zipsy
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What Is This Hole On The Belly Of The 787?

Tue Jul 02, 2013 1:13 am

I'm interested what this hole on the belly of the 787 is for,any ideas?
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[Edited 2013-07-01 18:15:09]
 
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Stitch
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RE: What Is This Hole On The Belly Of The 787?

Tue Jul 02, 2013 1:47 am

This looks like it is at the front of the wingbox, not the back, and I believe the APU battery drain plug is in the aft area per Boeing presentations.
 
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Web500sjc
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RE: What Is This Hole On The Belly Of The 787?

Tue Jul 02, 2013 4:05 pm

the new battery drain?
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KarelXWB
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RE: What Is This Hole On The Belly Of The 787?

Fri Jul 05, 2013 12:20 pm

The battery exhaust should look like this:

Close, but no cigar http://vine.co/v/OjqeYWWpVWK
 
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HAWK21M
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RE: What Is This Hole On The Belly Of The 787?

Fri Jul 05, 2013 4:13 pm

Any reason why the colour looks different in the opening thread pic of the area in question.
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zipsy
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RE: What Is This Hole On The Belly Of The 787?

Sat Jul 06, 2013 1:43 am

Found a better photo
 
Dalmd88
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RE: What Is This Hole On The Belly Of The 787?

Sat Jul 06, 2013 12:36 pm

I'll take a guess. Exhaust for avionics cooling?
 
ferpe
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RE: What Is This Hole On The Belly Of The 787?

Sun Jul 07, 2013 4:46 am

Quoting zipsy (Reply 5):
Found a better photo

The hole is placed directly underneath the air cond (ECS) packs and should therefore be part of them I guess. Looks like some kind of drain hole perhaps for mositure? I think you can even see it in the principle picture below, the right hand pack has a tube that goes to the skin to expel something.

http://i298.photobucket.com/albums/mm262/ferpe_bucket/ECSdrainholeof787_zps23ba7701.jpg

http://i298.photobucket.com/albums/mm262/ferpe_bucket/787airconditioningpackinstallation_zps9de3a6f7.jpg

Seems like the form of the exit has evolved, my photo is from early prototypes and it is a flush back-angled exit, your exits seems to be with an exit cavity.

[Edited 2013-07-06 21:50:10]
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zipsy
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RE: What Is This Hole On The Belly Of The 787?

Sun Jul 07, 2013 8:36 pm

I thought is was some sort of drain for moisture too.Makes perfect sense
 
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bikerthai
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RE: What Is This Hole On The Belly Of The 787?

Mon Jul 08, 2013 2:16 pm

Quoting ferpe (Reply 7):
Looks like some kind of drain hole perhaps for mositure?
Quoting zipsy (Reply 8):
I thought is was some sort of drain for moisture too.Makes perfect sense

Don't look like a drain hole for moisture. Moisture drains are relatively small and usually mounted flush with pressure valve.

Don't think it's the battery vent drain as the batteries are located in the electronic bays (fore and aft). That vent is also small.

Strange how the hole is recessed with what I presume to be a titanium fitting as it is not painted. So, what ever it is it, the exhaust temperature is expected to be greater than 250F (120 C).

bt
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kanban
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RE: What Is This Hole On The Belly Of The 787?

Mon Jul 08, 2013 4:54 pm

BT, I agree with you, however it is odd that it is only under one pac with a keel beam between them. Could we have something above the pac that requires exhaust venting?
 
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bikerthai
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RE: What Is This Hole On The Belly Of The 787?

Mon Jul 08, 2013 7:48 pm

Quoting kanban (Reply 10):

I wish Tom was still around. He would have been able to answer this off the top of his head.

bt
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zipsy
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RE: What Is This Hole On The Belly Of The 787?

Tue Jul 09, 2013 2:38 am

 
ferpe
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RE: What Is This Hole On The Belly Of The 787?

Tue Jul 09, 2013 7:28 am

Yes, it is the Nitrogen generation system exhaust, it is placed together (a bit behind) the left ECS pack, here a picture of it, one can see the exhaust:

Non French in France
 
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7BOEING7
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RE: What Is This Hole On The Belly Of The 787?

Tue Jul 09, 2013 8:48 pm

Quoting bikerthai (Reply 9):
Don't look like a drain hole for moisture. Moisture drains are relatively small and usually mounted flush with pressure valve.

Except on the 777 where they all have "little fins" that cover the drains. They are easy off/on for drain replacement. This was an FAA requirement to prevent any fluid (fuel) getting back into the airplane "bilge" during a negative pressure condition.
 
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bikerthai
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RE: What Is This Hole On The Belly Of The 787?

Wed Jul 10, 2013 2:49 pm

Quoting 7BOEING7 (Reply 14):
This was an FAA requirement to prevent any fluid (fuel) getting back into the airplane "bilge" during a negative pressure condition.

So, would this be true for the 787 and new models? Or have they found new ways to deal with the back pressure?

bt
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