Horten Ho 229

infobox Aircraft
name =Ho IX
type =Fighter/Bomber
manufacturer =Gothaer Waggonfabrik



caption =H IX V1 prototype
designer =Horten brothers
first flight =1 March 1944
introduced =
retired =
status =Cancelled at the end of World War II
primary user =
more users =
produced =
number built =3
unit cost =
variants with their own articles =

The Horten Ho-IX (often called Gotha Go 229 or Ho 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 was a personal favourite of German Luftwaffe chief Reichsmarschall Hermann Göring, and was the only aircraft to come close to meeting his infamous "1000, 1000, 1000" performance requirements.

Design and development

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.

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 centres 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 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.

Ho 229 was of mixed construction with the center pod made from welded steel tube 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. Whether this was done for reasons of stealth, gunfire protection, or simply because late-war Germany experienced shortages of metals and Hortens needed to reinforce the plywood for transonic flight is a matter of largely unreferenced debate and speculation. Control was achieved with elevons and spoilers. The aircraft utilized retractable tricycle landing gear and a brake parachute for landings. The pilot sat on a primitive ejection seat.

Testing and evaluation

The first Ho IX V1, which was an unpowered glider, flew on 1 March 1944. It was followed in December 1944 by the Jumo 004-powered Ho IX V2 (the BMW 003 engine was preferred but unavailable at the time). Göring believed in the design and ordered a production series of 40 aircraft at Gotha with the RLM designation Ho 229 before it had taken to the air under jet power. The program was undeterred when the sole Ho IX V2 crashed after an engine caught fire on 18 February 1945 after only two hours of flying time. An order was put in for further prototypes and 20 pre-production aircraft. On 12 March 1945, Ho 229 was included into the Jäger-Notprogramm for accelerated production of inexpensive "wonder weapons."

During the final stages of the war, the US military initiated Operation Paperclip which was an effort by the various intelligence agencies to capture advanced German weapons research, and to deny that research to advancing Soviet troops. A Horten glider and the Ho 229 V3, which was undergoing final assembly, were secured and sent to Northrop Corporation in the United States for evaluation. Northrop was chosen because of their experience with flying wings—inspired by the Horten brothers' pre-war record-setting glider. Jack Northrop had been building flying wings since the N-1M in 1939.

Northrop's small single-seater prototype (N9M-B) and a Horten flying wing glider (Ho IV) are located in the Planes of Fame museum in Southern California. The only surviving Ho 229 airframe, the V3, is located at the National Air and Space Museum's Paul E. Garber Facility in Suitland, Maryland. Five partial airframes found at the Gothaer Wagonfabrik factory assembly line were destroyed by soldiers of U.S. VIII Corps of General Patton's Third Army in April 1945 to prevent capture by the advancing Soviet forces.Fact|date=June 2008

Variants

;Ho IX V1:Unpowered glider, 1 built and flown.;Ho IX V2:First prototype, 1 built and flown.

Gotha Developments:;Ho 229 V3:Revised air intakes, engines moved forward to correct longitudinal imbalance, 1 captured in production.;Ho 229 V4:only minor differences to V 3, in work at Friedrichroda but not much more than the tubular framework completed ;Ho 229 V5:only minor differences to V 3, in work at Friedrichroda but not much more than the tubular framework completed ;Ho 229 V6 :Projected definitive single-seat fighter version, Mockup in production at Ilmenau.

Horten Developments:;Ho IXb (also designated V 6 and V 7 by the Hortens):Projected two-seat trainer or night -fighter, not built.

;Ho 229A-0:Projected expedited production version based on Ho 229 V6, not built.

pecifications (Horten Ho 229A (V3))

From manufacturer's estimatesaircraft specifications

plane or copter?=plane
jet or prop?=jet
ref=The Great Book of Fighters [ Green, William and Swanborough, Gordon. "The Great Book of Fighters". St. Paul, Minnesota: MBI Publishing, 2001. ISBN 0-7603-1194-3.]
crew=1
length main=7.47 m
length alt=24 ft 6 in
span main=16.76 m
span alt=55 ft 0 in
height main=2.81 m
height alt=9 ft 2 in
area main=50.20 m²
area alt=540.35 ft²
empty weight main=4,600 kg
empty weight alt=10,141 lb
loaded weight main=6,912 kg
loaded weight alt=15,238 lb
max takeoff weight main=8,100 kg
max takeoff weight alt=17,857 lb
engine (jet)=Junkers Jumo 004B
type of jet=turbojet
number of jets=2
thrust main=8.7 kN
thrust alt=1,960 lbf
max speed main=Mach 0.92, 977 km/h
max speed alt=607 mph
max speed more=at 12,000 m (39,370 ft)
combat radius main=1,000 km
combat radius alt=620 mi
ferry range main=1,900 km
ferry range alt=1,180 mi
ceiling main=16,000 m
ceiling alt=52,000 ft
climb rate main=22 m/s
climb rate alt=4,330 ft/min
loading main=137.7 kg/m²
loading alt=28.2 lb/ft²
thrust/weight=0.26
avionics=
armament=
*2x 30 mm MK 108 cannon
*R4M rockets
*2x 500 kg (1,100 lb) bombs

ee also

aircontent
related=
*Horten Ho XVIII
similar aircraft=
lists=
*List of World War II jet aircraft
*List of flying wing aircraft
see also=

References

;Notes;Bibliography
* Shepelev, Andrei and Ottens, Huib. "Ho 229 The Spirit of Thuringia: The Horten All-wing jet Fighter". London: Classic Publications, 2007. ISBN 1-903223-66-0.

External links

* [http://www.nurflugel.com/Nurflugel/Horten_Nurflugels/horten_nurflugels.html Horten Nurflugels]
* [http://jpcolliat.free.fr/ho9/ho9-1.htm Horton HO 9]