Not a question... just a massive thank you for what you do. I'm just a regular guy with a passing interest, and wanted to know how a jet engine works. I've now watched loads of your videos and I find them absolutely fascinating. Even though I'm a novice, I think that you explain the very technical terms as clearly, concisely and as understandable as possible. Thank you sir!
@randomtux12346 жыл бұрын
Hes the master
@williamchamberlain22636 жыл бұрын
John Clarkson right on
@C-M-E5 жыл бұрын
You know what's interesting, while some of us have a higher level of engineering experience or just mechanical knowledge and what he says lines up with established knowledge, if you didn't know any of that base material you'd just have to take his word that he knows/knew what he's talking about and not showboating as a guy who pushes a broom around a jet engine shop. =D
@thomasdiaz78596 жыл бұрын
This is the best explanation anywhere. Thanks! I teach at FSI and I have guided many low time pilots to this video.
@chrisconley35799 жыл бұрын
Ive always had the understanding that "bleed air" had 3 types (as you said). Starting purge, running balance/cooling (the air sent to the center bearing is also needed for air flow stability along with cooling), and service air (used for running services outside the engine.
@donberg017 жыл бұрын
Bleed air valves are for air start purposes. Bleed air from the 13 stage or whatever the manufacturer deems is for deciding and air conditioning packs. On the Lockheed C 130 I worked on, you start #1 engine then open bleed air valve so the manifold is filled with bleed air to start #2,3,4 engines. Great video! (You must start the APU to utilize it's bleed air to start #1!)
@smudent2010 Жыл бұрын
We call that a crossbleed start, airlines do it a lot on start to save the starters and apu
@ShannonSmith4u27 жыл бұрын
this guy and his videos are awesome. the bleed valves are like a compression release in older, bigger motorcycle engines that you couldn't kick over unless you released some combustion pressure
@sbeutler5 жыл бұрын
We used bleed air on our ships for a lot of various things. Masker air was used to make the ship sound like a rainstorm to submarines. Prairie air to come out of the leading edge of the prop to change the signature of the ship. Anti-icing air for our intakes when it gets below icing conditions. We could also do cross bleed starts to start other turbines.
@vasaricorridor7989 Жыл бұрын
veyly intalesting ...
@kamakaziozzie3038 Жыл бұрын
You Sir, are a super stud jet turbine bleed air expert. Thank you for a bit of your knowledge!
@tobyrabbit79488 жыл бұрын
Thank you so much for doing these videos and answering questions. I am learning so many things about jet engines that have been on my mind for a number of years. I Have always been interested in this subject but being a big dummy do not know the correct question to ask or things get real complicated real fast and other commentators seem to be all over the place. You have a wonderful, natural gift. Teaching seems to be in your genes. It is also very obvious how much joy you feel when the word turbine is mentioned. You absolutely love your job.
@ToothyGus6 жыл бұрын
In my previous experience bleed valves were called "blow off valves" in industrial centrifugal compressors. Those would be open until the compressor reached operating rpm and would slowly close after the VIGV reached maximum opening perecentage. Then the VIGV would close slowly and modulate as per requirement. That was done to prevent the compressor to go from idle to load all of a sudden which can cause surging.
@goom10018 жыл бұрын
thank you for the information regarding the bleed air. I'm working as a process control tech, one day we had a problem in one of the power generators. They were GE gas turbines with GE redundant control system mark VI. Operations couldn't start the generator because of a problem in the bleeding valves, there were only two bleed valves. After tracing back inside the turbine compartment, we have noticed that the bleed valve actuators are operated by the turbine's compressor output and this compressed air was controlled by a solenoid valve located in the accessory compartment where you will find the lube oil system ad the started motor with. After testing the solenoid alone by forced signal through the control system, we have found it functional and healthy. We asked the operation to try the generator for another start " cool down between every start was set at 30 minutes". Again another failure in the bleed valves. At the end we had managed to test the valves actuators alone together at the same time by using an external source of air supply and found a big deviation in time, about a 22 seconds difference. It was confirmed that this wasn't normal, and the main issue was in the second valve actuator leakage. It has been replaced and the deviation was set to be less than 3 seconds after the second startup of the gas turbine. The limit switches on every valve actuator was the main reference to us, because it was unsafe to start the turbine while the doors of the compartment were open. My questions: Are aircraft engines equipped with the same setup? Is this a real issue in aircraft engines? Are the bleed valves in the aircraft engines designed to also be used as a surge protection when startup? sorry for the long story, thank you again for your explanation.
@AgentJayZ8 жыл бұрын
It's hard to make a comment since I don't know which engine you are talking about. Not all industrial gas turbine engines have an aviation equivalent.
@foxtrot78910 жыл бұрын
I could listen to you all day long...
@yousircancallmejoker10 жыл бұрын
My school uses your videos all the time! Your going to be the reason I pass my powerplants classes haha
@AgentJayZ10 жыл бұрын
Thanks, dude, but always remember, I supply infotainment, which is only the starting point for your journey...
@dannytriplett86256 жыл бұрын
AgentJayZ I've been Netflix style binge watching your videos. My question is about the bleed air valves. Is the purpose of the valves to unload the compressor to allow for it to reach the target rpm unimpeded by compression resistance? Thanks
@Kiera_Jackson742 жыл бұрын
Funny you should know I grew up in rural Manitoba... my first jobs were all farm related. When I was a teen we flew Cessnas and Cubs like motorcycles and snowmobiles. Later working with the turbine crop dusters they always had trouble with bleed valves and shut downs. I've never flown an actual jet but the few times I flew those planes I was told if you can't land it you'll die and if you hurt it, the owner will kill you instead.
@vasaricorridor7989 Жыл бұрын
a cowboy from the wild west...yeehaaa
@chipfission4667 жыл бұрын
Thank you very much for explaining different types of bleed air and what they are for. also for addressing the load.
@64jorthom10 жыл бұрын
I want to thank you for this and all your videos, this is good infromation about the air bleed valves. When the engines starts, it makes easier to turn the engine and other reason is to cool down other componets of the engine. There is on point, the turbo prop entgine, this one doesn;'t use the power turbine. Thanks a lot. Please send some snow to here.
@johnhull63636 жыл бұрын
JORGE E Thomas they are there to prevent destructive compressor surge in axial flow compressors...they require minimum flow .....all other uses of bleed or recycling valves is sympathetic....
@rizendell10 жыл бұрын
On the R.R. Alison turbine engines Ive worked on, for helicopters, the bleed air port has 2 functions. When the engine is at 60% or idle, air blows out of it back into the atmosphere so that the compressor doesn't blow the flame out in the combustion chamber. at 100% the airflow reverses to help feed the compressor and keep the engine cool. It all happens with no moving parts, its just part of the design of the compressor fan (13:1) in this case.
@jumpmaster15k10 жыл бұрын
Great video. You opened up a can of worms with this subject. There are so many different uses for bleed/discharge air. You have everything you talked about plus more depending on the engine. There is labyrinth seal pressurization, engine anti-icing, aircraft inlet anti-icing, fuel system purge, emergency oil pressurization, balance piston seal pressurization and much more.
@AgentJayZ10 жыл бұрын
Oh, I know it... and thank you very much for even mentioning balance air... way to go, dude !!
@jumpmaster15k10 жыл бұрын
Thanks. I figured I'd stir the pot a little with some of these.
@jimmyb65412 жыл бұрын
Sir thank you so much for your good works I am learning alot
@pinkdispatcher10 жыл бұрын
Cool, I was about to ask what exactly it was. When he said that it was a single-spool turboshaft engine I figured it had to be a mechanical load. Neat idea to use what you already have and where you have a good idea about its power consumption. But sucking/blowing air through these sharp-edged variable holes is certainly going to make a huge noise. I was aware of all the different kinds of "bleed air", but never thought about the possible confusion. Another major use for "customer bleed air" is wing de-ice/anti-ice in most jet airliners.
@DScottDuncan10 жыл бұрын
Hi Jay, Thanks for the full explanation of 'bleed air'; it seem all kinds of systems like to suck air off of the compressor! Please note that I placed 'air' in between 'suck' and 'off'!! That homemade load machine is interesting & sounds like it would work to me, however most likely very noisy! I'll be watching for that video... Darren
@ishamkader26964 жыл бұрын
Thank you 😊 boss🤝👍..simple but yet easy to visualise and understand.
@code123ns10 жыл бұрын
I wish you lots of luck, since I would very much like to see that thing run :)
@billyost14796 жыл бұрын
Jay, several military helicopters use turbine engines that use a bleed air system you may not be aware of. These engines include the T53 (all models), L-712 (to include the L-11 or L-7-11and all following models). There are many more gas turbine engines that we use in the military that use the same bleed air system. However, none of these same type systems use the air... for ANYTHING. These engines produce an excess amount of compressed air by the time it reaches the centrifugal compressor. So, to control over compression in the outer combustion chamber there is a system of bleed air that is comprised of a large vacuum operated bleed valve that in turn opens a bleed band that surrounds the case halfs usually just after the second last axial compressor stage. The band is a stainless steel band that when tightened it prevents bleed air. Whan the actuator is in open position the band allows a specific amount of air to escape right to the atmosphere as directed by several other system.... such as the fuel control, the torque sensor and for some a few other sensors. This bleed air system was the real first coined 'bleed air' because it is what it is, just bleed air, not 'service air'. But service air didn't sound right so any system using the name calls it bleed air. A truly well engineered turbine engine shouldn't need that kind of bleed air system... but it does. For ninety percent of all other engines... that's wasted service air. PS: Also, these same engines use a separate bleed air system that actually is used for service air. Most are just used for 'anti-icing' around the intake cowling. This air is of the highest pressure as it comes from what we call the 'hot air gallery'... and yes, after being squashed as it does in a turbine engine... it really does get hot. This gallery sits right over the blades of the centrifugal compressor. The point at which the air is at it's hottest. As we techs know... hot is bad, even for intake air. The hotter the intake air is... the less expansion it is capable of during combustion.
@FerasAbuTaha10 жыл бұрын
Good Afternoon Jay!! You Grew A Beard Mate! Keep Up The Good Work Brother!!!
@PatrickLipsinic7 жыл бұрын
One part you may or may not have mentioned on here what bleed air is used for besides a/c, cabin pressurization. It's is also used for de-ice on the leading edges of the wings, vertical & horizontal stabs, windscreen and engine inlets. Also engine starting either from an APU or ground start cart like you use to start your engines at the test cell and to help pressurize hydraulic systems. I work on KC-135's and seen the different ways bleed air is used. There are great videos on KZfaq that go over the bleed air systems of many different aircraft types like from 737 to a 747.
@AgentJayZ7 жыл бұрын
Cool. All of these uses are indeed mentioned in this very video. "Customer bleed" is the term I use...
@beuttenmuller10 жыл бұрын
such nice clarification ! thanks from Brazil !
@brycerichert6 жыл бұрын
Nice... Wish I could change professions this late in the game.
@eventfulnonsense7 жыл бұрын
Man your videos are awesome! It's sad you hadn't reached yet the 100k subscription mark.
@CuteCat20020010 жыл бұрын
The Heisenberg of engines.
@AgentJayZ10 жыл бұрын
Ha! Thanks for the compliment ! ... but it could also mean that i am also uncertain about everything turbine related ...
@CuteCat20020010 жыл бұрын
I was leaning more towards the fact that you deserve a nobel prize
@WasimAkhtaraircraftengineer10 жыл бұрын
Runduh R You got my say on that case as well. i cant agree with you more . this guy needs appreciation for what he is doing
@messoudi7716 жыл бұрын
Thank you sir Greetings to you from Algeria
@MrAureli2248 жыл бұрын
thanks agent jay z for all your videos very cool to learn about jet engines
@bileltobbal14212 жыл бұрын
thank you so much for this amazing informations they help me a lot on my research
@latrogeniwile588 жыл бұрын
Another fabulous video! Thanks.
@glooozo10 жыл бұрын
Another great video, thanks!
@maxgdh76183 жыл бұрын
I am confused. My prof told us that bleed valves, or what he called them, bleed hatches are used to bleed off the excess air in order to avoid surge of the compressor. Though, maybe he was right partially, since the only showpieces we have in our uni are the vintage soviet engines, and their age vary from 40 to 60 years or even more, and the older the engine, the more unorthodox it's construction is.
@ritishgobin2 жыл бұрын
Thank you sir for the video
@roberts909510 ай бұрын
What I would like to know is the history of the use of compressor bleed for customer pneumatic power. What was the first engine to be designed with a system specifically to tap air off the compressor for airframe pneumatic power? What was the first aircraft, military or civil to use compressor bleed for pneumatic power? I'd also like to know what the first aircraft was to use an air cycle machine or pack for environmental control.
@lasignora100010 жыл бұрын
Jay, at 3:53 you talk about cooling the sump. Is there also a rotary pump that draws the air and oil out of the sump? Also, tell your developer to build a heat sink and install it around the ad on compressor. Have the working engine draw air through the heat sink. (naturally the heat sink needs to be configured right.) When the pressure drops around the heat sink, heat will be forced into the air. You will yield more psi and the process will be much more efficient.
@AgentJayZ10 жыл бұрын
The scavenge pumps on this engine are gear pumps, and they are designed to handle a mixture of oil and air. Most of the cooling air exits out of the sump vent, but some of it is in the form of bubbles in the oil drawn out by the scavenge pump. The scavenge pump has a greater capacity than the amount of oil being pumped in.
@AgentJayZ10 жыл бұрын
... and for the heat sink idea... I think I'll leave the design just the way it is, the way the hundreds of professional engineers working for years on this project intended it to be. No matter what anyone thinks about their "innovative" or "game changing" idea... they have to remember the ability and talent they are attempting to improve upon. I do, and so do all the rest of us. Cheers !
@1324HELMUT7 жыл бұрын
Thank You, I wish that when I was young I could have learned about the systems on a jet engine. Thank Geo
@Guysm1l3y10 жыл бұрын
Holy balls, that thing is going to be putting out a lot of air. I love it! I assume the goal is to get the company more involved with rebuilding and testing those -501 engines?
@AgentJayZ10 жыл бұрын
We share our test cell with Maddex Turbines, and they already do a lot of 501 work. This new setup will allow us to measure torque on the output shaft under full power. It is a specific request made by an important customer that uses these engines to produce electricity. And yes, we will have a 3,500 Hp air compressor on our hands...
@salehjawad10476 жыл бұрын
I relly learn too mutch from ur vids Thankyou
@SquillyMon7 жыл бұрын
I never thought about how the engineers would have had to make so many provisions for air...like the blanket of air that surrounds the flame to cool it... No wonder jet engines can handle such an enormous flame within!!! Prior...I just thought it could handle those temps magically...and i was correct to always question that in my mind... AWESOME!!! Not understanding something mechanical, and knowing that I don't, bothers me, seriously.
@Hitman230565 жыл бұрын
Thank you so much Sir
@CrawfordMethod10 жыл бұрын
I am wondering why a compressor section would be used for the load, as opposed to something already fully developed like a water brake. Although I guess this "air brake" load is self-cooling and can take the shaft rpm directly without reduction. Makes me chuckle a bit, visit a wood shop and all the jigs and fixtures are made of wood, in the metal fab shop the same bits are made of metal, I guess in the turbine shop everything is made of turbines!
@AgentJayZ10 жыл бұрын
The only things developed for loading the 501/T56 are reduction gearboxes and electrical generators ( which need to power something in order to be a load ), or the prop reduction gearbox and propeller. Both of those options are more complex and expensive than just adding another compressor, which is designed to turn at 13,800 rpm ( I incorrectly say 13,600 in the video). A water brake would require a reduction gearbox rated at 10,000hp, and a supply of water, plus we would have to buy the thing... We have lots of T56 compressors...
@michaelmartinez13456 жыл бұрын
This is very resourceful, how the available t-56 compressor could be used to load the massive power coming from the Allison 501 turboshaft engine... It eliminates the need for an expensive and complex gearbox. I wonder what the torque & horsepower ratings will be, coming through that shaft...
@FabricatorFactory6 жыл бұрын
Cool. Happy Canada day from Newfoundland. Should get a mike to reduce the residence. Great video.
@SQUADRONSIXTYNINE7 жыл бұрын
Thank you ! A very informative video!
@bucktir10 жыл бұрын
Of the three types of "Bleed Air" discussed; which is responsible for Engine Surge and how does clearing a surge (throttling back) prevent an engine from destroying itself?
@K1w1scot10 жыл бұрын
The bleed valves are the ones you mean. They help offload the diffuser at lo-rpms because the engine compressor is so efficient. With regards stall/surge conditions. once established, the bleed valves have no control over them (as far as I know...certainly not from the ones I've worked on, anyway). That is purely a function of offloading the engine, either thru decreasing the RPM on a variable speed engine or thru offloading engine pressure with a constant speeder such as the 501. However, sometimes this just isn't possible, especially if the engine has suffered a mechanical failure. In which case, it's time to reach for the yellow and black painted handles and hope for the best.
@YOLO-tq3el2 жыл бұрын
Amazing!
@ekkehardg.985110 жыл бұрын
Thx for this once again! 3500 HP compressor? Hook this up to your engine-lift-thing :-) (Maybe open the roof first...) I would like to wish you a powerfull pre-christmas time! Can't wait for the next vid!
@Jp-ek8sj7 жыл бұрын
I saw your video while I was searching for an explanation about active clearance control(ACC) but the video was about bleed valve and bleed air .it would be helpful if u could explain about ACC in modern tubofan engine such as ge90/genx.
@816banzaibob8 жыл бұрын
I know that you are somewhat sensitive about answering questions that have already been answered.....completely understandable. However I have been trying to find the answer to this question in your videos and I have not yet had any luck. So....I will ask: Is there a quantifiable limit as to how much bleed air an engine can divert away from the combusters without effecting the performance of the burning of the fuel? A large commercial jet obviously uses vast quantities of compressed air to run various systems....is there a practical limit as to how much can be used without effecting thrust characteristics? Thanks much!
@spenceronni78 жыл бұрын
Bleed air is bled from the compressor to be used for a lot of different purposes. If air was bled from the combustors, there would be a lot of extremely hot and high pressure air and burning fuel that would ruin various engine and airframe accessories and components. Hope that helps.
@MrShobar9 жыл бұрын
Bleed air also used (most importantly) for wing deicing and inlet anti-icing.
@AgentJayZ9 жыл бұрын
MrShobar No. Deicing is done on the ground by a crew with glycol fluid sprays, and in the air with inflatable "boots" on the leading edge of the wing.The only wing anti-icing I have seen is with electrical heating strips on the leading edge of the wings. Engine inlet anti-icing does use compressor bleed air, and when it's on, it reduces engine power by a few percent.
@MrShobar9 жыл бұрын
I was an engineer with the Boeing Company some years ago. We used bleed air for wing deicing on the wing leading edges on all of the airplanes since the 707 (the B-47 and B-52 too). Regards.
@AgentJayZ9 жыл бұрын
Good to know. I am an engine guy, not an airplane guy, and I really need to stick to what I know. Thanks!
@MrShobar9 жыл бұрын
Your presentations are extremely informative. I really appreciate the work that you do.
@badazrod10 жыл бұрын
I have been studying the dynamics of internal shockwaves ( Mach+). Do you know of any good material on this as it pertains to turbine engines? Can you explain any of it in layman's terms? Thanks JayZ for all the knowledge you share!
@K1w1scot10 жыл бұрын
Most airflow within a standard jet engine is subsonic, remembering that the speed of sound is not constant, rather a function of fluid temperature. So throughout the core of the engine, the speed of sound varies due to temp differential. Once outside, however, it's a function of the ambient temp. This also applies to the inlet. That's why variable geometry intakes are required for high performance aircraft. As AgentJayZ mentions, down below, have a gander at the Rolls Royce book "The Jet Engine". It's basically the sumpy's bible.
@Dogfight20003 жыл бұрын
Awesome video. Could you explain about free turbine engine ?
@AgentJayZ3 жыл бұрын
I have several videos about power turbines. Search bar on my channel page.
@calummacfarlane847610 жыл бұрын
I imagine that this single shaft engine is the reason the engines on older hercs are shut down with the props locked in fine pitch, so they will be easier to start, where as the newer ones (J model etc) shut down with them feathered. I imagine the J model must have received a different engine with a free turbine.
@AgentJayZ10 жыл бұрын
You are thinking exactly right. Both types of engines have their own type of response to pilot input. If you can find a pilot who's flown aircraft with a single-shaft engine (Garrett TPE331), and a power-turbine engine (P&W PT6), ask him / her about it.
@pinkdispatcher10 жыл бұрын
Yes, the C130J uses Allison (now RR) 2100, which have a free power turbine. A good comparison could be Do-228 (TPE331) vs. Twin Otter (PT6a), which have very similar mission profiles and are also the two most common types at Lukla in the Himalayas. Look it up.
@calummacfarlane847610 жыл бұрын
I can answer half of that question myself as I have a couple of hundred hours on Twin Otters. As my first experience of a turboprop I found it to be a lot more responsive than I expected, especially at high torque. I've never flown a single shaft engine so can't comment on how it feels to fly but I'd be interested why Garret went for that design when the PT-6 configuration has so many benefits. I can't imagine it saving weight or being easier to maintain, maybe a lot of efficiency is lost in the twists and turns of the PT-6's intake. I can't be sure that is the reason though without doing some research. Hopefully one day Jay will feature them in one of his videos!
@CP14040510 жыл бұрын
Calum MacFarlane My **guess** is that since (in the case of a single spool/transmission setup) there is near zero lag when the power levers are advanced since the engines/props/transmissions are already spinning at 100% RPM.... In the case of a two shaft arrangement, particularly at lower power settings, there could be a bit of lag when power is advanced... maybe it takes time for the turbines/props to fight inertia and spin up.(?)
@calummacfarlane847610 жыл бұрын
In both cases the prop should be governing at the speed set by the pilot. I would guess response is dictated by how quickly a demand for power can be fed to the power turbine. In a twin spool arrangement the gas generator has a lot more freedom to change the mass flow than when it is bolted to the prop reduction gear.
@jeffmclaughlin77316 жыл бұрын
Regarding cabin bleed air (air passing from the compressor directly into the cabin) is it safe to assume that the smells of fuel inside the cabin, are from worn bearing seals, or from jet fuel that somehow flows in that direction? I travel a lot and some planes smell more that others. I love your efforts here and actually bought the gas turbine book that you showed us. Keep up the good work!!!
@AgentJayZ6 жыл бұрын
Fuel is introduced well downstream of any compressor bleed. A leaking front bearing seal may allow oil into the bleed air, but usually bleed air does not directly pressurize the cabin. It is used to run a small compressor, much like an automotive turbocharger, so that there is no way engine air can get into the cabin. That's as far as I can go, because I'm not a plane guy.
@LK-pc4sq7 жыл бұрын
T-58 bleed air used to extend the air refuling probe.
@HoundDogMech6 жыл бұрын
I realize it been almost 5 years since this video was posted but Back in the late 60's when in the USAF I ran the P&W J52 P3 in combined systems test cell of the AGM28B Hound Dog Missile and it had a series of bleed Valves around the compressor case at about the No 5 or 6 compressor wheel. I remember I had to check them when activated from the control room during the engine check portion of the combined systems check. What was the function of these bleed valves on the J52 P3? Any Ideas?
@AgentJayZ6 жыл бұрын
Bleed valves are usually used for anti stall. Please watch my video called compressor stall, then the follow up vid for it.
@sydklinge215010 жыл бұрын
I have a little CAE-140 engine from a MA-1 GPU and I see a compressor bleed air path for a couple more functions. One assists in the actuation of the butterfly valve for the main compressor bleed (from the start cart), and the other leads, via a filter, to the hydromechanical fuel control unit. But maybe these aren't considered 'bleed air' because there is very little actual flow of air?
@K1w1scot10 жыл бұрын
They will, most likely, be servo or sensing pressures as opposed to bleed air. Though I am unfamiliar with the type of donk you're referring to, this is pretty standard for most turbines.
@corystansbury10 жыл бұрын
Nice hat!
@rcpatchett4 жыл бұрын
Jay you have gone over several bleed air, on different engines, but can you find or create a video that shows how the two different systems work (Bleed Band System, Bleed Valve System). I have scoured FAA.gov, 8083, and jeppessen books and the best i can find are some poor drawing diagrams that don't explain or show their functions well at all. thank you.
@SquillyMon7 жыл бұрын
Excellent description of a complex subject. Those two side by side bleed valves...can I think of them as a sort of "Compression Release" for startup purposes ? They let air bleed out during startup, to allow things to get up to a self sustaining speed more easily, without so much resistance? The other types I understand from your description...
@AgentJayZ7 жыл бұрын
+SquillyMon The bleed valves prevent aerodynamic stall of the compressor blades at lower rpm, allowing the compressor to function. It would be more accurate to say that they increase compression. It helps to ignore everything you know about piston engines.
@SquillyMon7 жыл бұрын
AgentJayZ Oh Jeez... LOL
@joeSHMO834710 жыл бұрын
Regarding the bleed air uses, what kind of pressure(psi) and air movement(cfm) run through the bleed air systems?(as in the Orenda engine I figured that the different uses of it require different amounts of air and use "restrictions" in some fashion. Love the channel Jay!
@AgentJayZ10 жыл бұрын
For the internal engine air bleeds for cooling... I have no idea; the rates of flow are not listed in the engine information manuals, and the pressures will depend on engine rpm. The customer bleed air is variable on demand, and it's pressure will depend on what stage of the compressor it is sourced from. Different designs for different engines. The airflow through the bleed valves depends on when they close, which is different in different engines, but it is very large.
@MrSoeminwin10 жыл бұрын
Why the air bleed band can prevent engine surge?
@roaddog45310 жыл бұрын
depending on what craft is asking the question ...myself I would refer to it as a dummy load
@gwin32798 жыл бұрын
Thans
@deSloleye10 жыл бұрын
The big disadvantage I see with the single shaft systems is the power needed for starting. You've mentioned the LM1500 and LM2500 are started with about 100hp, can you give an indication of how much hp this engine needs to start? I imagine it would be quite a bit higher than engines producing thrust or powering a free power turbine. It also looks like this load system wouldn't produce much load until the engine got to running RPM. I imagine that would make starting easier than normal, right?
@MrAureli2248 жыл бұрын
is bleed air hot? is it because of compressing the air?
@Pelo19697 жыл бұрын
Also bleed air for leading edge flaps on F-4 Phantom
@892guns6 жыл бұрын
On the load for the allsion, I am assuming that closing the valves on that compressor increases the load since the air has now where to go.
@AgentJayZ6 жыл бұрын
It's more complicated than that. The bleed valves are not there to unload the compressor at design speed. They are there to increase air speed through the compressor at lower rpm to prevent stalling. When a compressor stalls, it stops working, and it requires less power to turn it. So... at operating speeds, opening the bleed valves would unload the compressor, but they are not used that way. At lower rpm, the bleed valves must be open to allow the compressor to work; closing them would cause a stall, which is not good for it, but also technically unloads it. I suggest you watch my video about compressor stall.
@hommie78910 жыл бұрын
another great video thank you for the effort just to educate us very selfless on your part and I appreciate it. question for you the bleed air you called customer bleed air for systems on plane is this the same one planes use to start other engines with or is that a different bleed air outlet? looks small for the size of hose starters use but I don't know. Thanks again Jay
@MrShobar9 жыл бұрын
The Orenda no-doubt has transpiration-cooled turbine blades. Correct?
@batuyilmaz14643 жыл бұрын
There is also a bleed air exit (I guess from the 4th stage of the Compressor for this case) that is used for anti-icing of the inlet guide vanes, am I wrong?
@thetomschaeffer4 жыл бұрын
Thanks so much!!
@MinhLe-by2te8 жыл бұрын
This technical man is like the chemical man ( in Breaking Bad ).
@jettelo4 жыл бұрын
Nice hat Big ole pimp. The only real jett
@hohonguitar84177 жыл бұрын
hi sir.. thank u for ur nice efforts. I have a question about ,is there a difference between compressor bleed valve which is used to avoid compressor stall and surge and a bleed valve from which bleed air is usually taken for the purpose of de-iceing,cabin pressurisation,etc
@biggen2ooo10 жыл бұрын
Is the cooling air that cools the bearing also what pressurizes around the bearing inclosure to keep oil that gets past the seal out of the engine? what would the range of air pressure and what temps would you see when engine is at operating power? Is the air that is used by the plane systems closed circuit like when a car uses vacuum servos where there is no leak of pressure or vacuum in cars and just the pressure itself is doing the work? Thanks for the hard work you have a first rate site.
@castlebravo10 жыл бұрын
Yeah the internal cooling air is also used for seal pressurization, in both labryinth seals and pressurizing some carbon seals. The pressure depends on the engine type, engine compressor ratio and where in the compressor the air is taken from. The bleed air used in aircraft systems like air conditioning, anti-ice, cabin pressurization is exhausted overboard once it's been used, so it's not a closed circuit.
@mark-12349 жыл бұрын
If this is one of those questions that's been answered a million times, just say so and I'll hunt for it on my own (or you can point me in the right direction). I'm just curious; as busy as you must be, what motivates you to take the time to make these videos?
@AgentJayZ9 жыл бұрын
That question has been placed on the list for upload #350. right now I'm editing #349.
@mark-12349 жыл бұрын
Cool. Will look forward to it. You're very knowledgeable and apparently enjoy sharing/teaching, which makes your videos the preferred source of learning (at least for me). You seem like someone I could really enjoy working for; that is, if I could handle the Canadian climate. ;)
@kevinokwach9077 жыл бұрын
Agent Jay z... I have a question but it's not about the bleed valves/ air. where do carbon deposits on the main oil filter come from specifically for PT6A-27?
@PlumdogMilli0naire8 жыл бұрын
is that a vibration analysis kit hooked up on the t56 turbine? also thanks for the great vids! being a jet engine troop i love watching these videos and seeing other engines!
@Max-sl7xs4 жыл бұрын
Do you have a video where you explain how the different chaising parts are held toghether?
@AgentJayZ4 жыл бұрын
If that's not a typo for casing, I don't know what you mean.
@Max-sl7xs4 жыл бұрын
@@AgentJayZyes, it's my fault. It should be casing. (My native language is not english so I apologize for spelling mistakes)
@Dan84329 жыл бұрын
I noticed you said that the bleed valves open on the 501 because the high pressure section can't handle the air from the low pressure section on start. That makes sense but I guess I am confused because you later said the 501 was a single shaft engine. Why are the bleed valves needed on a single shaft engine lacking an HP system? Thanks!
@AgentJayZ9 жыл бұрын
Dan8432 I meant the lower pressure stages at the front of the single shaft compressor are more efficient at low rpms than are the later, higher pressure stages on the same rotor. It does get confusing sometimes.
@Pyrepenol10 жыл бұрын
Are there any questions that you wish someone would ask? Your answer is my question.
@K1w1scot10 жыл бұрын
Great vid, once again, thanks (missing playing with donks). Now with regards the inlet appertures on your load compressor. What's the risk of inducing compressor stall on the load unit? It must surely induce majorly turbulent airflow onto the first stage, doesn't it? Have you done a video of the unit running? I'd love to see the results. Thanks, once again.
@degl123410 жыл бұрын
The air, coming out from that 'mecanical load' cmpressor, should have quite a high temperature, like 300+ celsius. This air will be sucked to the main engine intake as they are close. So, isnt it bad for the engine to be feeded by such a hot air?
@AgentJayZ10 жыл бұрын
Good point. We'll be watching for that.
@rileyconroy68995 жыл бұрын
@@AgentJayZ Any update?
@phaecops6 жыл бұрын
Bleed valves seem so much simpler than variable stators for avoiding compressor stalls on engine start. My don't jet engines use bleed valves?
@AgentJayZ6 жыл бұрын
They do. Bleed valves are a less precise, but adequate solution to the problem of axial compressor stall. Variable bleed valves are better, and almost as good a solution as are variable stators.
@fbdsbfkjshnsgjkf6 жыл бұрын
I have a question for you ? I am a AD in the Navy i work on the T-56A-14 or 501. Why is it that that you guys are taking the air on the old compressor section from the bleed valves on the 5th and 10th stages vs the 14 stage on the diffuser section, wouldn't you rather have 14 stage bleed air?
@sivad8710 жыл бұрын
Amazing video! So that is basically the same concept as an engine dynamometer used to produce a variable and measurable load to test the performance? How is the output tq being measured by the driven compressor? Is this as simple as psi air to percent aperture will equal tq required to produce and how are these numbers determined or is there some type of load sensor directly attached to measure output? Thank you for the great videos!
@AgentJayZ10 жыл бұрын
The T56 aircraft turboprop has a torque meter on the drive shaft, and we will be using that.
@phaecops6 жыл бұрын
What is the typical temperature and pressure of bleed air for customer utilities?
@eduardodoqui257810 жыл бұрын
Jayz is the guy.
@ahmedalali63335 жыл бұрын
Thanks man !
@turtlemann148 жыл бұрын
why don't they call the bleed valves compression release? also, on the engine "dyno" don't you need a valve on the exhaust side of the compressor more than the inlet or is there enough restriction in the end plate that the bleed air system will do? i assume the intake restriction is for unloading the engine at startup. if you were to shut the intake valve quickly while the "dyno/load" was at high load, would it attempt to stall the compressor?
@AgentJayZ8 жыл бұрын
+jon “tweakit” spon 1) because that's not a good description of what they do 2) restricting the inlet is more effective than restricting the outlet. Where is the throttle plate for a piston engine? 3) that is the basic idea, although we may need to restrict both the inlet and discharge...
@bandeterence.61618 жыл бұрын
I have been trying to figure out how the shaft start rotating when the engine is at rest
@bandeterence.61618 жыл бұрын
I wish to know which device causes the rotation of the shaft, how is it connected and where is it located in the engine?
@AgentJayZ8 жыл бұрын
The starting of rotation from rest is cause by the starter. It brings the rotor up to a speed where it can supply enough air flow to support combustion and allow the turbine to function as the source of torque to turn the rotor at operational speeds.
@nothingmuch66854 жыл бұрын
so there is customer "bleed air" for aircraft usage, and then there is internal cooling air, that's the air ducted thru the engine thru pipelines and valves used to cool certain parts of the engine most specifically, the combustion section and the turbine section. But what about the external cooling you were talking about? like I know that it mixes with the gas path downstream of the exhaust, but what does it specifically do?
@AgentJayZ4 жыл бұрын
"cooling air"... and if you read the chapter on combustors in any of the books I recommend, you would become enlightened.
@nothingmuch66854 жыл бұрын
@@AgentJayZ I've just recently found out your channel, kinda nervous about an upcoming exam so yeah :) what books would you suggest? I'm really sorry for these urgent questions.
@ninetynine54868 жыл бұрын
Great Videos and something i like to watch. I have one question i.e. you said the HBV assist in starting? I thought they are there to help in surge operation to release the pressure from compressor.
@AgentJayZ8 жыл бұрын
+Ninety Nine They help the engine to run at very low rpms without having the compressor experience aerodynamic stall. That region of operation includes starting.
@crazymotionride10 жыл бұрын
I've always wondered what compressor stall is, ive read descriptions but they are all a bit abstract so hard to get my head around. Especially when the air reverses flow and flames come out the front, i really don't get how that happens.
@K1w1scot10 жыл бұрын
Stall/surge is primarily an axial flow problem (tho not exclusively so, I should add). It's because an axial compressor works thru a series of convergent (accellerating) and divergent (pressure recovery) ducts. A divergent duct works closely to its designed airflow limits. Outside of this, the airflow becomes turbulent and stagnates. However, the compressors in front of the stagnated section are still compressing so all of a sudden that air can no longer pass thru the engine and must go out the only way it can...thru which it came. And BOY do you need a change of undies if you hear one up close! I should mention this is a rather simplistic explanation, but I hope it helps.
@2004vert10 жыл бұрын
AJZ, Good video about bleed air. In an airliner does the cabin ventilation and pressure come from bleed air? If so, what is the proximate cost in loss of engine efficiency ? The reason I ask, in the early days of jet airliners there seemed to be never a lack of cool air in the cabin but now you get baked until you have reached 10,000 feet or so. I think cabin air is being recirculated to cut down on the use of bleed air off the engines to save fuel. Thanks for you time, John Valos
@AlfredoPachecoJr10 жыл бұрын
In airliners, it all comes from the bleed air. As for the A/C, the bleed air will cause parasitic power loss. It all depends on the many factors to determine the amount of loss. One method to help ease the use of bleed air for cabin cooling/heating is the use of the "Recirculation Fan". Larger engines don't experience as much power loss as would smaller engines. If you look at the King Air 350, when you apply prop and anti/deice heating, you get a significant loss of power. The more equipment/systems that demand for bleed air, the more the engine must work to compensate for the loss of air flowing through the engine. If you want to get more in-depth, I'd suggest checking this site out to get all the technical info: www.b737.org.uk/index.htm
@AlfredoPachecoJr10 жыл бұрын
Also, in regards to the loss of engine efficiency question, it all depends on the ITT (Inlet Turbine Temp). When you use bleed air, your taking away cooling air for the turbine. The more or higher demand for bleed air, the less cooling air you will have. This will cause higher ITT's. So, to prevent this pilots will lower thrust settings to compensate for the increase in ITT. Most of today's engines have an updated FADEC that can do this automatically. Some, however, must be monitored manually (like the CRJ). So the "loss of power" that an engine will have with the use of bleed air is based off how much cooling air is lost and how much less the engine must operate to not exceed ITT limits.
@AlfredoPachecoJr10 жыл бұрын
Here is a forum discussion about bleed air and power loss in turbofan engines. forums.jetcareers.com/threads/turbofan-power-vs-bleed-air-extraction-the-mechanics.86319/
@AgentJayZ10 жыл бұрын
I think you are right, John. You can feel nowadays that the A/C doesn't come on until takeoff, and the engines are really working. As with any business these days, penny pinching is the whole strategy, and any bleeding of air from the compressor of a turbine engine reduces the power output, so for a given power, it costs more fuel. Aircraft designers and engine engineers are fine with that, but it really bothers the accountants, and they control the world, don'tchya know...
@2004vert10 жыл бұрын
AgentJayZ Thanks for your quick reply. John
@gbowne15 жыл бұрын
I think people also get it confused with RAM air and APU Bleed
@hughw24626 жыл бұрын
I was wondering if you could explain how blow off valves (or BOVs) function? It is my understanding they are operated not just during startup and are activated somehow by a pitot tube measuring airflow velocity and are hydraulically opened/ closed. Is there some sort of control unit in between? Could you clear this up?
@AgentJayZ6 жыл бұрын
None of the engines I have worked on have a mechanism called a Blow Off Valve. After you mention that term, nothing makes any sense at all. Sorry.