Horten Ho 229 (Gotha Go 229) The Horten Ho IX (often called Ho 229, or Gotha Go 229 due to the identity of the chosen manufacturer of the aircraft) was a late-World War II prototype flying wing fighter/bomber, designed by Reimar and Walter Horten and built by Gothaer Waggonfabrik. It is the first pure flying wing powered by a turbojet, and has been described by some as the first aircraft designed to incorporate stealth technology. It was a personal favorite of German Luftwaffe chief Reichsmarschall Hermann Göring, and was the only aircraft to come close to meeting his "1000, 1000, 1000" performance requirements. Its speed was estimated at 1,024 km/h (636 mph) and its ceiling 15,000 meters (49,213 ft). In the early 1930s, the Horten brothers had become interested in the flying wing design as a method of improving the performance of gliders. The German government was funding glider clubs at the time because production of military aircraft was forbidden by the Treaty of Versailles after World War I. The flying wing layout removes any "unneeded" surfaces and, in theory at least, leads to the lowest possible drag. A wing-only configuration allows for a similarly performing glider with wings that are shorter and thus sturdier, and without the added drag of the fuselage. The result was the Horten H.IV. In 1943, Reichsmarschall Göring issued a request for design proposals to produce a bomber that was capable of carrying a 1,000 kg (2,200 lb) load over 1,000 km (620 mi) at 1,000 km/h (620 mph); the so called 3 X 1000 project. Conventional German bombers could reach Allied command centers in Great Britain, but were suffering devastating losses from Allied fighters. At the time there was simply no way to meet these goals — the new Junkers Jumo 004B turbojets could give the required speed, but had excessive fuel consumption. The Hortens felt that the low-drag flying wing design could meet all of the goals: By reducing the drag, cruise power could be lowered to the point where the range requirement could be met. They put forward their private project, the Ho IX, as the basis for the bomber. The Government Air Ministry (Reichsluftfahrtministerium) approved the Horten proposal, but ordered the addition of two 30 mm cannon, as they felt the aircraft would also be useful as a fighter due to its estimated top speed being significantly higher than that of any Allied aircraft. The Ho 229 was of mixed construction, with the center pod made from welded steel tubing and wing spars built from wood. The wings were made from two thin, carbon-impregnated plywood panels glued together with a charcoal and sawdust mixture. The wing had a single main spar, penetrated by the jet engine inlets, and a secondary spar used for attaching the elevons. It was designed with a 7g load factor and a 1.8x safety rating; therefore, the aircraft had a 12.6g ultimate load rating. The wing's chord/thickness ratio ranged from 15% at the root to 8% at the wingtips. Control was achieved with elevons and spoilers. The control system included both long span (inboard) and short span (outboard) spoilers, with the smaller outboard spoilers activated first. This system gave a smoother and more graceful control of roll than would a single spoiler system. The aircraft utilized retractable tricycle landing gear, with the nosewheel coming from an He 177's main gear. A brake parachute slowed the aircraft upon landing. The pilot sat on a primitive ejection seat. It was originally designed for the BMW 003 jet engine, but that engine was not quite ready and the Junkers Jumo 004 engines were substituted.

• published: 18 Dec 2013
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