Measurements in mm All radii from hub center. Pitch is measured from perpendicular to propshaft radius chord pitch 24.5 25 70.8 33.5 30 66.9 42.5 37 63.2 51.5 38 58.8 60.5 38 55.0 69.5 38 51.4 78.5 38 47.4 87.5 38 43.8 96.5 38 40.0 105.5 38 37.5 114.5 38 36.1 123.5 38 34.2 132.5 36 32.5 141.5 34 31.5 150.5 32 30.0 159.5 30 28.7 168.5 25 27.0 177.5 20 25.5 186.5 15 23.9 195.5 10 22.4 The design conditions for this prop were 2-bladed, 360rpm, 0.4m (16") diameter, 2.9m/s speed and thrust of 59N. This was based on an input power of 200W. JavaProp gives an efficiency of 85 to 86% using the E193 foil. It's slightly better using the MA409 foil.