Horten H.III

The H.III series was an incremental development of the Horten H.II with reduced sweepback of 23°, span increased to 20 m (65  ft 7 in) and modified lateral controls. The wing trailing edges had three movable surfaces; the innermost was a landing flap, but the outer pair were geared differential elevons with the outer elevon having a large upward deflection and only slight downward movement, conversely, the inner elevon had large downward movement and slight upward movement. Aerodynamic balance for control surfaces was by a geared tab on the IIIa and b, but on IIId, f, and g the outer flap had a 20% Frise nose which also countered adverse yaw: out-of-balance aerodynamic loads on the elevators were trimmed by a rubber bungee trimmer with the trim datum set by the pilot. ==Operational history==

The H.III was designed to compete at the 1938 Rhön Gliding Competitions at the Wasserkuppe and two aircraft were available at the start of the competition, to be flown by Heinz Scheidhauer and Werner Blech. As the competition progressed the two H.IIIs were achieving reasonable results with Blech leading over Scheidhauer. Near the end of the competition the weather deteriorated with cumulonimbus clouds and rain showers. Blech recognised that he could win the competition outright with a high-altitude flight in one of the clouds. ==Surviving aircraft==

The centre section of the H.IIIh, (werknummer 31) built at Göttingen in 1944, is preserved at the Smithsonian National Air and Space Museum. The glider was captured by the British Combined Intelligence Objectives Subcommittee in 1945 at Rottweil, moved to Freman Field in America, by 1946 and transferred to Northrop Corporation at Hawthorne, California along with a Horten H.IIIf and the Horten VI V2 in 1947. ==Variants==

;Horten H.IIIa :Original version, flown by Heinz Scheidhauer in the 1938 Rhön Gliding Competition. Scheidhauer entered a cumulonimbus cloud during a competition altitude flight and was next seen descending by parachute, presently followed by the hail shattered remains of his H.IIIa. Scheidhauer was suffering from frostbite and lost several fingers. ;Horten H.IIIf :A H.IIIb built with a prone-position cockpit and modified control systems. Three built, ;Horten H.IIIg :Special two-seater centre section with tandem seats for training purposes. Four aircraft were built with one being converted to the sole H.IIIh. ;Horten H.IIIh :A single H.IIIg modified with the a second cockpit filled with test equipment, survived the war with the remains held by the Smithsonian Institution, displayed at the Steven F. Udvar-Hazy Center. ==Specifications (Horten H.III)==