Next project and more questions.

[wngovr]

I finished my pneumatic cannon. It ain't too purdy but that thing rocks. Now Im collecting parts for an advanced combustion spud chucker. Combustion is where it's at for me so i want to do this one up right nice. I've done a lot of reading these passed few weeks but before i get too involved in my design I need to know


If I use a chamber fan, does it matter wich end of the chamber the propane meter feeds into?

If I have a regulator on the propane tank, do I need a pressure guage on the meter?

Its a bit off subject but I read everywhere on this forum peoples concern about using bell reducers (for pneumatics) because they aren't pressure rated. I mail ordered 4 the other day, and when I got them I noticed they had NSF PW on them. I think bell reducers look much better than bushings, and the wells in these reducers are deeper than in the bushings. Just incase anyone is interested

FlexPVC.com
PVCFittings.com
p.n. 429-338 3 x 2 reducing couple bell 9.95 ea

[BlackH]

Its better to put it closer to the end cap and let your gas enter there to.

"If I have a regulator on the propane tank, do I need a pressure guage on the meter?"

I thought about that too and no its not (I think) I put my PSI guage on the meter and it works like a charm (I got mywhole meter and guage for 10$ in South African R, so I think its alot cheaper this way)

http://www.spudfiles.com/forums/bh-2400 ... 14078.html

[starman]

Feed the propane in on the same general end of the chamber as the fan...more opportunity for mixing when the fuel is injected. Mount the fan on the opposite side of the chamber from the barrel breech end. Have the fan blowing into the chamber, sucking fresh air from a vent on the fan side of the chamber and exhausting spent gas out of the breech/barrel side.

You don't absolutely need a gauge on the meter pipe if you have one on the regulator, but put one anyway...they are measuring 2 unique points in the fuel system. It's nice to see your metered fuel pressure after it's been locked down.

Great find on the pressure rated bell reducer.

[MrCrowley]

Nice find on the bell reducers, I think that link came up on SpudTech as well. It's sort of another mis-conception that you can't get pressure rated bell reducers.

Back in the late SGTC days, most people agreed that they did exist, but were rare. Now it's kind of been exaggerated that the only place you get them is Aussie

[jimmy101]

If I use a chamber fan, does it matter wich end of the chamber the propane meter feeds into?

If your chamber fan actually does what it is supposed to do then no, it does not matter where the fuel is injected.

I would recomend a chamber fan that is significantly smaller than the chamber ID. A 1" to 1.5" fan would be good for a 3" ID chamber.