The LR87 is a liquid-fueled rocket engine first used on Titan Intercontinental Ballistic Missiles (ICBMs). LR87 variants also powered the first stages of Titan space boosters in the Gemini manned spaceflight program and various Titan space launch vehicles. Though this powerful engine is in reality two engines working together, it is considered a single unit. The LR87 first flew in 1959.
The pipes around the top of the engine’s two parts deliver fuel and oxidizer to high-speed turbopumps. The pumps then push these propellants to the bell-shaped thrust chambers, where the liquid mix becomes a mist and ignites, creating thrust. The machinery between the thrust chambers generates hot gas to drive the turbopumps.
LR87s came in several different models and used a variety of propellants. Early production LR87s used liquid oxygen and kerosene propellants. Later models used hypergolic fuels, which are liquids that ignite when mixed together. Hypergolics have an advantage over other propellants because they can be stored in the rocket at room temperature for long periods of time, making launches faster and simpler.
The LR87 is a fixed thrust engine -- it cannot be throttled, and it is not restartable in flight. Both of the engine’s thrust chambers can gimbal, or tilt slightly, for steering.
TECHNICAL NOTES:
Burn time: About 165-200 seconds depending on engine model and propellants
Propellants burned: 25,500 gal (170 gal per second)
Turbopump speed: 24,000 rpm
Thrust: 430,000 lbs.
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