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I just took the Commercial Airplane written, and one of the most

annoying parts was the performance stuff. That is, given temperature,

pressure altitude, weight, and headwind, calculate takeoff or landing

distance. In every airplane handbook I've seen, this involves tracing

tiny lines across three different graphs. In the DA40 handbook they

even use a very coarse linear interpolation so the lines are very

unsatisfying.There ought to exist standard analytic formulas for all this, since I

don't think each manufacturer has measured each separate point on each

curve. For example, the first graph in the sequence is always density

altitude which is quite standard. But what is a good source for those

formulas?I have most of the standard flying books including the famous

Aerodynamics for Naval Aviators, but they don't give much detail. I've

looked at a bunch of Aeronautical Engineering textbooks, but they seem

to be designed for undergraduate majors and it would take a long time

to get from basic principles to simple formulas which is all I want.

So can anyone suggest a good source to explain how the manufacturers

generate these graphs?Many thanks in advance.

-- Robert Almgren, June 20, 2009