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I amongst others have posted on the site but our thoughts and questions are unanswered. If you don’t have the resources it is probably better to remove the option.
I put these thought on a few weeks ago,
Otherwise great site and I wish you well.
john ashcroft · 7th March 2021 at 6:06 pm
There maybe an easier way of pressurising the system. I don’t know if it will be lighter but should be simpler and lower cost.
You are looking at using a low performance rocket to vaporise and heat your rocket; I am going to suggest a different low performance rocket, taking a few ideas from Robert Truax
Have you considered a “hot water rocket”?
Essentially Water is superheated, probably resistively in a simple carbon steel tank. It can then be used to vaporise LOX directly, or could be used to pressurise and vaporise LN2. Pressurised LN2 could be vaporised by passing through etoh. (similar to Sea Dragon, though methane to pressurise RP-1)
Vaporized LOX or LN2 can be heated to 373K by direct injection of superheated water to the gas in the tanks. Not required for simple engine testing but should lower pressurant mass in rocket.
If you drop me an email I can run some numbers past you.
john ashcroft · 13th March 2021 at 6:39 pm
Some numbers: To vaporise 32kg of LOX to pressurise the LOX tank would require some 11kg of superheated water at 240C, 33bar. Tank maybe 8kg.
Some could be used to vaporise/pressurise tank of LN2, you would need 25kg of LN2 in a tank maybe 17kg, to be jetted into the etoh/water tank, vaporising/pressurising.
Using superheated water to heat presurants in tanks to 373 would save some weight but would add complexity.
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