Bet none here have heard of this odd-ball use of rocket power for
propulsion. It came out in 1954:
"Turb-O-Prop is the trade name for a new form of model plane power – a
jet-driven propeller using solid rocket fuel for thrust. The fuel used
is one or two capsules of the Jetex No. 50 type. Burning this fuel
produces high velocity gases, which are exhausted through two jet
tubes to provide thrust to rotate a 6" diameter aluminum propeller.
Depending upon the fuel used and rate of fuel burning, the total
engine run is approximately 30 seconds. During this time, sufficient
thrust is developed to fly a regular 1/2A freeflight model. Weight of
the complete engine, less fuel, is ¾ of an ounce. Static thrust of the
prop is about 2 ounces, r.p.m.'s are approx. 4,000."
"Along with the instant-starting features of this type of engine,
there is a complete absence of torque. This allows the prop to be used
on small models and, when combined with low weight, should give
phenomenal flight performance. The propeller is free-wheeling, of
course, when power is exhausted. No moving parts are heavily loaded,
therefore the engine, with proper care, should have a very long life.
Mounting on models is by means of a short mounting bracket which has
two holes for wood screws or machine bolts. Price of the Turb-O-Prop –
complete with prop, combustion chamber with gasket and mounting
bracket – is $3.98."
More here .... https://archivesite.jetex.org/motors/motors-accessories.html
Edward