http://groups.yahoo.com/group/microhybrids/ Microhybrids Sat, 30 Jan 2010 23:35:30 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/895 http://groups.yahoo.com/group/microhybrids/message/895 I uploaded a pic of a 16g hybrid converted for pressure testing. The collar around the motor tube is threaded through the case into the combustion chamber. The Mon, 14 Dec 2009 21:04:01 GMT Abu Bar-Fartootsi http://groups.yahoo.com/group/microhybrids/message/894 http://groups.yahoo.com/group/microhybrids/message/894 That was my initial reaction too, that the "nozzle in the second test was too big".  But on further consideration I wonder if it wasn't just the difference Mon, 14 Dec 2009 00:10:12 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/893 http://groups.yahoo.com/group/microhybrids/message/893 Sam you have to measure the nozzle opening to see if it eroded. Try different size drill bits to see which fits. I used a .1 inch or #39 drill to make it. If Mon, 14 Dec 2009 00:03:08 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/892 http://groups.yahoo.com/group/microhybrids/message/892 After we get some hard data on a thrust stand, we will move on to 16 g cartridges. Ed Sun, 13 Dec 2009 22:01:57 GMT KellyFamily http://groups.yahoo.com/group/microhybrids/message/891 http://groups.yahoo.com/group/microhybrids/message/891 What was odd about that was the two tests were done using the same fuel grain and the same nozzle. I can't imagine that there would be that much difference Sun, 13 Dec 2009 21:15:10 GMT fly_boy_bc http://groups.yahoo.com/group/microhybrids/message/890 http://groups.yahoo.com/group/microhybrids/message/890 Your first test looked perfect. The second looked like the nozzle was too big but it was dark so it's hard to tell. Consensus is that what you use as a fuel Sun, 13 Dec 2009 00:13:19 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/889 http://groups.yahoo.com/group/microhybrids/message/889 Looks good Sam! Long burns! Sat, 12 Dec 2009 23:56:44 GMT kellyfamily1127 http://groups.yahoo.com/group/microhybrids/message/888 http://groups.yahoo.com/group/microhybrids/message/888 First off, after my first firing where my nozzle was too big, I wanted to do another test with the graphite nozzle. So this is what I did. The fuel grain was Wed, 09 Dec 2009 01:41:39 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/887 http://groups.yahoo.com/group/microhybrids/message/887 Matt, Is that your test firing on youtube... I can spot one of the o-rings flying. Ed Mon, 07 Dec 2009 15:28:34 GMT fly_boy_bc http://groups.yahoo.com/group/microhybrids/message/886 http://groups.yahoo.com/group/microhybrids/message/886 I have always found the nozzles on C motors to be too large. Mon, 07 Dec 2009 13:33:30 GMT KellyFamily http://groups.yahoo.com/group/microhybrids/message/885 http://groups.yahoo.com/group/microhybrids/message/885 I did my first test: http://www.youtube.com/watch?v=mnooNeW3AkQ looks really good. I was using a spent C6 as the fuel and nozzle. It was about as loud as a D Mon, 07 Dec 2009 01:57:15 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/884 http://groups.yahoo.com/group/microhybrids/message/884 sounds good Ed Mon, 07 Dec 2009 01:39:17 GMT KellyFamily http://groups.yahoo.com/group/microhybrids/message/883 http://groups.yahoo.com/group/microhybrids/message/883 I pressurized it outside and it seemed to have gone ok, but I didn't do it under water. If all goes ok I might test it tomorrow. If I get it tested I will Mon, 07 Dec 2009 00:50:54 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/882 http://groups.yahoo.com/group/microhybrids/message/882 did you get it to pressurize ok? Mon, 07 Dec 2009 00:49:51 GMT Flash Gordon http://groups.yahoo.com/group/microhybrids/message/881 http://groups.yahoo.com/group/microhybrids/message/881 Sam that sounds good until we have tested these motors... the aluminum tube does not have much mass ... but the cap screw, cart and injector can become