Question about APU's

Nismaxdan · February 7th, 2007, 00:16

Please no one jump down my throat.

I was looking at the back of a B727 and an MD80 series yesterday and I realized that there was no exhaust for the APU at the back. I would like to know where the APU's and the APU's exhaust are on those two aircraft.

staplegun · February 7th, 2007, 00:32

The B-727 was originally designed without an APU, airlines realized they would need one so Boeing stuck it (behind?) in the wheel well... I'm going from ancient memory here. The exhaust is in the upper right wing-root area, which is why you don't see it in the back.

The MD-80 APU exhaust is in the back, on the upper right? side of the tail cone, again ancient memory from me...

:^*

Kevin

IFly85 · February 7th, 2007, 03:45

Yeah, we have one here at school that was donated to us. We use it in the Maint. program as a trainer. But, the APU on the 727 is located between the gear just forward. The inlet is on the left side and the APU exhaust is on the right wing root coming out of the top pretty mugh right outside of the rear emergency escape hatch over the wing.

Doug Taylor · February 7th, 2007, 04:52

Correct on both. Right above the R/H pylon on the DC-9 series aircraft and the 72, I think, is right above the wing. Below the wing is the pack fan/ground blower, but I *think* it's right above the right wing.

It's almost been 9 years since I've plumbed on the 72 so I might be mistaken.

Chris_Ford · February 7th, 2007, 10:57

Quote:

Originally Posted by Doug Taylor

It's almost been 9 years since I've plumbed on the 72 so I might be mistaken.

Nope, you're right.

Maximillian_Jenius · February 7th, 2007, 11:04

Quote:

Originally Posted by Doug Taylor

Correct on both. Right above the R/H pylon on the DC-9 series aircraft and the 72, I think, is right above the wing. Below the wing is the pack fan/ground blower, but I *think* it's right above the right wing.

It's almost been 9 years since I've plumbed on the 72 so I might be mistaken.

So what is the ventral hole on the vertical stabilizer for on the DC-9/80/90?

NuevaLuna · February 7th, 2007, 11:28

Quote:

Originally Posted by Maximillian_Jenius

So what is the ventral hole on the vertical stabilizer for on the DC-9/80/90?

Thats the intake for the ram air

CapnJim · February 7th, 2007, 12:40

Dough, is this the right time to ask the inevitable "Why does your horizontal stab never line up when you're taxiing?"

I only hear that once a week in the morning Newark lineup, I'm sure you hear it every day.

Ian J · February 7th, 2007, 12:44

Quote:

Originally Posted by CapnJim

Dough, is this the right time to ask the inevitable "Why does your horizontal stab never line up when you're taxiing?"

I only hear that once a week in the morning Newark lineup, I'm sure you hear it every day.

Have I gone mad, or has Jim actually stepped into an aviation-related thread?

(I kid, I kid!)

MusketeerMan · February 7th, 2007, 13:46

Quote:

Originally Posted by ChinookDriver

Have I gone mad, or has Jim actually stepped into an aviation-related thread?

(I kid, I kid!)

Well...you figure at some point he's got to get bored with starting anti-Christianity/Creationism threads.

Maximillian_Jenius · February 7th, 2007, 13:48

Quote:

Originally Posted by CapnJim

Dough, is this the right time to ask the inevitable "Why does your horizontal stab never line up when you're taxiing?"

I only hear that once a week in the morning Newark lineup, I'm sure you hear it every day.

I used to think that it was for crosswind correction. But now I believe that because the elevator is controled by horizontal stab and not power. So it doesn't level out (on the ground) unless there is enough force (wind) to do so. And once airborne the stab moves the elevator.

Am I right?

NuevaLuna · February 8th, 2007, 09:52

The elevators on the dc-9, md-80, and 717 series are controlled by a control tab and a geared tab (the 2 small tabs) on the elevator. The actual elevator is essentially a free-floating airfoil.

Maximillian_Jenius · February 8th, 2007, 11:04

Quote:

Originally Posted by NuevaLuna

The elevators on the dc-9, md-80, and 717 series are controlled by a control tab and a geared tab (the 2 small tabs) on the elevator. The actual elevator is essentially a free-floating airfoil.

So esentially I was correct. I said horizonatal stab, when I meant control tab!

Chris_Ford · February 8th, 2007, 11:33

Quote:

Originally Posted by Maximillian_Jenius

So esentially I was correct. I said horizonatal stab, when I meant control tab!

Essentially you were 100% wrong. But you may choose to believe what you wish.

.

February 7th, 2007, 00:16	#1
Nismaxdan Senior Member Join Date: Dec 2006 Location: Daytona Beach, FL Posts: 868	Question about APU's Please no one jump down my throat. I was looking at the back of a B727 and an MD80 series yesterday and I realized that there was no exhaust for the APU at the back. I would like to know where the APU's and the APU's exhaust are on those two aircraft. __________________ One day you will all look up to the heavens and shout, "Oh Lord please help us..." and I'll be like ohtfn.

February 7th, 2007, 00:32	#2
staplegun Senior Member Join Date: Jan 2007 Location: Park Ridge, IL Posts: 1,154	Re: Question about APU's The B-727 was originally designed without an APU, airlines realized they would need one so Boeing stuck it (behind?) in the wheel well... I'm going from ancient memory here. The exhaust is in the upper right wing-root area, which is why you don't see it in the back. The MD-80 APU exhaust is in the back, on the upper right? side of the tail cone, again ancient memory from me... :^* Kevin

February 7th, 2007, 03:45	#3
IFly85 Senior Member Join Date: Apr 2003 Location: MEM Posts: 463	Re: Question about APU's Yeah, we have one here at school that was donated to us. We use it in the Maint. program as a trainer. But, the APU on the 727 is located between the gear just forward. The inlet is on the left side and the APU exhaust is on the right wing root coming out of the top pretty mugh right outside of the rear emergency escape hatch over the wing.

February 7th, 2007, 04:52	#4
Doug Taylor Agent Smith Join Date: Dec 1969 Location: KSDL Posts: 41,926 Blog Entries: 1	Re: Question about APU's Correct on both. Right above the R/H pylon on the DC-9 series aircraft and the 72, I think, is right above the wing. Below the wing is the pack fan/ground blower, but I think it's right above the right wing. It's almost been 9 years since I've plumbed on the 72 so I might be mistaken. __________________ Doug Taylor http://76school.flyblog.com (old!) http://30west.flyblog.com (updated 11/28)

February 7th, 2007, 12:40	#8
CapnJim Old Skool Join Date: Feb 2003 Location: G-town, Near D-town. In T-state... er... whatever Posts: 4,499	Re: Question about APU's Dough, is this the right time to ask the inevitable "Why does your horizontal stab never line up when you're taxiing?" I only hear that once a week in the morning Newark lineup, I'm sure you hear it every day.

February 8th, 2007, 09:52	#12
NuevaLuna Junior Member Join Date: Feb 2005 Location: kickin' it in the A T L Posts: 71	Re: Question about APU's The elevators on the dc-9, md-80, and 717 series are controlled by a control tab and a geared tab (the 2 small tabs) on the elevator. The actual elevator is essentially a free-floating airfoil.

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