Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
744 APU Fairing?  
User currently offlineDocLightning From United States of America, joined Nov 2005, 18699 posts, RR: 58
Posted (5 years 3 weeks 15 hours ago) and read 3620 times:

So I was at LAX yesterday and we went right behind a 744 (actually, two of them. One Air China and one KL) when I noticed that the fairing over the APU looks radically different from the rest of the body panels. The APU fairing is made up of myriad small panels, many of them probably not much more than a foot on a side.

Anyone know why? I don't think this is the case on the 777.

6 replies: All unread, jump to last
 
User currently offlineLowrider From United States of America, joined Jun 2004, 3220 posts, RR: 10
Reply 1, posted (5 years 3 weeks 14 hours ago) and read 3602 times:

What look like panel lines are actually lines of rivets. See the following closeups for a comparison:

View Large View Medium
Click here for bigger photo!

Photo © Gregg Stansbery


and

View Large View Medium
Click here for bigger photo!

Photo © Craig Murray



APUs need to be contained in a stronger structer than the rest of the tail cone due to risk of fire and rotor burst. Some aircraft accomplish this by enclosing the APU with a shroud or box, others simply reinforce the area around it. Perhaps the paint and construction methods on the 777 hide the rivet lines better.

[Edited 2009-03-29 12:59:33]


Proud OOTSK member
User currently offlineZANL188 From United States of America, joined Oct 2006, 3433 posts, RR: 0
Reply 2, posted (5 years 3 weeks 14 hours ago) and read 3593 times:
Support Airliners.net - become a First Class Member!



Quoting DocLightning (Thread starter):
The APU fairing is made up of myriad small panels, many of them probably not much more than a foot on a side.

Anyone know why? I don't think this is the case on the 777.

APU Fairing has round head rivets that protrude above the skin, most other areas are flush rivetted and the rivets don't show as much.


View Large View Medium
Click here for bigger photo!

Photo © C.S. Photography
View Large View Medium
Click here for bigger photo!

Photo © Nikolas Stassinopoulos



View Large View Medium
Click here for bigger photo!

Photo © Klaas Reinder Sluijs
View Large View Medium
Click here for bigger photo!

Photo © Craig Murray



View Large View Medium
Click here for bigger photo!

Photo © John F. Zielinski




Legal considerations provided by: Dewey, Cheatum, and Howe
User currently offlineBoacvc10 From United States of America, joined Jul 2006, 587 posts, RR: 0
Reply 3, posted (5 years 2 weeks 5 days 18 hours ago) and read 3250 times:



Quoting Lowrider (Reply 1):

APUs need to be contained in a stronger structer than the rest of the tail cone due to risk of fire and rotor burst. Some aircraft accomplish this by enclosing the APU with a shroud or box, others simply reinforce the area around it. Perhaps the paint and construction methods on the 777 hide the rivet lines better.

Is there a reason for the APU on the B747 to be in line with the vertical stablizer, fuselage, yet the B777 has it on the side ?

Does it make a bit of difference ?

Also, generally (I am not a pilot) how much generating capacity does the APU have in KW, and where is its fuel tank / supply ?

BOACVC10



Up, up and Away!
User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 4, posted (5 years 2 weeks 5 days 17 hours ago) and read 3248 times:



Quoting Boacvc10 (Reply 3):
Is there a reason for the APU on the B747 to be in line with the vertical stablizer, fuselage, yet the B777 has it on the side ?

Both the 747 and 777 have their APU mounted on the center line of the aircraft. The 777 just uses a 'screw driver' type tail cone.



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineLowrider From United States of America, joined Jun 2004, 3220 posts, RR: 10
Reply 5, posted (5 years 2 weeks 5 days 12 hours ago) and read 3176 times:



Quoting Boacvc10 (Reply 3):
Also, generally (I am not a pilot) how much generating capacity does the APU have in KW, and where is its fuel tank / supply ?

The 747 Classic has two 90 KVA gens mounted on the APU. The fuel supply is the #2 Main tank. I believe the 400 has the same gens, but a different model APU. I would imagine the fuel supply is the same source.



Proud OOTSK member
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 6, posted (5 years 2 weeks 5 days 5 hours ago) and read 3079 times:



Quoting Boacvc10 (Reply 3):
Is there a reason for the APU on the B747 to be in line with the vertical stablizer, fuselage, yet the B777 has it on the side ?

Does it make a bit of difference ?

The knife-edge tail on the 777 has a slight drag advantage over the conventional cone. However, it's harder to build and has some maintenance issues related to turning the APU exhaust. It's a trade without a really clear winner...Boeing went back to the cone for the 787 so the drag benefit couldn't have been that huge.

Quoting Boacvc10 (Reply 3):
Also, generally (I am not a pilot) how much generating capacity does the APU have in KW, and where is its fuel tank / supply ?

It varies from airplane to airplane...787 will be the largest at (I believe) 250 kW. Fuel source for all Boeing-heritage twins is the no. 1 main tank (aka the left wing).

Tom.


Top Of Page
Forum Index

Reply To This Topic 744 APU Fairing?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
747sp/744 Wing-body Fairing posted Sun Dec 7 2008 22:20:02 by SCAT15F
Qantas 744 Engine Questions posted Sat Feb 28 2009 17:03:19 by Wdwfreak
Bathroom In The Cockpit Of A 744? posted Fri Jan 16 2009 20:00:53 by SXDFC
Boeing 744 Flying With Biofuel posted Tue Dec 30 2008 05:12:58 by Gonzalo
Should B Offer 744 Re-engine Program? posted Sun Dec 14 2008 22:05:45 by SCAT15F
Getting Hold Of An APU posted Sat Dec 13 2008 19:50:41 by Spudsmac
744 Upper Deck Cabin Width posted Wed Nov 19 2008 14:20:15 by LY777
How Long Can An APU Run? posted Mon Oct 20 2008 10:35:56 by Litz
Loud Engine Noise On CX 744 posted Fri Oct 10 2008 11:29:32 by 744
Cargo Comparison Between 744, 773ER, & A380 posted Wed Sep 10 2008 19:52:25 by Kaitak744

Sponsor Message:
Printer friendly format