Horten brothers

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Walter and Reimar Horten were teenage air enthusiasts in Germany between the World Wars, a time in which the Treaty of Versailles limited the construction of military airplanes, and in which German military flying had gone underground, taking the form of civil 'clubs' where students trained on gliders under the supervision of decommissioned World War I veterans.

This back-to-the-basics education, and an admiration of German avant-aircraft designer Dr. Alexander Lippisch, led the Hortens away from the dominant design trends of the 1920s and '30s, and toward experimenting with alternative airframes -- building models and then filling their parents' house with full-sized wooden sailplanes. The first Horten glider flew in 1933, when both brothers were still in their teens.

The Hortens' glider designs were extremely simple and aerodynamic, generally consisting of a huge, tailless albatross-wing with a tiny cocoon of a fuselage, in which the pilot lay prone. But the great advantage of the Horten designs was the extremely low parasitic drag of their airframes. They were 'slick' and scalable to high speeds.

By 1939, with Adolf Hitler in power and the Treaty of Versailles no longer in effect, Walter and Reimar had entered the Luftwaffe as pilots. (A third brother, Wolfram, was killed flying a bomber over Dunkirk.) They were also called upon as design consultants, although they suffered a disadvantage in that their reputation was very much grass-roots, among Germany's aeronautical community, rather than through official connections.

The Hortens had made the natural leap to powered flight in 1937, with the twin-engined pusher-prop airplane Ho VII (an earlier glider had a mule engine). The Luftwaffe, however, paid mostly lip service to their designs until 1942, when grudging (and partly under-the-table) support was given to a twin-turbojet-powered fighter/bomber design, designated under wartime protocols as the Horten Ho IX.

The Horten Ho 229, the world's first jet-powered flying wing

Securing the allocation of turbojets was difficult in wartime Germany as other projects carried higher priority due to their rank in the overall war effort. Although the turbojet-equipped Ho IX V2 reached almost 500 mph in trials, the project was soon given over to the theretofore low-tech aircraft company, Gothaer Waggonfabrik, as the Horten Ho 229 (subsequently often erroneously called Gotha Go 229).

The Ho 229 was a fighter jet with great potential, but arrived too late to see service. Among other advanced Horten designs of the 1940s was the supersonic delta-wing Ho X, designed as a hybrid turbojet/rocket fighter with a top speed of Mach 1.4, but tested only in glider form (as the Horten Ho XIII).

As the war ended, Reimar Horten emigrated to Argentina, where he continued designing and building sailplanes and one twin-engined flying wing transport, which was unsuccessful commercially. Walter remained in Germany after the war and became an officer in the post-war German Air Force Luftwaffe. Reimar died on his ranch in Argentina in 1994, while Walter died in Germany in 1998.

Restored examples of the Horten III and Horten VI sailplanes are displayed at the Udvar-Hazy facility of the National Air and Space Museum (NASM) in Washington, DC.Two of the Horten's sailplanes built in Argentina can be seen at the Museo Nacional de Aeronáutica located in MORON few miles west of Buenos Aires. The turbojet powered Ho 229 V3 brought to the U.S. as part of Operation Paperclip for evaluation is in storage at the NASM awating possible restoration, and an example of the Horten IV sailplane is located in the "Planes of Fame" aircraft museum in Chino, California. A restored Horten IV is also on display at the Deutsches Museum in Munich.