UALPHLCS
Topic Author
Posts: 3233
Joined: Thu Jun 28, 2001 5:50 am

The Most Lift On A Wing

Sun Sep 01, 2002 1:19 pm

Where is the most lift being generated on the wing? Is it near the wing root, where the wing is thickest and the air has to move the fastest or farther out on the wing? Or is lift generated equally along the whole wing?
A little less Hooah, and a little more Dooah.
 
FredT
Posts: 2166
Joined: Thu Feb 07, 2002 9:51 pm

RE: The Most Lift On A Wing

Mon Sep 02, 2002 3:53 am

Ideally, you have an elliptical lift distribution. I e, if you plot the lift distribution along the wing, you'll end up with one quarter of an ellipse. With this lift distribution, you get the best efficiency out of the wing. That is why the wings of the Spitfire have the famous elliptical shape even though it is a lot harder to manufacture efficiently.

Most wings are built as compromises between this ideal lift distribution and other factors though.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
UALPHLCS
Topic Author
Posts: 3233
Joined: Thu Jun 28, 2001 5:50 am

RE: The Most Lift On A Wing

Mon Sep 02, 2002 2:09 pm

So for example the greatest lift on a 777 wing is somewhere just past the engine nacelle to somewhere just inside the wingtip?
A little less Hooah, and a little more Dooah.
 
JRSLim
Posts: 9
Joined: Tue May 28, 2002 10:56 am

RE: The Most Lift On A Wing

Tue Sep 03, 2002 6:25 am

Well heres the little info I know:

The lift generated by any portion of a wing will depend on its airfoil, chord and angle of attack. If you look at most airliners, they have high lift airfoils and longer chords near the root of the wing, this should be where the most lift is generated. One factor to keep in mind is wing twist. Most wings, and I believe this includes most airliners, have a wing twist where the end of the wings has a smaller angle of incidence (angle of wing to the fuselage centerline) than the roots. This is so when the inside of the wings reach the angle of attack where they will stall -- the ends of the wing will still be generating a little lift -- this is for stability and predictability during a stall.
Hope this info helps --
Shaun
Go Where Eagles Dare
 
UALPHLCS
Topic Author
Posts: 3233
Joined: Thu Jun 28, 2001 5:50 am

RE: The Most Lift On A Wing

Tue Sep 03, 2002 12:10 pm

Ok this is great and Iv'e learned alot. But to put this in the simplest terms, Ive got to explain this to my wife, IS most of the lift being generated in the middle of the wing just outboard of the engines?

If I had a model of a 777 and my hands supported the plane just past the engines, would that be an accruate (if crude) display of what is supporting the plane in flight?
A little less Hooah, and a little more Dooah.
 
aeroguy
Posts: 66
Joined: Wed Aug 15, 2001 1:33 am

RE: The Most Lift On A Wing

Wed Sep 04, 2002 1:56 am

Put simply, no. With an elliptical lift distribution, the maximum lift is at the wing root. Everywhere else along the span (including near the engines and the tip), the lift will be less than at the root.
Why all this talk about elliptical lift distribution? Ideally, you want as close to an elliptical lift distribution as possible in order to minimize induced drag. Regardless of planform, induced drag is a function of spanload only. It's probably a safe assumption to say that airliner wings are designed for near-elliptic lift distributions since minimizing drag is so crucial.
 
UALPHLCS
Topic Author
Posts: 3233
Joined: Thu Jun 28, 2001 5:50 am

RE: The Most Lift On A Wing

Wed Sep 04, 2002 4:48 am

So the ellipsis runs from wingtip to wing tip with the fuselage at the Perigee (correct term? or apogee I get them mized up). Not as I previously understood from wingroot to wingroot independent of one another? Is this correct? So if we picture an arch from wingtip to wingtip the fuselage is in the middle supported by the arch, which is just a simple representation of the amount of lift the wings are creating. Is that the simplest explaination?
A little less Hooah, and a little more Dooah.

Who is online

Users browsing this forum: No registered users and 14 guests