1. Very high efficiency propellers are similar in aerofoil section to a low drag wing and as such are poor in operation when at other than their optimum angle of attack.

2. The aerofoil section characteristics are obtained analytically by the extension of the image system for a single vortex and for a single source to those for vortex and source distributions.

3. The A wing is powerful! This is primarily because the aerofoil section has been carefully developed so meter for meter the A-Wing is one of the most powerful wings on the market

4. The geometry of the blade in the thrust position comprises at least one horizontal cross sectional form, which is an aerofoil section with a curved camber line and a substantially varying thickness profile along the longitudinal extend of its chord line.