Saturday, 11 April 2009

I tested the accumulator today to 2000 psi and it was perfect. Here are a couple of pics

I also managed to calibrate the pressure relief valve to 15oo Psi and also manage to find a small regulator on the net to reduce the input N2 from 1800 psi to 900 psi. I will complete the system next week and test it to measure the thrust and burn time

Tuesday, 7 April 2009

April 7th update

I found the problem with the rocket. The firework was not generating enough heat in the plastic so was not splitting the N2O properly. I soaked a cardboard tube in oil and inserted it in the rocket, drilled out the nozzle to 8.5mm and increased the injector to 2mm and it worked like a dream. The rocket burnt for 8 seconds on full thrust with half a bottle of N2O. Unfortunately the video camera crapped out so no footage of the test

There was 3mm of polyprop left so maybe I need a bigger diameter rocket. I need to test the rocket for longer to see how long it will burn for

I made an accumulator for the N2O. Basically when the rocket is horizontal gas will be passed to the motor. The accumulator has a sliding piston inside with N2O one side and compressed air or CO2 on the other. The air is pressurised to 1200 psi and when the rocket is fired the pressure will keep the N2O liquid so no gas is passed to the motor allowing a full clean burn. The accumulator will be pressure tested on Saturday April 11th. If its OK I will test the motor soon after.

I'll post some pics later