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Old 01-10-2008, 10:18 AM
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BMatthews
 
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Default RE: WINGSPAN AND WING ROOT TO PRODUCE LIFT AT WHAT SPEED WITH A WEIGHT OF

To do a complete analysis of all the stuff there's a number of formulas to run your material through. Part of the plan is also your airfoil choice. Depending on the size and speed of your model this will determine the maximum lift coefficient that you can operate at before the wing stalls. For example the SAE heavy lift models can operate up close to a Cl of 2 while a light indoor model may only be able to get to 1 or so. This is largely due to the reynolds number effect. So keep that in mind if you are wanting to operate in one of the more extreme aspects.

I don't keep the formulas handy but I know that others have dug them up from web searches. Try key words like "aerodynamic lift drag calculation" or "wing lift drag calculation" and I'll bet you find them soon enough.

For a quick test run your planned wing size through Foilsim (google for it from the NASA site) and alter the one airfoil they give you to be the planned camber and thickness and then input the wing size and expected weight of your model. Then alter the angle (angle of attack) and speed until your "model" is running around a Cl of 1. Then switch to the lift readout and see how many lbs of lift you have.