Yakovlev Yak-1000
| Industry | Aerospace |
|---|---|
| Founded | 1934 |
| Headquarters | Soviet Union |
| image = YakovlevYak-1000.jpg | caption = Overhead perspective of the Yak-1000 | aircraft_type = Experimental aircraft | national_origin = Soviet Union | manufacturer = Yakovlev | status = Unflown | number_built = 1 | developed_into = P-15 Termit
The Yakovlev Yak-1000 was a Soviet experimental supersonic aircraft designed to test the aerodynamic configuration and operational characteristics of a cropped delta wing, a concept derived from captured German research, combined with the advanced Lyulka AL-5 turbojet. However, the aircraft encountered significant stability issues during ground taxiing due to the tandem landing gear arrangement and aerodynamic challenges associated with the delta wing design, which prevented it from ever achieving flight.
Background and description
In June 1950, a directive from the Soviet Council of Ministers tasked Yakovlev with creating a supersonic fighter powered by the 50 kN (11,000 lbf) thrust-class Lyul'ka AL-5 axial compressor turbojet. Following advice from an aerodynamic expert at TsAGI, Yakovlev was instructed to employ a rhomboid or cropped delta wing shape based on German aerodynamic data obtained after World War II. The initial specification demanded a top speed reaching Mach 1.7—an ambitious target given that global speed records had only recently surpassed the sound barrier. Due to delays in the AL-5 engine's development and the absence of an equivalent Soviet replacement, the project shifted focus toward serving as a technology demonstrator for evaluating the innovative wing design. Consequently, the less powerful 15.9 kN (3,600 lbf) Klimov RD-500 engine was installed, with anticipated maximum speeds near 1,100 km/h (680 mph) and a takeoff weight around 2,407 kg (5,307 lb).
The Yak-1000 featured a semi-monocoque fuselage with circular cross-section, incorporating an air intake positioned at the nose. The engine was located aft of the pressurized cockpit and expelled exhaust through an extended tailpipe at the rear fuselage. Two air brakes were installed beneath the aft fuselage to assist in speed control. Fuel storage included forward tanks holding 430 litres (95 imp gal; 110 US gal) and rear tanks containing 167 litres (37 imp gal; 44 US gal). For maintenance purposes, the entire rear fuselage and tail section could be detached to provide engine access.
The aircraft’s most notable innovation was its compact, three-spar wings exhibiting an aspect ratio of just 1.46. The leading edges were swept back at 60°, with a quarter-chord sweep angle of 51°11'. The wing thickness-to-chord ratio measured 3.4% at the root, increasing to 4.5% at the tips. The trailing edge featured an 11° forward sweep and incorporated full-span flaps along with inset ailerons.
The low-mounted horizontal stabilizer mirrored the delta shape of the wings but was thinner, with a thickness ratio of 5%. Control surfaces included a small rudder and mass-balanced elevators of modest size. The landing gear employed tandem main legs similar to those on the Yak-50, which retracted rearward; however, the forward wheel remained partially exposed when stowed. Additional outrigger struts retracted backward into mid-span underwing fairings. On the ground, the Yak-1000 rested in a distinct nose-high attitude, aided by its steerable single nosewheel.
Development
The prototype was finalized on 27 February 1951 and commenced taxiing tests on 2 March. The following day, it reached taxi speeds of up to 250 km/h (160 mph), but a strong crosswind caused the aircraft to tilt, compressing the strut on the opposite side. This resulted in the plane being pushed off the runway as the ailerons failed to correct the tilt, leading to damage that halted further testing. Efforts were made to address the instability issues that had emerged, yet Yakovlev showed little enthusiasm for the project, which was ultimately terminated in October 1951.
It took approximately five more years of experimentation for Soviet engineers to fully understand the unique aerodynamics of delta wings, culminating in the Mikoyan-Gurevich Ye-4 prototype for the MiG-21 and the Sukhoi T-3, both delta-wing aircraft that first flew between 1955 and 1956.
P-15 Missile
The design principles and projected capabilities of the Yak-1000 caught the attention of Alexander Yakovlevich Bereznyak from MKB Raduga, who adapted its compact profile and small delta wing configuration into a concept for a ship-launched missile. This concept evolved into what became known as the P-15 Termit. The initial P-15 prototype utilized a liquid-fueled rocket engine and radar system, replacing the air-breathing jet engine's intake and exhaust but retained a similar wing and fuselage layout. Later iterations adopted folding wings and a distinctive inverted Y-tail design; however, elements of the Yak-1000’s design remain evident.
Specifications (estimated)
References
Bibliography
- Gordon, Yefim; Komissariov, Dmitry; Sergey. OKB Yakovlev: A History of the Design Bureau and its Aircraft. Hinckley, England: Midland Publishing, 2005. ISBN 1-85780-203-9.
- Gunston, Bill. The Osprey Encyclopedia of Russian Aircraft 1875-1995. London: Osprey, 1995. ISBN 1-85532-405-9.
- Gunston, Bill (1997). Yakovlev Aircraft since 1924. London: Putnam Aeronautical Books. ISBN 1-55750-978-6.