SpudFiles

how reliable is metered propain or butain , i mean will it fire first time everytime ( obviously if theres spark.. ect)
what is the best way to make this system as i have read up about it and well im lost

As long as your meter is accurate and you vent the air properly, it should never misfire.

what he said

"Thats what she said" ok im done

robbo@robbo wrote:how reliable is metered propain or butain , i mean will it fire first time everytime ( obviously if theres spark.. ect)
what is the best way to make this system as i have read up about it and well im lost

Yes indeed, assuming your chamber and ignition design is well configured and metering system is accurate and reliable...all not very difficult to accomplish. My Thunder Combustion design has zero misfires and very repeatable performance.

Actually, hate to differ with everyone else (well, actually, I don't ). The mixture can be off by a lot and the gun will still fire if it is well mixed and if the spark is OK.

For propane you have a range of about 3 fold that will still ignite (roughly 3% to 9%). So the meter doesn't have to be all that accurate. For a 1 liter chamber (61 ci) that means propane can be anywhere from 30cc to 90cc. That's a pretty big range.

Of course, performance will suffer somewhat the farther you are away from the stoichiometric mixture. But consistence is generally more important than raw power. I would prefer a gun that launches a spud a consistent 50 yards over a gun that sometime launches the spud 100 yards and sometimes just 10 yards.

So, I would say that with a good chamber fan the mixture isn't all that critical. Without a good chamber fan then mixture is even less important since the gun may not fire even with the correct amount of fuel.

Good consistent spark is most important.
Fan is the second most important.
Mixture is third is most important.