Power Turbines 4 Different Ones

[@shawndinterman2219]

All this goes way over my head but I love the guys passion and enthusiasm so it makes me watch

[@phasm42]

Speaking of enthusiasm, you may like Clint's Reptiles.

[@baron30001]

Very interesting video. I work in a large utility plant at a big manufacturing site in new zealand. We run 4 solar mars 100 turbines and power turbines to make 10mw of power off each unit. We then use the hot gas to heat out boilers to make super heated steam to run site manufacturing process equipment as well as a large steam turbine to make more power. After the gas has been through the boilers we then use whats left of the heat to heat domestic hot water for use on site. By the time the gas from the gas turbine gets to the top of the exhaust stack its only about 90 deg. I am still amazed as to how powerful and reliable such a small piece of equipment can be.

[@AgentJayZ]

Canada calling here... would you please make sure to capitalize the name of your truly great country? Thank you!

[@grahamj9101]

When you got home, you probably discovered that the pretty picture you showed us was of an Industrial Spey with ..... an RT45 power turbine, produced by Cooper Industries of Mt Vernon, Ohio. As you surmised, the power turbine has two plain journal bearing, with the thrust taken by a tilting pad thrust bearing, known as a Michell bearing in the UK and a Salisbury bearing in the USA. Having been involved in the design of the power turbine for the Marine Olympus as a very young designer, my recollection is that the plain bearings of R-R's industrial and marine power turbines were supplied with oil while stationary, to provide a 'jacking' effect and reduce the breakaway torque needed on start-up. PS Tilting pad journal bearings are also available.

[@AgentJayZ]

I knew that you would know all about this, in intricate detail!

[@timcross2510]

@@AgentJayZ you crack me up

[@grahamj9101]

@@AgentJayZ Not surprisingly, I was immediately able to recognise the gas generator as an Industrial Spey. The design style of the power turbine appeared to be that of Cooper Industries, with whom I dealt when they were designing their power turbine for the Industrial RB211. I did google 'RT45 turbine' and soon found an ASME paper, authored by two Cooper Industries engineers, describing its development. I was gratified to see that they gave a credit to two of my former colleagues at R-R IMD.

[@MegaFPVFlyer]

Wow, the whole discussion of journal bearings and breakaway speed was really interesting. I thought everything involving gas turbines would use ball bearings.

[@grahamj9101]

Aircraft gas turbines and aero-derivative industrial/marine gas turbines exclusively (well, almost) use rolling element bearings. Having said this, the Marine Tyne that AgentJayZulu showed us recently just might have a plain journal 'steady' bearing somewhere on its LP shaft. Some free power turbines (such as the RT45 that AgentJayZulu has shown us here) for aero-derivative gas generators have plain bearings, because they have been designed on the 'heavyweight' principle for long life, possibly the lifetime of the installation. The gas generator may have to be repaired and overhauled several times during the life of the power turbine. There are purpose-designed free power turbines with rolling element bearings, but these are typically based on aero engine technology and principles. They may be based on the LP turbine of the turbofan from which they are derived and may even be an integral part of the engine change unit. An example of this is the R-R MT30 engine, as used in the Royal Navy's carriers and the US Navy's Zumwalt class destroyers.

[@timcross2510]

Just like I learned everything about trees to make my hour upon hour of drives as a salesman into a great exploration instead of a mind numbing drive through green nothingness, your videos for the past decade (can it be that long!)have made me love the genius and beauty of things that have been not given the attention they should. You have made an airplane lover a person who loves turbine tech. AND I REALLY AM GLAD YOU HAVE DONE THIS!

[@herlyskjbatista6795]

I’m studying to get the A&P license. Keep doing this. I learn a lot from you!!!

[@gregeconomeier1476]

I was amused to see a turbo shaft fly by in the background around 14:40. Awesome scene management.

[@Hossman757]

Excellent video but I think what most people have a hard time grasping is that the shaft that Is driven by the Tp is a separate shaft that runs through the center of the shaft that is part of the Ng. Most people don't really realize that they are 2 different parts of the engine coexisting, exchanging energy to produce torque to drive mechanical gear devices. In the case of ones used in Natural Gas fed powerplants there is a 2 for 1 in electricity creation. The Tp drives a generator and the waste heat is used to boil water and drive a steam turbine. In the oil industry the Solar power cells (turbines) produce electricity for the facility and other units drive the compressors and pumps to move produced Natural Gas and Oil.

[@apollorobb]

What i found interesting was all of the external plumbing on the 116 PT . And the other units didnt have it or even seem like there were connnections for it on the others .What is it all used for ?

[@kjdude8765]

Stator cooling air.

[@tomling9310]

It amazed me how easily the PT turns with such a light touch, nothing wrong with those bearings 👍 very smooth.

[@PerceptualTruth]

It sounds like you settled on JayZulu. Said with such confidence at the intro! Now to watch the rest B) Edit: I'm an engineering student in thermo and aerodynamics this semester. Thanks for making these videos and explaining everything the way you do. It's really cool to read about this stuff in a textbook and hear about it in lecture and then come here to have it all come together and make sense. Every time I see a plane in the sky now I think about everything I've watched and learned and can't help but appreciate the engineering and understanding necessary to develop these incredible machines! Thanks :)

[@DeliveryMcGee]

Hee, finally going with the truly international pronunciation of the last letter. (For those not in the know, it's how you say it on the radio.)

[@captainmidnite93]

Tapped and de-tapped to a lot of these on oil platforms, Solar Saturn's were common. Had a couple mega-watt units on the bigger structures. Thanks J.

[@AgentJayZ]

There appears to be very little attention paid to noise reduction on those platforms... not enough room for it.

[@captainmidnite93]

Good observation. It's rock show loud walking up to them , then you open the door (which can shut the unit down if not bypassed-oopsidaisy) ... Sound and blast/flame suppression is pretty much reserved for living quarters.

[@warrenjones744]

Well I can honestly say I never had any questions or really cared about Gas Turbine power equipment. However since you took the time to present it and I am interested in anything mechanical it was a very interesting look into a world few of us see or perhaps even know about. My knowledge base is expanded a little and I am thankful for it. Cheers Mr. Zulu

[@conantdog]

Interesting that you're showing us power turbines I've heard you talk about them many times over the years and it's great to see you with a new backdrop 👍

[@reactorfour1682]

I’ve always found that these videos have encouraged me to go out and read about jet engines.

[@AgentJayZ]

I am very satisfied with that effect. It's one of my aims.

[@jamesherrera6973]

Kept them videos coming. Love to watch and learn. I'm an aircraft engine mechanic for apaches helicopter

[@Miata822]

I puzzled on the plumbing surrounding one of the power turbine. Freezing the video at 27:23 I see the tubes are for cooling air. Is that air supplied by compressor bleed air from the engine (gas generator) or from a separate mechanical source?

[@kjdude8765]

He answered a similar question above, it's compressor bleed air.

[@CDhn455]

Do you ever perform the preventative maintenance, restore, or rebuild power turbines? Seems like it would pretty similar to what you do with jet engines and gas generators.

[@santiagocarbajales]

in one of the power plants i work there are two pratt & whitney ft8 swiftpacs. they have a GG mounted with a 4 stage PT. the output shaft of the pt is coupled with a 60 MVA generator. each PT generates 25 MVA of power wich is aproximated 33.500 Hp. really good machines, very reliable

[@pnwtrekker8529]

Even though I have zero knowledge in the design, operation and maintenance of jet engines, I do find your videos fascinating and always informative. This one especially. ThX much AgentJayZ!!!

[@robertlackey7212]

I am curious , do these machines , power turbines and gas generators have "standard" flanges or are adapters used ? Also I read somewhere that Kawasaki industrial engines were designed to be industrial engines from the beginning and were better industrial engines as a result , what would be the possible differences between a dedicated industrial engine and a converted aero engine ?

[@AgentJayZ]

That's two questions, requiring far more space for answers than here. A possible future video...

[@grahamj9101]

I'll leave AgentJayZulu to answer you in more detail in a future video. However, suffice to say for the moment that "dedicated" industrial gas turbines are known by those of us who have been involved with aero-derivative machines as "heavyweight" gas turbines. Their engineering is more closely allied to that of steam turbines. Their structures and casings are altogether heavier, they have to be warmed up slowly and they cannot be started and run up to maximum power in two minutes or less.

[@neilharper6317]

Wonderfully explained! Keep up the good work, AgentJayZ! In aerolab days back in school, some of us were either snoring or having terrific migraine headaches at this. Your videos are both cool and awesome. :)

[@TheTruckslover]

No better Sunday morning than learning about power turbines while drinking coffee, thanks for the videos good sir.

[@Joemama555]

what are the tubes on the upstream side of the elm 116/2 for?

[@fletcherreder6091]

Stator cooling. 27:38

[@SquillyMon]

I'm still marveling at the duration of time that the shaft on the first power turbine rotated. Unbelievably smooth and totally amazing !

[@greghelms4458]

Yet again proven why I watch these. Awesome.

[@Colaholiker]

I wonder what the external piping on the Alst(h)om power turbine is. It kind of reminds me of the gaseous fuel distribution pipework on an LM1500 or similar, but with this being a power turbine that has no combustion going on in it, there is obviously no need for such. For an oil/lubrication system, it looks a bit too much to me, so what is it? Extra cooling?

[@JAMESWUERTELE]

That’s what I’m thinking also. We have LMS100’s and those just have the active blade control on the turbine but nothing on the PT casing.

[@AlessandroGenTLe]

A question: why there is the need of a separate power turbine and the power is not taken directly from the gas generator shaft? Is it because of efficiency? Is it to separate the torque user from the torque producer (but that could be done with a clutch)?

[@AgentJayZ]

Some very large designs for electrical generation do that, but not the engines we deal with, because: 1)- Aeroderivative engine designs are derived from aircraft jet engine designs. It is relatively simple to convert a jet engine to a gas generator for use with a power turbine... you just take off the jet nozzle. Explained in this video. To make a single shaft engine with all exhaust energy converted to mechanical output would require a complete redesign of the turbine section, and this is the most expensive part of the entire design process.' 2) - After creating this new design, you would need to use a reduction gearbox on the output shaft, because engines in the 10 to 100MW class need to turn faster than 3600 rpm, which is the speed to make 60HzAC current. A reduction gearbox for a 25MW engine is very expensive, and is another source of loss, reducing efficiency. So: more expensive to design and build, saves on a power turbine, but needs a reduction gearbox, (which needs more maintenance than a PT), and the whole arrangement is less efficient.

[@AlessandroGenTLe]

@@AgentJayZ thanks a lot mate! Salutes from Milan, Italy

[@Justice-Seeker]

Very interesting stuff. Honestly had no idea it worked like this, thanks for the explanation. This made me wonder, why two independent drive shafts? One reasonable explanation I found was "The advantage of the two-shaft gas turbine is that compressor and high-pressure turbine are driven at optimal speed for the respective power." In case anyone else wondered.

[@fascistpedant758]

Awesome video! Thanks. Would the rated pressure ratio be measured after the compressor or between the GG and the power turbine?

[@AgentJayZ]

After the compressor would be called CDP, and not what we are discussing here.

[@jangisgand6140]

I have a question and I have looked around to see if you have already answered it, but I didn’t find anything. Do you know what causes the sound that is sometimes referred to as ‘burping’ or ‘honking range’ right after the fuel is ignited? A good example of this is the J65 in the A-4.

[@tommy13t]

Very interesting to learn about the bearings in the generators. Love these videos .

[@vm1887]

Thank you for the video. Please what is the function of the manifold pipe at the alston turbine?

[@lloydevans2900]

On that power turbine with the ball bearing (the ELM-11/16), what is that arrangement which looks a lot like a fuel injection manifold? I can only assume it's for lubrication since the power turbines with journal bearings don't have it. But it does look like an excessively complicated manifold just for lubricating a few bearings, so is it for something else, and if so what?

[@AgentJayZ]

I am not sure, but I will see what I can find out.

[@oisiaa]

haha, it's definitely a face-plam moment when someone says that a jet engine at full AB has 0 power or that an aircraft at 1000km/h has more power than one at 200km/h while at the same fuel flow.

[@SheepInACart]

I don't disagree that the no speed = no power logic is erroneous, and the fact that aircraft rapidly accelerate from stationary during take off should prove as much, but I feel you've swung to far the other way. There is a change in engine power output with input speed, pressures and temperature, and while variable intake ramps/output nozzles on some designs can help aircraft partly mitigate that, I'd be very surprised if any fast design like concord or a fighter jet makes equal stationary power (or the same efficiency, thus power per fuel flow) as it will at higher subsonic speeds. Likewise even if based on the same engine core, a stationary power plant for a ship or gas pipeline isn't really expecting to have its intake moving at hundreds of kilometers per hour, and will likely see deviation from its design specification should this be the case.

[@AgentJayZ]

Hamish... blah. The original contention was that if the engine is not moving, then no power is being generated. Busted. Out of the park.

[@fascistpedant758]

@@SheepInACart Actually, no matter how much force the engine exerts on the plane, if the plane remains stationary no energy (thus no power) is imparted to the plane. Though a lot of energy may be imparted to the surrounding air.

[@ASJC27]

That debate is a result of unfortunate imprecise terminology. Of course a stationary jet engine produces power. Power is more or less entirely dependent on the rate of fuel burn. However, propulsive efficiency and therefore propulsive power are 0 in a stationary engine, because all of the energy is contained within the jet stream and none in the airframe. The faster the aircraft is moving, more of the energy is captured in the motion of the aircraft and less is "left behind" but the total is the same. Remember that the exhaust jet speed is relative to the engine. Say we have an engine with a 1000 m/s exhaust jet. If that aircraft is moving at say 500 m/s, the exhaust is still 1000 m/s relative to the aircraft, but only 500 m/s relative to a stationary observer on the ground. So a big chunk of the kinetic energy remains within the aircraft (~67%), but some is wasted in the remaining exhaust speed. An extreme hypothetical example: say the same aircraft is flying at 1000 m/s. In this case the aircraft's speed is the same as the exhaust speed relative to it. A stationary observer however would see a completely still jet exhaust relative to himself, so in this case all of the kinetic energy is captured by the aircraft. In other words, propulsive efficiency is 100% and all of the engine's power is propulsive power. But the total power is the same in both examples. The takeaway is that terminology maters. It is important to say whether we're talking about engine power or about propulsive power.

[@AgentJayZ]

Again... You are using the term propulsive power as if it only applies to the aircraft. It also applies to the air being thrown backward. Bing Bang Boom.

[@battleshipnewjerseysailor4738]

On the power turbine with the ring manifolds, I assume they are for cooling air, care to confirm that Agent J ZULU?

[@AgentJayZ]

Your assumptions are approved for service.

[@battleshipnewjerseysailor4738]

@@AgentJayZ Thank you sir, I love putting my engineering skills to use

[@bentboybbz]

So the stators direct air in a uniform fashion into the turbine that spins thus producing output basically ? Or have i just not grasped the idea ?

[@kjdude8765]

Correct. The stators smooth and guide the exit air of the gas generator to maximize the portion of the energy that is extracted with the turbine blades.

[@bentboybbz]

@@kjdude8765 Thanks. Ive been pondering whether or not im slow or if that was partially correct. For like 4 days lol. 👍☺✌

[@kjdude8765]

Watch this video for more info. kzbin.info/www/bejne/fWjSf3hrrraphK8

[@CDhn455]

What is the extraction efficiency is for a free power turbine? I'm thinking along the lines of a car where there is a 20% power loss between the engine and wheels. I would guess that the power turbines have higher extraction efficiency, but I could be wrong.

[@AgentJayZ]

Depends on a lot of things. Too many things for a comment box. Gotta go!

[@fascistpedant758]

For what it's worth, turbocharger turbines are typically 80-90% efficient.

[@Mishkx]

one of the power turbines in the vid. had some lines around it, witch look like the fuel manifold lines on the jet engine, what are they for? water cooling for turbine guide vanes?

[@AgentJayZ]

Cooling air for the stators.

[@Stummel01]

Were does this air come from? Gas generator or special pump/compressor?

[@AgentJayZ]

Compressor bleed.

[@williamphillips3550]

First time I've seen a video posted 8 seconds ago...

[@vinayakhuracan5182]

You rolled it gently buy it keep on rolling for few seconds with such a giant turbine that made me realize how precisely they are mounted 😱incredible engineering 👨‍🔧

[@bobqzzi]

You do an excellent job of explaining things. Very well done.

[@ianaristotlethompson4186]

Another great video. It seems there are no lengths you will not go to for our benefit. Top man.

[@ElectraFlarefire]

Really good summery and overview.. With some fun rants in the middle. :)

[@WarblesOnALot]

G'day there, Agent Juliet Zebra, ("Zulu" became "Zebra" not long after WW-2..., at the same time when "Able" became "Alpha" & "Baker" became ""Bravo", and "George" became "Golf", and "Uncle" became "Uniform", and "June" became "Juliet", and "Freddy" became "Foxtrot"...; they didn't change quite everything in the "Radio-Telephone Phonetic Alphabet", but most of the British-isms became AmeriKan-isms. For some "reason"). Ah, ahem..., what you're calling a "Power Turbine" is, technically squeaking, a High-Temperature, DUCTED RAM-AIR TURBINE... (!). "Turbine" being a fancypants word which means "WINDMILL" It's otherwise described as a "ROTATING AEROFOIL ARRAY"... Which are mounted on a Shaft, and when subjected to a moving Gasflow (Windspeed..., Combustion-Products, Chemical Decomposition Products or Steam....), the carefully arrayed Aerofoils duly spin the Shaft on which they're mounted, thus extracting anything UP TO 59.3% of the Total Kinetic Energy (Thermal Plus Massflow/Velocity) which was contained within the moving Gasflow entering the Array (see Betz' Law Of Wind, to unpack that...). If one lived on Planet Fantasyland, whereinat a Turbine was able to extract ALL of the Energy from the Gasflow going into the Turbine..., then NO AIR could ever emerge from the Turbine's Eflux Orofice - because it wouldn't have sufficient Energy in it to move beyond the Trailing-Edges of the (mythically "100% Efficient") Turbine Blades...! I have no idea why some people claim to have trouble underconstumbling that the Turbine Stages of a Jet Engine are nothing but Fire-eating Windmills in a Duct, the output Shaft of which runs the "upstream" Air-Compressor Stages (Succesive "Multi-Bladed Fan-Type Propellers) stacked between Stator-Arrays inside a constrictive Annular Duct...) all blowing the Compressed-Air which they collectively produce - into a Ring of Tubular Fireboxes arranged to fart their Fiery Exhaust Gases onto the aforementioned Ducted Windmills, all stacked betwixt their own sets of Stator Vanes.... Totally simple to comprehend..., but they're a seriously tricky thing to design and fabricate, manufacture & then debug - to the point where they become actually sufficiently reliable as to be safe to sell - for other people to be allowed to operate. I'm glad that YOU know enough to work on the bloody things, because they're several steps above by abilities to twist Spanners. Such is Life, Have a good one... Stay safe. ;-p Ciao !

[@grahamj9101]

Zulu is used in the NATO and ICAO phonetic alphabets with which I am familiar. And a free power turbine is just another turbine. As I've just explained to another subscriber, the latest big aero-derivative industrial machines typically use the aerodynamics (if not the actual blading) of the LP turbine of the parent aero engine. Instead of driving a fan, the turbine is driving a generator. In some, the pressure rise of the fan is lost: in others it is replaced with extra stages on the LP compressor.

[@tpcoachfix]

Do these have thier own lubrication systems?

[@AgentJayZ]

sometimes shared with the engine, sometimes independent.

[@grahamj9101]

If both the gas generator and power turbine have rolling element bearings, then both will almost certainly use the same synthetic turbine oil (eg, ETO 2380). However, a power turbine with rolling element bearings might have a separate lub system (or a supplementary supply arrangement). It may have to continue turning when the gas generator is shut down, if, for instance, it is connected to an electrical generator that takes tens of minutes to run down, because of its large rotational mass. A power turbine with plain bearings will need a completely separate lub system, because it will require an altogether more viscous oil. However, it may well share this with the electrical generator it is driving.

[@MrMrMeile]

A question, if you run up an Gasgenerator whit out an Power turbine attached, up to its max RPM, does it consume the same amount of fuel as when a Power turbine is attached? Or how does the Gasgenerator reacts to a load change at the Power Turbine? Is there a feedback from PT to GG? whiteout And if an device produces only hot air it is in first line a heater, not an Engine. Engines extract a second type of Energie from the burning of the fuel, if only heats comes out it an furnace... And we dont speak from power output of an furnace instead its heat output. Best Regards have no pressure

[@MrMrMeile]

If you run an Gasgenerator whit out an accelerating nozzle or an Power turbine. its only power output are somewhat hot exhaust gasses

[@AgentJayZ]

A gas generator without a jet nozzle or a PT is working without a load, so it will reach its rpm limit while burning quite a bit less fuel than if it was loaded. Very similar to revving a car engine in neutral.

[@Bigfoot_With_Internet_Access]

I can relate to that turbine, we bigfoots are misunderstood too

[@jhgrc]

What are the pipes in "hornet engine" power turbine. Looks like afterburner manifold but are they cooling air or cooling oil/liquid tubes or what?

[@imagiro1]

Look at around 27:22 - there is the diagram. You can read "stator cooling air".

[@jhgrc]

@@imagiro1 Thanks, I went forward on video as I stopped when AJZ went for gas turbines. I see at 27:22 he did not stop at the diagram and explain the cooling. Is it compressor bleed air cooling or some external air cooling circuit?

[@gafrers]

Awesome. So well explained.

[@tombmaster972]

what enery converion efficiency does power turbine like these in your video usually have? and is the increase in turbine diameter for more output torque?

[@gordondenzler8721]

Thanks for that some of us have always wondered how everthing works your hard work made this interesting and informative

[@C-M-E]

Semi-related question that, in my somewhat limited reading on the subject, I have not yet come across a direct answer; other than cramming a ton of volume into a smaller area, is there a particular reason the turbine blades of a power turbine or even the general exhaust turbine blades aren't larger to contact as much of the power stream as possible?

[@grahamj9101]

By "larger," I assume you mean longer, ie, longer blades (and vanes). The design principle of most turbines in gas turbine engines is that the axial velocity of the gas through the turbine is kept approximately constant. The acceleration of the gas takes place in the circumferential direction. In simple terms, the blades (and vanes) are designed to be as long as they need to be to accord with this design principle. If, however, you mean wider, in terms of chord, then the blades are made no wider than they need to be to function aerodynamically. Make them any wider than necessary, then the turbine would become longer and heavier, which is hardly desirable in something powering an aircraft. Having said that, "heavyweight" industrial gas turbines do tend to have wider chord, lower aspect ratio blades (and vanes), not for aerodynamic reasons, but for robustness and longer life.

[@C-M-E]

@@grahamj9101 Ah, that makes more sense. I didn't take into consideration the centrifugal forces. Initially what I was thinking was why they weren't longer to grab more of the air stream but presumed it was to funnel the gases onto the impulse face, i.e. concentrating the largest force on the smallest area. I did factor in rotational weight in design principle. Thank you for the clarification!

[@scottmarshall6766]

66,000 foot pounds. Mind Boggling. HP = Torque x RPM/5252. 30000 = 66000 (RPM/5252) So at 30,000 Hp the turbine rotor will be going 2387 RPM. Slower than I would have imagined. I was thinking the turbines ran at higher RPM with lower (relative) torque, but the opposite seems to be true. Unless I totally misunderstood one of the numbers. Just playing with the numbers trying to get a feel for it. BIG power. Thanks Agent Jay Zulu, interesting stuff.

[@AgentJayZ]

Sounds about right for the turbofan. For electrical generation, it should go at 3000 or 3600. But then 30K is a bit light on the power. Our older models put out 34,800, and the newer ones are over 40.

[@charlottejet4338]

Bang on.

[@LongStep]

Questions: Can you please talk about small gas turbine engines? Small, mini, micro and efficiencies/ inefficiencies. I have had a hard time finding small axial flow turbines and information about them. (examples like: FJ44, Williams F107 or F112) Is there an accessible small engine out there? I appreciated your T-58 rebuilding video series. Is that the best engine available in the

[@AgentJayZ]

T58 is not a thrust engine. Smallest engine I have any knowledge of is the Garrett GTC85 in our start cart. I've never heard of a Williams falling into hobbyist or collector hands. The smaller they Get, the less efficient they are.

[@LongStep]

@@AgentJayZ thank you for the quick reply

[@grahamj9101]

Let's be clear about this: there's absolutely nothing new about sticking another turbine behind a turbojet. GE did it to the J79, back in the 1950s - but it was still an aircraft engine. The CJ805-23 had an aft fan, with the fan blades carried on the tips of the turbine blades. R-R also built and tested an aft fan version of the Avon, but the project was abandoned. However, Frank Whittle did it years before at the end of WWII, when he put an aft fan behind his W.2/700 engine, together with a reheat system, which he called his No.4 Augmentor. The engine, which was intended to power the Miles M.52 supersonic research aircraft, was ground run, before the whole project was cancelled by the government.

[@AgentJayZ]

The CJ805-23 turned out to be such a success, that GE went all in and designed the TF39, and then the CF6, influenced by what was learned. Two things stand out: greater bypass ratio was better for thrust and fuel economy, and having the fan in front has the effect of supercharging the core. The elegant Spey had the fan in the right place, but could have used greater bypass ration. I think you were in the right place at the right time to see a lot of this evolution taking place.

[@grahamj9101]

@@AgentJayZ The Spey was turned into the Tay in the mid-1980s, which powered the Gulfstream IV. The engine had a single-stage fan with three booster stages. If you have a copy of 'The Jet Engine' (fifth edition), you will find a pretty picture of it on pages 72/73. Unfortunately, the decision to launch the Tay came rather late in the day. R-R Derby should have come up with higher bypass versions of both the Spey and Conway, long before they put all their eggs in the one basket of the RB211 (and Derby very nearly broke the whole basketful). If you look in the book at page 195, you will see a diagram of a flap blowing engine. This was a Spey-based project that we were playing with in design, not long after I moved to Bristol. As I recall, we were going to use the variable-pitch fan technology that had been tested and developed in the M45 SD-02. This was a 9:1 plus bypass ratio engine project that was tested at R-R Bristol in the mid/late-1970s. The big failure, as far as I was concerned, was not proceeding with the RB401 project at Bristol, because of lack of funding. This was a lovely little high bypass turbofan, intended to enter the small bizjet engine market, as a replacement for the Viper. I remember the project director saying, "There are three ways that we can finance this engine .....". I cut in before he could complete his sentence with, "Yeah, beg, borrow or steal!"

[@barjan82]

The most powerful turboprop currently (however it's a single shaft design) is the Kuznetsov NK-12 with some massive 15k HP output 😎 Second in the row is the multi shaft design Europrop TP400-D6 with 11k HP 😁

[@marlibread]

All.i took away from this.."they've got to work on their marketing"...🤣😂🤣😂😂🤣😂🤣. Thanks for the knowledge. This was excellent.

[@samehbrais9354]

Why do only Gas engines have stator vanes ahead of the rotor blades unlike the turbojet enigines? as far as i have researched they are pretty much the same thing but serve different purposes. And some sources proivde that even turbojets could have stator vanes ahead of the rotor blades.

[@AgentJayZ]

You mean inlet guide vanes instead of stators. Stator vanes are always downstream of the rotor blades in a particular stage of compression. You mean turbofans instead of turbojets. I don't know of any turbofans that have inlet guide vanes ahead of the fan. I think that makes the engine easier to start if the fan is less efficient at very low rpms. Turbofans are not used in industrial applications, unless the design is modified so that they are not turbofans anymore.

[@grahamj9101]

@@AgentJayZ Many (but by no means all) low bypass turbofans have vanes ahead of a multi-stage fan. Some may just be multiple struts supporting the front bearing housing, but others are most definitely inlet guide vanes (eg, Conway and Spey). I'm not that familiar with the F404, but doesn't that have a VIGV 'flap' arrangement in front of the fan? In contrast, the EJ200 doesn't have any vanes in front of the fan - nor does the Pegasus, the Adour and the TF41 (hence the Industrial/Marine Spey with no IGVs in front of the LP compressor). I'm not aware of any high bypass turbofans with single-stage fans that have vanes in front of the fan. The TF39's fan is a curiosity - but I've seen that described as a 'one-and-a-half stage' fan.

[@AgentJayZ]

Yes, I made the assumption that the question was about high bypass airliner engines.

[@lansilver9217]

Is it to stabilize or direct the unstable ( possibly) gases into the gas engine for max input .....?? I.e. effecient, directed air flow inwards = max efficiency on output power....

[@mosipd]

Wouldn't the fact that it takes significant amount of _power_ to just turn the compressor mean that the engine is obviously producing power when stationary?

[@jaemyungkim5226]

i am punked. totally enjoyed it. thanks. JZulu~

[@stephc4427]

Excellent! Superb! Thank you!

[@CDhn455]

This was an awesome video, but sorry, I have another question. At the beginning and very end of the video, what are the two rings of nozzles on the power turbine on the right? They look like the fuel rings for an afterburner. Is it air or liquid cooling of some sort?

[@MegaFPVFlyer]

I'm wondering the same thing. If I had to hazard a guess I'd say water injection based on the look of the plumbing, but that would be kinda odd since the power turbine would already run significantly cooler than the gas generator turbine without any auxiliary cooling

[@kjdude8765]

It's cooling air for the stators.

[@Bluenoser613]

This is a very useful video.

[@customxcycles8090]

Can you explain the concept of bypass air and how it affects thrust? Love the videos man.

[@AgentJayZ]

If you're starting from scratch, then a comment box won't do. Any of the books I recommend in my video called "Books!" will explain the benefits of the turbofan over the turbojet, and bypass ratio is a big part of that. Alternately, reading a few pages that turn up from a search for "turbofan" will also be interesting reads.

[@SuperAWaC]

Those all look pretty rusty, could they be brought back up to working condition, or are they parts donors?

[@eastcoastandy2905]

Alright Agent J Zulu, time to tell folks to look up the international phonetic alphabet. You're so good at helping people understand!

[@bayestraat]

Is there such thing as an engine where its compressor blades that rotates with the compression wall - zero tip clearance?

[@AgentJayZ]

The compressor rotor needs to have rotational speed relative to the stators, so there needs to be a place somewhere with one part moving and one not. The clearance needs to be as small as possible at that interface, but the parts have to move.

[@xcalibertrekker6693]

Thanks for the info. Also Agent Jay Zed sounds more cool. ;-)

[@h7qvi]

Hate seeing stuff rusting. Should build a cheap wooden enclosure over those engines that can easily be towed away, or else a few tarps.

[@AgentJayZ]

A cheap wooden structure of an acre in area ( at least), that can handle our snow loads in winter? Such a thing does not exist. And, as anybody who's tried to use one knows, tarps are great at keeping moisture in, maximizing corrosion.

[@raygun23]

Does the 1994 pt have ball bearings because it runs less often? Or because the oil system is better?

[@AgentJayZ]

Its a choice the designers make. Ball bearings last for years, and journal bearings can last longer in continuous service. I do not know the history of this unit.

[@johncasor9698]

yes you have beaten that one to death already... Haha... Another Great Teaching Video... And thanks a bunch...

[@zapfanzapfan]

Sunday sermon in the Church of Turbine :-)

[@ProDjMx]

Such great videos! Thx for sharing your knowledge.

[@charlottejet4338]

I thoroughly enjoyed this video. Power turbines are my thing. I have experienced that 'vacant expression' when explaining to the less well educated what they are.

[@AgentJayZ]

With that name, I bet you have the coolest business card. Send one to Jet City!

[@joespratt413]

Why does the 94’ pt have what appears to be a fuel manifold attached to it?

[@imagiro1]

Agent JayZulu shows a diagram around 27:22. According to that diagram it's a "stator cooling air" manifold.

[@leodikinis7390]

@@imagiro1 a lot of plumbing for cooling air... don't think there would be any fluids being injected.

[@shoutout.kokain8713]

Hello Agent Jay Zulu, i might have missed it, but have you ever introduced your cute puppy on your youtube? he's awesome! thanks

[@TeemarkConvair]

great in depth soliloquy [because the air-head no power people won't be able to comprehend],awesome. you always manage to enlighten even an olde pharte such as myself. couple of curiosities: at 10:00 in the background appears a partial engine in a frame at about 45 degree angle.. whats that? and at 21:45 whats the last engine in that lineup? and, why keep all those "junk" pieces of material if they are just "rusting away". thanks mr Zed lol

[@AgentJayZ]

That's an afterburner assembly for a Spey, next to ABs for an F404 and a couple J79s. In the other yard, the far engine is J65 out of an A4 Skyhawk. A lot of the parts are stainless steel or titanium alloy. We have too much of this sort of surplus to store it all indoors, but we don't really want to scrap it completely.

[@starlite528]

@@AgentJayZ so you're hoarding?

[@maazsiddiqui6324]

Question. What does stators do especially those who are variable?

[@AgentJayZ]

Stators take the velocity that has been gained by the air due to the action of the rotating compressor blades, and convert it to pressure. The Variable stators help manage the angle of attack of the compressor blades to avoid stalling the compressor. You may want to watch my video called Compressor Stall, and it's follow up video.

[@maazsiddiqui6324]

@@AgentJayZ thankyou sir

[@jurepecar9092]

With the recent Airbus announcement, can you do a video discussing different fuels for turbines? Kerosene vs propane vs hydrogen ... how must a jet engine be adapted to run on any of them? Thanks.

[@AgentJayZ]

Only the fuel control and delivery system needs to be changed between liquid or gaseous fuel use. For the basic fuel burning core of the engine, nothing needs to be changed. Heat is heat, man, and bring it on!

[@jurepecar9092]

@@AgentJayZ So, say you have a hydrogen powered gas generator. Is it then a steam generator? Does the power turbine need to be the size of steam turbine? I wonder how does this affect turboprop concept.

[@AgentJayZ]

No, it is not a steam generator. Water vapor in heated exhaust resulting from combustion of hydrogen in air is not steam. We can't back up any further; you'll need to do some learning on your own. Besides, I thought your question was about different fuels...

[@grahamj9101]

Having been involved in fuel system and combustion design, I can support AgentJayZ's reply in respect of the fuel control and delivery arrangements, which includes the burners. For the same energy content and release, the volumetric flow of a gaseous fuel must be considerably greater than that of a liquid fuel. However, the combustion chamber itself rarely needs any changes . Take a look at some of AgentJayZ's videos and compare the relative diameters of the manifolds and burner 'pigtails' for gaseous and liquid fuels. Similarly, the internal passages and outlet orifices of gas burners have to be enlarged, relative to the equivalent liquid fuel burners. Now think about how difficult it can be to design a dual fuel burner, which has to have internal passages to carry the full flow of either fuel. Been there, done that.

[@grahamj9101]

​@@jurepecar9092 There is obviously a substantial proportion of water vapour in the combustion products of any hydrocarbon fuel. When hydrogen is burnt, the combustion products are, equally obviously, water vapour.

[@johncasor9698]

The improved, 3rd generation, LM2500+ version of the turbine delivers 40,500 shp ...

[@MrLunithy]

I've worked on and around a few Power turbine "Agfa Sea?" with about the same thrust as 747 engine 8 mega Watt generator and older Kongsberg Gas Turbines that were fun to start ... big bangs .... fire balls into the sky lol.

[@iahsleumas8419]

you are awesome my friend

[@ThomasHaberkorn]

Love those rants

[@khaledyousfi7160]

I'm sorry I I'm out the subject, but please, coukd you give us a brief explanation to how we can find out a breakdown.

[@AgentJayZ]

1 what do you mean by breakdown? 2 there are no brief explanations. 3 ...

[@khaledyousfi7160]

@@AgentJayZ I mean a panne

[@AgentJayZ]

Well, I have no idea what that is. Strike two...

[@MarkLoves2Fly]

Super cool!

[@aaraspensor]

Exhaust gases from that power gas turbine can even easily be used to boil the water for steam turbine.

[@AgentJayZ]

That is often designed into the installation.

[@Xerkus]

@@AgentJayZ Got it. Steampunk was real all along. The only missing link was gas turbines

[@Yaivenov]

Turn a couple GE-9x into turboprops and build a C-130 as a tilt rotor. =3

[@wickedcabinboy]

J Zulu, some people will not be educated despite your best efforts. Know that there some of us who have learned much about turbines and their various configuration and applications from your channel. I was completely clueless about even the basic concept of these engines before I discovered your channel. While I would be a fool to pretend that I have anything more than a basic understanding of these wonders of human engineering it baffles me how anyone can imagine such enormous machines burning huge quantities of fuel and turning at many thousands of RPMs don't produce power. It seems they are misunderstanding the definition of the word. This may stem from willful or unintended ignorance. The second of those two you can correct. The first, not so much. Thanks once again for your amazing videos. By the way, have you begun your flight training?

[@matte2160]

Beautiful Pink Floyd call back.

[@MichaelHeinrich1]

Look at that you Honda Civic guys.. 🤣🤣

[@gordonlawrence1448]

It's surprising how small they are for how much power they push out. I was taking a look at some helicopter power plants and they are miniscule compared to for example a deltic engine of the same power. As for the "mechanical argument" get them to look at quantum mechanics. That deals with things that make a single atom look absolutely enormous never mind a molecule. IE the smallest as yet detected particles compared to an atom are almost the same ratio size wise as a human compared to the entire universe. IE the Planck Length is roughly 1.6E-35 meters. An atom is huge by comparison. IE Hydrogen atoms at room temp are about a ten million billion billion times bigger.

[@michelgosselin956]

nicely explained now I know how steam plant run with exaust gas turning a shaft

[@deezynar]

There is an axial flow jet engine that produces a high velocity blast of gas which is ducted to a two stage, turbine motor, that converts the energy of the flowing gas into torque.

[@gersongomes9925]

ative a legenda com tradução.

[@greghelms4458]

Prize idea. A drawing to win a weeks volunteer work with you in the shop. Coupled with being a guest star in one of your videos. How about it? Lol

[@princebatswater]

20000hp at 7350rpm equals about 14000lbFt ??

[@SupremeRuleroftheWorld]

13:00 its 90.000 newtons/sane numbers.

[@gcmsinc]

Good Stuff. What would the average power efficiency of a power turbine be? Useful Gas Producer power vs wasted GP power.

[@AgentJayZ]

Graham is a better person to ask about this, but I think I've heard 85% to 90% efficiency for industrial power turbines used with aeroderivative gas turbine engines.

[@grahamj9101]

AgentJayZulu (I must get used to the new handle!) is in the right ball park, in terms of what is termed the polytropic efficiency of a turbine.. A free power turbine is essentially no different in efficiency relative to the LP turbine of, say, a big turbofan engine. In fact, the latest big aero-derivative industrial and marine engines often use the aerodynamic design (if not the actual blading) of the LP turbine of the parent turbofan. Considering the RT45 power turbine that we haver been shown here, I've found an ASME paper describing its development, back in the late 1970s. With its Industrial Spey gas generator, a thermal efficiency of around 34percent at max power was quoted.

[@gcmsinc]

@@grahamj9101 85% to 90% is much better than I would have thought and assuming that's running in the normal operating range of 90 - 100% of it's rated power output. So much more efficient than a reciprocating engine.

[@zapfanzapfan]

Combined cycle which then uses the waste heat for district heating gets up to 90-ish % thermal efficiency. The best I have seen for a pure gas turbine without using leftover heat for something else was 46% but that was a few years ago, maybe it has improved since. That one was in the 100MW range.

[@ASJC27]

@@gcmsinc That's just the power turbine's efficiency, not the overall cycle efficiency. The gas generator will have its own thermal efficiency and the total efficiency is the product of the GG's thermal efficiency and the PT's isentropic efficiency. The most modern engines cores can achieve a thermal efficiency in the low 50%. A modern power turbine will have about 90% efficiency, so overall efficiency (the product of the two) is about 50%, or just shy of it. That's similar to large reciprocating diesels. With exhaust heat recuperation, higher numbers can be reached. For example, the most efficient combined cycle electric power generators achieve 65% overall efficiency.

[@GeofreySanders]

Any point to a multi-spool power turbine? Seems like 'no' but I can't quite noodle it out.

[@AgentJayZ]

Any theoretical benefit in having the later stages turn at lower rpm would be offset by the fact that now you have more than one mechanical output shaft, and they each turn at different rpm...