From Albert Eatock
Bracebridge, Ontario, Canada
The aerospike engine described in your article (“Flight of the aerospike”, 6
July, p 36) cannot change direction by pumping exhaust—it may change
direction by pumping fuel to one side. Further, this is unlikely to be “simple”,
since you end up with at least three pumps as against one in the steerable
nozzle engine (excluding backup pumps).
Referring to the diagram that shows the conventional nozzle and the
aerospike, it would appear that combining the two, that is having a spike inside
a nozzle, would result in considerably greater thrust per pound of fuel.
