Airspeed at sea level

I got interesting airspeed calculator Excel-sheet from Petri Flander. I have been calculating those things with my aircraft design program and by hand before, but it is surprisingly handy to see the effect of various flat plate drag areas and their effect to the airspeed. Great input for my program which I am writing the UI for with Qt right now, I may do also graphical output for these parameters, would be fun to have. This was actually also useful to reverse-engineer the flat plate drag areas of various aircrafts. For example I came up with 4,7 ft2 for Cirrus SR20 where Lancair ES (=same as Columbia 400) is 4,0, so Cirrus is a slightly less efficient than the Columbia (which is evident also from the performance numbers comparing SR22 and Columbia 400). Interesting is that I came up with 9 for C152, which is a terribly bad figure. And Zenair CH701 produced a number around 18 which was reverse-engineered from real performance numbers I have heard from a Zenair pilot. Couldn’t get much worse than that. BD-5 has very low figure of 0,9 and Vmax probe is at 0,3 (these were obtained from elsewhere). A composite BD-5 with rear body laminar flow suction (with more laminar body shape as well) and some high tech airfoil like the NLF414F could be super-efficient. However, the issues with low Reynolds number from Vmax probe apply, it will have seriously dangerous stall charasteristics without modifications to the airfoil or wing.

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