Thiokol/Reaction Motors
YLR99-RM-1
The reaction motors division of fire Cole chemical corporation was chosen to design and produce the engines for the three North American X-15 hypersonic research aircraft in 1956. The time specified by the contract, two years from signing to delivery, turned out to be unrealistic, considering the complexity of the engine. To keep the X-15 program on schedule, the first two aircraft were fitted with twin reaction motor XLR11 engine; the same engine used in the Bell X-1, Douglas, D558-II, Martin Marietta, X-24A/B.
The first powered flight utilizing a single XLR99 engine was made by eight. Scott Crossfield on 15 November 1960, ten months after program test flights commence. Their craft was launched from Boeing NB 52A 003, which is now on display at the museum. The YLR99-RM-1 was an upgraded version of the XLR99 used with the X-15A.
Technical specifications:
Burn Time: over 150 seconds
Pump Feed: centripetal
pump, Drive: turbine
Chamber Arrangement: single chamber
Trust: 58,000 pounds.
Fuel & Oxidizer: anhydrous ammonia, and liquid oxygen.