Encyclopedia Astronautica
RS-27A



rdyrs27a.jpg
RS-27A
Credit: Boeing / Rocketdyne
Rocketdyne Lox/Kerosene rocket engine. 1054.2 kN. . Isp=302s. Replaced the RS-27 as the main system for the Delta and in the MA- 5A for the Atlas. RS2701B main engine, and twin LR101-NA-11 verniers. First flight 1989.

The RS - 27A powerplant comprises an RS2701B main engine, and twin LR101 - NA - 11 verniers. Introduced in 1990 on the McDonnell Douglas' Delta 7000 series launcher it replaced the RS-27 as the main system for that launcher. It continues in service as part of the Atlas MA- 5A powerplant. Application: Delta 7000 series. First Flown: 1990. Flown: 14 Delta plus 8 Atlas to the end of 1993. Mounting: gimballed-mounted for pitch/yaw control with gimballed verniers for roll control. Engine Cycle: gas generator. Oxidizer: liquid oxygen at 250 kg/sec. Fuel: RP-1 hydrocarbon at 111 kg/sec. Mixture Ratio: 2.245:1. Oxidizer Turbopump: 1900 kW, 6784 rpm (7085 rpm at altitude), 70 atm discharge Pressure: Fuel Turbopump: 1289 kW, 70 atm discharge Pressure. Thrust: 890 kN sea level/1054.2 kN vacuum. Thrust Chamber Length: 234 cm. Thrust Chamber Materials: 347 CRES austenitic stainless steel. Thrust Chamber Cooling: regenerative, two passes of fuel through 292 tubes. Combustion Chamber Pressure: 48 atm at injector end. Combustion Chamber Temperature: 3315 Celsius. Combustion Chamber Materials: 347 CRES austenitic stainless steel. Combustion Chamber Cooling: same as thrust chamber. Combustion Chamber Ignition: hypergolic fluid cartridge enclosed in burst diaphragms. Burn Time: 274 sec. Verniers: each LR101-NA-11 at 21.8 kg mass, 4.63/5.30 kN sea level/vac thrust, 209/246 sec sea level/vac Isp, 1.8 mixture ratio, 5.6 expansion ratio(9.8 cm exit diameter), 283 sec burn time. Designed for booster applications. Gas generator, pump-fed. Two vernier engines provide roll control.

Thrust (sl): 890.100 kN (200,102 lbf). Thrust (sl): 90,770 kgf. Engine: 1,091 kg (2,405 lb). Chamber Pressure: 49.00 bar. Area Ratio: 12. Propellant Formulation: Lox/RP-1 Lox/RP-1. Thrust to Weight Ratio: 102.468075150265. Oxidizer to Fuel Ratio: 2.245. Coefficient of Thrust vacuum: 1.80185738739855. Coefficient of Thrust sea level: 1.60185738739855.

Unfuelled mass: 1,091 kg (2,405 lb).
Height: 3.78 m (12.40 ft).
Diameter: 1.07 m (3.51 ft).
Thrust: 1,054.20 kN (236,994 lbf).
Specific impulse: 302 s.
Specific impulse sea level: 255 s.
Burn time: 274 s.
First Launch: 1987.
Number: 20 .

More... - Chronology...


Associated Countries
See also
Associated Launch Vehicles
  • Delta 6925 American orbital launch vehicle. Four stage vehicle consisting of 9 x Castor 4A + 1 x EELT Thor/RS-27+ 1 x Delta K + 1 x Star 48B More...
  • Delta 6920-8 American orbital launch vehicle. Three stage vehicle consisting of 9 x Castor 4A + 1 x EELT Thor/RS-27+ 1 x Delta K with 2.4 m (8 foot) diameter fairing) More...
  • Delta 6925-8 American orbital launch vehicle. Four stage vehicle consisting of 9 x Castor 4A + 1 x EELT Thor/RS-27+ 1 x Delta K + 1 x Star 48B with 2.4 m (8 foot) diameter fairing) More...
  • Delta 6920-X Three stage vehicle consisting of 9 x Castor 4A + 1 x EELT Thor/RS-27+ 1 x Delta K with 3.05 m (10 foot) diameter fairing More...
  • Delta 3 American orbital launch vehicle. Delta 3 was an attempt by the manufacturer to provide the ultimate development of the original Delta booster. The core vehicle was beefed-up to accomodate much larger solid rocket boosters and a new cryogenic upper stage. However problems were incurred during development, resulting in the first two launches being failures. Meanwhile the satellite launch market crashed and the new vehicle was left without customers. The venerable Delta 7925 soldiered on for NASA, and the new Delta 4 series captured the USAF EELV requirement. More...

Associated Manufacturers and Agencies
Associated Propellants
  • Lox/Kerosene 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. In January 1953 Rocketdyne commenced the REAP program to develop a number of improvements to the engines being developed for the Navaho and Atlas missiles. Among these was development of a special grade of kerosene suitable for rocket engines. Prior to that any number of rocket propellants derived from petroleum had been used. Goddard had begun with gasoline, and there were experimental engines powered by kerosene, diesel oil, paint thinner, or jet fuel kerosene JP-4 or JP-5. The wide variance in physical properties among fuels of the same class led to the identification of narrow-range petroleum fractions, embodied in 1954 in the standard US kerosene rocket fuel RP-1, covered by Military Specification MIL-R-25576. In Russia, similar specifications were developed for kerosene under the specifications T-1 and RG-1. The Russians also developed a compound of unknown formulation in the 1980's known as 'Sintin', or synthetic kerosene. More...

Associated Stages
  • Delta Thor XLT Lox/Kerosene propellant rocket stage. Loaded/empty mass 101,700/5,690 kg. Thrust 1,032.00 kN. Vacuum specific impulse 295 seconds. More...
  • Delta 3 - 1 Lox/Kerosene propellant rocket stage. Loaded/empty mass 104,377/6,822 kg. Thrust 1,085.79 kN. Vacuum specific impulse 302 seconds. The first stage of the Delta III is powered by a Rocketdyne RS-27A main engine which has a 12:1 expansion ratio and employs a turbine/turbopump, a regeneratively cooled thrust chamber and nozzle, and a hydraulically gimbaled thrust chamber and nozzle that provides pitch and yaw control. More...

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