Sponsor Message:
Civil Aviation Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Why Does The 744 Wing Curve Down At The Ends?  
User currently offlineUal747 From , joined Dec 1969, posts, RR:
Posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2878 times:

I didn't realize this until I took my first trip on the 744. The wings curve downward at the last few feet on each wing. Also, if you notice sitting in front of the wing, the last 10-20 feet of the leading edges have a different angle than the rest of the wing. What are the purposes of these features?

Wingtip Bent Downward

View Large View Medium
Click here for bigger photo!

Photo © Carlos Borda



Leading Edge

View Large View Medium
Click here for bigger photo!

Photo © Søren Geertsen



UAL747

14 replies: All unread, jump to last
 
User currently offlineHA_DC9 From United States of America, joined Jul 1999, 656 posts, RR: 1
Reply 1, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2872 times:

They curve down because of the weight of the fuel in the wing.

User currently offlineMSYtristar From , joined Dec 1969, posts, RR:
Reply 2, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2868 times:

Just a guess here: Would it have something to do with the heavy fuel load on the aircraft?




User currently offlineAS739X From United States of America, joined Apr 2003, 6196 posts, RR: 24
Reply 3, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2864 times:

Its called fuel, and weights 6.7 lbs/per gallon if Im not mistaken. Anything that has flex in when producing lift as in the wing will have flex the other way when not producing lift.
ASSFO



"Some pilots avoid storm cells and some play connect the dots!"
User currently offlineBig777jet From , joined Dec 1969, posts, RR:
Reply 4, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2860 times:

AS729X~

You are correct. 6.7 lb per gal of kerosene fuel.


Big777jet



User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4491 posts, RR: 21
Reply 5, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2856 times:

If I recall, isn't this part of the reason the B-52 has those outrigger wheels on the ends of the wings?



I got my head checked--by a jumbo jet
User currently offlineUal747 From , joined Dec 1969, posts, RR:
Reply 6, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2844 times:

I'm not talking about the entire wing flexing due to fuel. I know that the entire wing will flex because of the weight of fuel. I'm talking about how the very tip of the wing, close to the winglet has an extra downward bend to it. Even when the wing flexes upward during flight, there is a bend in the tips.


View Large View Medium
Click here for bigger photo!

Photo © Propfreak



UAL747


User currently offlineUal747 From , joined Dec 1969, posts, RR:
Reply 7, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2839 times:

Also, when talking about the leading edge, I'm talking about how the wing is swept backward. The outer most parts of the wings past the #1 and #4 engines are swept back at a different angle.

UAL747


User currently offlineClickhappy From United States of America, joined Sep 2001, 9664 posts, RR: 68
Reply 8, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2824 times:
AIRLINERS.NET CREW
PHOTO SCREENER

move this to the Tech Forum!

User currently offlineWn700driver From , joined Dec 1969, posts, RR:
Reply 9, posted (11 years 6 months 2 weeks 1 day 13 hours ago) and read 2820 times:

I would guess it has something to do with the fact that the outermost portion of the wing is actually an extension "tacked" onto the original wing design. IIRC, the -4XX 747s have an extra two metres of span (per wing), in addition to the winglets themselves.
To me, it appears that (in flight at least), that last outer portion is actually even (0 degrees to level), whereas the rest of the wing has a dihedral form, giving the illusion of a "droop."

That's my take on it anyway; and worth exactly what you paid for it,  Big grin


User currently offlineHa763 From United States of America, joined Jan 2003, 3671 posts, RR: 5
Reply 10, posted (11 years 6 months 2 weeks 1 day 12 hours ago) and read 2759 times:
Support Airliners.net - become a First Class Member!

The droop at the end of the wing would have to do with the length of wings and the extra weight of the winglets.

The leading edge is a straight line. There is no change in angle. It is the wing flexing that makes it seem like the angle the wing is swept back is different at the area past the outer engine.


View Large View Medium
Click here for bigger photo!

Photo © Glenn Alderton
View Large View Medium
Click here for bigger photo!

Photo © Martin West



User currently offlineN949WP From Hong Kong, joined Feb 2000, 1437 posts, RR: 1
Reply 11, posted (11 years 6 months 2 weeks 1 day 12 hours ago) and read 2748 times:

The section of the wings outboard of the No. 1 and No. 4 engines do indeed have a slightly reduced sweepback angle. The purpose of that is to reduce wing flutter. I read about that in a book (forgot the name) that documents the development of the 747.

'949


User currently offlineDeltaMD11 From United States of America, joined Dec 2002, 1701 posts, RR: 34
Reply 12, posted (11 years 6 months 2 weeks 1 day 7 hours ago) and read 2620 times:

The wing droop at the end of each wing is the 6ft wing extension you're seeing that Boeing put on the -400's.

Bryan



Too often we ... enjoy the comfort of opinion without the discomfort of thought. - John Fitzgerald Kennedy
User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 22
Reply 13, posted (11 years 6 months 2 weeks 1 day 5 hours ago) and read 2574 times:

I'm pretty sure it's the weight of the winglets, nothing more...


Boeing747 万岁!
User currently offlineNa From Germany, joined Dec 1999, 10817 posts, RR: 9
Reply 14, posted (11 years 6 months 2 weeks 1 day 5 hours ago) and read 2531 times:

Actually the degree of the leading edge angle of all the 747 wings is higher up to the outer engine joint. The reason is aerodynamics. I´m not a technician, but that´s for sure the reason for that. The A380 will be similar. The leading edge angle degree near the fuselage will be higher than on the outer parts.


View Large View Medium
Click here for bigger photo!

Photo © Alexander Kueh



Top Of Page
Forum Index

This topic is archived and can not be replied to any more.

Printer friendly format

Similar topics:More similar topics...
Why Does The BAe-146 Have 4 Engines? posted Thu Jun 27 2002 05:37:54 by Brons2
Why Does The L-1011 Smoke So Much posted Sun Jun 9 2002 06:44:18 by BR715-A1-30
Why Does The An-124 Visit Your Town? posted Tue Jun 4 2002 03:58:12 by CannibalZ3
Why Does The 747 Have It's Abnormal Structure? posted Tue Jan 29 2002 04:16:12 by Legolars
Why Does The "start New Topic" Button Do This... posted Mon Jul 30 2001 00:10:01 by SJCguy
Why Does The 747-400 Have Three APs? posted Fri Mar 2 2001 01:05:37 by Timbo
Why Does The Body Of A/c Break Into Three Parts? posted Mon Nov 27 2000 16:14:44 by Aerosol
Why Does The CRJ Have A High Angle Of Attack posted Fri Feb 18 2000 21:49:44 by LH423
Why Does The WN Flight Crew Dislike The 733? posted Mon Jul 3 2006 02:42:36 by GuitrThree
Why Does Airbus Add Lights On The Side Of The.? posted Sat Mar 25 2006 18:41:29 by AirCanada014