How to start a jet engine
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- Опубліковано 16 вер 2024
- Want to start a jet engine? Here's how...
Note: this video was created after I had already posted dozens of videos where we start and test jet engines. People were asking how it's done, exactly.
If you are one of those very few people who are complaining that I don't start it up here... well, you need to be a bit more aware of what's all around you. Jeez.
I have posted hundreds of jet engine test videos... many with afterburner, so have a look at them.
This is a GE LM1500/J79, and it is the real thing. No RC, no GPU; a real turbojet that took the F-104 to Mach 2.5, and made the F-4 into the most versatile jet fighter ever.
Index of all videos: members.iinet.n...
Why would anyone dislike this video? There's nothing to dislike. Straight forward and simple! Total opposite of the actual engine shown!
Yeah simple... we start a jet engine with a jet engine.
Thanks so much for this video. ALL other "how-does-a-jet-engine-work" videos ignore this very important starting point, leaving viewers ignorant. Well done AgentJayz :)
Man ! u r the best Turbo machinery guy on UA-cam ! I don't know if ur father or brother is a turbojet engineer or not but the exposure u have to turbojet engines is HUGE and what takes u to the next level is ur willingness not to JUST share it on UA-cam for views but to share it in a clear cut novice manner .....
Awesome , keep it up !!!
I was totally confused on how the jet engine starts initially by what powers the turbine to rotate.. Now its clear that only with external air supply... Thank u very much
30 years in aviation on the ramp side.. worked with everything from jt3/4 's to cfm's to rb211 to pt8's and the venerable DARTS. have heard many starts but this explanation was excellent. . sucke squeeze bang blow..
When I worked on the SR 71 in the 1960s, it was really fun. Our start cart had 2 Buick 401 Wildcat V8s with open headers. My ears are still ringing.
I guess you're the expert, but the books I've read say the engines were 455s.
Hardly an expert, and it's been 50 years. I have read that the Buicks were swapped out for Chevy 454s in the mid 1970s. What I do remember is how exciting it was to pull down on that throttle and hear that J 58 come to life. If you did it wrong the pilot could get very upset. The probe could drop out on a 'hanging start' and everything had to coast down. They had a tanker to catch!
I really enjoy your channel. You are the undisputed expert!
HI AgentJayZ et al,
I'm neither a pilot or aircraft mechanic, but I really enjoy your channel and learning how turbojets (and turbofans) are put together, how they work, are rebuilt, and maintained. As a child I spent many hours at a grass runway with my Dad. He was a private pilot and had served in the US Air Force as an aircraft mechanic. He even towed home a Taylorcraft one time (wings off and the tail wheel in the car trunk), put a new skin of ceconite on it, and sprayed it bright yellow, right there in our home garage. I must have inherited my flight genes from him.
I also subscribe to Mentour Pilot and enjoy the cockpit side of the story too. Captain Petter just did a piece on 12/6/2019 titled "Sucked into a Jet engine?". Since we're all interested in jet engines, I thought you and your subscribers might enjoy watching that one particularly if you've not seen it yet. It's over at:
ua-cam.com/video/l8O1VW-DKAo/v-deo.html
Thank you and your team again for the dedication to your profession and sharing your knowledge and enthusiasm!
Regards . . .
super cool! having autism and loving engines of every type and researching about them and how they work, I found this video extremely informative and satisfying to watch. Thank you
This video is so educative you have no idea. I had to go to the library on a friday night to suffice my curiosity. Thanks for the content!!
The SR-71 was started with a cart that had 2, 454 CI, super high performance
Buick engines mounted on it. Both engines worked simultaneously to rotate
a large gear extremely fast. The gear turned over the jet engines until they
started and ran by themselves. Pneumatic start carts like the one seen here,
just weren't strong enough to crank over an SR-71 (J-58) engine.
The engines were stock 455 wildcat Buicks. Each engine was started individually. There is one of these start carts on display, along with an SR-71 that you can sit in, at the Boeing museum in Seattle.
@@AgentJayZ later on they used 454 engines
Douglas Oakley Buick didn’t make the 454 though, Chevy did
@@bigdaddy7119
You're right. Sorry. I meant to say
"455 wildcat engines." My mistake.
It's been over 40 years since I
worked on the SR-71. Thanks for
the correction.
The biggest difference I noticed between starting an older engine like a JT3D and a newer one like a CFM56 was that you had to talk to the CFM56 during the slower start process. The JT3D started like an old Chevy Six and the CFM56 seemed like it needed coaxing, encouragement and patience. Both great engines in their own right, though.
Some folks might also be interested in hearing about a cross-bleed start.
Finally found the right video, been searching how does the engine starts but couldnt find the appropriate video, thanks man🙏
For other mysteries, try putting the subject into the search bar on my channel page.
Might have made a video on it already.
Dang, and I thought he was going to start the engine
Need... to ... open... eyes, and click... just one... of his... engine... test run... videos...gasp!
Hundreds of 'em...
AgentJayZ hello I’m Michael Milburn I live in wayland mi. I like your videos on those jet engines it’s a interesting learning thing you show us I’m wondering if you can send me a memberbilia such as that one hooded sweatshirt you wear in some of the videos my address Is 1175 eagle drive wayland mi 49348 apt 104 if you can do that that will be ausome my wed address is Michaelmilburn75@ Gmail.com thanks bro you rock keep up the good work
Yjhjg
Your video's are great,
Thanks for taking the time to make them.
Airliners rarely use ground air starter unit or engine cross bleed. Only when APU is unservicable or not practical to use. Each engine is started by APU bleed air.
Well that explains the answer a pilot gave me years back when I asked how a jet engine was started.
He said "With a running jet engine". In a way, it seemed a lot like the egg vs chicken debate for an answer. lol
Thank you for this explanation.
Imagine for a moment if these engines were started via pull cord somehow.
"Who wants to start the jet?" 123 NOT IT! lol
ME 262 had a gas engine starter...
Your videos are brilliant and always very enjoyable to watch!
Ray here, N1 is gas producer speed in a split shaft engine. This is an engine whose exhaust gas 'blows' or pushes the power turbine blades around, the power turbine (N2) drives the external connected load. This is standard arrangement in helicopter and small industrial style machines under about 1MW. The term 'multistage' refers to the number of compressor and turbine blade discs in the engine. A typical small industrial may have 7 stages of compression blades followed by 3 turbine stages.
The part of the 747 engine you are turning so easily is the LP system, and it does not drive any of the auxilaries, like fuel pumps, oil pumps, generators, etc. It also is not the part of the engine turned by the starter.
The part that needs to be spun up to start the engine is the HP system, and you can't reach that from the outside.
"all that is needed" is to get the HP system, or "core" back up to minimum starting rpm.
This is only possible at certain airspeeds and altitudes.
Clear and concise. Than you for taking the time to explain it all.
we started our aircraft off the aux power unit, which was a small turboshaft on the aircraft. we only used the ground cart for maint. the apu started from hydro pressure
Watching this before I go to work because I'm a painter and decorator and need to know these things........
The GEnx is electric start. There is no bleed air and no air turbine. The accessory gearbox drives a generator. This generator also functions as an electric motor to turn the high pressure shaft for starting the engine. Electric power is provided by one of two Lithium Ion batteries or by the APS5000 APU.
So, now I got to know how engines start with the help of bleed air of the APU in commercial jets! Thanks for the video!
Yes, we've discussed this before. The stranded one was likely hot-started, causing engine damage, and I would bet that Chuck was the only one who could get away with such a thing. I doubt it's ever been done since.
very nicely done video. I am a master auto diesel mechanic and I never knew how a jet engine started. Thanks for the info.
At the gate prior to push back, and during boarding,the aircraft cabin environment systems(packs), are not running. The cabin is cooled or heated by the jetway's system that's connected to an external ground air port, on the plane. Prior to bush back, the jetway air system is shutoff, after the APU is started up. The APU provides pneumatic air to run the packs, that heat, or cool the cabin. Also the APU provides high pressure/ high volume pneumatic air, to start the first engine. The engine that gets started first, is the one that provides primary nose wheel steering, and brake hydraulic pressure.You'll notice, if on the plane, during pushback, that just before you hear one of the main engines start to motor for the starting sequence, that the air conditioning shuts off. That's because the aircraft system sends all available APU pneumatic air to the engine starter, and disables any air that runs the packs.
I can see this quickly becoming one of my new favorite UA-cam channels. Just this one video alone (although I understood in principle before I got here) was excellent. Well described, sir! Thanks, and subscribed! :)
Who’d have thought when I used to work with you at TCT I’d be watching you years later on UA-cam!
Such a great place to escape from!
different planes have different starting procedures, but whatever they use, it's always that way.
I think fighter jets on active duty all have their own start cart, always waiting right there beside them. Also a few spares nearby in case there are any problems. As you can see from my videos, the start cart can go from not running to having the jet at idle in about 2 minutes. The only way to get the jet started faster would be to have the start cart constantly running. Maybe that is done.
What an informative video. Its always great learning about machines that we use everyday and take for granted. Thanks for the upload
@sephiroth1349 I'm not sure if your engines have air impingement or air turbine starting, but one thing is for sure: Whatever the air from the APU does, the GPU supplies it to the same place.
Basically the only difference between an APU and a GPU is that the GPU has wheels.
For example, a B727 has an onboard Garrett GTC85. Our start cart is a Garrett GTC85.
great video I always wondered how they start those things on the tarmac.
I thought the point was you was going to start it
Explained in the info section, and in the first minute of the video... Thanks for watching.
We called the jet engine starter in the Navy a huffer. I worked on Pratt & Whitney tf30 p408.
Always good to hear from someone who was there, in the days when these things were in their prime.
@@AgentJayZ
Thanks for compliment I worked on A 7 Corsair IIs during the Vietnam war. With VA 155. Involved in operation linebacker and linebacker 2 that brought the North Vietnamese to the bargaining table.
@blobusus The lightest, most self-sufficient method of starting a jet is with a gas-generating cartridge powering a small turbine starter. It's similar to our air turbine startr, but designed for higher temperatures. And instead of the start cart, the starter is supplied gas from one or more cartridges on board the plane.
for an example, search for Canberra cartridge start..
The Canberra has Avon engines, very similar to the industrial Avons we test.
Only one angle drive meshes with the main rotor. It drives the only radial driveshaft passing through the 6 oclock strut on the fron frame. At the bottom of that is the main gearbox, containing another angle drive, which makes all the gears spin in the same plane as the main rotor, just 2.5 feet below it. Connected to one of the spinning gearshafts in the gearbox is the starter drive.
Always wondered what makes turbines spin in the first place. Thanks for clearing this up.
:: "WRONG" ::end Terminator quote:: .... But seriously, as an engineer working in the aviation industry (for a company that manufactures many of the engines you are demonstrating here) I have learned so much from your videos. It's tough not getting to see most of things that I work on up close and personal. Your videos have been serving to fill that void. Thanks and keep up the great work. Maybe I will get to visit some time.
“And we don’t like bangs”. The understatement of the century.
@dave4shmups The actual engines used inside APUs built into airliners are the same as those built into ground power units.
Our start cart has a Garrett GTC85 for an engine. The same unit was built into 707s and 727s, as well as many other aircraft.
I worked at test cell at nellis afb....ran the engines for the f15 and f16 jets....a lot of fun and noisy....how he started this was the same way...
Yes, that's true if you are watching one of my videos, and we are using the air turbine starter. That's most of them.
The Olympus uses a hydraulic starter, and the J47 uses an electric starter.
@Pyanities Yes, there is a centrifugally activated clutch that disengages the starter at about 2500 rpm.
We wanted to hear it Start
That is in all of my many, many engine test run videos...
I just asked you a question about this on another video VERY INTERESTING I am very surprised a jet engine can not start under its own power I assumed they used onboard electric motors powered by batteries to spin the turbines up to that initial idle speed. Some of the best videos I have ever seen on UA-cam. Thanks again
I maybe completely wrong but most jet airliners have an APU (Auxiliary Power Unit) that is used to spool up their engines. The APU again if I'm not mistaken can also assist in relight should an engine flame out in flight. Although if just one engine flames out the remaining engines can be used to power the dead engine back to life if possible. I'm not saying all jet aircraft are that way but most modern heavy airliners are to my knowledge.
You are not wrong. The engine in our start cart is the same as the APU in a Boeing 727.
thank you for the video, i worked for the airlines for 6 years and i was the leader on the airstart team, there is nothing like jump starting a airbus 330
The airlines use bleed air from the APU to start the engines. If the APU, or the bleed from the APU is inoperative, we use a start cart to start the first engine, and then cross bleed start the other engine(s).
Yeah, I think we covered that. Ten years ago. But you are absolutely correct, sir!
@@AgentJayZ You are welcome (sincerely). My comment was for non-aviation types who might have been watching this video. Not everyone watches every video you create.
@@oscarb9139 Thank you veey much, I need such information as Im studying for tests.
@@mashedtomato2079 Sure thing. What tests?
@@oscarb9139 Airframe and Powerplant licenses
Silly but true... although nowadays, the "external" help is an on-board APU that can be started using aircraft batteries.
Batteries power the electric motor used to start the gas turbine engine in the start cart, which supplies air to the small power turbine in the starter of the LM1500, which turns the main shaft of the LM1500...
@VERGIS92 On the ground, anything is possible. You'd need a fairly large electric motor. Something that would provide about 500 lb-ft of torque, and not overheat if it took twenty seconds or so to get up to about 1000 rpm..
@cheetawolf Yes, those 4 things are projections into the gas path, and I have no idea why they are there.
They are not big enough to be any sort of aerodynamic device, and they are not connected to any air lines for sensing pressure, nor are they connected to any liquid lines which might be part of a washing system.
I'm only guessing, but I think they are blanking plates for what would normally be a water wash system.
Not needed in a test cell.
Yes, you are right, and some modern engines are using electric starters again. We work on engines, and have little contact with the aircraft, so I can't really answer your question.
The only reason I'm here is to see and hear a jet engine starting..
But thanks, now I completely understand the principle
Hi I'm studying Aircraft Maintenance at Centennial college in Toronto. You're videos are very helpfull!
Excellent explanation. Igniter box energized 500 rpm, Around 1500 rpm fuel on ignition start, at around 3000 rpm minimum self-sustaining rpm, starter off, 5000 rpm idle. Do those figures vary much with other engine models or with turbo fans?
Once again, I really appreciate your videos. Learning all this stuff took my fear of flying away. Educational. Thank you
If the starter is assisting the engine in gaining speed , it isn't being driven by the engine... it is still driving the engine. Once the engine reaches about 3000 rpm, a centrifugal mechanism disengages the starter clutch.
I been watching you tube to understand the process of jet engine working, non as good as this THANK you for this
A bit annoying that you didn't actually start the engine, but thanks for the how part.
It's annoying that you didn't read the info, or listen to what I say at the beginning, or have even one particle of curiosity to look at any of my hundreds of videos of jet engine starts.
@@AgentJayZ My apologies. This is what happens when UA-cam sends you suggested videos and you visit the person's channel for the first time. Lesson learned.
Totally an aviation nut myself! Dis guy right here always watch the plane video from here with my rock playlist crancked to 11. Metallica, Delta Parole, ACDC etc. AWESOME!
dude that was exactly what i wanted to know, straight to the point. that one gets a like
This took me back to my flight line days, Thanks
To quote the gunshop owner in Terminator:
Hey... just what you see, pal.
What starts the gas turbine turning on the starter? electric motor?
Yes. A 24VDC starter motor.
Most modern airliners have what is called an APU, or auxiliary power unit. It is most commonly found in the tail of the aircraft although some may be mounted near the center of the aircraft with the exhaust routed out the side. It is basically a small turbine engine not unlike what is in his yellow start cart. In addition to providing electricity to the aircraft during the times the main engines are shut down it also provides the bleed air needed to start the main engines and for air conditioning. It is usually started when the aircraft is taxing to the gate and shut down after a cool down period once it is unloaded and diring taxi for takeoff. Often times passengers riding in a 727 just behind the wing could sometimes see a small jet of flame as the APU was started. I have also seen start carts that were powered by 8 cylinder Detroit diesels running compressors istead of small turbines.
@dave4shmups A turboprop is a combination of a small gas turbine engine (1-5 thousand Hp), mated to a power turbine(usually) driving a gearbox which reduces the speed of its output shaft ( and increases its torque), to which is attached a propeller.
An exception is the Garrett TPE-331, which drives the gearbox with the main shaft of the engine; no power turbine needed.
So, starting a turboprop is exactly the same as starting a jet engine: RPMs, ignition, and then fuel.
In some combinations of airspeed and altitude, an engine can be started with the air moving through it. Not an easy thing, though.
Very Nice Explanation, I struggled to know how does it actually starts OR what makes a front big fan to rotate. Got the answer. Thanks!
Being a much smaller turbine engine, the start cart uses two car batteries to supply power to its 24VDC electric starter.
All that and no start?
In nearly 8 years, about half a dozen people have made the same complaint.You're the latest.
I finally added a change to the info section to help you and others afflicted similarly.
Cheers!
Started LM2500 many a time with bleed air from the GTG, Using the auto start mode done manual start when the PM book called for it. (didn't know they made an LM1500. (Mississippi gulf cost, USA)
Good presentation, you deserve being commended for your presentation. :)
I love your videos so much! Thank you for taking the time to do these.
Dam they give tutorials for everything now
I once had a lecturer from the military told me about the "Buddy Start".
placing a 'running' engine's exhaust facing another engine's compressor which needs to be start.
not sure if its true, but it sure is one heck of an idea only found in military.
Yeah, heard this legend before... but think about it: these aren't toys, and you can't just move them around. They are aircraft, and if you have the ability to move the dead one up to the tail of the live one, or back the live one up... you probably have the ability to power the starter of the dead one.
This may have been done once or twice back in the day, but I can't see it ever being approved of by the designers or the owners of the engines/aircraft.
I'm calling bullshit.
I've been in a Boeing 737-800 that used a cross bleed start. This was probably due to problems with the APU as the first engine needed a compressor for start, After push back with the first engine running the aircraft increased in thrust which shook the aircraft for a few seconds until the second engine wind milled. I knew exactly what was happening and enjoyed understanding just how much thrust is needed to to transfer 30 psi to the other engine.
I thought the alternate startup sequence was pushing the aircraft and the pilot then puts it in gear and releases the clutch
LMAO!!!
With a turbojet like the J79, you gotta let that clutch out easy, big guy.
Kevin,that only works if you can get a down hill run.
@mightyfinejonboy Don't know if it has a name. With our tests it seems to be the resonation of the jetpipe cused or influenced by the heat.
It doesn't come out on video, but our vaporizer makes a thunderous bass tone. It has an exhaust stack about 24 inches diameter and 25 feet tall. It's shown in a couple of my videos.
YOU didn't start the engine,... cleverly saved the fuel.. hehehe lol
Did you read the description?
...Special message there just for you.
@@AgentJayZ I already read out the description, but I was in the joke mood. Please don't mind.
There have been dozens of hammer-rung-my-bell stumbling idiots over the years making a very similar comment to your joke one. Sorry if I did not pick up on the humorous intent:)
The way you explain it, it almost sounds like you're running ignition for a while before you shoot fuel. I hope I'm wrong there, sounds wasteful. And im curious, if the apu is running, can that start the mains?
The start sequence is always rpm, spark, then fuel. Adding fuel before ignition is a guaranteed boom, and a very likely destroyed engine. Wasting sparks? Nope. Once the engine is running, the ignition is turned to OFF. For the whole time the engine is running, and that can be literally years, non-stop.
In an aircraft, the APU is often a potential source of starting power.
Makes total sense.... and you explained it at the end... duh. I dont know what I was thinking when I typed that... but the apu question I really didn't know about but does make sense watching that again and you saying the other engines can start one...
Thank you!
LOL - Ok, I don't want to argue, you obviously know a lot more about this than I do. I did go on to watch several more of your vids, and if you watch a number of them, the things I found a little hard to follow in this one iron themselves out a bit. I agree that starting a piston engine is quite different, my point was you could compare and contrast. ...And thank you, by the way, these are very interesting vids.
that was really helpful, thank you! now i can finally start my jet engine
your videos rock.. thanks for sharing..
Hm I already had a good idea of how the engine start worked but this did raise some other curiosities - I'm curious how the bleed air is both diverted and redirected to the other engines sequentially.. it's not a difficult mechanical question - presumably it's a few simple valves and a pipe running by all the engines - but just the specifics of how they do it is something I think would be cool to know... also need to refresh myself on ram air turbines and apu involvement or non-involvement in restarting engines... bah human memory sucks =D
The RAT is nothing more than a pinwheel with an alternator attached. It can power communications and flashy lights maybe. APU is an electric start turbine started first on the ground and used in flight as a generator it can power the entire aircraft and supply bleed air to start the other engines on the ground.
If you lose engine while flying you still have all the air going through, assuming you're still flying, so restart can be done without the air-cart/APU or bleed air.
As far the manifold and pipes of bleed air; that is a part of the airframe so you prolly gotta lookup pilot youtubers for those video explanations...
should have started up the engine!
Should have read the info, and maybe watched the freaking video.
AgentJayZ u clickbaited us >:(
Fortnite Dumbass...You are an idiot, and can't be helped.
@@AgentJayZ jesus christ bro! Killed them haters! Lmfao
So... you're telling me that you start a turbine to run a turbine to start your turbine??
Many larger aircraft have an on board APU that can supply air or electric power to start the main engines.
Excellent video. I was guessing how you did it until now. Thought it was an electric motor but now i know ))
Thanks for the videos! We love em here in NY!
Fill fuel tank. Push start button. Stand back. turn off fuel. Refill tank.
Really clear explanation!! Thanks for sharing!
Thank you for this video. I was waiting for this kind of explanation for a while. Finally, you made it clear.
after the turbine is fully functioning, do the spark plugs for the combustion chamber continue to generate sparks or the fire that is already there to keep combustion?
Like a candle, once it's lit, there is no longer a need to strike a match.
Good question.
Now it clear my doubts...
We can use start carts, but primarily we use the aircrafts APU or JSF (jet fuel starter) to get them up and running. Same concept as a start cart, it's just built into the aircraft.
Replaced three lm1500 turbines with electric motors. North slope Alaska. Had one come apart during the project....
great, thanks for the explanation, it all makes sense now. it wasn't easy to understand how gross thrust tests could be done just from the theory. The engine actually needs a small push
Some engines are normally started with an air turbine arrangement like the one you show, but that is not the normal, standard, most common starting system most jets use, most of the time. Most are spooled up by electricity from outside, battery, ground cart, APU... and once they're up to about flight idle revs, you switch the starter off and make it a generator. Alright, you (of course) know this - the point is how you explain it. You might start with a few words about starting a car engine.