RS-27A Credit - Boeing / Rocketdyne

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.

• Used on stage: Delta 3 - 1. on launch vehicle: Delta 3 .

• Used on stage: Delta Thor XLT. on launch vehicle: Delta 6000.