HEEELLLLP! (ignition troubles)

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
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DYI
First Sergeant 5
First Sergeant 5
Antigua & Barbuda
Posts: 2862
Joined: Sat Jul 07, 2007 8:18 pm
Location: Here and there

Fri Apr 02, 2010 9:47 pm

For a hybrid running at 20X maximum, you'd ideally use a 20 psi gauge for fueling. It really isn't economical to use one gauge for both fuel and air; two +/- 1% gauges can be had for $70 from McMaster, whereas a single digital gauge of sufficient accuracy to use for both fuel and oxidizer would cost several hundred. My first manometric meter used a 0-15psig +/- 1% gauge from McMaster (with 0.2psi graduations) and performed well from 2X to 20X. I kept two gauges for oxidizer, depending on whether I was using pure oxygen or air.

The only successful example that I've seen of a single gauge manometric meter is the one on HyGaC, and that gauge goes for just under $1k at current prices (0 - 5000psig, +/-0.02%, if I remember correctly).

I should have realized this issue earlier. If it isn't causing your problem, then it will cause one later. You either need two reasonably accurate gauges with suitable pressure ranges, or one extremely accurate one.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
randompkguy
Private 4
Private 4
Posts: 60
Joined: Fri Jul 27, 2007 11:12 pm

Sat Apr 03, 2010 2:50 am

I was planning on getting the two from mcmaster (f'in love that place :D despite the high prices) but i just got impatient, so i used what i had (I'm sure you know what that is like)
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