Fig. 4. Principle of the Huth annular-biplane system.

CROSS-SECTION

Diagram showing different aerofoil shapes and aspect ratios (A.R.).

Fig. 3. A simple experiment in annular aerofoils.

Fig. 6. Huth annular biplane of 1909.

Fig. 7.-Cedric Lee Monoplane No. 1 of Tilghman Richards, 1912.

Fig. 8. Project by Warren and Young for a light twin-engined two-seater of 90 h.p. (1937). The elevator is fitted between fin and fuselage. There is no tailplane.

Fig. 10. Principle of the Willoughby Delta design.

Fig. 9. Model of the "annular wing" of Antes, 1933.