Example: old Graupner 7x5.
Front and side view from a flatbed scanner.
The same turned into silhouettes in a grafics program.
PropellerScanner window with parameters and calculated geometry.
Blade chord, twist (blade angle beta), and pitch (!!!) distribution over radius.
JavaProp parameters.
Geometry data from PropellerScanner with front, side, and top view.
Calculated power and thrust coefficients as well as efficiency.
Flow field meaning prop wash speed relative to flight speed (idealized).
As I said, not perfect but better than wind tunnel measurements you don't have.(Notice the table above the coefficient diagrams.
The 9th column indicates that there is no blade stall at advance ratios (v/nD) bigger than 0.25. Best effiency is 70% at 0.65 advance ratio, not bad for such a small prop.
The prop's efficiency depends mainly on a proper choice of diameter, pitch, and rpm. Compared to that, the actual geometry is of minor importance. Of course, you'd notice a big difference (between various geometries) in contest flying. Meseems in the first place the OP's task is rather finding the best motor/prop combo for the job than optimizing it.
Last edited by UStik; 07-31-2014 at 08:21 AM.