Originally Posted by
Intruder
The pressure recovered from the inlet, sending the air through the bypass tubes directly to the afterburner, "provides" the air for the thrust, in the same way the compressor "provides" the air for the thrust in the engine core or the fan "provides" the thrust in a fanjet.
I understand that if you did force analysis or put load sensors on the shafts and bearings, you'd see that the fan and compressor rotors are trying to pull the airplane forward, and the turbine rotors are trying to pull it backwards. And if you did the same thing for the stationary parts of the engine, you'd see that the forward walls of he combustion chambers and the compressor stators were trying to push the airplane forward, and the aft walls of the combustion chambers and the turbine stators were trying to push the airplane backward. But the thrust all ultimately comes from the expanding fuel-air mixture being burned. The compressor consumes one form of energy -- the rotation of the shaft -- and produces another -- compression of the air. I guess similarly the inlet nozzle in the J58 consumes one form of energy -- the forward motion of the airframe through the air -- and produces another -- compression of the air. But it doesn't really "produce thrust" any more than a ram air intake "produces power".
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