
Thanks in advance!
Space between the meter pipe and chamber.. It may contain air, combustion gas or fuel.. When the metered propane or gas is delivered, some remains in this space instead of entering the chamber. This throws off the calculated mix, so experimentation is used in several shots to get the metering tuned to your plumbing.spudnutbutthut wrote:what is dead space?
Your maths is disregarding something important.hi wrote:Ive used mapp gas. it doesn't give that much of a difference. maybe a 10% power difference, but it costs a lot more.
oh woops i went and rechecked the page i got my info from, and i realized those are the percentages for propylene oxide my mistake.jimmy101 wrote:propylene = propene = C<sub>3</sub>H<sub>6</sub> = CH<sub>3</sub>-CH=CH<sub>2</sub>
Which isn't on the SpudWiki Common Fuels page.![]()
(Which I strongly recommend MrPed reads.)
Combustion formula:
2C<sub>3</sub>H<sub>6</sub> + 9O<sub>2</sub> --> 6CO<sub>2</sub> + 6H<sub>2</sub>O
Ignoring the 0.5% propane in the mix ...
So, for each propene you need 9/2 O<sub>2</sub>'s. Air is ~21% O<sub>2</sub>;
(2/9)(0.21)(100) = 4.67% by volume
if the propene displaces air from the chamber during fueling.
If the propane is injected into a sealed chamber then you need a bit more,
((0.0467)<sup>2</sup> + 0.0467)(100) = 4.9% by volume.
At least, that's the numbers I get.
I always get two shots/spud in a 2" barrel. Just cut the spud in half.Ragnarok wrote:Cost of a potato: ~40 pence. I might get two shots from a potato if using a 1.5" barrel (which would make the chamber extreme overkill), so 20 pence of potato a shot.
Yes they would if the system was already optimized. Since a combustion spudgun is hardly optimized then I doubt the increased cost is justifiable. For a fraction of a pence per shot you could just use a larger chamber and get the same performance boost.Most companies would kill for that.