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User currently offlineJetliner145 From , joined Dec 1969, posts, RR:
Posted (11 years 1 week 23 hours ago) and read 2933 times:

Hello all,
This is something that has been puzzling me. I know that the DC-9, MD-80, & the B717 all have APUs, but what puzzeled me was where is the air intake? Where does it come out? I've looked at many pictures of all those types of aircraft, and I just can figure out where they {APUs} are. If anyone can help please do. Thanks

jetliner Smile/happy/getting dizzy

9 replies: All unread, jump to last
User currently offlineNKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5
Reply 1, posted (11 years 1 week 23 hours ago) and read 2906 times:

On the underside of the aft fuselage, immediately fwd of the aft airstairs. It's not very visible since the ram air scoop is seldom deployed except during starting cycle or commanded open.

Can't speak for the 717.

User currently offlineFBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7
Reply 2, posted (11 years 1 week 23 hours ago) and read 2908 times:

The APU is located in the aft fuselage,aft of the rear pressure bulkhead,just forward of the ventral airstairs.
The air intake is on the underside of the fuselage,not the air intake at the bottom of the vertical fin as many believe. It is a "scoop" like affair extending during APU start. It retracts after starting and two "flap" doors open and supply air to the running APU. The exhaust is on the right hand side of the fuselage,just above the rear half of the engine pylon.

"Luck and superstition wins all the time"!
User currently offlineLMP737 From United States of America, joined May 2002, 4782 posts, RR: 22
Reply 3, posted (11 years 1 week 23 hours ago) and read 2901 times:

Unlike the MD-80 the APU intake on the 717 is located on top of the fuselage. There's a noticeable noise reduction also.

Never take financial advice from co-workers.
User currently offlineAtlamt From United States of America, joined Sep 2001, 242 posts, RR: 3
Reply 4, posted (11 years 1 week 21 hours ago) and read 2880 times:

The MD-80's were plagued with air turnbacks due to smoke in the cabin/ burning smell caused by the apu ingesting hydraulic fluid. The drains for the tail compartment are just forward of the apu intake. The 717's apu intake was moved for this reason.

Fwd to MCO and Placard
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17351 posts, RR: 67
Reply 5, posted (11 years 1 week 20 hours ago) and read 2869 times:

This should clarify where the exhaust is located

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Photo © Philippe Bleus

"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineJetliner145 From , joined Dec 1969, posts, RR:
Reply 6, posted (11 years 1 week 18 hours ago) and read 2846 times:

Thanks everyone for explaning.

jetliner Smile/happy/getting dizzy

User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 66
Reply 7, posted (11 years 1 week 17 hours ago) and read 2847 times:

Just barely visible here.

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Photo © Peter Fagerström

Look just above the silver part of the engine on the far side, and just forward of what appears to be a drain mast. You will see a small square area that is the APU inlet door in the closed position. In the non-ram position you would see a rectangular opening, transverse, and in the ram, there would be a slight extension of the aft part of the door into the slipstream.

Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineDalmd88 From United States of America, joined Jul 2000, 2725 posts, RR: 14
Reply 8, posted (11 years 1 week 9 hours ago) and read 2796 times:

Ok I've looked at a bunch of pictures of the 717. Where is the intake? All I can see is the Ram intake at the bottom of the vertical, the apu exhaust on the right side, and the aircycle machine exhaust on each side.

User currently offlineBR715-A1-30 From , joined Dec 1969, posts, RR:
Reply 9, posted (11 years 1 week 3 hours ago) and read 2784 times:

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Photo © AirNikon

See the hole with the red rectangle around it? That is the APU intake for the 717. The exhaust is in the same position on the other side.

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