In Rockets
Plug nozzles belong to a class of altitude compensating nozzles much like the aerospike which, unlike traditional designs, maintains its efficiency at a wide range of altitudes.
The ideal contour of a plug nozzle is a long tapering 'spike' with a doughnut-shaped combustion chamber situated at the base, hence sometimes this nozzle is also called a "spike nozzle". To save weight, this design is shortened without a large drop in efficiency.
The exhaust is confined by atmospheric pressure so that at different altitudes the varying pressures will allow the exit area to change. This allows optimized atmospheric compensation. With the shortened (or truncated) nozzle, the recirculation of trapped gases at the base of the plug causes a small thrust which offsets the loss due to the non-ideal shape.
Read more about this topic: Plug Nozzle
Famous quotes containing the word rockets:
“The Thirties dreamed white marble and slipstream chrome, immortal crystal and burnished bronze, but the rockets on the Gernsback pulps had fallen on London in the dead of night, screaming. After the war, everyone had a car—no wings for it—and the promised superhighway to drive it down, so that the sky itself darkened, and the fumes ate the marble and pitted the miracle crystal.”
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