The Reaction Motors LR99 engine was the first large, throttleable, restartable liquid-propellant rocket engine. Development began in the 1950s by the Reaction Motors Division of Thiokol Chemical Company to power the North American X-15 hypersonic research aircraft. It could deliver up to 57,000 lbf (250 kN) of thrust with a specific impulse of 279 s (2.74 km/s) or 239 s (2.34 km/s) at sea level. Thrust was variable from 50 to 100 percent, and the restart capability allowed it to be shut down and restarted during flight when necessary.
After one hour of operation, the XLR99 required an overhaul. Operating times nearly twice that were recorded in tests, but declared largely unsafe. The basic X-15 aircraft carried fuel for about 83 seconds of full-powered flight, while the X-15A-2 carried fuel for just over 150 seconds. Therefore, each XLR99 was capable, in theory, of between 20 and 40 flights before an overhaul.
Like many other liquid-fuel rocket engines, the XLR99s used regenerative cooling, in that the thrust chamber and nozzle had tubing surrounding it, through which the propellant and oxidizer passed before being burned. This kept the engine cool, and preheated the fuel. The basic engine has a mass of 910 lb (410 kg).
Operational historyedit
The LR-99 was used exclusively to power the X-15 research aircraft after initial trials that used a pair of Reaction Motors XLR11s.
^ abWilkinson, Paul H. (1964). Aircraft engines of the World 1964/65 (20th ed.). London: Sir Isaac Pitman & Sons Ltd. p. 39.
External linksedit
Wikimedia Commons has media related to Reaction Motors XLR99.
– National Museum of the United States Air Force
December 07, 2023
reaction, motors, xlr99, reaction, motors, lr99, engine, first, large, throttleable, restartable, liquid, propellant, rocket, engine, development, began, 1950s, reaction, motors, division, thiokol, chemical, company, power, north, american, hypersonic, researc. The Reaction Motors LR99 engine was the first large throttleable restartable liquid propellant rocket engine Development began in the 1950s by the Reaction Motors Division of Thiokol Chemical Company to power the North American X 15 hypersonic research aircraft It could deliver up to 57 000 lbf 250 kN of thrust with a specific impulse of 279 s 2 74 km s or 239 s 2 34 km s at sea level Thrust was variable from 50 to 100 percent and the restart capability allowed it to be shut down and restarted during flight when necessary LR99An XLR 99 rocket engine Type Liquid propellant rocket engineNational origin United StatesManufacturer Reaction MotorsMajor applications North American X 15 Contents 1 Design and development 2 Operational history 3 Applications 4 Variants 5 Specifications YLR 99 RM 1 5 1 General characteristics 5 2 Components 5 3 Performance 6 See also 7 References 8 External linksDesign and development editThe engine is propelled by liquid oxygen and anhydrous ammonia pumped into the engine by turbopumps at a mass flow rate of over 10 000 lb 4 500 kg per minute After one hour of operation the XLR99 required an overhaul Operating times nearly twice that were recorded in tests but declared largely unsafe The basic X 15 aircraft carried fuel for about 83 seconds of full powered flight while the X 15A 2 carried fuel for just over 150 seconds Therefore each XLR99 was capable in theory of between 20 and 40 flights before an overhaul Like many other liquid fuel rocket engines the XLR99s used regenerative cooling in that the thrust chamber and nozzle had tubing surrounding it through which the propellant and oxidizer passed before being burned This kept the engine cool and preheated the fuel The basic engine has a mass of 910 lb 410 kg Operational history editThe LR 99 was used exclusively to power the X 15 research aircraft after initial trials that used a pair of Reaction Motors XLR11s Applications editNorth American X 15Variants editXLR99 RM 1 prototype engines for initial testing and flight trials YLR99 RM 1 Service test engines fitted to X 15s for later flights 1 Specifications YLR 99 RM 1 editData from Aircraft engines of the World 1964 65 1 General characteristics Type liquid fuelled rocket engineLength 82 in 2 083 mm Diameter 39 3 in 998 mm at the nozzleDry weight 910 lb 412 8 kg Fuel liquid ammonia LNH3 Oxidiser liquid oxygen LO2 LOX Components Pumps turbopumps 200 lb s 90 7 kg s driven by High test peroxide H2O2 decomposed by a catalystPerformance Thrust 15 000 lbf 66 72 kN to 57 000 lbf 253 55 kN Combustion chamber temperature 4 982 F 3 023 K 2 750 C Combustion chamber pressure 600 psi 4 137 kPa Specific impulse 239 seconds Propellant consumption 0 0035 lb lbf s 0 36 kg kN s Burn time Thrust to weight ratio 62 1See also editReaction Motors XLR11References edit a b Wilkinson Paul H 1964 Aircraft engines of the World 1964 65 20th ed London Sir Isaac Pitman amp Sons Ltd p 39 External links edit nbsp Wikimedia Commons has media related to Reaction Motors XLR99 Reaction Motors XLR99 Rocket National Museum of the United States Air Force XLR 99 Retrieved from https en wikipedia org w index php title Reaction Motors XLR99 amp oldid 1109314288, wikipedia, wiki, book, books, library,
