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Old 12-12-2012, 05:24 PM
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MJD
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Default RE: Optimized speed calculator

It sounds like you are assuming an airplane will fly at pitch speed. That is hardly ever true.

A static thrust measurement or calculation has no meaning with respect to the airspeed that your aircraft will attain. Thrust is not constant with airspeed. If static thrust had any bearing on the potential airspeed of an aircraft then pylon racers would use 3D props and we'd be bolting helicopter rotors to the front of our sport aircraft.

Wing airfoil parameters? You can find that on the internet by googling "airfoil data".

Wing parameters? You mean how to calculate the aerodynamic drag of a wing?

Not sure what this speed calculator is but it sounds like it is trying to condense complex physics into a few simple numbers and rule of thumb formulae. For example, an 8% wing profile will have less drag than a 16% profile? Is that always true? A 1.7m wing has more drag than a 1.4m wing? Is that always true? No and no.

The problem with simple calculators using broad parameters and assumptions, is that they can be made to work well for a few sets of conditions when the parameters are derived from empirical observation under those conditions. In other words, changing the rules to fit the data. But when you stray too far from those conditions then the reality of how complex the matter really is rears its head and the "calculations" lose meaning.