Monday, 20 February 2012

On Sunday we repeated the test (%75 with zeolite catlyist) which we had a leaky o-ring last attempt and there was a huge difference in perofrmance. I dont really like spectators but my parents wanted to see the new workshop and I said they could stay for the test.

After two warm up pulses I gave the engine a two second run during which we couldn't see any activity from the nozzle although the nearby grass was being ripped to pieces. It took me a few seconds to realise what was going on, but then I realised that the exhaust was completely superheated gas. We probally ran it for about 12 seconds   in total in 2-5 second bursts before the small tank ran out. towards the end fire stared coming out of the nozzle which looked quite spectacular and I was worrying that the nozzle was melting but we later discovered that it was the steel wool. The exhaust started getting a bit clowdy towards the end meaning the catlyist was loosing activity but we refilled the tank for another test without changing it to see how long it could last. The next run was cloudy for one quick burst then liquid started coming out. I still have no idea how much thrust it made but it was definitely loud. It is clear that we are going to have to optimise our pack design. I think larger pieces of zeolite with a more uniform shape will help, as there is more than enough catlyist but it is getting blown out too fast. I recorded the test in high speed @ 440FPS so although it was only recording for about 5 minutes, the video is about an hour long and I dont ahve any time to edit it. Its quite booring anyway but if people really want to see it I would be happy to edit out the good bits.

We have have also been working on the new test setup. I had ordered just enough teflon line fittings to make 4 hoses, (which is how many we need) thinking it would be east to make the hoses up. As it turns out making the hoses is a delicate art and I have managed to mess up two of the three I have attempted. The first one leaked because the Teflon end was not square, and the steel braid on the second one caught on the fitting so it twisted when tightening. Because it would take a few weeks to net new fittings from overseas I just ordered 4 pre made hoses from inside Australia. They were quite expensive, but I really want to have the new setup mechanically finished by this weekend. Next time I order hose fittings I will be ordering more than I need. I have also been searching for a suitable quick disconnect for some time and came across a "brake quick disconnect" in a auto-parts suppliers catolog. I need a fitting that seals on both end to prevent getting covered in peroxide when disconnecting it. It is apparently "lossless" which one would hopee it would be if using it on their car brakes. It has teflon seals and is rated to 2000PSI.... Perfect!

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