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Old Sep 28, 2012, 01:05 PM
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United States, MI, South Lyon
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Help!
Tetsing of various planforms

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Old Sep 28, 2012, 01:35 PM
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Cromer,Norfolk, UK
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If you keep the wing area/section/speed the same, the lift force, if I understand it correctly, will not change. The planform will change the pattern of lift distribution (as well as mass distribution) which will have an impact on handling etc, but lift force is a function of lifting area, lift coefficient, and airspeed, rather than planform. I think! I may be incorrect.
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Old Sep 28, 2012, 11:18 PM
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Old Sep 29, 2012, 06:50 AM
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United States, UT, Salt Lake City
Joined Oct 2007
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Maybe, maybe not
the slower and smaller the subject becomes , the more a low aspect ratio is favored.
You will love this part
The air always takes the path of least resistance and the only way you can get any pressure difference (lift) is to have enough surface ,arranged such that the lifting surface can develop higher and lower pressures. A high aspect setup works - but only as speed increases.
It is obviously a bag of compromises where you have to pick and choose to get performance you are after.
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Old Sep 29, 2012, 09:12 AM
Grad student in aeronautics
United States, GA, Atlanta
Joined Oct 2010
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Just as different planforms will have different span efficiency factors, they will also have different lift curve slopes ( dCL/dalpha). Aspect ratio will have the largest effect on this.

I'm still not sure exactly what you're testing. Are you testing their maximum lift ability?
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Old Sep 29, 2012, 10:46 AM
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Old Sep 29, 2012, 01:21 PM
An itch?. Scratch build.
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South Wales U.K.
Joined Mar 2003
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Can't quite visualize how you are doing it, but my first thought was basically the tow line glider hook location. I assume you would need something to mount the wings on, a 'fuselage' ?, possibly even with a rear stabilizer ?.
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Old Sep 29, 2012, 02:18 PM
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Old Sep 29, 2012, 04:54 PM
Grad student in aeronautics
United States, GA, Atlanta
Joined Oct 2010
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I think I understand a little better. It sounds like you are calculating lift based off of the moment it applies about the pivot point, and you want to know how best to pick the moment arm, which will factor into the equation.

Ideally you would place the moment arm at the center of pressure, which is where lift and drag act. However, this location changes with angle of attack.
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