In relation to a post of Georges Katz on http://aircommand.blogspot.com/2012/01/progress-update.html I started thinking about a system for cluster launcher with 3 boosters and a main rocket. There could be a problem with the forces from the boosters pulling on the main rocket and the strength of the bottleneck. In case of the Polaron G2 - Phase 2 the tensile force will be 2000N. (3 boosters and a main rocket on 17 bar and Ø22 mm nozzles)
One of the manners to solve this problem is to make a release system for each of the boosters and the main rocket. In the normal way (gardena launcher / cable tie launcher) there will be a problem of synchronisation between the nozzles to release. If one nozzle is released 0.1sec too early the rocket could be damaged.
After some brainstorming I came up with the idea to design a release system with electromagnets. * Connect a metal plate above the collar of the bottleneck Ø of the plate +-80mm * Reinforce the bottleneck * install 3 electromagnets around each launch tube that make contact with the metal plate. Make sure they are well attached to the launch platform * connect all the electromagnets to a power supply and use a switch so you can cut off the power to all magnets simultaneously. You just have to push one button to launch the cluster rocket
You can even use the same switch for different launch pads so you have a drag race between different rockets.
I made a drawing of the principle (top en front view)
To take rockets to greater heights, a staging mechanisme may be a way to reach this goal. By dropping some weight the upper part can fly higher. So I started to develop my own system with easy to obtain components.
The idea is to attach the second stage to the first with tie-wraps and release it with a release ring. This is a system that has proved its worth in launching water rockets.
The mayor difficulty was to make a piston out of standard materials that's cheap and won't leak and let the air flow free from the first stage to the second but not back to the first (after launch). This piston should pull the string of the release ring.
After some days I knew how I would make it.
Beneath you can find some pictures, drawings and a short film
Piston with release ring:
Bottlecap and nozzle 2nd stage:
bottlecap and tie-wraps 1st stage
Complete staging mechanism:
Drawing of Piston
Drawings bottle caps and tie wraps Complete staging mechanism:
film with: * test on the launch pad - the pressure in the 1st stage is release by the abort valve * test with 2 dummy rockets * first flight - see also flights 11/11/2011
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