Sailplane data

At 00:28 10 February 2011, Francisco De Almeida wrote:
I can't really think of any other way of calculating the lift
coefficient of an airfoil theoretically.

A lot of good people have found more straightforward ways to compute the
lift coefficient, which is in fact very easy to calculate. The maximum
lift coefficient, the drag coefficient, the pitching moment coefficient
are the hard ones.

Perhaps you could consult a standard textbook on glider aerodynamics,
e.g.
Prof. Fred Thomas "Handbook of Sailplane Design".



If you have the aerofoil profile, then Xfoil (freeware from a very
respected aerodynamicist) will give you a reasonable 1st guess at all of
these for 2D flow. XFLR5 extends Xfoil to 3D wings (originally intended
for RC gliders, but should probably* be OK for full-scale sailplanes).

Using Fourier coefficients to calculate 2D (or 3D wing) characteristics,
is a real throw-back to the 50's - useful in a textbook derivation to
give an analytical solution, but no-one does it any more.

Doug


*usual caveats apply - these are not guaranteed to give the right answer,
so use with caution!