Editing Horten Ho 229 (section)

==Design and development==
[[File:Horten H.IX V2.jpg|thumb|The Horten H.IX ''V2'' before a test flight]]

During the early 1930s the [[Horten brothers]] had become interested in the [[flying wing]] configuration as a method of improving the performance of [[Glider (sailplane)|gliders]]. At that time the German government was actively funding glider clubs as a response to the production of aircraft suitable for military roles being forbidden by the [[Treaty of Versailles]]. The flying wing layout theoretically offered the lowest possible weight, and without the added drag of the [[fuselage]]. Their first aircraft of this configuration was the [[Horten H.IV]].<ref name = "bbc 229">{{cite web |last = Dowling |first = Stephen |url = http://www.bbc.com/future/story/20160201-the-wwii-flying-wing-decades-ahead-of-its-time |title = The Flying Wing Decades Ahead of its Time |publisher = BBC News |date = 2 February 2016}}</ref><ref name = "smith strange2020">{{cite web |url = https://www.smithsonianmag.com/smithsonian-institution/truth-stranger-fiction-hortens-all-wing-aircraft-design-180976095/ |title = Truth Is Stranger Than Fiction With Horten's All-Wing Aircraft Design |publisher = Smithsonian |first = David |last = Kindy |date = 21 October 2020}}</ref>

In 1943 [[Hermann Göring]] issued a request for design proposals for a bomber capable of carrying a {{convert|1000|kg}} load over {{convert|1000|km}} at {{convert|1000|km/h}} which was known as the "3×1000 project". German bombers could reach Allied targets across [[Great Britain]], but were suffering devastating losses from Allied fighters.<ref name = "bbc 229"/> At the time, no conventional means for aircraft designers to meet these goals seemed viable because while the new [[Junkers Jumo 004]]B [[turbojet]]s provided the speed, excessive fuel consumption limited range. The Horten brothers concluded that a low-drag flying wing design could meet the goals, as by reducing drag, [[Cruise (flight)|cruise]] power could be reduced so the [[Range (aircraft)|range]] requirement could then be met. They put forward their private project, the ''H.IX'', as the basis for the bomber.

While removing the vertical stabilizer reduced drag, it caused yaw control problems. In traditional aircraft, a [[vertical stabilizer]] works passively to ensure that [[Slip (aerodynamics)|sideslip]] is minimized by producing a force perpendicular to itself when any sideslip occurs. The lack of a vertical stabilizer meant that flying without any active yaw control would lead to an uncontrolled sideslip, and potentially [[Spin (aerodynamics)|flat spins]]. This was resolved with split ailerons, which increase drag on one side. While designs without vertical stabilizers require more active control by the pilot or a future flight control systems and lead to bank angle restrictions, they do reduce aerodynamic drag slightly.<ref>{{Cite web |title=Horten Ho 229 V3 {{!}} National Air and Space Museum |url=https://airandspace.si.edu/collection-objects/horten-ho-229-v3/nasm_A19600324000 |access-date=2024-02-21 |website=airandspace.si.edu |language=en}}</ref>{{Failed verification|date=October 2024}}

The Government Air Ministry (''[[Reichsluftfahrtministerium]]'') quickly approved Horten's proposal, but ordered the addition of two {{cvt|30|mm}} cannons, as they felt the aircraft might also be useful as a fighter due to it being significantly faster than existing Allied aircraft.<ref name = "smith strange2020"/> German officials assigned the designation ''Ho 229'' to the aircraft. Göring was reportedly impressed with the design and personally intervened to ensure that three prototypes were ordered at a cost of 500,000 [[Reichsmark]]s.<ref name = "smith strange2020"/> The Air Ministry issued an order for 100 production aircraft, but this was later reduced to 20.<ref name = "Metzmacher 199">Metzmacher 2021, p. 199.</ref> Furthermore, as the Horten brothers lacked production facilities, it was decided that the manufacturing would be done by an established company, [[Gothaer Waggonfabrik]].<ref name = "LePage 246">LePage 2009, pp. 24-26.</ref> This arrangement was complicated by Gothaer's alleged efforts to persuade the authorities to favour its own projects, which included flying wings, over the Ho 229.<ref name = "Metzmacher 1916">Metzmacher 2021, p. 191, 196.</ref>

Observing the Ho 229's design and development difficulties, Russell Lee, the chair of the Aeronautics Department at the National Air and Space Museum, speculated that an important motivation for the Horten brothers was to prevent them and their workers from being assigned dangerous roles by the German military.<ref>{{Cite news |url = https://insider.si.edu/2018/04/desperate-for-victory-the-nazis-built-an-aircraft-that-was-all-wing-it-didnt-work/ |title = Desperate for victory, the Nazis built an aircraft that was all wing. It didn't work. |date = 5 April 2018 |publisher = Smithsonian Insider |access-date = 4 May 2018 |language = en-US}}</ref> Looking beyond the Ho 229, the Horten brothers produced numerous flying wing designs, such as the [[Horten H.VII]] fighter-trainer and the [[Horten H.XVIII]] [[Amerikabomber]].<ref name = "LePage 199303">LePage 2009, pp. 199, 303-305.</ref><ref name = "smith strange2020"/> According to the aviation historian Jean-Denis G.G. LePage, other German wartime projects were inspired by the Horten brother's work.<ref name = "LePage 201">LePage 2009, p. 201.</ref>

The H.IX was of mixed construction with the center section built up from welded steel tubing with a diameter up to {{cvt|160|mm}},<ref>{{Cite web |date = 12 September 2014 |title = How is it Constructed? |website = Horten IX V3 (Ho 229) Technical Study and Conservation |url = https://hortenconservation.squarespace.com/how-is-it-constructed/ |archive-url = https://web.archive.org/web/20140912044314/https://hortenconservation.squarespace.com/how-is-it-constructed/ |archive-date = 12 September 2014 |access-date = 24 March 2021}}</ref> while the outer box wing spars were of [[pine]].<ref name = "airspace 2016"/>

The outer wings were skinned with thin [[plywood]] panels that were glued together with a sawdust mixture and covered with [[fireproofing|fireproof]] paint.<ref name = "airspace 2016"/> The wing had a single main spar, penetrated by the jet engine inlets, and a secondary spar used for mounting the [[elevon]]s. It was designed with a 7g [[Load factor (aeronautics)|load factor]] and a 1.8× safety rating giving the aircraft a 12.6g ultimate load rating. The wing's chord/thickness ratio ranged from 15% at the root to 8% at the wingtips.<ref name="WOTR" /> There was little available interior space, making the addition of additional equipment or crew members difficult or impossible.<ref name = "LePage 305">LePage 2009, p. 305.</ref>

The aircraft was fitted with retractable [[Tricycle gear|tricycle landing gear]], with the [[Landing gear|nose gear]] on the first two prototypes from a [[Heinkel He 177]]'s tailwheel system, with the third prototype using an He 177A main gear wheel rim and tire on a newly designed nose gear leg. A [[drogue parachute]] slowed the aircraft upon landing. The pilot sat on a primitive [[ejection seat]] and a special [[pressure suit]] was developed by [[Drägerwerk|Dräger]]. While originally designed for the [[BMW 003]] turbojet engine, this engine was not ready, and the [[Junkers]] [[Jumo 004]] engine was substituted.<ref name="WOTR"/> [[Aircraft flight control system|Flight control]] was achieved via a combination of elevons and [[spoiler (aeronautics)|spoilers]]. This control system included both long-span (inboard) and short-span (outboard) spoilers, with the smaller outboard spoilers activated first; it reportedly provided a smoother control of [[Aircraft principal axes#Vertical axis (yaw)|yaw]] than would have been by a single-spoiler system.<ref name="WOTR" />