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Posted: Fri Jul 10, 2009 11:27 pm
by THUNDERLORD
Spain707 wrote:First post.
I joined to discuss ideas I have for an automatic propane cannon.

this is very similar to what thunderlord was saying...
Welcome to SF's!
Here's a link that reminded me of a side thought I had when Judgement_arms had discussed the gas assist idea before that.
I simply dreamed up using the piston to press a check valve or a lever connected to one to vent chamber. (rather than for loading...I Prefer a BFB for that).
Seems like it would be timed right since the projectile would be exiting just as the chamber vent valve opens.
Should also close in time for fresh fuel/air mix too.
jackssmirkingrevenge wrote:Any reciprocating piston internal combustion engine is a full auto hybrid, only the projectile happens to be connected to the launcher and comes back every time you fire the damn thing....
Yeah, but on a conventional engine the piston rod connects to a crankshaft which turns the (lobe shapes) cam shaft.
And the lobes press (lifting) the valves to vent and intake fresh fuel/air...
I sort of "Linearize" [new word] it, simplifying things (like gas assist exhaust, pressurised fuel/air mix...no not pre-mix...,switch based on bolt position ignition, etc.)...

As far as the piston (projectile) being connected to a rod, I've wondered of a concept similar only the rod connects to a lever, to transfer slow moving high mass into higher velocity lower mass...and another using the piston similar to the piston in a spring-air gun, except combustion force pushing it rather than spring force...
Most of my thoughts involve blow-forward bolt concepts going back to JSR's original I discovered on Youtube.
(Many variations of that) :wink: 8)

Oh,...Those small model motors have reed valve IIRC, (no complicated mechanics), I wonder if a spring could be used (rod,crankshaft removed) and have one still firing??? Course there's heat loss issues(?)

On topic, I can't really see the pulse jet's as much more than projectiles if a simple enough design was at hand. (But even then they probably need wings for lift).