Is it possible to calculate ideal L/D ratios for core-burning
no-nozzle solid motors?
It would seem many factors are involved, not the least of which would
be erosive burning losses. In an "ideal" core-burn, no-nozzle motor,
how does one calculate the peak thrust time? I suppose that ideally
the motor would be running at peak efficiency when the grain web is
half-burned, or some point along that line ... or is peak efficiency
at ignition, when the web is thick and the core narrow?
Further on the no-nozzle motor matter, might an "exit cone" (if that's
the proper term) improve performance at sea level or up very high? If
that exit cone had to be simply divergent. not a bell, at what angle
of divergence is greatest Cf created?
(Am I correct, thinking that with such a no-nozzle motor, the thrust
is simply F = At x Pc, so adding an exit cone, I suppose, might add a
thrust coefficient Cf to the equation. Or am I all wet and barking up
the wrong trees?)
Edward