Aerospike engine
Aerospike is a type of rocket engine that maintains aerodynamic efficiency across a wide range of altitudes. A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust. Aerospike engines have been studied for a number of years and are the baseline engines for many single-stage-to-orbit designs.
About Aerospike engine in brief
Aerospike is a type of rocket engine that maintains aerodynamic efficiency across a wide range of altitudes. A vehicle with an aerospike engine uses 25–30% less fuel at low altitudes, where most missions have the greatest need for thrust. Aerospike engines have been studied for a number of years and are the baseline engines for many single-stage-to-orbit designs and were also a strong contender for the Space Shuttle main engine. No such engine is in commercial production, although some large-scale aerospikes are in testing phases. Several versions of the design exist, differentiated by their shapes. Rocketdyne conducted a lengthy series of tests in the 1960s on various models of these engines. Later models were based on their highly reliable J-2 engines and provided the same sort of thrust levels as the conventional engines in the same machinery. The design has the advantage of being a stack, allowing several smaller engines to be placed in a row to make one engine larger while augmenting performance with the throttle control.
In the toroids the spike is bowl-shaped with the exhaust exiting in a ring around the rim. The spike forms one side of a \”virtual\” bell, with the other side being formed by the outside air. The idea behind the design is that at low altitude the ambient pressure compresses the exhaust against the spike. Exhaust recirculation in the base zone of the spike can raise the pressure in that zone to a fraction of 1 bar, higher than the near-vacuum in front of the vehicle, thus giving extra thrust as altitude increases. It gives no overall thrust, but this part of the nozzle also doesn’t lose thrust by forming a partial vacuum. The thrust at the base part of a nozzle can be ignored atlow altitude. In theory, this can be achieved by blowing a small amount of gas out of the truncated spike for best efficiency. In reality, this requires an infinitely long spike for the best efficiency, but by blowing the exhaust out of a short amount of the outer center of a spike can achieve something similar.
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This page is based on the article Aerospike engine published in Wikipedia (as of Jan. 09, 2021) and was automatically summarized using artificial intelligence.
