Encyclopedia Astronautica
Gamma 2


Bristol Siddley H2O2/Kerosene rocket engine. 68.2 kN. Out of production. Isp=265s. Used on Black Arrow launch vehicle. First flight 1969.

Gamma engines were manufactured by Bristol Siddley and used on the Black Knight and Black Arrow launch vehicles. Propellants were High Test Peroxide and Kerosene. Black Knight used 4 chambers in two pairs on the Y and Z axes. The motors were gimballed to provide thrust in all axes.

Black Arrow was a three stage vehicle. The first stage had an 8 chamber layout with 4 pairs of Gamma engines gimballed as with Black Knight giving thrust in all axes. The second stage had two Gamma chambers with extended nozzles to give full expansion in vacuum. Both engines were gimballed to provide thrust in three axes.

Thrust (sl): 64.600 kN (14,523 lbf). Thrust (sl): 6,590 kgf. Engine: 173 kg (381 lb). Thrust to Weight Ratio: 40.2196531791908.

Status: Out of production.
Unfuelled mass: 173 kg (381 lb).
Diameter: 1.37 m (4.49 ft).
Thrust: 68.20 kN (15,332 lbf).
Specific impulse: 265 s.
Specific impulse sea level: 251 s.
Burn time: 113 s.
Number: 4 .

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Associated Countries
See also
Associated Launch Vehicles
  • Black Arrow British orbital launch vehicle. Britain's only indigenous launch vehicle. Following cancellation of the project in July 1971, one final launch was permitted, which successfully placed the Prospero satellite in orbit. More...

Associated Manufacturers and Agencies
Associated Propellants
  • H2O2/Kerosene Hydrogen peroxide is used as both an oxidiser and a monopropellant. Relatively high density and non-toxic, it was abandoned after early use in British rockets, but recently revived as a propellant for the Black Horse spaceplane. Rocket propellant RP-1, or its foreign equivalents, is a straight-run kerosene fraction, which is subjected to further treatment, i.e., acid washing, sulphur dioxide extraction. Thus, unsaturated substances which polymerise in storage are removed, as are sulphur-containing hydrocarbons. More...

Associated Stages
  • Black Arrow-2 H2O2/Kerosene propellant rocket stage. Loaded/empty mass 3,537/535 kg. Thrust 68.23 kN. Vacuum specific impulse 265 seconds. More...

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