Tuesday, February 26, 2008

Hardware, Rocket Hardware

If I learned any lesson from last years attempt its KISS keep it simple stupid.
A 4 engine vehicle with 39 valves is not going to fly reliably. Toward that end this years vehicle is going to be much simpler. Today I got a package...



The more I work on this stuff the smarter John Carmack gets... these are 6 5086 spun aluminum hemispheres from AMS industries.




They are 30" ID 0.1875 inch at the base 0.171 thick at the edges. 19 lbs each half. This should conservatively give me a burst pressure between 600 and 800 PSI. I'm shooting for 500, so I may lighten them a bit. The edge thinning is a lot less than AMS said it would be so I could have gone down a size in the thickness and saves some weight.

Given KISS what is the simplest system that will do the level 1 prize?
A Peroxide monoprop.
Everyone who works with peroxide spends inordinate time playing with cat packs. So I'm going to test a liquid catalyst like the Germans used 65 years ago. Using 85% peroxide I'm well under the melting temperature of 316 stainless so no cooling is needed I can just use a stainless chamber. I can also buy No clog spray nozzles in 316 from McMaster Carr and use off the shelf spray nozzles. The big question I have is with a liquid catalyst, what do I need to L* or chamber length? So I got a simple experiment I hope to run this weekend, its a long Stainless tube with 316 stainless pipe fittings welded in one end. In the pipe fittings I screw in off the shelf low clog spray nozzles and install thermocouples down the length of the tube to see what length is necessary to get maximum decomposition temperature.

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