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Old 09-14-2005, 07:18 PM
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Mike Connor
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Default RE: Plane choice


ORIGINAL: stupidaso

I was being very simplistic with the "thrust minus drag equals speed" comment, merely to demonstrate my question on 2 vs 4 cycle engine use.

I certainly realize there are more factors involved.

Thank you for the formula, I will definitely use it.

And thanks for schooling me! I knew throwing that out there would generate some good info.

Stu

You are on the right track. When thrust and drag is equal then speed is constant. Increase the thrust and you increase the speed. While a ballpark thrust can be calculated, the drag is much more difficult to come up with.

The pitch and rpm formula may give you a ball park speed in some cases, it also can be way off. A good radar gun or accurate time and distance figures are the most accurate way to calculate speed.