Walter Horten (born 13 November 1913 inBonn; died 9 December 1998 inBaden-Baden,Germany) andReimar Horten (born 12 March 1915 inBonn; died 14 March 1994 inVilla General Belgrano,Argentina), sometimes credited as theHorten Brothers, wereGerman aircraft pilots. Walter was a fighter pilot on theWestern Front, flying aBf 109 forJagdgeschwader 26 in the first six months ofWorld War II; he eventually became the unit's technical officer. Reimar was also trained as a Messerschmitt Bf 109 pilot; however, later in August 1940, he was transferred to the glider pilot school in Braunschweig. He earned his PhD in mathematics from the University of Göttingen, having resumed his studies in 1946 with help from Ludwig Prandtl. The Hortens designed the world's first jet-poweredflying wing, theHorten Ho 229.
Between theWorld Wars, theTreaty of Versailles limited the construction of German military airplanes. In response, German military flying became semi-clandestine, taking the form of civil "clubs" where students trained on gliders under the supervision ofWorld War I veterans. As teenagers, the Horten brothers were involved in these flying clubs.
This back-to-the-basics education, and an admiration of German avant-aircraft designerAlexander Lippisch, led the Hortens away from the dominant design trends of the 1920s and 1930s, 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, by which time both brothers were members of theHitler Youth.[1]
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. The great advantage of the Horten designs was the relatively lowparasitic drag of their airframes.
By 1939, withAdolf Hitler in power and the Treaty of Versailles no longer in effect, Walter and Reimar had entered theLuftwaffe as pilots. (A third brother, Wolfram, was killed flying a bomber overDunkirk.) They were also called upon as design consultants, though Germany's aeronautical community tended to regard the Hortens not as part of the cultural elite. However, both were members of theNSDAP.[2]
Walter participated in theBattle of Britain, secretly flying as the wingman forAdolf Galland, and shot down seven British aircraft.[3]
In 1937, the Hortens began using motorized airplanes, with the debut of the twin-enginedpusher-prop airplane H.VII (an earlier glider had a mule engine[clarification needed]). The Luftwaffe, however, did not actually use many of the Hortens' designs until 1942, but gave enthusiastic support to a twin-turbojet-poweredfighter/bomber design, designated under Luftwaffe protocols as theHorten H.IX.[4] For their completion of the three Ho 229 prototypes (V1, V2, V3), the Horten brothers were awarded 500,000 Reichsmark (approximately US$2–3 million in 2021 terms).[3][5]
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 229 V2 nearly reached a then-astonishing 800 km/h (500 mph) in trials, the production of the third prototypeV3 was given over to the coachbuilderGothaer Waggonfabrik, subsequently called Gotha Go 229. The Go 229 was captured by theU.S. Army at the end of World War 2, and the nearly completeV3 third prototype aircraft was shipped to the US to be studied. It is presently stored at theSmithsonian Institution inWashington, D.C.[2]
The Ho 229 had potential, but it was simply developed too late to see service. The Horten brothers also worked on theHorten H.XVIII, an intercontinental bomber that was part of theAmerikabomber project, and a prototype for a smaller version was ordered for the 1000 x 1000 x 1000 contest, for a bomber capable of flying at 1,000 km/h (620 mph) with 1,000 kg (2,200 lb) bombs with a 1,000 km (620 mi) range.
Among other advanced Horten designs of the 1940s was the supersonic delta-wing H.X, designed as a hybrid turbojet/rocket fighter with a top speed of Mach 1.4, but it was only tested in glider form as the Horten H.XIII.
As the war ended, Reimar Horten emigrated toArgentina after failed negotiations with the United Kingdom and China,[6] where he continued designing and building gliders, including one experimental supersonic delta-wing aircraft and the four-engined flying wingFMA I.Ae 38 Naranjero, intended to carry oranges from producers to Buenos Aires. Walter remained in Germany after the war and became an officer in the post-war German Air Force. Reimar died on his ranch in Argentina in 1994, while Walter died in Germany in 1998.
In the late 1940s, the personnel ofProject Sign, theU.S. Air Force'sflying saucer investigation, seriously considered the possibility that UFOs might have been secret aircraft manufactured by theU.S.S.R. based on the Hortens' designs.[7]