Originally posted by niklas
Hello
Does anyone know where the prop pitch angle is measured? Is it the AoA of the prop tip, or 0.5 of the radius? I mean due to the twist the Blade has many AoA (standing aircraft).
Thank you
nik
Yes, the blade angle of a propeller is variable from root to tip, however, for comparison of various propellers, the blade angle at the three-quarter radius is normally used as a reference.
So, when you use the propeller curves for performance calculations, the family of curves for each propeller are also marked with the blade angles at the three-quarter radius. The same convention is used for propellers with manual pitch settings. The blade angle is defined as the acute angle between the chord of the propeller section and the plane of rotation. In the very rare cases where that convention has not been adopted, the station at which the blade angles have been measured has always been given. However, 0.75r appears to be standard practice for every document I've seen dating back to the early thirties.
Hope that helps
Badboy
