Elliptical Planforms: A Capsule History

Frederick Lanchester, an Englishman born in 1868, discovered high efficiency elliptical planforms. In 1897 Lanchester presented a paper on the origin and nature of lift generated by an aerofoil (a term he coined). The Physical Society of London immediately rejected his idea.

Not accepting defeat Lanchester continued to work and 10 years later published Aerodynamics. In his book Lanchester presented the concept of the elliptical distribution of lift, and the vortex theory of the finite aerofoil. The vortex theory predicted the existence of the tip vortex. Lanchester predicted all of this with no testing or evidence to guide him; he didn’t use models or wind tunnels.

Lanchester also secured a patent for bent up wing tips to control tip vortices, in 1897. Lanchester devised these theories about the same time the Wright brothers were learning to fly. 20 years later other aerodynamicists proved his theories correct.

During WWII the English exploited elliptical lift distribution in the design of the Spitfire airplane wing. This arrangement was chosen because it gives the most lift for the least amount of drag.

Racing yacht designers began to use the elliptical planform in their mainsails during the 1930’s and now designers use elliptical sails that can sometimes be almost rectangular.

Planform- the shape of an object when viewed from the top-down perspective (plan view).

As a note, this is a brief history of this shape. I am by no means an expert.

Aerohydrodynamics of Sailing, C. A. Marchaj
Eric Sponberg