Launcher plane

GSR ("ГСР" in Russian means "Supersonic Launche Plane") is a plane with delta wing of 38 meters length. Its wing has variable angle, double delta (80° on the nose and 60° in the final part of the wing), the wingspan is 16 m and wing surface of 240 m² including 18.5 m² for the vertical stabilizers at the end of the wing. To stabilize the plane in flight those are tilted of 3° inside compared to the symmetry plane of the apparatus. The wing is fine and have a curvative profile of 2.5% on nose area and up to 3% at the end of the wing.

The control of the GSR was carried out by the rudders on the vertical stabilizers, the elevons and the wing flaps. The GSR was equipped with a cockpit with 2 ejector seats. To improve the visibility at the landing time the nasal part of the fuselage inclined 5°. Thereafter this functionality was used for the Soviet supersonic aircrafts such as the TU-144 and the strategic reconnaissance aircraft T-4 "Сотка" OKB P.O.Suhogo.

The GSR takes off like a conventional plane with 3 landing gears which are spread against the flight. The main landing gear is equipped with 2 wheels to reduce the room inside the fuselage. The size of this housing is of 5.75m. In the higher part of the GSR take place the orbital space-plane, in the nasal part, and the auxiliary rocket. The fuel used on the GSR is liquid hydrogen used in 4 turbo ramjets (TRD) (engineering and design department A.M. Lioulka) which produce a thrust of 17.5 tons each one. These engines are also used during the supersonic flight. The empty weight of the GSR is 36 t and could transport 16 t of liquid hydrogen (213 m3) for an inside volume of 260 m3.

The particularity of these engines was to use of the hydrogen gas to actuate the turbine of the compressor (as remembered G.E.Lozino-Lozinsky later, "... other alternatives to the engines of the GSR were looked at, however they were not studied in depths"). The spray of hydrogen was put on the entry of the compressor. Thus, it has solved with success the realization of the power unit without combining TVRD, GPRD and TRD. TRD engine with hydrogen was unique, Soviet industry never did something similar until now (experimental models were elaborate in the Central Institut of Plane's Engine).

The engine received the name AL-51 (at the same time with OKB-165 the TPDF of third generation AL-21F was elaborate, and for a new engine the selected index started to 50).

In the first days, when OKB A. Lioulky received the requirements of the engine its diagram was not clear. Then S.M. Shljahtenko arrived from TsIM (one year later he was the chief of the institute) with a certain foreign review (probably, Flight or Interavia) which contained a "tested diagram of an engine with gas hydrogen". According to this article the engine had very attractive characteristics and a great specific impulse.

Shljahtenko is shocked by the review: "Look, they have already a test engine which will fly today or tomorrow! And us always nothing!". The engineers take up the challenge.
The first studies show that indeed the diagram is very attractive and the result are quite simply fantastic. On this basis the construction of the engine is launched. The technical project signed in 1966 is dispatched with OKB-155 G.E.Lozino-Lozinsky.

Thereafter the project undergoes many improvements. It was in constant evolution. The materials implemented for the realization existed, technologies, the factories were good, but the tests of the prototypes did not give the awaited characteristics. The tests continued 5-6 more years until 1970 before the "SPIRAL" project is stopped.

The limiting thrust characteristics of the engine are functions of the temperature of gas in the turbine: if it is too high the components will melt, but more the temperature will be high more important will be the speed of the plane. The engineers did not decide to make an engine with combined cycle because the techniques of realization was too complex. In fact they thought of making "simply" a turbo-compressor engine and to use it only in the border line conditions. Making an ideal engine did not interest them in this case: economic qualities of the TRDG are much larger in comparison of the GRD (powering rockets), even if the engine has an output 2 times weaker than the theoretical one it is nevertheless 5 times more sparing than a rocket.

With materials of that time building the TRDF engine's components could allow a speed of Mach 4. Even now by using technologies like ceramics, composite materials, cooled paddles it increase the speed only at Mach 5. The advantage of hydrogen is that it can be used like cooling agent, initially, to cool the air (firstly) and the paddles of the compressor (secondly).

In the project the engine was distinguished from a traditional ramjet because the turbine is pulled by hydrogen gas which goes then actuat the compressor which gives the air to the combustion chamber. This system of divided conduits makes it possible to increase the pressure in the tube and by consequence to increase the specific impulse of the engine.

The engine for the intermediate alternative of the GSR, running on the kerosene, was produced by the office: OKB-300, linear turbojet with increased room (TRDF). A new development received the P39-900 index. Work was directed, probably, by Grigory L'vovich Lifshits which was the first assistant of the general engineer of OKB-300. After cancel of the SPIRAL project work on made on engines at OKB-300 haven't got any further.

The second important innovation of the GSR was the air compression, at supersonic speeds, by the lower fuselage section of the nasal wing part. Thermal resistance was ensured by the use of fireproof materials. Recently, publication of archival files on this subject shown that it was planned to use the principle of SPIRAL for the creation of a supersonic passenger aircraft (Mach 6). However the pre-project didn't mention civil use of the SPIRAL. A military alternative of the GSR envisaged to use it in a large range pathfinder. The GSR-scout (with kerosene) was to have a maximum speed of Mach 4-4.5 and an operating range from 6000 to 7000 km at Mach 4. But the use of hydrogen could augment speed until Mach 6 and range to 12 000 km (for a cruising speed of Mach 5).

The GSR plane was the first hypersonic plane which was studied in TsAGI (speeds: Mach 4 to 6), the photograph on the right is the model used in the wind tunnel. 2 model kits completed the aerodynamic test cycle in the wind tunnels in 1965-1975. Many tests proved the accuracy of the technical choices for this plane. At the 40em congress of the International Nations of Aeronautics (FAI) in 1989 in Malaga, in Spain, the representatives of the American delegation (NASA) largely appreciated the plane because "it is elaborate according to modern requirements".

The auxiliary 2 stages rocket.

The auxiliary rocket is made of 2 stages half embedded on the top of the GSR. For the acceleration phase it was planned to use (in pre-project) hydrogen and liquid oxygen or fluor-hydrogen. According to the requirements and the putting into orbit of a greater payload, the choice was done on the couple hydrogen-oxygen. Oxygen was preferred to fluorine because it is easier to produce although it is voluminous and decreases the maximum speed to Mach 5.5 (Mach 6 for fluorine).

With fluorine, for oxidant, for the auxiliary rocket, the specific impulse is 460 s the mass of the tank is only 9-10% of the system's mass, whereas with oxygen the specific impulse is 455 s and the mass stand for 7.5-8%. The length of the rocket is 27.75 m including 18 m for the first stage with the tail deflector and 9.75 m for the 2em stage with the payload (the orbital space-plane). The alternative of the rocket with oxygen-hydrogen is 96 cm longer and 50 cm thicker. According to pre-project it was expected that the engine of the second stage has a thrust of 25 t (the elements of the rocket will be elaborate at OKB-456 S.P.Glushko) the engine will receive the name of RD-301. As for the first stage of the rocket it consists of 4 engines of 25 tf each one.