Understanding How an Aircraft's Jet Engine Starts! A look at the Start Sequence of a Turbofan Engine
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- เผยแพร่เมื่อ 1 ต.ค. 2024
- Hello. In this video we consider a turbofan engine on a commercial aircraft. These engines are started through a set of switches in the cockpit. The start sequence of the engine, gets initiated when the air from a high pressure air source enters the starter unit in the accessory gear box.
In this video we see and understand what is start sequence by looking at the different components on the engine and how each component contributes to the engine start.
hope you enjoy. thank you.
Please Watch and Subscribe for more videos!
One important correction, N1 rotation begins before fuel is introduced. When the N2 shaft is spun by the starter, it will suck air through the engine, which will turn the N1 shaft at a low speed. This rotation must be confirmed before fuel is introduced, as lack of N1 rotation could indicate a seized engine.
Thank you for the information!
@@JxJAVIATION Thank you for jet engine start steps.
thank you very much
Thank you, I have always wondered about that. Thanks for explaining.
Good explanation, I was wondering how N1 starts, now I know...
This Video would be WAY BETTER with out the robot voice
Very true. That robot voice sucks.
True
False
Forreal, if you take pride in what you do you should be confident in speaking your knowledge
He doesn’t give a $hit because he’s too lazy to bother.
You nailed it! This is so good I chose to use it in my classroom of aircraft mechanics students.
WOW! Thank You. A PLEASURE!
Where has this video been my whole life? I've watched so many videos just to understand this but they all deviated. Thanks a lot. Good video.
You're very welcome! Please do Watch other videos on my channel as well.
You should also watch this one. It is also
as good th-cam.com/video/GzhdxSsoT0g/w-d-xo.html
One of the things I did on pushbacks, before I give the pilots permission to start. I notice the wind. A strong rear wind would turn the fan blades in the opposite direction. If the wind is really strong from the rear, I would alter the angle in order to prevent a hot start.
That's very interesting information! thank you! :)
I want to learn this
What is a hot start? Very interesting!
It’s always refreshing to work with push back crews who have that kind of situational awareness
@@hugolafhugolaf in order to make more power, engines must get hotter. We measure this heat by the temperature of the gasses that are exhausted out of the engine, known as exhaust gas temperature or EGT. During an engine start, the EGT is monitored to not exceed a certain value before the engine is started and stabilized. If it does exceed this value, that is known as a hot start.
This is the most crisp and on the point explanation of turbofan engine start i have ever watched. Thanks a ton for your work. Liked and subscribed.
Thank you so much! :)
With a shit computer generated voice ? WOW
Thank you. As a flight sim enthusiast I really wanted to understand the N2 importance initially and why N1 is important later for most of the flight. You nailed it.
Thank you mate!
Think of it this way: N1 is your thrust, and N2 powers your systems. The N1 shaft has many more turbine stages, in order to extract as much energy as possible from the jet exhaust and use it to run the fan. That's where most of your thrust comes from. The N2 compressor gives you bleed air, which runs your AC, anti-ice, and engine starters. The gearbox linked to the N2 shaft runs a generator and a hydraulic pump.
Thanks, I dont know why so many videos skip how to initially get the turbine spinning, that's what I needed to know.
You are Welcome!
So when the engine starts, is that the rumble noises u hear when ur being pushed back?
Usually one of the engines is started during pushback!
@@JxJAVIATION oh ok
Enough. Use a human narrator.
I got 25 seconds in. I can't listen to this.
yes. noted
In Diehard 2 the guy gets chewed up in the engine . How is it that the engine chews him up up and spits him out.But in reality a bird can disable an engine?
I agree -- that robot voice sucks. Is the producer of this video too lazy to talk?
You're videos are so educational thank you for sharing!
thank you for watching!
The accessory gearbox is like a drive belt on the cars. It drives the fuel pump and the oil pump and the hyrdaulics. It is driven by the Hp turbine. So to drive the Hp turbine itself we can drive this gearbox itself.
That is a good explanation!
Thank you very much for sharing this information, you took away the darkness of my ignorance.
Glad it was helpful!
The _shaft_ from the accessory gearbox does not disengage from the N2. The gears in the starter unit disengage from the shaft. The shaft is still required to drive the accessories.
Did some research: The shaft which drives the accessories is separate from the shaft that is used to start the engine.
@@JxJAVIATION Engine type? The N2 (or N3) shaft drives the accessory gearbox (permanently attached) on most engines. There are various components attached to the gearbox: Hydraulic pump, EEC power generators, fuel pump, electrical generator and starter motor. i.e. The starter motor is mounted on the gearbox (CF6, RB211, CFM56, etc). You said that "the shaft from the N2 starter unit disengages from the N2 shaft" and the graphic in the video shows the accessory gearbox shaft disengaging from the N2 rotor. What actually happens is that the starter disengages from the gearbox. According to your graphic, all the accessories would stop working.
I’m with the imperfectstranger on this one. On modern turbofan engines the starter is just another component on the accessory gearbox. Sure, some really old single spool military engines had starters attached to the compressor and were mounted to the shaft at the front of the engine, but that design is now very much obsolete.
Amazing. I thought they were kick started by the most obese person on a flight. That's often the flight attendant on US flights.
Haha! Can understand that! Isn't much different in other places as well!
Oh, these robotic voices are so annoying. So much so that I have to turn it off. It's like listening to fingernails scrapping across a chalkboard.
aww man. There are other videos without the robotic voice!
absolutey FANTASTIC! thank you!!
You are welcome. Check out my other videos as well
Thanks so much for the info, nobody out there explaining “how a turbine works” shows how the turbine starts or accelerate. Thanks again ❤️
You are Welcome! Check out my other videos as well!
Why would you use a robot voice? Total turnoff....
Aww man. Had some issues with my recording equipment. There are other videos without the robot voice.
One of the poorest explanations of how anything works I've ever heard.
Aww man!
The robot voice made your video unwatchable
Apologies for that! Check out my other videos without the robot voice!
GREAT PRESENTION. I enjoyed the video fully. Thanks for sharing ✈️🛫
Thanks for watching! Do Check out my other videos as well!
Very tedious - especially since the voice is computer generated.
Apologies for that. Check out my other videos without the robot voice.
obvious but still better to be explained than to just guess ...
True!
Hate the damn computer voice. Couldn't make it past 1 minute.
Aw man! Too bad. Check out my other videos without the robot voice
Fragmented & Incomplete description. Exhaust from Hi Pressure Turbine forces LPT which itself rotates fan.
There’s always a portion of magic in the procedure nobody has ever fathomed
That is the beauty of it!
Good info thank you. But im sick of listening to robots. How hard is it to talk?
I was not able to do audio recording for a few videos including this one. There are other videos which do not have robot voice. You can check them out!
Beautifully explained... Looking forward for more videos!!! 💯
Thank You so much! Please do share the videos! and Watch my other videos as well!
I have to agree. Your clear and easy-to-understand explanations together with the fantastic animations are first rate! Well done and thank you.
Ask a Pilot.
Could be helpful or could watch this video
What about the Boeing 787. It uses an electric Starter?
Yes, it uses an Electric Starter!
Really great explanantion. Thank you. My lecturer insist us to watch this vid, does not have any regret at all. 🔥🔥🔥
You are welcome! This has definitely made my day today. Thank you. Do watch my other videos as well and please share. :)
Was it too expensive to get a human to talk ? I'm not listening to that shit.
Aw man! Apologies for that. Check out my other videos which do not have a robot voice.
Great video.☺️ I just subscribed to ur TH-cam channel.☺️
Most find qn answer how jet engine starts.....thanks man
No problem!
I’m an A+P who no longer works in the industry so I really appreciated that you did not call this a jet engine but a turbo fan. Most high bypass engines have a twisted arrow on the inlet so the crew can verify the correct rotation before initiating ignition and fuel. Thanks again!
You are Welcome! Check out my other videos as well!
I am confused. This isnt a jet engine?
@@majestikstyle It’s not a true jet engine It’s a turbine which uses a series of compressor blades mounted on wheels in the convergent duct thus compressing the air. After which fuel and ignition are introduced in the hot section driving another series of blades in the divergent duct mounted to a common shaft that also drives the compressor section. A high by pass fan is also used for thrust around engine case .
A true jet is much simpler in design.
@@powerwagon3731I thought turbo fan is just the better version of an jet engine
How to increased the RPM OF that engine
Increase the fuel flow to the engine
Nice work! Very helpful!
What's with the creepy AI voice-over?
Apologies for that. Check out my other videos without the robot voice.
I disliked because of the robo voice.
Aw Man! Check out my other videos without the robo voice
a fucking engine voice telling us
hahaha. easiest way to know!
Superb demonstration
Thank you so much!
Great explanation sir ! It's just mind-blowing awesome...
Thanks a ton! :)
A robot voice? Really?
Unfortunately yes
It’s on autopilot
Personally, I Think The Robotic Voice ADDS To Value Of This Long Overdue Explanation.
WOW! Thank You!
Too slow will not watch to the end
Apologies for that. Check out my other videos without the robot voice.
very neat, concise and clear presentation
Thank You!!
We don't know exactly where, when airplanes begin but i believe there is a wire to connect the engine to start.
Some engines need wire, pipes, tubes etc
This video just solved one of the biggest doubts i had as aplane enthusiats. Thank you very much, and you've gained a new subscriber :)
Thank You so much and WELCOME! Check out some of my other videos as well!
What were you doubting if I may ask
@@lewismuange3786 Well I understand why many people are wondering what is right, as I've seen multiple TV shows telling it wrong. I even remember the startup sequence being described as "compressed air pushing down the pistons" in "Ultimate Airport Dubai". Which is of course laughable.
Robot voice: good-bye
Aww man. Can check out other videos without the robot voice!
Thumbs down for robot voice
What about the content??
@@JxJAVIATION Robot voice sucks!!! How am I supposed to get to the content?
AWESOME video
The diagrams are very easy to understand and the slow-rate voice really helps to follow the explanation. Thank you
You are Welcome!
Its 2020 and flight schools still teaching trash. Best way to teach airplane systems is either with real airplane opened or watching videos like this from someone that really knows his stuff.
Thank You! It really means a lot!!
🗨️☃️
;)
Thanks, Stephen Hawking, that was super education!
Thank you so much man! Made my day!
@@JxJAVIATION ... al. EducationAL. But also a super _free_ education, so I guess it kinda fits!
I just had to replace a torque converter on a car and there are similarities, that's how I arrived at your video.
Plus TheFlightChannel is like super addicting, and also super sad and frustrating
Thanks again! I'm all about making days!
@@egregiousqueef7781 Great to have you onboard! Check out my other videos as well. As you mentioned its free aviation education! :)
It doesn't just ignite this magic JETA fuel which is supposed to be like heating oil or diesel.....then Bosh ! Your flying down the runway ....does it???? This alone should make you ask the right questions....aka its using AIR as its only FUEL!!! Yes you heard me AIR!!!!!
Well the air wont move until something pushes it right?
As an important point with regards starting a turbo fan engine. The air starter for the engine is fed low pressure high volume air. A popular understandable mistake is that the starter is fed high pressure air.
The air pressure is generally around 45 psi. The volume of air supplied is what provides the energy to drive the air starter.
Yes that is a very good point! Thank you for sharing!
Some jet engines now start electrically. On the 787 they have what are called VFSG for Variable Frequency Starter/Generators. The starters are also the generators once the engine runs on it's own.
Yes, just focused on the Pneumatic Starter
@@JxJAVIATION Love the video.
And each engine has two VFSG's (as does the APU).
Good point. And most business jets.
Thanks,Now I know by your video, what I searched for
This not always true. The GEnx and the Rolls-Royce Trent 1000 engines on the 787 is electrically started. The APU provides electrical power and along with the Lithium Ion Batteries directly spin the high pressure spool via the generator-motor mounted on the engines. Fuel is injected once the required RPMs are reached. There is no bleed air or an air start mechanism.
Yes true! Modern aircraft use an electric starter just like the one for the APU!
2:59 finally a video explaining what started the engine! Most videos just start with "air is sucked in" lol
Cool! :)
the incredibly long pauses between sentences are way too long.........boring
Aw man. Apologies for that!
Very informative n Interesting..🛫🛫
Thank You. Check out my other videos as well! and please share!
@@JxJAVIATION Sure..Regards..🛫🛫
I could certainly do without the now all-too-common fake voice, but otherwise interesting.
Yes noted that!
This “Explanation” is neither use nor ornament. For a Professional it’s over simplified and for a Layman it’s just Gobbledegook. I’ve been in the Aviation Industry all of my Life and this Video tells me practically nothing. For the American Audience it may sound quite informative but you ain’t getting no Marks in an Exam about Jet Engines. If you must use a Computer to generate a Narrative then I suggest you choose some other Pass-Time.
Hey! Its just a general aviation video! Cant be sharing specific procedures here!
This could have been a great video, but it was spoiled by the most ridiculous artificial VoiceOver!
Why couldn’t it have been narrated by human being??? It would’ve been fantastic otherwise
Well, Thank You! When I made this video, didn't think so many people would watch it, so went ahead with the robot voice!
I enjoyed the video, but I am hoping for two future upgrade. First, as was mentioned, the quality of the AI voice was so poor it was distracting. I know there are better ones out there.
Second, an exploded view with more detail would be greatly appreciated. I know that's a lot more work! :)
Yes thank you! Will keep those in mind. Do check out my other videos as well!
The graphic appears to be a 787. I worked on the 787 Common Motor/Starter Controller, which was the 1st all electric start of an engine of its size; otherwise the information is mostly consistent with other turbine engines I've worked on.
On the 787 there is an electric starter, but I was giving an idea about the air starter unit!
Quite good apart from silly robot voice ?????
yes. the robot voice was a bad addon to this video!
AIR-STARTER. THE AIR IS THE "LIQUID FUEL." A COMPRESSOR BLOWS THE STATORBLADES RINGS WHICH YOU DONT SHOW US! A HOSE FROM THE COMPRESSOR CART. THEN IT CREATES ITS OWN MOMENTUM AND ELECTRICITY. OH MY HOW MANY TRILLIONS THEY HAVE TAKEN FROM THE CUSTOMERS.
Yes it is!
Thanks good explanation.
Thanks for watching!
Do everybody a favor and get rid of the dull, boring, emotionless dragging robot voice and narrate this thing. I'm only halfway thru it, and had to stop
Apologies for that. Check out my other videos without the robot voice.
What about the EEC? You didn’t talk about it.
I made a separate video about the FADEC which should be useful
@@JxJAVIATION can share the link for that video thanks
@@JxJAVIATION why does slower air going into the engine becomes quieter?
@@LordBagdanoff this one: th-cam.com/video/3Nl11tSz4OE/w-d-xo.html
@@LordBagdanoff Its not because of the air but because of the lower shaft speeds in the engine
Sir this video, i like most. Marvelous video. Thank you sir.
thank you and welcome!
Very annoying...
computerized...
voice...
Apologies for that!
We don’t have all day with this video !
Jets do run on compressed air. They don't carry any fuel and they don't need any fuel.
The Jet Fuel Hoax
Oh Well!
Nice I understand the others I never got it ,
that''s great
Insert your key and press the gas
Please hire a narrator.. The robot voice makes this video seem quite unprofessional
Yes, should look into that. Check out my other videos too please
Great explanation, very helpful
Glad it was helpful! Check out my other videos as well!
Is this narated by Microsoft Narator? :):):)
A similar narrator
Not quite sure that air source to the starter is high pressure...Even for B 777 large engines, minimum air pressure from APU is 15 PSI, and minimum pressure from cross bleed start is 25 PSI minimum. The key point is not pressure but airflow.
Well the pressure is expanded in the starter turbine, which causes the turbine to rotate. I would say LP is the air conditioning supply from the ground cart. But for engine start HP air is regulated as per requirement by the bleed valve!
I guess this should be expressed in terms of air volume per time, or Cubic Feet per Minute, at least in the U.S. measurement system.
I mean 25 PSI in a 2 inch pipe is not the same as 25 PSI in a 4-inch pipe
thanks a lot for this video....crystal clear
You are welcome!
A.I. narration. Automatic dislike
SAD :(
There are other videos with AI voiceover!
Oh thank you so much for this info.
Yeah, non-English speaking utuber😂
Yeah! Welcome!
A real voice would have transformed this.
Yeah. Unfortunately can't change it now. Check out my other videos without the Robot voice
That AI commentary is awful. 20 seconds in and I'm skipping. Sorry.
Apologies for that! You can check out my other videos without the AI voice!
@@JxJAVIATION Thanks, I'll check them out.
Really wanted to watch but can't stand the annoying robo voice.
Apologies for that! Check out my other videos which do not have the robo voice.
The robotic voice is VERY annoying.
Apologies for that. Check out my other videos without the robot voice.
The new GEnx engines use electric starters instead of bleed air.
Yes they do!
Excellent. Complete & concept educate. Thanks 😊
Most welcome 😊
What a video thank you so much. I just want to request from you, can you describe accessory gearbox duty basically?
You are welcome! Will make a video on it soon!
this way too simple just so you know guys
Cool!
Sorry, I just can't listen to the computer voice.
It may be useful. Or you could check out some of my other videos!
Did you miss the sequence of the 3 rubber bands ? Thanks , simple and we'll put. It sure beats 24 volt starting motors and ring gears.
I was expecting..
"Next press the switch to release the Hamsters in to the rotating wheel"
Thank you so much the detailed explanation but can you please provide more information about accessory gear box and its way of operating and stopping mechanism .
You are Welcome! Noted and will do a video on the AGB soon!
Never mind don't want to listen a computer talk
Aw man! Check out some of my non robo voice videos please!
Cleverly narrated by a robot-no human involved.
Yes! Hope it was useful!