Couple things.
1.symmetry is over-rated. Think Flat Cat and Edmonds Deltie among numerous others. So you don’t HAVE to have 2 gliders.
2. Difference between Boost Glider and Rocket Glider, does the motor stay with the glider or not?
Easy if you keep the motor attached to the main, you can eject the glider off the main (so technically this would be a parasite boost glider, as the glider doesn’t “carry” the motors.)
I think however you really WANT the motors to separate WITH the glider (so technically a rocket glider, which will descend with the expended booster motor casing.) This could be tougher.
Although you don’t have to have the symmetry, the MPC Lunar Patrol setup could be unilateral or bilateral, and could be e helpful start for either boost glider or rocket glider configs, as far as holding all the pieces in place during boost phase. If you go with the boost glider, you can friction fit the motor into the base tube which is ATTACHED to the booster, with an inch or so of motor sticking out forward, then just slide the glider over the forward extension. Ejection charge (or for zero delay motor, the burn through) will pop the glider right off.
If you go the rocket glider approach, you will need some some more secure “bracing” of the glider to keep it from slipping from side to side or tilting. A burn string or band will be all you need to keep the glider from coming off laterally AND IMO should also be good enough to prevent it from slipping FORWARD at boost or backward at any time.
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A true delta wing glider I think would be a more efficient choice than something like am MPC Flat Cat OR Estes Tercel type.
I like but would modify the burn string attachment, change it to an elastic band, my go to has been #16 rubber bands, since they are already looped and don’t require knots. IMO elastic is FAR better than non-elastic burn bands because they STAY tight. Maybe it’s me but with only a single loop of no elastic cord no matter how tight I make it, it seems like it starts to get loose in minutes, giving you some waggle where you don’t want it.
Many of my models use a pair of #16 rubber bands for a combination of rotor retention AND motor block, I have yet to see them fail in either, so I think for low power if properly used they would easily and reliably hold one or more “strap on” boosters in place. You’d want to run them through the body tube(s) of the booster(s). You could even use the vent holes (which if nose cones are glued in you will DEFINITELY NEED). You do NOT have to route them through the sustainer, you should be able to wrap them around the outside onto some kind of hook. You’d need to rig some sort of stiffener or brace to keep the string or band from “cutting” through the paper tube, but lots of easy and hard ways to skin that cat.
The gliders will function as stabilizing fins during first part of boost, once they pop off (I’m guessing at or just before sustainer coast phase) you will still need some degree of maintained finnage on the sustainer. I theeeeenk you should need far less finnage on the sustainer after separation for 2 reasons, first the rocket should be at Max Q (at least for the stack), which is likely much faster than at the end of the rod or rail, so whatever fins remain should be at ideal velocity for subsonic flight. Second, likely CG is going to shift waaaaaay forward when you drop the boosters, especially their motors.
Here’s an interesting part. I am not sure if the rocket with the strap on boosters will go much higher than the SAME rocket WITHOUT the boosters. Rationale: for black powder strap on boosters, main engine burnout (THRUST DURATION) may not be much different from the booster motor burnout, for example of you have a C6-7 sustainer and two C6-0 boosters, I’d expect all three to cease thrust at roughly the same time. For thus sustainer, there is no more positive acceleration, it’s now in coast phase, and I am presuming the smoke delay produces essentially zero thrust.
DRAG will go down, yes.
MASS will go down, but while this would be good for altitude under THRUST, in coast phase the mass becomes your kinetic energy.
So without any thrust, it’s a contest between kinetic energy keeping the rocket moving up and both gravity and drag slowing it down. So I’m not sure which wins.
OTOH, if you use a long burn sustainer motor, you should do better with boosters if they are short burn. With black powder low power motors (which are pretty much all you can use it this case, mixing black powder and composites brings a host of solvable but annoying problems), Thrust duration seems pretty short with all your choices,
