Horten H III h

Horten craftsmen built this Horten III h, Werk Nr. 31, in 1944 at Göttingen. Uncertainty surrounds the subtype designation 'h,' but the glider probably first flew as a two-place Horten III g, and then Reimar modified it into a single-seat glider, installed special test apparatus, and changed the designation to 'III h. During September 1944, Josef Eggert of Zimmer Unter den Burg, a small town near Rottweil, Germany, flew the unmodified III g 20 times and amassed 14 hours and 17 minutes of total flight time. Eggert reported excellent handling qualities, but he apparently chose not to grapple with adverse yaw because he commented specifically on the very tight but flat turns that were possible using only the drag rudders. Eggert warned that stall recovery was good but only when the aircraft was properly trimmed.

The special equipment consisted of a portable box-shaped device, approximately one meter square and half-a-meter wide, rested behind the pilot's seat. Atop the box a sprocket and chain drove cables leading forward past the pilot's left shoulder. A boom projected from the lower leading edge of the center section, right of the nose, and it apparently supported a precision angle-of-attack instrument. Remnants of two other crude but functional devices that precisely measured yaw remain fitted to the center section today. Clearly the sailplane featured in a flight test program but more specific information remains unknown. Photographs are all that remain of the box, sprocket, chain, boom and drogue device. These items were stripped from the glider long before transfer to the National Air Museum (it became the NASM in 1966).

From 1933 to 1990, Reimar Horten, with help from his brother, Walter, designed and built a series of swept-wing aircraft without fuselages or tails and they did not use any other surfaces for control or stability that did not also contribute lift to the wing. The National Air and Space Museum owns a Horten II L, Horten III f, Horten III h, Horten VI V2, and the Horten IX V3 turbojet fighter bomber.

Horten craftsmen built this Horten III h, Werk Nr. 31, in 1944 at Göttingen. German Registration LA-AI was applied to either side of the ventral fin. Uncertainty surrounds the subtype designation 'h' but the glider probably first flew as a two-place Horten III g, and then Reimar modified it into a single-seat glider, installed special test apparatus, and changed the designation to 'III h. During September 1944, Josef Eggert of Zimmer Unter den Burg, a small town near Rottweil, Germany, flew the unmodified III g twenty times and amassed 14 hours and 17 minutes of total flight time. Eggert reported excellent handling qualities but he apparently chose not to grapple with adverse yaw because he commented specifically on the very tight, but flat turns that were possible using only the drag rudders. Eggert warned that stall recovery was good but only when the aircraft was properly trimmed. According to Eggert, Heinz Schiedhauer and Hermann Strebel conducted all test flights with the special equipment fitted while another aircraft flew above the glider taking pictures. A standard Ho III had a maximum speed of 210 km/h (130 mph) and a best glide speed of 63 km/h (39 mph).

The special equipment consisted of a portable box-shaped device, approximately one meter square and half-a-meter wide, rested behind the pilot's seat. Atop the box, a sprocket and chain drove cables leading forward past the pilot's left shoulder. A boom projected from the lower leading edge of the centersection, right of the nose. Apparently, the boom supported a precision angle-of-attack instrument. Remnants of two other crude but functional devices that precisely measured yaw remain fitted to the centersection today. One unit was attached just ahead of the windshield. The other hangs beneath the centersection, forward of the landing skid fairing. A drogue device that resembled a small missile hung from a cable beneath the left wing. It extended into the aircraft's wake.

The sailplane obviously featured in a flight test program but information that is more specific remains unknown. Photographs are all that remain of the box, sprocket, chain, boom and drogue device. Someone stripped these items from the glider long before transfer to the National Air Museum (it became the NASM in 1966).

Late in April 1945, American officials seized this sailplane and took it to Klippenek where personnel had collected other captured German aircraft. A British C.I.O.S. (Combined Intelligence Objectives Subcommittee) team discovered the Horten IIIf on June 11, 1945, along with the Horten III h, Werk Nr. 31. The team found the gliders at Rottweil on the Neckar River, approximately 100 km (60 miles) southwest of Stuttgart, Germany. Another team that included the great British sailplane authority, Chris Wills Sr., examined the gliders later that month. A member of this team wrote an official intelligence report describing both sailplanes "in perfect condition in trailers, with a full set of instruments." This same report describes the Horten H III h equipped with two seats but no special equipment, raising the possibility that the Allies tested the wing after they recovered it but there is now no evidence of a second seat.

Wingspan 20 m (66 ft)

Center Section Length 5 m (16.4 ft)

Height 1.6 m (5.4 ft)

Weights, Empty 250 kg (550 lb, special equipment not included)

Gross, 360 kg (792 lb)

Suggested further reading:

Lee, Russell. "The National Air and Space Museum Horten Sailplane Collection: HortenII L, IIIF, IIIH, and VI-V2," "Bungee Cord," Vol. XXIII No. 4, Winter 1997.

Myhra, David. "The Horten Brothers and Their All-Wing Aircraft." Atglen, Penn.: Schiffer Publishing Ltd., 1998.

Nickel, Karl, and Wohlfahrt, Michael. "Tailless Aircraft in Theory and Practice." Reston, Va.: American Institute of Aeronautics and Astronautics, 1994.

Selinger, Peter F., and Horten, Reimar. "Nurflugel: Die Geschichte der Horten-Flugzeuge 1933-1960." Graz, Germany: H. Weishaupt Verlag, 1983.

Russ Lee, 9-2-04