Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

wingtip aerodynamics

Wikiposts
Search

Notices
Tech Log The very best in practical technical discussion on the web

wingtip aerodynamics

Thread Tools
 
Search this Thread
 
Old 12th March 2010 | 21:54
  #1 (permalink)  
Thread Starter
 
Joined: Mar 2010
Posts: 2
Likes: 0
From: scotland
wingtip aerodynamics

Hi all

This is my first post on the forum and you will probably laugh at my question but it is annoying me now.

I am trying to work out the aerodynamic effect winglets have on an aircraft in the glide and turn but all I can find out is it reduces the induced drag with a slight increase in lift. Surely there is more to it than that.....

Can anyone help me please...how does the winglet make a differance on thrust, drag, lift and weight on the turn and glide....I cant see them make any differance on weight but maybe less thrust required due to a decrease in drag while gaining a slight increase in lift....

Any advice would be gratefully received..
stuckoutthere is offline  
Reply
Old 12th March 2010 | 22:49
  #2 (permalink)  
 
Joined: Jan 2007
Posts: 200
Likes: 0
From: Vermont
Yaw moment and stability...
Mansfield is offline  
Reply
Old 13th March 2010 | 14:05
  #3 (permalink)  
15 Anniversary
 
Joined: Jun 2009
Posts: 1,344
Likes: 80
From: Bedford, UK
interested too

poking my nose in because I would be interested to know this to. From what little I learnt 25 years ago, seem to remember that one reason then cited was to avoid the end effect of the wing, ie circulation falling off the end of the wing, so it increased the efficiency of the wing by reducing a negative practical correction to (potential flow) theory. Presumably that could be equated to same lift at lower aoa and therefore same lift for less drag. Dihedral effect would also influence stability as mentioned above by giving a small added force at long radius arm, ie tip of wing.
Mr Optimistic is offline  
Reply
Old 13th March 2010 | 15:06
  #4 (permalink)  
 
Joined: Jun 2001
Posts: 2,627
Likes: 2
From: UTC +8
Just curious: Had the designers overlooked the winglets on the B777 . . . B787?
GlueBall is offline  
Reply
Old 13th March 2010 | 15:34
  #5 (permalink)  
 
Joined: Dec 2002
Posts: 2,775
Likes: 353
From: UK
Had the designers overlooked the winglets on …
A notice on the wall of the Hatfield aerodynamics department (Aahh de Havilland) read “a good wing does not require winglets”.
This was the home of the team who designed the original Airbus wing, and only after being pushed (marketing?) added ‘endplates’ to the A320 wing.
safetypee is offline  
Reply
Old 13th March 2010 | 20:10
  #6 (permalink)  
Community Builder
20 Anniversary
 
Joined: Dec 2002
Aviation Qualifications: ATP+Mil
Posts: 3,985
Likes: 568
From: Where the Quaboag River flows, USA
Safetypee

That sign was later stolen and put on a wall in Bordeaux, France at AMD design headquarters. They succumbed to winglets, too.

GF
galaxy flyer is offline  
Reply
Old 13th March 2010 | 20:19
  #7 (permalink)  
 
Joined: Dec 2003
Posts: 476
Likes: 0
From: Massachusetts Bay Colony
Not a scientific response but I remember one of my aerodynamics profs at university saying that when Ohio State University was doing research into winglets, the discovered that the best angle for mounting them was...horizontal. By which he meant, they don't really do a whole lot that a well designed wingtip won't do.
Pitts2112 is offline  
Reply
Old 13th March 2010 | 20:46
  #8 (permalink)  
 
Joined: Oct 1999
Posts: 398
Likes: 0
From: United Kingdom
Dunno about the whys and wherefores, but a B757 with winglets burns around a tonne less fuel than an unmodified airframe on a return flight from the UK to Cyprus. Must be doing something good.
Bally Heck is offline  
Reply
Old 13th March 2010 | 21:20
  #9 (permalink)  
 
Joined: Dec 2008
Posts: 10
Likes: 0
From: On the edge of insanity
Just a couple of inputs

"Horizontal" winglets = larger wingspan = doesn't fit

Winglets can increase weight due to higher aero loads and therefore additional structure
massman is offline  
Reply
Old 13th March 2010 | 21:22
  #10 (permalink)  
 
Joined: Oct 2005
Posts: 8
Likes: 0
From: Lightning Country
This article Wingtip device - Wikipedia, the free encyclopedia may prove helpful.
kalooli is offline  
Reply
Old 13th March 2010 | 22:49
  #11 (permalink)  
 
Joined: Dec 2004
Posts: 793
Likes: 3
From: edge of reality
“a good wing does not require winglets”.

Probably true... I'm not an aerodynamiscist.. Supposedly the winglet will reduce induced drag..it also acts as a wing fence and generally improves performance and fuel efficiency...
There's usually more than one way to do a job and using a winglet as opposed to developing a more efficient wing is an option...
Interesting that one of the most aerodynamically efficient (and maybe THE most aerodynamically efficient aircraft outside of the military), the Piaggio Avanti, does not have winglets.... a result of something over 70 hours of wind-tunnel testing... the average military fast jet would typically get about 40+ hours of wind tunnel development.
MungoP is offline  
Reply
Old 14th March 2010 | 17:22
  #12 (permalink)  
 
Joined: Jan 2005
Posts: 319
Likes: 0
From: north
uh.. winglets basicly increase Aspect Ratio and Area with
the aerodynamic & structural pro's and con's that go with that.
Wing fences don't do that, they just reduce lateral flow of air
along the wing.

As mentioned, winglets also increase stability around the vertical
axis which means a bit more rudder might be required in e.g. a
decrab on landing. (which might reduce max xwind limit on some types)

M
XPMorten is offline  
Reply
Old 20th March 2010 | 22:17
  #13 (permalink)  
Thread Starter
 
Joined: Mar 2010
Posts: 2
Likes: 0
From: scotland
thanks for the replies.

What I am struggling to understand is if the aircraft is in a banked turn the upper wing will be travelling faster. This means that the winglet, which has an aerofoil shape, will be producing lift. With this lift and the cant angle will it cause the aircraft to turn more into the turn or will it try to draw it out the turn and back level?
stuckoutthere is offline  
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.