Horten Ho 229
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| Horten Ho 229 V1 | ||
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| Description | ||
| Role | Fighter | |
| Crew | One, pilot | |
| First Flight | ||
| Manufacturer | Gothaer Waggonfabrik | |
| Dimensions | ||
| Length | 7.47 m | 24 ft 6 in |
| Wingspan | 16.65 m | 54 ft 8 in |
| Height | 2.77 m | 9 ft 1 in |
| Wing area | 52.5 m2 | 565 ft2 |
| Weights | ||
| Empty | 4,800 kg | 10,582 lb |
| Loaded | 6.912 kg | 15,238 lb |
| Maximum takeoff | 9,000 kg | 19,841 lb |
| Powerplant | ||
| Engines | 2x Junkers Jumo 004 B turbojets | |
| Thrust | 8.8 kN | 1,980 lbf |
| Performance | ||
| Maximum speed | 977 km/h | 607 mph |
| Combat range | 1000 km | 623 miles |
| Ferry range | 1,900 km | 1,184 miles |
| Service ceiling | 16,000 m | 52,000 ft |
| Rate of climb | 1,320 m/min | 4,330 ft/min |
| Wing loading | kg/m² | lb/ft² |
| Thrust/Weight | ||
| Avionics | ||
| Avionics | ||
| Armament | ||
| Guns | 4x 30 mm MK 108 | |
| Rockets | R4M rockets | |
| Bombs | 2x 1000 kg bombs | |
The Horten Ho 229 (often erroneously called Gotha Go 229 due to the identity of the chosen manufacturer of the aircraft) was a late-World War II flying wing fighter aircraft, designed by the Horten brothers and built by Gothaer Waggonfabrik. It was a personal favourite of German Luftwaffe chief Reichsmarschall Hermann Göring, and was the only plane to be able to meet his infamous performance requirements.
In the 1930s the Horten brothers had become interested in the all-wing design as a method of improving the performance of gliders. The all-wing layout removes any "unneeded" surfaces and –in theory at least– leads to the lowest possible drag. For a glider low drag is very important, with a more conventional layout you have to go to extremes to reduce drag and you will end up with long and more fragile wings. If you can get the same performance with a wing-only configuration, you end up with a similarly performing glider with wings that are shorter and thus sturdier.
Years later, in 1943 Reichsmarschall Göring issued a request for design proposals to produce a bomber that was capable of carrying a 1000 kg load over 1000 km at 1000 km/h; the so called 1000/1000/1000 rule. Conventional German bombers could reach Allied command centers in England, but were suffering devastating losses, as allied fighter planes were faster than the German bombers. At the time there was simply no way to meet these goals; the new Jumo 004B jet engines could give the speed that was required, but swallowed fuel at such a rate that they would never be able to match the range requirement.
The Hortens felt that the low-drag all-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 current private (and jealously guarded) 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 30MM cannon, as they felt the aircraft would also be useful as a fighter due to it's estimated top speed being significantly faster than any allied aircraft.
Reichsmarschall Göring believed in the design and ordered the aircraft into production at Gotha as the RLM designation of Ho 229 before it had taken to the air under jet power. Flight testing of the Ho IX/Ho 229 prototypes began in December 1944, and the aircraft proved to be even better than expected. There were a number of minor handling problems but otherwise the performance was outstanding.
Gotha appeared to be somewhat upset about being ordered to build a design from two "unknowns" and made a number of changes to the design, as well as offering up a number of versions for different roles. Several more prototypes, including those for a two-seat "Nacht-Jager" night fighter, were under construction when the Gotha plant was overrun by the American troops in April of 1945.
The Ho 229 A-0 pre-production aircraft were to be powered by two Junkers Jumo 004B turbojets with 1,962 lbf (8.7 kN) thrust each. The maximum speed was estimated at an excellent 590 mph (950 km/h) at sea level and 607 mph (977 km/h) at 39,370 ft (12,000 m). Maximum ceiling was to be 52,500 ft (16,000 m), although it's unlikely this could be met. Maximum range was estimated at 1180 miles (1,900 km), and the initial climb rate was to be 4330 ft/min (22 m/s). It was to be armed with two 30 mm MK 108 cannon, and could also carry either two 500 kg bombs, or twenty-four R4M rockets.
It was the only design to come close to meeting the 1000/1000/1000 rule, and that would have remained true even for a number of years after the war. But like many of the late war German designs, the production was started far too late for the plane to have any effect. In this case none saw combat.
The majority of the Ho-229's skin was a carbon-impregnated plywood, which would absorb radar waves. This, along with it's shape, would've made the Ho-229 invisible to the crude radar of the day. So it should be given credit for being the first true "Stealth Fighter". The US military initiated "Operation Paperclip" which was an effort by the U.S. Army in the last weeks of the war to capture as much advanced German weapons research as possible, and also to deny that research to advancing Russian troops. A Horton glider and the Ho-229 number V2 were secured and sent to Northrop Aviation in the United States for evaluation. Later, Northrop Aviation developed the B-2 "Spirit" stealth bomber. During WWII Northrop had been commissioned to to develop a large wing-only long-range bomber (XB-35) based on photographs of the Horton's record-setting glider from the 1930's, but their initial designs suffered controllability issues that were not resolved until after the war. Northrops small one-man prototype (N9M-B) and a Horton wing-only glider are located in the Chino Air Museum in Southern California.
The Ho-229's design employed a thoroughly modern wing shape far ahead of its time. The wing had a twist so that in level flight the wingtips (and thus, the ailerons) were parallel with the ground. The center section was twisted upwards, which deflected air in flight, and provided the majority of its lift. Because of this twist in its shape, If the pilot pulled up too suddenly, the nose would stall (or, lose lift) before the wingtips. This meant that the craft's noise would inherently dip in the beginnings of a stall causing the plane to accelerate downwards, and thus it would naturally avoid a flat spin. A flat spin is difficult to recover from, and many rookie pilots have crashed from this condition. Horten also noticed in wind-tunnel testing that in the beginnings of a stall, most airfoil cross-sections began losing lift on their front and rear edges first. Horten designed an airfoil cross-section that developed most of its lift along the centerline of the wing. Since the center line had high lift and the front and rear edges had low lift, it was called a "Bell-Shaped lift curve". The wings were also swept back at a very modern and optimum angle (his gliders from the 1930's used this sweep long before it became popular) which enhanced its stall-resistance, and also lowered its wind-resistance which helped its top speed. This made the Ho-229 easy to fly and very stall-resistant in all phases of its operation.
The only existing Ho-229 airframe to be preserved was V2, and it is located at the National Air and Space Museum (NASM) in Washington D.C. The airframe V1 crashed during testing, and several partial airframes found on the assembly line were destroyed by U.S. troops to prevent them from being captured by advancing Russian troops.
See also
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