Quote:
Originally Posted by TomcatViP
no again. Sry. But you are in inviscid and incompressible.
Those eq are valid only bellow Mach 0.3. Btw 0.3 and O.6, this can do a nice guess-estimate if you had a coeff. Above 0.6, you can't rely on this way for calculating perfs.
Remind that 0.X is the LOCAL maxima of speed.
Thx however for the details you pushed here.
REM: If you had used your calculation to estimate the time of accel from Stall speed to 200mph, I won't have said anything (if you have added a coef in 2Pi*Alpha). Or the cruise speed (WWII).
~S
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Well, Mtt used exactly same rough calculation as Holtzauge to estimate the speed at different power. When the speed difference is around 10-15kmh, the changes in induced drag, propeller thrust and drag coefficient due to compressibility are so small that the error is less than 0.5kmh. That is certainly good enough, given that most data here is without compressibility corrections.
However, field is open for you interpretation, of course.
10-01-2012, 08:26 PM
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