zionstrat
Posts: 225
Joined: Sat Apr 28, 2001 3:26 am

737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 2:01 am

I'm sure this will be an easy one for anyone with familiar with 737 technology, however I noticed a 'mini' flap for lack of better words on a recent flight and would like to understand it's purpose and operation-

If you look at the "main" outboard flap, there is a smaller extension on the trailing edge that seems to extend before the main flap extends. At take off, it appears that it is primarily this 'mini' flap that is extended, while the "main" flap also extends at higher settings-

Here's a picture in case I'm not explaining well- It is the final "segment" of this flap that is extended in this picture.


Click for large version
Click here for full size photo!

Photo © Martin Bauer



I'm interested in the name, and the purpose- Why not a single flap that simply extends farther down? It doesn't appear to act as a split flap.

Thanks in advance!
 
A/c train
Posts: 674
Joined: Sun Jun 10, 2001 7:57 am

Flaps

Wed Oct 17, 2001 4:38 am

This I believe is just a triple slotted flap, this increases camber and adds lift for takeoff and also acts to slow the a/c down on approach, clever bit of kit!!
regards
a/c
 
OPNLguy
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RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 5:08 am

A/C nailed it, just Boeings choice of design versus the "barn door" type that are found on DC-9s/MD-80s etc. The three sections are known as the fore flap, the mid flap, and the the aft flap.

FYI, Only the -100 thru -500 have triple-slotted trailing edge flaps like these, and all the NG variants (-600 thru -900) have a double-slotted design that was an improvement over the old.
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
david b.
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Joined: Fri Jun 15, 2001 7:18 pm

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 5:10 am

What is that little thing at the end with what looks like a little hole in it?
Its pointing towards the plane.
Teenage-know-it-alls should be shot on sight
 
Mr Spaceman
Posts: 2723
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RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 5:33 am

Hi David B.

I believe what you're asking about is the exit port for the fuel jettison valve.

If the pilots have to dump fuel for an emergency landing, etc, this is where it flys out! I should be able to find a photo.

Chris  Smile

"Just a minute while I re-invent myself"
 
310_engineer
Posts: 163
Joined: Tue Dec 05, 2000 7:16 am

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 5:46 am

Hi Chris
It's the logolight!
Never heard about a 737 with fuel jettison.

Cheers
Mike
 
sabenapilot
Posts: 2442
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RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 5:49 am

Mr Spaceman,
From an ex-B737 pilot, the B737 can not dump fuel!!!

David B.,
The little thing at the end of the wing pointing towards the plane is nothing more then the logo light.
It points at the tail and is switched on during night to make some publicity...

 
OPNLguy
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RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 5:50 am

>>>If the pilots have to dump fuel for an emergency landing, etc, this is where it flys out! I should be able to find a photo.

I wish you luck, since the 737 doesn't have a fuel dump system...  Big grin

The item that Davod B is curious about is called a "logo" light, and it is indeed pointed towards the aircraft. In fact, it's specifically aimed to illuminate the entire vertical stabilizer of the aircraft, so better night ID of aircraft, as well as showing the airline's logo for promotional purposes. There's also one on the opposite wingtip. Some larger aircraft (the 747 is one that comes to mind) have theirs imbedded on the top side of the horizontal stabilizers on each side, shining up from there.

Not all aircraft have logo lights, and on Boeing's at least, they are an option....
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
sabenapilot
Posts: 2442
Joined: Sat Feb 26, 2000 6:18 pm

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 6:18 am

Seems we all replied at the same moment guys, resulting in 3 posts saying more or less the same....

 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 6:36 am

Hey, great minds work alike...  Smile

(Don't ya just love this global village stuff?)
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
sabenapilot
Posts: 2442
Joined: Sat Feb 26, 2000 6:18 pm

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 6:49 am

Global village?
I'd say open university!
Over the last few months I have replied to numerous technical questions related to the B737. In most (but not all) cases they came from HAWK21. It seems to me some guys are doing their type rating course on this forum.... or at least they let others answer their test questions.  Wink/being sarcastic
Anyway, I'm glad I could help you all out guys...
Keep the questions comming!
 
310_engineer
Posts: 163
Joined: Tue Dec 05, 2000 7:16 am

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 7:08 am

I think he will never make that mistake twice.

Sabenapilot:
What do you think what happens with us (SN) tomorrow?

Cheers
Mike
 
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 7:11 am

Hi guys,

Well, now that I've pulled my head out of my ass, I can say to David B. --- I'm sorry about that!

I'm sure glad I stated that I "Believed" it was for dumping fuel, instead of "I'm sure it's for dumping fuel". It's been made very clear to me that I believed WRONG! Thanks guys for straightening that out.

That logo light (in the photo) sure looks like a hole in the wingtip fairing (where fuel would be dumped) and not a light, because it's so dark.

Also, thanks for wishing me luck in finding pics of a 737 dumping fuel, but as I'm sure you know, I didn't find any. In fact, I couldn't find any photos of any type of airliner jettisoning fuel. I've seen many photo's of this on Airliners.net. I wonder what the keywords are?

Not to go way off topic about the 737's flaps, but, can someone tell me why a 737 doesn't have the ability to dump fuel? Could it be that the jet's Maximum Gross T/O and Landing weight's are almost identical?

Chris  Smile/happy/getting dizzy

"Just a minute while I re-invent myself"
 
OPNLguy
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

Chris

Wed Oct 17, 2001 7:39 am

A couple of pix, plus a link to my answer on a previous message thread from April...


Click for large version
Click here for full size photo!

Photo © Peter D. Baumgartner



Click for large version
Click here for full size photo!

Photo © Richard Zeman


http://www.airliners.net/discussions/general_aviation/read.main/446390/6/

ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
cdfmxtech
Posts: 1319
Joined: Wed Jul 05, 2000 11:37 am

RE: Mr Spaceman

Wed Oct 17, 2001 8:23 am

UR correct (Max TO weight and Landing weights are very close to one another - therefore no need for fuel jettison).
 
User avatar
HAWK21M
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RE: 737- Can You Expain "mini" Flap?

Wed Oct 17, 2001 11:21 pm

Logo light all right.
 Smile

80% of my questions are on the B737.But I'm from maintenance.Just want to clear any doubt I could think of on this aircraft.

Experience is what this forum has Which no book can replace. Smile
regds
HAWK.
I may not win often, but I damn well never lose!!! ;)
 
Mr Spaceman
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RE: 737- Can You Expain "mini" Flap?

Sat Oct 20, 2001 6:45 am

Hi guys.

Thanks for letting me know that the nearly identical Maximum Gross T/O and Landing weights of the 737 is the reason why it doesn't have a fuel dumping system. The Boeing 777 sure isn't in the same boat. According to an article I'm reading, it can takeoff at Maximum Gross Weight and fly for 11 hrs before it reaches it's certified Maximum Landing Weight of 460,000 pounds. The 777 definetly needs the ability to dump fuel.

Question: In the photo of the Fokker F-28 below, is the red circle on the aft edge of the farthest wing fairing, a Logo Light?

Click for large version
Click here for full size photo!

Photo © Chris Coduto


Chris  Smile



"Just a minute while I re-invent myself"
 
NKP S2
Posts: 1665
Joined: Mon Dec 20, 1999 3:16 am

RE: 737- Can You Expain "mini" Flap?

Sat Oct 20, 2001 12:49 pm

Yes, it's a logo light on that Fokker.

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