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Bruce
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Joined: Tue May 18, 1999 2:46 am

THe Hole At The Back Of The Plane

Fri Feb 09, 2001 3:53 pm

I don't know any other way of describing it, on some 757/767 models it kind of looks like the plane's ***hole.

It looks like some kind of exhaust port at the extreme rear fuselage. What does that do? Do all jets have them?
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
 
exPratt
Posts: 306
Joined: Wed Mar 08, 2000 6:15 am

RE: THe Hole At The Back Of The Plane

Fri Feb 09, 2001 4:09 pm

The hole in the tails of 737, 757, and 767 airplanes is the auxiliary power unit (APU) exhaust. On the 727, it is in the right wing. On the 777, it is on the left side of the tail. On the DC-9/MD80, it is on the right side of the tail just over the engine.
 
Victor Hotel
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Joined: Fri Aug 25, 2000 8:29 pm

RE: THe Hole At The Back Of The Plane

Fri Feb 09, 2001 8:14 pm

I know about the APU's, and where they are, and what they do, but I am unsure as to how they work. I have a feeling they are a type of turbine(am I correct?), if so what sort and how does it work, If im wrong what is it and how does it work? Thanks in advance.
VH
 
FBU 4EVER!
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Joined: Sat Jan 27, 2001 6:53 am

RE: THe Hole At The Back Of The Plane

Fri Feb 09, 2001 10:00 pm

Yes,modern APU's are very small jet engines running at a constant speed.In earlier days (read piston engine times) they were small piston engines almost invariably referred to as "putt-putt's".
All output is being used to generate electric power for ground and in-flight use when ground or engine-driven generators are not available.They also provide a source of compressed air for air conditioning and engine start.Some planes do not have APU's,or it may have been an option.SAS DC-8's did not have them.
"Luck and superstition wins all the time"!
 
PHLyBoy
Posts: 70
Joined: Sat Feb 10, 2001 2:16 pm

RE: THe Hole At The Back Of The Plane

Mon Feb 12, 2001 7:59 am

As I understand, Boeing's 727 was the first Airliner to have an APU. I used to work for a Cargo carrier and always wondered why our old DC-8's needed a huffer cart to start the 4 noisy engines.
 
jjbiv
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Joined: Mon Jan 08, 2001 10:58 am

RE: THe Hole At The Back Of The Plane

Mon Feb 12, 2001 11:32 am

I believe most -8s had them when delivered -- correct me if I'm wrong. Perhaps the cargo haulers removed them for the weight advantage?
 
exnonrev
Posts: 598
Joined: Tue Oct 19, 1999 4:26 am

RE: DC-8/707 APUs

Tue Feb 13, 2001 3:15 am

The 707 and DC-8 never came from the factory with an APU. A few DC-8s got them when they recieved the CFM-56 conversion, but they had an overheating problem and were removed.

The only 707s to get a factory installed APU were the E-3 AWACS and the E-6 Mercury TACAMO aircraft. The installation is almost identical to the 727. The C-135 series (the real 717) has one installed in left rear cabin just forward of the boom operator position.
 
CX Flyboy
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RE: THe Hole At The Back Of The Plane

Tue Feb 13, 2001 8:01 pm

?? I thought this was where they throw rubbish out, and where the toilet flush goes when airborne!
 
XFSUgimpLB41X
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RE: THe Hole At The Back Of The Plane

Thu Feb 15, 2001 9:58 am

Anyone know how the fuel the APU turbine is? I have always wondered if they burn alot of fuel sitting there.
Chicks dig winglets.
 
Guest

RE: THe Hole At The Back Of The Plane

Thu Feb 15, 2001 10:25 pm

CX,

Seeing you're a pilot with Cathay, please tell me you were joking about what you posted above!!
 
AeroGlobeAir7
Posts: 569
Joined: Wed Jan 24, 2001 12:09 pm

RE: THe Hole At The Back Of The Plane

Mon Feb 26, 2001 7:52 am

The hole you speak of is the aircraft's APU (Auxhilary Power Unit). The APU provides electricity on the ground for the aircraft, for such functions such as engine start, air conditioning, heating, etc.

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