We don't think we've had enough big springs yet. Cue Richard Possnett: "The balloon would be hooked up to a spring mechanism which would pull it away from Vulture 2 upon bursting, and also function as a launch trigger at the best possible height. Although it may need quite a large spring, maybe a coil which winds up the cord would work better?"
David Steadman chipped in with this plan...
...while also offering something a bit more off-the-wall:
Tim Harris got right back to basics, but with some solid thinking:
He says: "By rigging to the ends of the beam, the beam will be be working in compression, with the mass of the payload and Vulture primarily supported by the rigging. This will enable the use of a much lighter spar.
"I have made the assumption that the payload will be heavier than the vehicle, and have done away with the counterweight. This might save a good chunk of weight and also allows the Vulture to be further out for a given length of spar. The centre of mass always hanging beneath the anchor point. (In the drawing the payload is approx. 3X the weight of the vehicle.)
"Because the rig is asymmetrical, it should kite into the wind the vehicle to leeward. you could add a streamer or small windsock for more stability.
"Once Vulture has launched, the payload should have a fairly gentle swing to the new C.O.M."
if your going to go with the triple orb launcher it should be named "Eccentrica Galumbits"
That is all
If the crowd was predominantly made up of Wile E Coyote and his family, then yes.
Too much is never enough...
I can't help but agree with lawndart (hangie pilot, perhaps?) in believing any idea of aerodynamic steering is pointless at that sort of altitude. Since the aim is to get the rocket aimed generally upwards as soon as things start happening in the balloon bursting department, it seems to me you have only two real options:
1) have it pointing in the right direction to start with, or
2) vectored thrust.
Good luck writing the flight control software for (2) - starting with an unknown position, attitude, and vector, and not very long to sort it all out before you lose all the thin-air friction advantage that the balloon's altitude gives you.
I'm not happy with triplet balloons, but even less happy with long carefully balanced struts, rails, and pointers: no-one seems to have remembered the good Doctor Newton and his 'equal and opposite reaction'. A passing fad, no doubt, but I can't help feeling that rocket going rapidly forwards is going to result in a certain amount of balloon going backwards - at the very least, it's going to tip in the reaction and that's going to cause the end of a launch ramp to tilt down. And that's ignoring the issue of a guide/release mechanism that is both light and able to force a direction change of better than sixty degrees without sticking.
Which leaves me with the launching upright approach. This has the advantage that it's gravity stabilised, assuming the mass of the payload is suspended somehow below the balloon(s).
What I would propose is not a three- but a six-balloon system. The balloons would be constrained in a light mesh into an annular shape - a poor-man's doughnut balloon.
This has the advantage that the balloons will automatically assume a hexagonal shape - with a space in the middle the size of the balloons, very suitable for a lightweight horizontal platform to be used for a vertical launch. It also has the advantage that a single balloon bursting doesn't shift the balance too much; the platform will still be vaguely horizontal and the hole won't fill.
BOTE calculations indicate that a 10 metre diameter balloon has a volume of about 105 cubic metres; a four metre balloon just over one sixth of that - very convenient. With six four metre balloons you have a four meter platform from which to launch vertically.
The question becomes then one of *when* to launch: ideally just before the first balloon pops. Presumably there is some sort of specification as to differential pressure for the balloons at bursting point; perhaps some sort of pressure sensor, and trigger just before the expected bursting point? Or, if the rocket motor can be ignited quickly enough, wait for the burst (a gyro will tell you you're tipping over) and then go.
You might want to arrange some automated bursting after launch; the balloon will of course rise faster once the load of the rocket is removed and might even catch up with it in the short term.
p.s. No hydrogen involved!