Sunday, 22 July 2012

Slow progress.

I spent the last few days machining the remaining 2 engines, mounting them and bending stainless tube. The engine mount design is not optimal and looks a bit clumsy but works.

The stainless tube is turning out to be a huge pain to work with. I was tempted to ditch it and use teflon stainless braided hose instead but I don't think the ends would have fit in the small space bellow the bottom of the solenoid. It took me about 10 attempts to make one stainless line. Now that I have one right it is much easier to make more. 

One issue I have run into is how to assemble the motor and plumbing considering that nothing can rotate freely once tightened. I am hoping that once I tighten the compression fittings I will be able to take the fitting apart to work on the engine.

We also need to test the final configuration of the thruster. Previous versions didn't have anti-chaneling rings as the catalyst fit tight and we went running them for long periods of time so it will be interesting to see if they make any difference initially. I am also adding a metering jet which should hopefully smooth out some if the pressure oscillations in the chamber. I was thinking of testing today but  Buren couldn't make it. 

I decided to include a pressure transducer on the vehicle as it doesn't add much weight and knowing the tank pressure will be useful when pressurising remotely and also when flying as you can get a fairly good estimate of how much propellant is left from knowing the initial pressure, volume and current pressure. 

Today was the day I said I wanted to have a strap down test done by. I am a bit disappointed we haven't got that far but looking back it was not a particularly realistic goal.

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