How Auxiliary Power Unit Works | Part 2 : Power

[@johnlinwoodgriffin2467]

I loved the transition to your engine-series background music when the animation shifted temporarily to the left engine start. I appreciate how you’re putting a lot of thought into the structure and flow of these videos!

[@AircraftScience]

Thank you very much!

[@SAR-uq6vv]

Another spectacular video, the quality of the video associated with the description of the system is brilliant. I can say that it enriches and facilitates learning far beyond the airplane manual.

[@trolltube3183]

The background music during engine startup is amplifying the power and strength of the b777 engine.

[@eldebo99]

The dramatic music check valve is opened so it can improve starter performance.

[@paulbush7095]

So much engineering ingenuity is taken for granted in our daily lives. These videos shed light on how science and engineering provide the quality of life that we enjoy.

[@michaelhoffmann2891]

This is amazing. I felt like I should be taking notes, as there would be an exam tomorrow! This is drinking from a firehose level, nothing dumbed down for layman consumption.

[@MarcPagan]

From a pilot, thanks for such well done research, and world class presentation. If the same people who did this presentation, taught my aircraft transition class/ground school, ...learning the aircraft systems during my one month stuck in a classroom would have been much more enjoyable :) ... and efficient, with regards to learning, and command of the information.

[@ZozoTravel]

Extremely amazing & informative video, thank you. 🙂

[@Wadethewallaby2001]

Oh my gosh, I’ve learned so much! I’m becoming more smarter each time. I learn something small. My brain is expanding!

[@sdas7731]

Excellent video. Learned a lot about apu.

[@hamzazarhoudy9766]

Special thanks to you for your amazing explanation .

[@TheSakzzz]

5:26 .. Thats why the cabin cooling fans go silent when the engine is being started! Always wondered that.

[@izzzy416]

Beautiful

[@quick65filly]

Seems simple. Very well done video.

[@rgavr]

Absolute cinema!

[@johnreylc]

Is it from engine 1 bleed to engine 2??? Or that's the way by 777 to start engine 2 from APU?

[@iamjesper]

Im wondering the same

[@AircraftScience]

The APU bleed is used to start the main engines. A cross-bleed start is carried out only when the APU bleed is unavailable.

[@iamjesper]

@@AircraftScience do you know why this is the way? Does the apu produce more bleed air than the single engine?

[@richardbriansmith8562]

Awesome Video 😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊😊

[@bigchungus1592]

this is incredible

[@HurinisEbuega]

4:51 air supply computer and 3:12 air supply cabine presure controller is the same?

[@IqbalHussaini-f9k]

خیلی عالی❤

[@discoverlight]

Amazing and spot on animation, I just have a question doesn’t the right engine gets started up with the bleed air from the left engine?

[@A-T-M-]

Probably because the pressure given by the main engines is much higher than what the mini turbine that starts the engines can handle.

[@aspiringcaptain]

The Engine Air Starter is not very big, it was made to be powered by the APU bleed, not the Left Engine Bleed which is much more powerful. This is observable as the APU is 1. Smaller than the Left Engine 2. Meant to supply bleed air for engine start and some other things on ground. Also, in case of engine failure, the remaining engine powers the panels and the pneumatic ducts. In flight, this pneumatic system provided by the engine is crucial. Unless you descend to 10,000ft, it wouldn’t work very well to shut off some of the pneumatic valves to attempt to restart the engine with the use of the Air Starter. Also comes the possibility that you lose both engines. At least then, the APU can help at to try to restart one of them if time and necessity occur.

[@willswain4073]

Fantastic video and graphics!!

[@demal1010]

What would be the pneumatic start option for the APU itself...?

[@AircraftScience]

The APU pneumatic start will be covered in the next part.

[@jaiyp77]

love your video, wait to watch part 3.

[@technicdesigns8736]

You have made an amazing job on explanation of a sophisticated engineering marvel in such a comprehensible way. Looking forward for more contents from you. Btw, how much time is it required for APU to reach 100% RPM?

[@AircraftScience]

After the starter engages, it takes approximately 45 seconds.

[@daviddeam7050]

Wow! Super Graphical Schematics on Everything, almost.

[@marcoacerbi3647]

Bravi! Video perfetti! Peccato che non sono parlati in italiano

[@xtradi]

Great illustrations. Are there illustrations for the way to produce the air that pilots/passanger breathes in an airplane?

[@AircraftScience]

I will be making a series on the air conditioning system. Stay in touch with the channel.

[@RounakKushwaha]

I can't even fathom how many hours went behind making it

[@MuhamadAimanHakim-c6k]

Wow man this video is super amazing

[@zlatimirzdravkov8940]

Thanks !

[@Milessavestheday]

Would you happen to know how much air pressure (PSI) that can be produced in the apu air supply tubes? You show the tubes large, so I'm guessing it's low pressure/high volume? Thank you so much for your videos!

[@AircraftScience]

APU duct pressure is 40 PSIG.

[@Milessavestheday]

@@AircraftScience Awesome! Makes sense the way you have it drawn up. Love all the details. Keep up the great work.

[@HurinisEbuega]

You said that the generator starts when it reaches 100%, but at 2:20 you say that the generator is turned on by the switch.

[@adibasdas]

is part 3 being prepared or is there anywhere else where I can rent it or watch it?

[@AircraftScience]

I'm working on it.

[@pritam4677]

Why cant we feed main rotor directly? Whata the purpose of exciter there ?

[@miketaggart3803]

Part one?? Got a link for it?

[@HurinisEbuega]

so APU pump turned on when aircraft needs a compressed air, and when it doesn't pump turned off?

[@RounakKushwaha]

Amazing 😍😍

[@sam37io]

How does the efficiency of apu compare with similar power ICE generator?

[@visakhvisakh6028]

Nice videos sir please do morw

[@john.enospahitamos3596]

🎉🎉

[@philipwetpus7006]

Can I switch off the apu when the airplane is in sky

[@sukhman7439]

I am not an engineer so please correct me if i am wrong here!! So what i understood is that APU send fuel and air mixture through ducts for the main engine to start. Am i right?

[@brlinf06398]

apu uses a permanent magnet to generate electricity to be transferred back to the apu and then through a rectifier again to make a magnet? so making electricity to make electricity?

[@jt92]

They have to do it that way otherwise the electricity generated would be at a voltage and frequency dictated purely by the APU's RPMs. You lose some efficiency but doing it that way allows the control unit to vary the voltage, polarity, and strength of the field windings in the main generator which allows it to generate very specific 3-phase frequency and voltage. Commercial jet airliners don't run on the 50/60hz power that homes do, they use 400 Hz power since it saves weight on cables. I don't know how they arrived at that specific number, but that's the standard they settled on and that's why they need that indirect generator system.

[@HurinisEbuega]

Why is air extraction from the auxiliary engine not as simple as from the main engine?

[@asharma9345]

Keep it up Bro.

[@Mayalex9927]

How does it power the landing gear?

[@AircraftScience]

When required, the APU can power the aircraft's hydraulic system and help operate the landing gear.

[@bertomeuleo6425]

very weel! nice !

[@MuhamadAimanHakim-c6k]

Now understand in depth how does an airliner jet engine works

[@MuhamadAimanHakim-c6k]

Thanks bro

[@AircraftScience]

My pleasure!

[@philipwetpus7006]

Please help me with the companies parts of Airplanes

[@timsmith2525]

Excellent video! Right up to the part where the music started. What is this compulsion to put music in instructional videos? Not only unnecessary, but distracting and annoying.

[@LuisCastanedaZacarias]

❤

[@miketaggart3803]

I was under the impression that once an engine is running, one uses that bleed air to start the other engine.

[@maddgaming72]

Older models mostly

[@balmar3]

Fascinating stuff. No slip rings, no commutator, I guess it's more reliable this way?

[@AircraftScience]

Yes. It's a brushless generator.

[@Layla-cl1kv]

Maaf buat hiburan mesin semprot dari samping jet engine

[@garikhanchet4688]

Promo-SM

[@pauloyoshizaki2103]

0

[@zlatimirzdravkov8940]

Thanks !