Horten Ho 229 - the first turbojet aircraft built on the aerodynamic scheme "Flying Wing" ("Unsichtbar"). It was the result of more than a decade of design activity of the brothers Reymar and Walter Horten (Valter und Reimar Horten), whose main goal was to create an aircraft with minimal resistance. As a result, the Horten Ho 229 did not have a fuselage as such. The thickness of the center section was sufficient to accommodate the pilot and the engine. Vertical plumage was absent. The course was controlled by spoilers mounted on the wing.
The participation of "Gothaer Waggonfabrik AG Gotha" was reduced to the preparation of mass production with some corresponding changes in the design. The main work was done by the Horten brothers on their own initiative two years before joining their work to the concern in Gotha. In 1942, Major Walter Horten and his brother, Chief Lieutenant Reimar, were recalled from combatant units specifically for work in the Sonderaktion 9, created under the auspices of the Luftwaffe exclusively for the implementation of the Unsichtbar project.
The basic idea was that a clean wing would have significantly less aerodynamic drag. The first glider "Horten I" flew back in 1931, when Walter Horten was just 16 years old. A wooden airframe with fabric covering was controlled by ailerons and steering brakes at the ends of the wing. The experience gained in the work on it was reflected in the creation in 1934 of the new "Horten II", which had a greater elongation of the wing and an arrow-shaped rear edge. Internal elevons were used as elevators, and external elevators - as ailerons. During 1935g. The Horten was equipped with an 80-powerful Hirth HM-60R air-cooled engine located inside the wing and working on a pushing screw through an elongated shaft.
Both brothers entered Luftwaffe at 1936 g, but continued their design activities. In 1936-1937 Three Horten IIs were built, competing in the Rhone at 1937. At 1938, the Hortens left the Luftwaffe and built a number of aircraft. The first of them "Horten III" served as a model for all subsequent machines of the brothers. The central section was welded from steel pipes, the single-spar wing was wooden. Two "Horten III" participated in 1938 in competitions in the Rhone, achieving good results. True, both aircraft were abandoned by their pilots with parachutes due to severe icing.
By this time, the work of the brothers had received notable official and unofficial fame. In 1939, Ernst Heinkel was interested in them, but negotiations came to a standstill because of his desire to register all subsequent patents in his name. Another negotiation took place with Villi Messershmitt, but again to no avail. After a short job at the Technical University of Bonn, the brothers returned to the Luftwaffe. However, participation in the political life of Walter Horten, along with his friendship with Ernst Udet (Reimar Horten was married to Udet's secretary) allowed the brothers to continue their design activities. Effective participation of the ministry aviation and the creation of Sonderaktion 9 at the Göttingen repair plant helped them. In addition, the brothers could use the Peshke hardware factory for auxiliary work. By the time the plant was handed over, the brothers had designed and built the Horten But IV glider, in which the pilot was lying. The lengthening of the wing was 21.66 instead of 10.66 on the Horten But III.
The Horten double-seat Horten Ho V with two 80-powerful Hirth NM-60R engines was the first engineered from the start. The engines were located in the wing and pushed the propellers through the elongated shafts. The brothers quickly realized the prospects for combining the beautiful aerodynamics of a flying wing with a turbojet engine. However, they understood that despite the good connections in RLM, the conservatism of the latter would be overpowered. This has spurred RLM in financing the work of "Sonderaktion 9", giving it a special status, withdrawing from under the direct supervision of the Technical Department.
Before working on the project of the Unsichtbar fighter jet, the Hortens created a Horten double training room. But VII, whose main task was to train pilots on an aircraft of such an unusual pattern. At the same time, the aircraft was supposed to serve to verify the development of a jet fighter. As a result, Horten VII was officially designated as an experimental aircraft for aerodynamic research and as a connected one.
The contract for 20 Horten But VII was transferred to the plant "Pawn" in Minden. In general, similar in configuration to the Horten But V, the new aircraft was equipped with two As-10 engines with an 240 horsepower and a retractable four-rack chassis. The two front wheels on separate racks were attached at the very line of symmetry and retracted. Two rear racks under the engine shafts were removed forward with a turn of 90 degrees.
The first Horten But VII was made and circled in Minden in the summer of 1943 g, but by the time the second aircraft was ready, a few months later, the RLM had lost interest in the “Unsichtbar”. The remaining 18 Horten But VII were never completed. Despite the loss of interest from officials, Horten continued work on a jet fighter, which they called Horten But IX - its assembly has already begun in Göttingen. At first, an engine-free Horten But IX-V1 was built for aerodynamic studies with a non-removable three-post chassis. RLM learned about the existence of an experimental aircraft only at the beginning of 1944 g, when it was already half finished. Although such a “private” initiative was strictly suppressed by the ministry, the brothers received support. The unusual layout of the aircraft captured the imagination of Hermann Wilhelm Göring (Hermann Wilhelm Göring), who provided personal support to the project and demanded that the flight tests be started in the engine version as soon as possible.
With the official support of the program Horten But IX received additional impetus. In the spring of 1944, the first successful tests of a motorless prototype were carried out. Work began on the second machine. Due to the unavailability of the VMW-003 turbojet engines by this time, it was decided to install Jumo-004 on the second experimental aircraft, which required some changes to be made to the design.
Horten But the IX-V2 was designed on the basis of the 7 overload, which, with a safety margin of 1.8, produced a destructive overload of the 12.6. Wing 14% relative thickness at the root and 8% at the ends with a symmetrical profile. The center section had an S-shaped profile. It housed the pilot, engines and landing gear. The center section is welded from steel pipes with plywood lining (with the exception of the area of the exhaust nozzles of the motors, sheathed with steel sheet). Solid wood consoles with metal tips. The front edge was made of so-called cast wood, which was a sawdust pressed with rubber. The rest of the wing was sheathed with plywood. Special varnish gave it a high purity. Wing with one main spar and one auxiliary, to which the steering surfaces were attached. Protected soft tanks total volume of 3000. occupied two thirds of the console volume. There were four tanks in each wing - two for and in front of the spar.
Two Jumo-004В turbojet engines were mounted close to the line of symmetry. They passed through the main spar and their air intakes significantly reduced the relative thickness of the center section. The protrusions on the surface of the wing were only the engine cowls, which could not fit into the contour, and the squat lantern of the cockpit. Tricycle chassis; the nose wheel was removed back, the main stand - to the line of symmetry. Initially, it was planned to use a four-post chassis similar to that of Horten But VII, but then preference was given to one high-strength nose strut, perceiving up to 45% of the chassis load. To reduce the mileage a brake parachute was provided. Longitudinal and transverse controllability was provided by ailerons, which, together with the flaps, occupied the entire rear edge of the wing. The flaps were associated with spoilers located just behind the landing gear. The course was controlled by spoilers on consoles immediately behind the main spar. It used a pair of spoilers of different lengths on the upper and lower surfaces of the wing. Spring wiring produced the first release of a small spoiler, and then, when it was produced completely, large. In this way, normal control of the aircraft at low and high speeds was ensured.
While the No-IX-V2 was being assembled, unmo-powered V1 was tested in Oranienberg near Berlin, which gave good results. But one day the pilot forgot to remove the generator fan in the stream, and the subsequent crash during landing stopped the tests. However, already carried out were sufficient to study the characteristics of the aircraft and begin mass production. At this stage of work "Gothaer Waggonfabrik AG Gotha" joined, which received the task to bring the design to mass production. Further work on the aircraft were transferred to the design office of the Civil Air Fleet. RLM assigned the car the designation Horten Ho 229, and at the beginning of the summer 1944. a contract was issued for seven experienced and 20 pre-production aircraft.
Designer "Goths" almost did not change the design, but reworked the cabin, equipping it with a simple ejection seat. Engine radings have been increased. A cold air blowing system was introduced for the skin in the area of the engine nozzles. Pretty much changed the chassis, designed for greater take-off weight.
Provided for the installation of four guns MK-103 or MK-108 near the engines. Under the center-section it was possible to hang two 1000kg bombs or two 1250l tanks. The all-weather Horten Ho 229 all-weather version for the centimeter range FuG-244 Bremen in the elongated nose fairing was also designed. The second and third aircraft built GVF - V4 and V5 were prototypes of this series.
While mass production took place at the Civil Air Fleet, in Göttingen in January 1945. was completed But-IX-V2, transported to Oranienberg for flight tests. On the first flights the nose landing gear was locked in the extended position. With normal take-off weight and flaps lowered on the 10O, the breakaway speed was 150 km / h with a takeoff in 500 m. With the nose wheel released, the speed reached 300 km / h. Handling justified the most optimistic assumptions. In March, the nose wheel began to clean up in flight. The 795 km / h speed was reached, but during landing the right engine stalled. Pilot Lieutenant Ziller ejected, the plane rolled over, fell to the ground and burned out. In total, the prototype flew two hours.
The assembly of the next prototype in Friedrichsrode was already completed. Horten Ho 229 VZ was to be the first prototype of the serial Horten Ho 229-A. The V4 and V5 were prototypes of Horten Ho 229-B, a two-seat all-weather fighter. The V6 was the second experienced A-series aircraft with MK-103 guns instead of MK-108. V7 was supposed to be a training double option. 12 March 1945. at a meeting with Goring, Horten Ho 229 was included in the "urgent fighter program", but after two months the Americans seized the plant in Friedrichrod. VZ was already prepared for testing, the V4 and V6 were almost ready, the nodes for the 20 pre-production Horten Ho 229-A-0 were ready.
Horten Ho 229 flight specifications:
Wingspan: 16,75 m
Length: 7,45 m
Height: 2,80 m
Wing area: 50,80 m2
Empty mass: 4600 kg
Normal take-off weight: 7515 kg
Maximum take-off weight: 9000 kg
Engine type: 2 TRD Junkers Jumo-004В-1, 2, 3
Thrust: 2 x 890 kgf
Maximum speed: 970 km / h
Cruising speed: 685 km / h
Practical range without PTB: 1880 km
Practical range with PTB: 3150 km
Maximum rate of climb: 1320 m / min
Practical ceiling: 16000 m
Crew: 1 man
Armament: four 30-mm guns MK-103, MK-108; 2x1000-kg bombs