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Bruce
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Wing Curve Question

Wed Jul 17, 2002 11:21 am

Hopefully this wont sound like a dumb question......but why do jets' wings curve down where they meet the fuselage? I notice this on 737/757/767/MD11 and some others...here's a good example - a photo of mine that was rejected (but I'm working on fixing it)

http://airliners.net/procphotos/rejphoto.main?filename=N383DN_rear_3.jpg

How does this curvature improve lift instead of having a "straight" wing like the DC9s and some others have?

bruce
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
 
Ziggy
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Joined: Thu Jun 21, 2001 11:07 am

RE: Wing Curve Question

Wed Jul 17, 2002 12:52 pm

The curvature is to provide greater amount of lift. With lift comes stress; So the closer to the wing root you get the more stress the wing can handle and the farther the less.

I can go farther into detail if you wish.

Ziggy  Smile
 
FredT
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Joined: Thu Feb 07, 2002 9:51 pm

RE: Wing Curve Question

Wed Jul 17, 2002 6:33 pm

To get the ideal wing efficiency, you aim for elliptical lift distribution.

However, you often twist the wing slightly to give the root a higher angle of attack in order to make the root stall first. If the wingtip stalls first, the roll moments caused by assymetrical stalls are great and to make matters worse, the ailerons are out there in the separated airflow reducing your ability to correct.

It is quite possible that there are further reasons, those swept wings tend to make a big mess out of things you think you know and I'm still getting surprised every now and then when dealing with aerodynamics I have no direct previous experience of..  Smile

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
broke
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RE: Wing Curve Question

Wed Jul 17, 2002 8:19 pm

The trailing edge of all wings have some curvature downwards along the trailing edge (TE). Supersonic and aerobatics wing sections would not show as much as other wings. When designing the wing section along the wing fuselage junction, you have to take into effect the resulting additional drag that the junction causes. The cleanest junction is one where the wing in perpendicular to the fuselage, but this is only possible on a mid-wing design. The Aerostar and the Jet Commander are examples of a mid wing. On low wing airplanes, you use the wing fillet fairings to try make the junction as perpendicular as possible. Calculating the effect of drag in this area is generally based on wind tunnel testing and flight testing and not on a pure theoretical basis. The curvature you are seeing is a solution to the desire to get the best lift with the least drag at the junction.
 
cosync
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RE: Wing Curve Question

Wed Jul 17, 2002 8:53 pm

that photo has been edited by the way. notice all teh black lines. thats why it was rejected.
 
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Bruce
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Black Lines?

Thu Jul 18, 2002 5:49 am

Are you talking about jagged edges - the black lines of the edges of the wings/flaps? yeah, it may have been a bit oversharpened.

There's nothing fake about it - it's only been edited for color/sharpness/size. I took this photo. It's a real 737-800, N383DN.

I'm working on fixing it for another try at upload. I was successful at another upload, a 727 from the same angle. but the 737 has much more of an angle, based on appearance, just like the big jets. I'm going to be uploading an impressive rear shot of a 767 and 777.


bruce
Bruce Leibowitz - Jackson, MS (KJAN) - Canon 50D/100-400L IS lens
 
cosync
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Joined: Sat Nov 17, 2001 7:53 pm

RE: Wing Curve Question

Thu Jul 18, 2002 2:15 pm

welll any editing at all wont be allowed on this site unfortunately:S
so ull have to liek take the picture again or do a super pro job on editing it.

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