SpudFiles

Alright, let me get how to use a hybrid meter straight. I'll take SB15s as an example. Would you put the propane into the meter, then once you have right amount, shut off the meter, then inject the propane into the chamber. Then would you measure some air into that meter, and once you get the right amount, inject that air into it?

So basically what i am saying is you first measure propane, then air, and inject them separately? Is that right?




<img src="http://img.photobucket.com/albums/v627/ ... ure501.jpg">

Mine is somewhat similar (same thing, minus the ball valve after the schrader, and a diffferent configuration), and I meter in propane (20 psi for 1x, 40 psi for 2x, 60 psi for 3x, 80 psi for 4x, 40 psi + 60 psi for 5x, 60 psi + 60 psi for 6x*), then open the ball valve leading to the gun and pump in air until it's the right pressure (0 psi for 1x, 15 psi for 2x, 30 psi for 3x, 45 psi for 4x, 60 psi for 5x, 75 psi for 6x).
As far as I know, there is no "measuring" of air, you just pump in the correct number of atmospheres depending on the amount of propane.

*These propane pressures are for my gun, not particularly everyone's.

I use a ball valve to inject the BUTANE into the chamber using a syringe and plastic tube, close the ball valve, pump in air via a bike pump and schrader valve.
The only problem i had was blowing up the pressure guage, this is fixed by isolating the guage with a ball valve before firing.
I don't see why a lot of people go to the trouble of building metering devices when the same job can be done a lot easier.
But whatever floats your boat

so noname, are those PSI's for your gun universal or just for your gun??

Read the whole post again.

noo i meant the second set of PSI's, they didn't ahve a star by them so i wasn't sure

The whole section inside those parentheses relate only to my gun, unless someone else's is literally the EXACT same gun.

okay thanks, just checking, so to calculate the atmospheric pressures would i just.... how would I do that? Just double atmospheric pressure, triple, et cetera, or do i have to detrmine something with chamber size?

Make a normal propane powered combustion cannon and all of your questions will vanish immediately.

i have made one. Metered too. and it works. all i'm asking is, if my atmospheric pressure is 14.7 psi, for a 2x mix the chamber pressure would be 29.4psi, and so on... I'm just double checking, i'm 99.999% sure that's what it should be, but i don't do 99.999% sure. I do 100% sure only

http://www.quizyourfriends.com/quizpage ... 743-625978&

Do some more research on how a hybrid works before you attempt building one.

Hint: Is the chamber pressure for a 1x mix (normal combustion) 14.7 psi?

noname, i have a distinct feeling you are feeling a little pissed at me. and my feelings are generally correct. As soon as i saw that quiz thread, i knew it was your indirect way of getting even with me. So yea, all I'm asking you is how to do one simple thing. NEver mind now, i figured it out.

If my chamber volume equals 100mL, and my meter volume equals sayyy 15 mL. Then for a 2x mix, I would need 200mL of air in my chamber- look at my air amount post. So I would have to inject an extra 100mL of air. I will use my meter to measure that, after having injected propane. I will first inject propane, then CLOSE OFF THE GUN VALVE. then presurize the 15mL meter to whatever pressure it would be to get to 100mL of air, using a fuelmeter calulation, I'm not sure what pressure it would be right now, don't feel like calculating it. Then I would inject that air into the chamber.

Does that make sense to you? Sorry if you're pissed off, it's just a question, I'll try to do a better job of researching in futgure, I just really want another opinion to make sure that I am right.

or would it just be easier to do hubbo17's suggestion in this thread

http://www.spudfiles.com/forums/french- ... 10219.html

I'm not pissed off at you, I just don't think you're quite ready to make a hybrid.
On the subject of your your 100 mL chamber and 15 mL meter scenario.
Look at the picture attached to get my meaning.
Step 1: fill "3" to 1x propane mixture pressure
Step 2: Open "2"
Step 3: Close "2"
Step 4: fill "3" to 1x propane mixture pressure
Step 5: Open "2"
Step 6: Fill "1" to 15 psi, with AIR
Step 7: Close "2"
Step 8: fire

k i see the pic, i presume this is for a 2x mix am i correct.... but why wouldn't you want to close 2 before you fill the ignition chamber with air?

I'm assuming you fill the chamber from a schrader valve that is part of the propane meter, to get all of the propane into the chamber.
Yes, that is for a 2x mixture.