Thursday, 2 June 2011

Peroxide ideas

I have had a few ideas for peroxide.

Firstly having read allot of posts by armidillo and unreasonable rocket, I have concluded that peroxide is not the holly grail i was wanting. Nothing ever is, and i was silly to think so but i was hoping that peroxide would be significantly easier than Nitrous. The problem i can see is that everyone using a catlyist bed ends up spending a significant portion of their time researching and testing them. 

If i was going to go down the catalyst pack route i would probably go with 90% peroxide and a silver mesh catalyst, as this seems to be the best combination of performance and ease of use. Problem is i cant really find any silver mesh so i would probably make my own. I had an idea to use activated silver pellets which are used in the production of formaldehyde, but i have no idea if it would work, and the minim order quantities are large. I suspect the pellets might be too delicate, as they are not really designed to withstand mechanical wear. I might be able to get some as a sample, but only once. For plating mesh myself, silver cyanide is needed which is quite toxic and i have no intention of handling any. It might be possible to get a company to do it locally, but I will need to experiment a bit to get the mesh right, and I cant see any company being happy about this. The whole catalyst business is allot of messing around and i would prefer something i know works even if its slightly more complicated.

What seems the most promising now is a bi-propellant %90 peroxide-hydrocarbon engine either ignited conventionally with a pyro igniter or with potassium permanganate dissolved in the fuel to catalyse and start ignition. I have no need for a restartable engine, but the second method would have manny advantages including reduced risk of hard starts. Anywhoo, i could always start with the first and move to the second later.

For the current nitrous all the valves and other bits i ordered from flow-fit online (uk hydraulics supplier) finally arrived on monday. It was about a month and a half since i ordered it and i was not happy with how long it took them. I think they forgot my order. I emailed them several times with no response. They only contacted me after i started a paypal dispute. I am glad i paid with paypal! They are quite cheap, but if anyone is considering using them i would recommend steering clear. Also I will need to degrease all the fittings as they come with mystery grease I assume is oil based.

I am still trying to find a reliable test for oil in my tanks and fittings, which i can use prior to filling with nitrous. Nitrous can form shock sensitive explosives when combined with hydrocarbons, and that was one of the factors contributing to the scaled composites disaster.

Also some cheap pressure transducers i ordered from ebay arrived yesterday. They were quite cheap ($40 inc chipping) and i am a bit sceptical they will work as advertised. Even if they are not particularly reliable i really only need a rough pressure measurement so they will do. If i cant get them working i probably wont have time to order more so I guess it will be gauges and a camera.

I am still fighting the urge to work on rocketry stuff as I really need to study for exams. On the 24 when everyone is going out after the last exam, there is know where else i want to be but in the workshop!

Also eventually I would like to try out two variations on my nitrous engine:

1. Run in monopropellant mode after engine gets warm
2. Run with peroxide.

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