Wednesday, 15 June 2011

Successful Tornado tube tests

Today saw the 1st tests of the BWR coupling in my last blog i descibed my new design on heat welding two bottle caps together, I tested four couplings on a 7L rocket i filled the rocket with 1800mls of water and pressurized the rocket to 120 psi and left it there for two minutes no signs of cracks or leaks only problem we had was a nozzle cap washer had not sealed properley and had a small leak occured i will have to give the couplings a flight test to really know how they will work but results look promising i will post a how to video on making the couplings soon.
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4 comments:

  1. George Katz15 June 2011 at 05:34

    That's good news Dan. Glad to see your tornado tubes holding up to the pressure. I look forward to seeing how they go under flight conditions.

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  2. dan b15 June 2011 at 09:23

    Thanks George i think they need a good couple of flights before they are fully proven just in the process of making a alignment jig to use on the couplings to get them straight once i have bonded them together whats your thoughts on them George? Would really appreciate any feedback
    Dan B

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  3. George Katz17 June 2011 at 23:30

    Just had a look at the tutorial again, and the couplings look very easy to make! :) I was wondering how you get both surfaces hot enough to melt and bring together. How much of a variation in alignment do you get? Do you find the PET bottle necks shrink while the lids are on the frying pan? I think its important to do a burst test on these couplings so that you know how close you are to the limit when you pressurise your rocket.

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  4. dan b4 July 2011 at 12:35

    The couplers have not been a success just lately the first batch i used worked fine and still do but the latest batch have been awful the caps have shrunk to much and do not screw onto the bottles enough which led to an explosion where the cap pops off the threads. i have not found the pet necks to shrink, for the alignment they stay quite straight,i am going to try another idea of cutting the hole into the caps before melting together this might help with the thread issue. if you have any good ideas please share George

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