Joined: Thu Jun 19, 2008 5:29 pm
Just asking your comments on this simple staging gadget I have come up with.
There's a booster (1st stage) and a sustainer (2nd stage) stacked the usual way. The sustainer has a male Gardena coupler as its nozzle, and it fits into a tube on top of the booster. It is also pressurized through the booster.
When under pressure on the pad, 3 (or 2 or 4...) bolts will keep the sustainer down in the tube. The bolts have springs to extract them; on the pad, the bolts hold the sustainer down, and the shear force from that keeps the bolts in.
At launch, the booster must accelerate so much that the sustainer is forced down in the booster's tube (ie. acceleration * sustainer mass > (area of tube * sustainer pressure) + friction forces). Shouldn't be a problem. There is now no more shear forces to hold in the bolts, and they will be shot away by their springs (and get lost, but hey, every respectable rocket leaves some junk behind ).
Later, the booster will lose some acceleration, and acceleration * sustainer mass < (area of tube * sustainer pressure) + friction forces. At this time, the sustainer's Gardena coupler will pop out of the booster, and continue on its own.
What do you think; will it work? Is it too inefficient to have no coasting phase between booster burn-out and sustainer "ignition"?