Cluster launcher

Discussion about Compressors, hose, pipes, fittings, launchers, release mechanisms, and launch tubes.
teper
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Cluster launcher

Post by teper »

Does anyone have instructions for a cluster launcher? I would like to build one. Air command has a great one, but they don't post instructions. Have a very small, very old, Unimat Lathe. It Can handle very small parts only. would it possible to have the total parts cost around or less than 50$. (Preferably Less)
SaskAlex
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Re: Cluster launcher

Post by SaskAlex »

I have a unimat, too. I'm often wanting a bigger lathe, but the unimat is still very handy for a lot of rocketry pieces.

How many bottles do you want in your cluster? Do you have a lot of scrap material to work with? The launcher I made for my JP-2 rocket launched a 3 x 2L cluster, with full bore nozzles and launch tubes in each. Most of the material was just scrap stuff. It was really cheap, and fairly simple. It wasn't the nicest looking thing, or the most robust, but it was a good starting point.

Another question to consider is how flexible you want this launcher to be. When I made my launcher it was only good for one particular booster design. You're definitely looking at more work if you want it to be able to accommodate different booster designs, but some people have done it.

Alex
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Re: Cluster launcher

Post by U.S. Water Rockets »

teper wrote:Does anyone have instructions for a cluster launcher? I would like to build one. Air command has a great one, but they don't post instructions. Have a very small, very old, Unimat Lathe. It Can handle very small parts only. would it possible to have the total parts cost around or less than 50$. (Preferably Less)
That all really depends on the type of rocket you intend to build.

If you look on our blog site http://www.waterrockets.multiply.com, you will find a tutorial on how to easily construct a cable tie launcher. The launcher is made almost completely from PVC pipe and wood and was very easy to make using common hand tools.

For clusters, people typically leave off the cable ties holding the boosters and use the central sustainer cable ties to hold the whole rocket down. If you use regular bottles at regular pressure the cable ties are more than enough to hold down the assembly. A few weeks ago we discussed using a lever or pulleys on the collar for a medium pressure rocket, but the lifting force on the central release in a cluster rocket is multiplied by the number of nozzles, so a 4 nozzle cluster at 120PSI would pull against the release with the force of a 1 nozzle rocket at 480PSI, so you would likely need to use a lever or pulleys to release the collar. If you use a gardena coupler on the sustainer and have it as your holding point, it may not hold up to that much pulling force, you your only choice is probably a form of cable tie release or something you make yourself.
teper
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Re: Cluster launcher

Post by teper »

I would like to try the gardena and see if it can hold the pressure and the force pulling on it.
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U.S. Water Rockets1
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Re: Cluster launcher

Post by U.S. Water Rockets1 »

teper wrote:I would like to try te gardena and see if it an old te pressure and te fore pulling on it. (sorry, te h key and te c and te v key on my keyboard are broken. Haing to opy and paste letters from oter posts.)
You can also try multiple gardenas with a common link between them to pull the releases all at the same time. If you do it fast enough it would be close enough to simultaneous.
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