1. Piercy, Piper and Preston (1) and Piercy, Preston and Whitehead (2) have developed a family of aerofoils which are the inverses of hyperbolas. These calculations give a family with a finite tail angle, equal to the angle between the asymptotes. It may sometimes be preferable to have a rounded trailing edge. It is the purpose of this note to describe a family whose members are inverses of ellipses.

2. It will be seen that, if the centre of inversion is on the major axis produced, symmetrical sections will result; whilst, if the centre is just off the major axis, a cambered section will be produced; and the inverse of the major axis (which is a circle) can be taken as the camber line.