How Auxiliary Power Units Work | Part 1 : Starting

Aircraft type.
* Boeing 777-300ER
APU engine.
* Honeywell 331-500
Aircraft systems explained
* Auxiliary power unit
* Electrical load management system
Major components covered.
* Main and APU battery, power distribution panel, APU engine, air inlet duct, inlet door, apu dc pump, electric actuator, fuel cluster, ignition unit, igniter plug and APU controller.
* Reverse flow annular combustor, centrifugal compressor, axial flow turbine, swirler, fuel nozzle, accessory gearbox, electric starter, pawl clutch mechanism, impeller, diffuser, stator, rotor, exhaust duct and fuel manifolds.
Software's used for making the video.
* Blender 3.6 and Filmora 10
Background music used in the video.
* (Filmora stock library)

[@SplashJohn]

I'm not in aviation, but I can recognize an excellent graphical and verbal presentation when I see one. Good work!

[@thabg007]

o man I remember the days on the flight line when I was in the Airforce having to listen to those screeching loud APU's 8-12 hrs a day, Yes I had (double) hearing protection. Its louder than the turbofan engine is (at idle). We used the APU to generate electrical & hydraulic pressure to load the gun system with ammo while at the same time removing the spent shell casings. There was a machine to connect to externally for electricity and hydraulics, it was taught to us in practice. But in real world use, it was never used, well at least not at the base I was at.

[@po1ly414]

A-10?

[@thabg007]

@@po1ly414 yea, how did you know?

[@aarond.8831]

A-10. One of the few that keeps its empties.

[@grumpyBSTRD]

Security forces and guarded c17’s and kc-135 refueler. Never knew wtf was screeching every damn day until I started getting into flight sims. It all made sense lol. Ear pro did nothing 😂

[@Greatdome99]

Military aviation equipment is exempt from federal emissions, noise and fuel efficiency stds, so they are usually loud, smoky and toxic. Commercial is not.

[@kellyfernandx]

I'm studying this to help my fiancé answer a test at work... omg this is so complicated lol the engineering behind airplanes is just insane... amazing

[@ryanreedgibson]

My dad and brothers worked on the industrial piping for the Honeywell plant that rebuilt these in Arizona. The plant did nothing but rebuild these APUs all day long. Awesome video!

[@SimonButler]

I work on 777s every day and still found this presentation informative and well made! Great job!

[@BlackFoxFalcon]

Masterpiece of engineering. Like pretty much everything in aviation.

[@CHOXON2CHOXOFF]

As usual, awesome animation and detailed. Keep going, we need such videos in our field for better understanding.

[@AircraftScience]

Thanks, will do!

[@jeylful]

Fabulous animation and explanation! Thank you!

[@pdks7088]

Absolutely amazing work. So helpful video!

[@grantnaval4519]

Now this. Is improvement! Amazingly done as always. From GE90 engine start and now goin' to the APU! Amazing and great! Thank you for this. As an aircraft mechanic with this type training. YOU MADE EXPLAINING. Easy. Always here to watch and see you go!

[@AircraftScience]

Thanks a lot!

[@gepset]

Great video. Interesting to see the APU follow the traditional British jet layout.

[@user-mv6hy3pe4s]

crazy quality I’ve ever seen about APU

[@demal1010]

Heading been a ramp agent for a certain amount of time for a regional carrier, who used CRJ200's that had the APU exhaust at ground level, you had to walk quickly past all the heat if you were walking back there. (However in frigid temps it was a nice heat source outdoors lol)

[@DavK637]

this is a damn good animation for those that are visual learners. thank you aircraft science for taking the time to make this

[@eneebarry6764]

It’s absolute and beautifully crafted animation and perfectly rendered here. Tombs up.

[@rhiannacoady8370]

I will be starting to make these in Honeywell in a few weeks!! So excited!

[@DropBear69]

This was excellent. Your videos are getting better with every release. Thanks heaps!

[@AircraftScience]

My pleasure!

[@flapjack413]

I've always wondered where the air intake for an APU was. Very cool!

[@john.enospahitamos3596]

Dont stop please. Thanks!

[@garyroachester1500]

Great presentation! can't wait for part 2

[@ccacrislan]

Absolutely brilliant, I really like and appreciate your job. Thank you. Always looking forward for more of your videos.

[@AircraftScience]

Many thanks!

[@oOSpecialProskillsOo]

i am probably never going to need this knowledge, but it was very well broken down and presented, great job

[@11snakePlayz]

This will be very useful for a project I'm working on in a game I play.

[@seantaggart7382]

The apu is awesome Its more than just a starter Its backup power and Emergency pneumatic! Its nice

[@lunganzimande8056]

Awesome video! Better than most CBTs

[@Humshkin]

Best visual video & best explanation ever!! ❤️❤️❤️

[@alexkazzeo6208]

Fantastic graphics, excellent explanation. Superbly done. Better than the Boeing one. Teach them something.

[@Magan-lg4bc]

Absolute GREAT.

[@southernpilot]

That was very well done.

[@JanV29]

Your videos are bonkers man !! Love them ❤

[@AircraftScience]

Thank you!

[@SticksTheFox]

The Video: Informative, technical, intresting The Music: Battlefield Butt Rock/ Command & Conquer

[@lmoraz]

Very good animation.. waiting for part 2, thanks

[@formatogrande397]

brilliant content

[@zlatimirzdravkov8940]

Thanks ! Useful video ! I guess it took you thousands of hours hard work!

[@stachowi]

This channel is amazing.

[@artysanmobile]

Superb video!

[@AusticHardOfHearingSinger]

Nice!

[@user-yf5td1zf6s]

it's good job, wonderful,brilliant

[@demal1010]

Would have been nice to see the pneumatic start option as well as the electric. It's not available till an engine or exterior air supply is running, so i hope it will be covered in an upcoming video.

[@AircraftScience]

I will cover the pneumatic start system in the APU bleed air section of the series.

[@jepleas9159]

The dark shadows with the black background make the details difficult to see. KZbin animators like Jared Owen and AiTelly include more contrasting shades and colors to make the details more visible. Nice work. Your effort really shows.

[@vishwajeet7806]

Very nicely explained ❤

[@davecrupel2817]

So the 777 apu has a pneumatic start option. Interesting. Makes sense if it needs to crank at altitude, and you want to conserve bat power.

[@richardbriansmith8562]

Awesome Video 😊

[@chitralisontakke7186]

Waiting for part 2!

[@sssaeedssahz.1434]

Excellent👌❤

[@n.s.shankar]

Brilliant❤

[@BobSmith1980.]

I love the graphics

[@aviationnmaps]

Remember that guy that asked you to make this a year ago?

[@AircraftScience]

Yes, thanks again for suggesting this topic.

[@lilawaffel186]

Where is part 2? This is so good thank you!

[@AircraftScience]

I'm working on it!

[@dilandias4018]

Awsome bro....thank you for such videos

[@AircraftScience]

My pleasure!

[@RounakKushwaha]

Sooo good

[@jaiyp77]

I'm very amazed with your animation videos, it really helps to fill my knowledge. But there's something I'm wondering about the engine, how does the fuel metering system work?

[@AircraftScience]

Hi, I have plans to cover this topic in the APU performance (part 3) video.

[@jaiyp77]

@@AircraftScience Thank you very much

[@r.robbie7918]

Great, ending this interesting episode without telling me HOW electricity and hydrolic pressure is generated... I assume it is coupled somewhere.

[@maheshanura5413]

Thank you very much sir.....🙏🙏🙏

[@AircraftScience]

Most welcome

[@suhailummer2697]

👌

[@CybershamanX]

(0:23) Oooo... So shiny! 😉😎

[@matthaxx7137]

Thanks. Question: Does the pawl clutch run the ratchets continuously after starting or is there some sort of disengagement mechanism once the APU is up to speed? Seems that there would be a lot of wear otherwise.

[@AircraftScience]

The clutch disengages once the motor stops at 50% RPM. As the engine speed increases, the pawls move outward against their spring tension due to centrifugal force. This eliminates contact and thereby reduces wear.

[@shenghan9385]

❤

[@udayakumar5348]

Small turbine works behind produce small amount of electricity and A/c to cabin and also bleed air to start engine

[@dalemanolas5994]

Is the alternator permanently geared in or does it have an electric clutch to engage it once the APU gets up to speed? Presumably the APU drives a hydraulic pump as well. Does that have a clutch? I'm just wondering if the starter motor has to spin all that stuff or is all of that disengaged during starting?

[@russchadwell]

Are there any "APU" engines that might be rigged to fly some sort of small aircraft? A means for some hobbiest to get some inexpensive second hand "jet" engines.

[@motionsick]

This complexity is the reason there are no competitors to Boeing and Airbus. Such a colossal undertaking building a single one of these aircraft.

[@orunabho]

I always thought there is an internal combustion engine there, a motor at work there. O, a jet engine!!! Nicely explained. What about thrusts it generates?

[@justing42]

It is negligible. They shut it off after engine start.

[@juggsauce]

Always wanted to find a timed-out, old apu and put it in an old truck. Power an electric motor. Wouldn't be very efficient but fuck would it be cool.

[@jiriprochazka9254]

What if it's raining and air inlet door are open? Is there some filter to prevent water getting inside the APU turbine?

[@troybowen3024]

You Really Haft To Be A Genius To Be A Pilot And Designer And Innovator Of These Jet Engines I Tip My Hat To Them

[@mubashirghani9344]

Please make video on APU bearings and seals..

[@AircraftScience]

Noted!

[@user-pg5px6qf7z]

Nice education video ❤! How about pneumatic start! Never use on line ! Ha!😂

[@myheart-ok4ie]

We want a video of how to run the engine via the APU

[@AircraftScience]

The main engine start will be covered in the second part of the series.

[@rickybrazzell7348]

Nice presentation but where is the generator part of the APU?

[@AircraftScience]

Coming soon!

[@ryanreedgibson]

When will part two be done?

[@AircraftScience]

Hopefully, late January.

[@musiegirma2728]

Can you do for airbus apu

[@Takeitlightly6]

That plane looks very pimped

[@apivovarov2]

turbine blades should be curved opposite to what is shown on the video . The angle is ok, but the curvature shape is not

[@MonkPetite]

And apu with an air starter as an option ? That’s a wrong stament. The igniters work before fuel is added. Fuel nozzles are mostly duplex. Meaning they have two stage function for starting and normal operations, you can’t dump all fuel less the 40 %.

[@Lx-photos]

Very dark. Nothing visible.

[@abdulla9042]

Hello, I can translate your video?

[@josephjeno6709]

When will come next part video

[@Kirmo13]

is the RPM expressed as a percentage of maximum speed?

[@AircraftScience]

Yes!

[@agungdwif]

Part 2???

[@AP-eh6gr]

NOW I know whats inside of the assh*le of every commercial plane!

[@WhyHow-vn6fo]

What software did u use bro

[@AircraftScience]

Blender.

[@WhyHow-vn6fo]

Tq for ur reply and please upload some videos about modelling

[@-fuk57]

Robot voice.

[@randygravel2057]

Ok this video ends where the apu is running. You forgot to tell how is the electricity made. Where is the “auxiliary power” made?

[@LezamaDamian]

Nice video. However, it's kind of too slow with long pauses, it would be way better if it were more dynamic. Also is it a human narrator or AI? A little more emotion would not hurt either 😊

[@AircraftScience]

Noted!

[@RounakKushwaha]

😮

[@tumurbaatarchinzorig273]

Landing gear pls

[@AircraftScience]

The next series will be on landing gear.

[@tumurbaatarchinzorig273]

@@AircraftScience Thank you so much!

[@lordpickle8424]

Thank you, come again!

[@jeffy210]

You don't really think about the fact there's a 3rd engine on a twin engine aircraft.

[@lilsnowycaraudio]

Actually 4 if you also take the rat into account

[@justing42]

@@lilsnowycaraudiothe rat is a pump

[@marioecheverria5152]

Where is the generator?? You explain the mechanical turbine but… the electrical part?

[@AircraftScience]

Part 2!

[@keitha.9788]

Get rid of the black background. It will increase the contrast and makes your diagrams more visible....

[@user-jq2rf4nf3o]

This is what I do with APUs - GTCP 36-55-c from an AH 64 and the M1A1 gen set from the Air Force for the Jet Ecec kzbin.info/www/bejne/nIPTY6h3jryUlaM

[@MrPLC999]

Nice to get an authoritative presentation for a change, instead of the usual tedious dumb-down BBC-style documentary where every sentence has to contain a word like enormous, massive, vast, prodigious, tremendous, monumental, colossal, immense, gigantic, mammoth, stupendous, etc, etc, etc...

[@thardyryll]

Good point. I get so weary of the gearhead shows where every host has to act like he has just snorted 20 lines of coke and meth just to make the presentation sound “exciting”.

[@engchoontan8483]

Get a truck mechanic to sit in class with paper notes version of this And similar to this, gas-turbine notes And also turbo-fan notes and turbo-prop notes and turbo-shaft notes Tell him to treat 28vDC as 24v truck battery. Impeller start as air-brakes of truck. Cascading battery to air tank to brakes to impeller to battery then battery and impeller the thingy. The thingy should impeller flow lub and fuel by crank and the battery should blow the bloody thing up. Redraw something over the weekend by combining 2 shafts like a cockster turboshaft into a 2 shaft turbo prop and use air around duct-in-duct to cool itself, vanes support. 2 shaft can exhaust thrust straight and rotor big. See what happens.

[@engchoontan8483]

Cocksters use wire mesh covers instead of stators and no chicken-chop

[@engchoontan8483]

Double shaft designs of turbo prop and turbo shaft allows intake to be almost anywhere and angle, same for exhaust and resultant thrust and also shaft. 3 items put almost anywhere and almost any angle. Terminology of variable geometry is expensive. Same for variable pitch and variable thrust vector (TVC - thrust vector control) Life hack = anti name-dropping, anti brand-dropping, anti deep-meaning, anti fancy wording, anti university terminology... Cross discipline, cross industry, ... Cheaper

[@zachansen8293]

that was a REALLY well done video. I'm much more likely to downvote a bad video than upvote a good one but I had nothing bad to say about this other than I'm sad the next one isn't out yet.

[@danko6582]

All that without even selecting Start!

[@nikolamilenkovic9586]

buuuum

[@palaboran2077]

Graphics far too dark. it spoils a good video.

[@erdum]

❤