true, but sort of round robin thinking.
as Der
@prfesser pointed out, major issues are the difficulty of obtaining a zero delay composite booster and the challenge of lighting the core burning sustainer. All the workarounds so far involve a delay between booster burnout (fuse takes a finite amount of time), as opposed to black powder to black powder staging which is almost instantaneous.
IF (and it is a BIG if) someone solves those problems (reliable near instantaneous staging at booster burnout), you are left with the same situation as black powder to black powder staging, which ALSO has the inherent risks of sustainer ignition
when conditions are not safe for flight.
There is a saying, “if you ain’t cheating you ain’t trying.”
safety is by definition paramount.
you COULD potentially cluster a rocket with BP and Cluster motors. there are issues with simultaneous ignition of combined motors (I theeeeeenk BP may tend to ignite faster, so may need to long clip whip on a pole that keeps the igniters in the slower motors until they clear the rod/rail, giving them a few milliseconds more time), and the booster BP motors can stage to both sustainer composite and BP motors, fuse fo composite, gap or direct for BP). Design would have to be such that entire flight is achievable and safe it ONLY black powder motors ignite, and you would remove the ejection charge from booster composite. You’d also want a longer burn Time for the booster BPs than composite, which may be hard to find. AND a longer delay on the booster BPs, so if booster composite doesn’t light, you still get an ejection event.
@Neutronium95 has a great point with that scary video. Off axis staging is frightening in any power rocket, from MicroMaxx up (MicroMaxx may be small, but can have very pointy nose cones!), although the risk is higher the greater the motor impulse.
so by the time you have enough BP motors to make the flight “reasononable” for a BP/Composite combo, you have a pretty heavy rocket. And since even BP to BP staging does NOT 100% prevent Off Axis staging (the few I have seen involved weathercocking usually associated with too weak a booster motor), just because you CAN (or might) make this work doesn’t mean you SHOULD.
I am a proud L-0, so aside from onboard cameras and maybe altimeters, I don’t fly electronics. Maybe somebody can chime in with what’s the lowest cost reliable electronic device that has safe lockouts? Tilt access would be ideal, but I’ve read that reasonable altitude lockouts would also be safe (I think assumption is if it reaches a certain altitude it MUST be vertical or near vertical, but I am not sure.)
something not addressed In above discussion is recovery of booster. outside of my own long gap (up to 53”) designs (which use an auxilliary small clustered Delayed BP motor on booster to deploy the chute 3 seconds after staging [remember, even after staging booster still often has VERTICAL velocity to bleed off] and works surprisingly well), the vast majority of BP stagers use tumble recovery for the booster. The is okay up to, say, 24mm motors, but heavy boosters with big motors tumbling From the skies aren’t exactly optimal either.
so back to
@Neutronium95 ’s concern, since BP motors are available for low and mid power staging, what do you GAIN by doing it with composites? At the point you NEED composites rocket size may be such that you really want some sort of electronic lockout regardless.
)
