone walk me through the flow in the combustion chamber. It is very odd looking in cutaways.
I have done that in a video on combustor efficiency, and airflow changing directions.
Can't remember what it's called, but my channel page has a search bar.
Of my understanding.... turbo-prop engine runs directly all stages of the compressor via its shaft.. Turbo-shaft runs a turbo at the end, that the hot gases spin an other turbo that its connected to a shaft.. similar to a torque converter on automatic transmission cars.. that system in case of power loss does not spin the compression section so it spins freely (very helpful at auto rotation, or if something gets inside the water jet of a boat) Am i correct.?
None of this makes any sense.
You seem unaware of the two types of drive systems: single shaft, and free power turbine. Both systems are used in various turboprops, and both systems are used in various turboshaft engines.
For a helicopter, you could use either a single spool engine (where the turbine drives both the compressor and the power output shaft) or an engine with a free power turbine which only drives the power output shaft. You can tell the difference between them by observing the rotor blades of the helicopter on engine start: If it uses a single spool engine, the blades will start spinning as soon as the engine starts turning, because the rotor and the compressor are mechanically linked. Whereas if the helicopter uses an engine with a free power turbine, the blades will only start spinning once the engine is producing enough power to spin the free power turbine - this will not be immediate, so there can be a delay between starting the engine and seeing the blades start spinning.
The free power turbine approach is far more common for helicopters though because it's much easier to control the power output and hence the speed of the rotor blades. This is done by controlling the fuel flow to the engine: More fuel burned = more power generated = more torque produced by the free power turbine = rotor blades spin faster.
The device which allows autorotation in a helicopter is called a spragg clutch. The position of this in the powertrain is important - the arrangement is power output shaft (from the engine), then reduction gearbox, then spragg clutch, then rotor blades. The spragg clutch is essentially a freewheel gear, similar in principle to what you find on the back wheel of a bicycle, but more heavily built since it deals with far greater power. This allows the rotor blades to spin faster than the output shaft of the gearbox, or for the rotor blades to spin even when the engine and gearbox are not spinning at all, but still allows the engine and gearbox assembly to drive the rotor.
Imagine if the helicopter is in flight, with the engine at full power and the rotor blades spinning at or near their maximum RPM, and then the engine suffers mechanical failure or is hit by bullets from an enemy aircraft, either way it quits completely. In mechanical terms, this is analogous to riding down the road on a bicycle, pedalling as fast as you can, and then you just stop pedalling. The helicopter rotor is equivalent to the back wheel of your bicycle - it can keep rotating regardless of what the engine is doing. That's what helicopter autorotation is.
Interestingly enough, the maximum altitude record for a helicopter (around 42,000 ft) is also the maximum altitude at which that same helicopter was forced to enter autorotation, because it went so high that the engines flamed out due to the intake air pressure being too low.
T-56-7 shaft rpm is 1020rpm, which is also the number of compressor blades it has as well.
When you have to clean them, it's depressing to know how many there are...
J79 *Air Dynamometer*
Something you don't hear every day.
Building a test setup voor every finishend engine must be a lot work. I just repaired some electronics for industrial turbines for a company like yours, but then in Europe, very well build and very over engineered stuff ( in a good way), a joy to work on.
If all goes well (cov19 regulations) the engineer who is my contact will show me some turbines up close. Allthough I am an EE, I also love mechanical things (worked a lot on cars and motorbikes as a hobby) so I hope he gets permission. (it is not just a tour, I need to do some measurements on a working fuel injector servo controller so I can go on with the repair.
Excellent. The coupling between gear box to load compressor and power turbine to gear box seems to be flexible (membrane) coupling.
Thanks.
My recollection is that the cardan shaft connecting the power turbine to the marine gearbox had membrane couplings at both ends, but it's a long time ago .....
the dummy engine is the source of the load, but how do you precisely measure the magnitude of the load, strain gauges on a shaft, or something to do with the output of the dummy engine?
Torque meter on the gearbox input shaft. Rev counter on that shaft as well.
Could I see some more video of that setup running in your test cell? Please, Jay.
Man I love this stuff. Thanks Agent Jay Z. Good luck on your moto tour. I would be there at Oshkosh too but I’m getting married in August. Next year yea?
The Marchetti 1019 and there is a Cessna 206 mod that use the RR250 as well.
Amazing video as usual, really cool to see the test bench and the aliment of the shafts to the gearbox had to be a real pain to get exactly right since you sure don't want any run outs at these rpms.
Your oversimplification is making the professional millwrights who made this all work laugh out loud... at you.
@@AgentJayZ Haha, I have no doubt what so ever about that.
Hi Jay. Strange request, but I'm looking for a compact turboshaft in the 25-75Hp range with an output of about 1500 to 6000 rpm. It would be great if it could operate on diesel or a common fuel. It's strictly recreational and educational, no aviation involved. Thanks.
Nothing that small. One thousand Hp minimum. Go piston.
You can go with RC TURBO PROPS. .. A JETCAT SPT 10 9kw power.
what does the f-35 have for an engine? how does it run the forward fan?
G'day,
The STOVL version of the F-35 has a Shaft-Driven Lift-Fan in a separate Bay forward of the Compressor..., between the Inlet Ducts...
My guess is that the Engine itself is an Afterburning Fan-Jet with a Central Shaft from a Freee(wheeling) Power Turbine located behind the Low Pressure Turbine Array..., and the PTO-Shaft "must" perforce run right up the central Long-Axis of the Engine.
The Freewheeling Power Turbine "must" therefore have the ability to feather it's Blades in order to prevent either overspeeding if left otherwise unloaded (during Forward Flight wirh the Fan shut down), or reducing the Exhaust Gasflow's propulsive velocity if the Freewheeling Power Turbine Wheel were to be stopped from rotating with the Blades pitched to recover energy from the passing Gasflow.
So my guess is that they feather the Freewheeling Power Turbine in the Bum to shut down the Lift Fan at the Front...(?).
And anybody who REALLY knows enough to be not guessing... (certainly not moi...!), is probably legally constrained from telling the likes of us anything much about it....
Secrecy Act, National Insuckuritity, and all that Marketing Jism..., OuuRaaah (!) kinda thing....
Such is Life,
Have a good one...
Stay safe.
;-p
Ciao !
Sorry, but Mr WarblesOnALot has done just that. The engine in the F-35B is a version of the P&W F135. It doesn't have a separate power turbine driving the lift fan. The fan is clutched and de-clutched from the LP spool of the engine. There's no great secrecy about this: you can find stuff on Wikipedia, which will tell you that the lift fan was designed by Lockheed Martin and developed at Rolls-Royce, together with the swivelling nozzle arrangement. I find this curious, because I was able to look over the designers' shoulders as they were designing the fan, just down the road at R-R Bristol.
It is also to enlightening to read the patent. In order to extract more power from the turbine when the lift fan is engaged, the jet nozzle have some kind of flap which is crucial for the whole concept to work.
now I understood why they use an alison 250 in a car (howmet tx)
Very cool setup and awesome explanation. The Y2K mention got me curious what bike is under the cover next to the BMW in the beginning.
Honda CTX 1300 V4. Intercity comfort missile that I use as a long distance sport tourer.
@@AgentJayZ Sweet! I'm on a VFR so I know the charm of the v4 comfort missile. Love your channel.
VFR is a bike I have always wanted, but never have owned. My Honda V4 is great, but only revs to 7 grand.
I was surprised to discover that you're in Fort St. John. (I have a cousin who lives there.) I would have thought that a bit out of the way to support a business like yours. Is the town the regional maintenance hub for one of the airlines?
I actually live a bit close to there
Incredible work - it lloks brand new. Wow.
Thanks for the presentation dude
Impressive Jay. Great video.
Very cool. thank you!
Great video thanks for the knowledge you demonstrated , fantastic channel.
Please give your dog a treat for me!
What is the dog's official part # ?
He is part of general oversight and safety audit team.
I am going to take some slight inspiration from that intake screen. No, not for keeping birds out of my jet engine, just for keeping birds and deer from eating my strawberries :-)
Very cool to see the j79 compressor section as the load. I have to assume it does, but does the load get an oil supply as well?
Thanks for the illuminating lesson. Would you do a follow up to this video and describe the differences and similarities of the f-35 engine turboshaft to what you describe in this video? Thanks
The only difference is that It can be intermittently operated, and when operating, it only extracts a portion of the exhaust energy, leaving a significant amount left for the rest jet nozzle to convert into thrust.
I don't work on that engine, so you know more than I do about it.
A lot of work went in to that test set up, looks good. Maybe you mentioned it and I missed it, but is this a one-off test or do you have a series of engines to test using this same set up?
How does the rear end of the compressor look like? Is there any kind of an iris or nozzle attached to it?
Regarding the J79 compressor as a load, would it have the same suction near the front as the real J79 engine running? I'd guess special care must be taken to prevent anything from being sucked into it. What does that backside of the J79 compressor load setup look like? Does it just vent into the room? Does it create any thrust? And one last question, to your knowledge, has there ever been an application where they used a jet engine compressor or similar to compress air on a mass scale? Not sure what you would need 160 psi @400+cfm for but it would be cool.
The amount of air going into the air dyno is the same as for a J79 at something around flight idle.
The rear of the air dyno is an open midframe, and the compressed air does just get released into the room. Lots of noise and heat.
If any process needed a 20 thousand Hp air compressor, this would be a good way to make that happen. I don't know of any such installations.
industrial turbo commpressors are used in some cases for large plants, i know of a refinery near me that has one.
no idea what kind of power this compressor is
also they are used in some blast furnaces to force air through the coke and iron ore to fan the fire
Jay what would be the advantage or reason of a hot drive over a cold drive engine in industrial install? The hot drive seems more complex with the shaft needing more engineering for the heat but not sure. That test set up took a long time to set up wow.
Either configuration works just as well. The vehicle or installation can be designed for either. It's usually a preference thing of the designers.
In an industrial application, a hot end drive with a free power turbine is usually the easier design option, as it eliminates the complexity of taking a long power output shaft through the middle of the engine. That's the the way industrial gas turbines with aero-derived gas generators have to be designed, of course. Even those huge, heavyweight industrial gas turbines that are single shaft machines, usually have a hot end drive.
Why do you use a inlet screen on this turbo shaft engine?
Usually you only have a bellmouth in front of the engine without a screen in front.
What are you doing up this late on a weeknight?
I've seen twin P&W PT6 on the Bell UH1
not sure of plane but it was a Turbo Prop with a Allison 250
I wondered why, when each engine works perfectly when normally placed
been so hot recently, how about Canada
So that's a reversing gearbox - what would you have done if you needed them to both rotate the same direction?
The gearbox manufacturer will make any ratio and direction specified. All you need to do is decide what you want.
It would almost certainly have required no more than an idler gear arrangement between the input and output gears of that gearbox.
Great explaination and showing of your set-up. One day might you show the controls for the testing and monitoring
Do you even watch?
Recent videos here show just that. Scroll through them and you'll see everything you ever wanted to see
33:05 Philly WOOO WOO!
Surely that compressor load needs far more power than that engine can deliver? Do you adjust the guide vanes or leave stators out?
Very impressive test!
Yes. The J79 compressor requires 30 thousand Hp at full rpm. We have removed three stages of stators at the back, and we have the VSV system set at minimum, which means the rotating blades have a very small angle of attack, and do very little at the higher rpms. If we opened up the VSVs, the blades would grab more air and require more power.
Do you adjust them for different engines to test? More powerful engines get more vsv?
Imagine 25 years ago being on the school bus telling your buddies about a show you watch at home? They be like you crazy.
Sir How Does Fuel is Supplied to Helicopter Turboprop Engine
Through which device it can be Done
Please tell me
Thank You SIR 🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏🙏
Tank, boost pump, line, filter, pump, FCU, line, nozzle.
Just like any engine.
Fantastic video, very detailed, just great. Two questions:
Is the torque sensor between the exhaust duct and the gear box? (Looks busy in there.)
Is the exhaust duct work fabricated by your team, right off a boat, or something else maybe?
Thanks a lot.
We measure the torque directly off the engine's output shaft, so we don't have to estimate losses in the gearbox.
We are using an exhaust manifold from a different model of turboshaft engine, slightly modified to fit our purposes.
@@AgentJayZ Thanks, good stuff, you really do a great job.
That was awesome 👏
My instincts seem to have been right. I was thinking, "Is the Allison / Rolls-Royce 250 really the most-produced turboprop engine? That must be PWC PT6". Wikipedia seems to agree: RR 250: 30,000 built, PT6: 50,000 built. And it seems that by now the CFM56 is rivalling the 250, with also over 30,000 built, and still adding to it by the hour.
The RR250 is one of the most produced turbine engines in history, but very few of them are turboprops. Almost all are the turboshaft version used in helicopters.
AN excellent example of the need to always use the correct words.
@@AgentJayZ Yes, _one of the_ most produced, no doubt, but I paid close attention, and you said "_the_ most produced gas turbine engine on the planet", and that honour probably goes to the PT6 (of which most are turboprops). The 30,000 vs. 50,000 was for all variants, -prop and -shaft, for both types. If you have other sources for your claim, I'm glad to be corrected. It doesn't seem to be very easy to get accurate numbers. You'd think that the manufacturers would be proud of those figures and display them on their website.
Looks like you are right about the numbers. 51,000 for the PT6 vs 30,000 for the RR250. They are both great engines, and I would never say anything negative about the PT6. I once called it the small block Chevy of turbine engines!
I'd like to see a turbine powered natural gas boost pumping station. Does it drive an inline turbine compressor section much like the set up here?
The natural gas pipeline compressors are large centrifugal units.
Since that compressor becomes more efficient as it approaches its designed operating speed, its input torque would(?) vary as well from nothing up towards nominal. Does this allow you leeway to adapt it to the output power of many different engines under test?
We would adjust the power consumed by the dyno by changing the angles of the variable stators, by changing the speed at which it is driven, and also by removing or adding stages of stators inside it. In this test, the vsv's are fully closed, it is running at design speed, and it has the last 3 stages of stators removed.
A fully intact J79 compressor at full rpm normally requires about 30K Hp. We need it to need 5500 Hp here.
how to adjust those complicated machines in a perfect line?
That's what millwrights do for a living.
We have fancy flexible couplings on the shafts.
@@AgentJayZ Thanks for the reply
Excellent. At 28:05, the part that holds marine (anchor) tag is capacitor/igniter box?
Thanks for the clarification.
Its not the ignitor box. Its a chamber into which all of the bearing sump vents are connected.
@@AgentJayZ Thanks for the clarification.
What is that book at 15:58?
I think it's a printed portion of the PDF of "the Jet Engine" published by Rolls Royce. It's an excellent book, available from many sources at various prices.
@@AgentJayZ in the t56 engine turboshaft
All the 4 turbines and shaft are driven by all the 14 stages of compressors
Or is are they divided to a stage for High pressure comps
A stage for LP comps and 2 stages for the shaft??
Excellent video, but I have a question. In industrial engines, the outlet airspeed isn't lower since the thrust is not requested? Thanks
I don't understand what you are saying, so I can't answer.
@@AgentJayZ my bad. You gave the answer in other videos. Thanks!!
First time I see the first gearbox to J79 compressor being connected by hydraulic fluid fascinating, actually I have a question's about the turbo shaft type
what and how can a Westland Lynx & Merlin start all engine's without rotor's moving
maybe you have already done a video on this engineering solution ?, please help sir
No hydraulic coupling. They are laminated steel flexible couplings.
You need to watch my power turbine videos.
Are industrial jets normally set on cruise control and constant RPM? or can you throttle up an down quickly between RPM's?
why they use a specific design for turboprop propeller ? just for output rpm ?
The Tyne was originally designed to be a fuel efficient airliner turboprop.
Your question does not make sense to me.
One of these days can you explain the airflow and operation of the AGT1500?
I try to stick to what I work on.
@@AgentJayZ , Fair enough. It powered my ride for almost two decades in all that time I couldn't get a good explanation of the necessity and function of the recuperator. Or maybe I was too dense to understand.
Anyway, I enjoy your channel, thank you.
Could the turboprop be put into an air boat? It's still technically a propeller just not aircraft propeller
I've seen an airboat with it's prop driven by an Allison 250, which in one of its configurations is a turboprop...
Do you use rim and face alignment for your shafts, or do you use a laser?
We've got real millwrights on our crew, and they handled all the intricate setup.
I keep wondering if it would be possible to design a combination turboprop/turbojet engine. I think props are more efficient power at low altitudes and low to medium speeds, and jets are more efficient at high altitudes and speeds. It makes me wonder if you could reasonably design one engine that would drive a prop at low altitude, and then feather the prop and run as a jet at high altitude.
Short answer: no.
Longer answer: aircraft design and aircraft engine design is undertaken by thousands of extremely capable people, and if this idea was worth the expense and complexity, it would be in service now.
A quick survey of reality shows: ...
Proposals for variable cycle engines have been around for decades and nothing has ever come of them. There was a proposal to have such an engine for the proposed Boeing SST. The engine would have have operated as a turbofan for take-off and subsonic flight for improved propulsive efficiency and reduced noise levels. For supersonic flight, a valve arrangement between the LP and HP compressors would be actuated to divert the flow and reduce the BPR. We did actually tinker with the Boeing valve at R-R Bristol back in the 1980s, but it's so long ago that I can't remember exactly how it worked.
@@grahamj9101 seems like the only really good mixed cycle engine was that if the A-12 and sr71, between turbojet and ramjet. Anything more complicated (ignoring the inlet aerodynamics) doesn't seem to appear anywhere. Would you agree?
@@deSloleye I wouldn't regard the engine to which you refer (AgentJayZ doesn't like to discuss it) as a variable cycle machine, any more than I would the Olympus 593 in Concorde, which I worked on. Yes, in both cases, in supersonic flight, the turbomachinery was producing only a small proportion of the thrust. And yes, that other engine became what is known in the trade as a 'leaky turbojet', in supersonic flight. That was, I believe, because even compressor delivery air was too hot to provide reasonable cooling for the afterburner section, so compressor stage 4 (I think I recall reading somewhere) was tapped off and piped externally through the external tubes that are prominent on the engine. I've actually seen two of those unmentionable engines, here in England, under the wings of the aircraft that they powered.