Encyclopedia Astronautica
A-9


Thiel Lox/Alcohol rocket engine. 288.7 kN. Single chamber engine for V-2 series C, A9. Tested 1942-45. Isp=255s. Never went into production in Germany, but formed the basis for successful post-war American and French rocket engines.

Throughout the early 1940's Thiel and his team sought to produce a single chamber 25 tonne thrust engine in place of the kludged prototype engine for the A4 that used 18 separate 1.5 tf chambers. They managed to demonstrate a 60 second burn time in the 18-chamber design, but the engine itself was considered too complicated to fabricate in production, requiring thousands of hand-assembled tubes to introduce fuel and oxidiser into the chamber. Thiel sought to replace these thousands of tubes with a simpler injection system - rows of simple bored holes on a flat injector plate at the head of the chamber. But this could not be accomplished before the A4 went into production, and the 18-chamber design was what flew in thousands of production V-2's.

German design of advanced rocket chambers for the A4 was centered at the Technical College in Dresden. The team there was led by Georg Beck, and included Karl Zinner (inventor of the "shower-head" injector), Hans Lindenberg, and Konrad Dannenberg. They shuttled between Dresden and Peenemuende during the long trial-and-error process of producing a rocket engine injector that would produce stable combusion. One design after another resulted in engines that created resonant vibrations during combusion that tore the engines apart, or uneven combusition that burned through the injector face. The team finally managed to produce the B7 injector plate for an 8-tonne thrust engine, and this was used for the Wasserfall surface-to-air-missile. It was only in 1945 that the Dresden team perfected the B8 injector plate, intended for use in the model 39a tapered head combustion chamber engine for the A4 production series C. The B8 used a circular slotted injector plate, with orifice holes arranged in complex radial, parallel and circular patterns. This design never went into production in Germany, but formed the basis for successful post-war American and French rocket engines.

Application: V-2 series C, A9.

Characteristics

Thrust (sl): 249.100 kN (56,000 lbf). Thrust (sl): 25,397 kgf.

AKA: Model 39a.
Status: Study 1942.
Diameter: 1.65 m (5.41 ft).
Thrust: 288.70 kN (64,902 lbf).
Specific impulse: 255 s.
Specific impulse sea level: 220 s.
Burn time: 115 s.

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • A9/A10 German intercontinental boost-glide missile. The A9/A10 was the world's first practical design for a transatlantic ballistic missile. Design of the two stage missile began in 1940 and first flight would have been in 1946. Work on the A9/A10 was prohibited after 1943 when all efforts were to be spent on perfection and production of the A4 as a weapon-in-being. Von Braun managed to continue some development and flight tests of the A9 under the cover name of A4b (i.e. a modification of the A4, and therefore a production-related project). In late 1944 work on the A9/A10 resumed under the code name Projekt Amerika, but no significant hardware development was possible after the last test of the A4b in January 1945. More...
  • A9/A10/A11 German winged orbital launch vehicle. The A11 was planned at Peenemuende to use the A9/A10 transoceanic missile atop the tubby A11 stage to form the basis for launching the first earth satellite - or as an ICBM.... More...

Associated Manufacturers and Agencies
  • Thiel German manufacturer of rocket engines. Thiel, Germany. More...

Associated Propellants
  • Lox/Alcohol Liquid oxygen was the earliest, cheapest, safest, and eventually the preferred oxidiser for large space launchers. Its main drawback is that it is moderately cryogenic, and therefore not suitable for military uses where storage of the fuelled missile and quick launch are required. Alcohol (C2H5OH) was the fuel used for the German V-2 rocket, and the first derivative rocket engines in the United States, Soviet Union, and China used it as well. Better performance was achieved by increasing the alcohol concentration in the post-war engines. But after better-performance rocket-grade kerosene was developed by Rocketdyne in the REAP program of 1953, use of alcohol was abandoned. More...

Associated Stages
  • A-9 Lox/Alcohol propellant rocket stage. Loaded/empty mass 16,259/3,000 kg. Thrust 288.68 kN. Vacuum specific impulse 255 seconds. Winged version. More...

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