Alcohol Launcher
Alcohol has an AFR of about 8. Air is 1.19g/L, Isopropyl is 785.4g/L. So for 1L of air, we need 0.15g Isopropyl, or .2ml???
Let's try from the chemistry...
- 2 C3H8O + 9 O2 -> 6 CO2 + 8 H2O
- air is 21% O2
bah... don't want to do the molar math.
This is a pretty good resource, they cite 0.241ml per 100in^3. 100in^3 = 1.63L, which is actually just a little less than the .2ml, so we'll stick right in there.
In comparison to black powder: IA has 24kj/g, BP has 3kj/g. 15.4grain = 1g, 9mm = 5grain = 1/3g. The equivalent IA would be 1/24g or .042ml. That would require 1/3L of air. A 45 would be up to 10gr, so .08ml Alcohol and 2/3L air.
Gasoline would work too, it has an even higher energy density.
V0.1 Design
Need to start with something simple-ish, but promising. I think bolt action carbine with manual steps to fill the chamber.
We'll go for a 1/2L chamber made from metal pipe.
I'm still a little fuzzy on the bolt action because it needs to retract from center, to bring a round up, push the round forward past center, then re-center. For this version, I'll probably just do that manually - the bolt will be an upside down T rather than an L. Or the bolt can be a hollow tube allowing the combustion to flow through and around it. It could also cover just the opening of the magazine and have a small peg sticking up.
The fill mechanism will also be fairly manual. Need one action to clear the chamber and another to fill with fuel. Filling will be done with a screw, syringe and nozzle. The nozzle will form a spray. A single turn of the screw will load the .06ml.
Vickers Mechanism
From this, when the round passes a certain point, the pressure pushes the whole barrel back. This also gives the gas room to expand before exiting, reducing muzzle flash and volume. Alternately, the entire barrel doesn't really need to move, if the pressure were to push back on a few mechanism that opened vents, that could be enough.
I'll fire the pellet rounds I already have.
To make the barrel, I'll get a long drill bit that's about the right size. I'll start with a solid steel rod and drill out the barrel. Then I need to make a manual rifle jig.
Pistol
Something based off this. Chamber will be in the handle, rounds will load shotgun style. It will need to be cocked after ever shot (with a slide).
The trigger will actually be more like a spring gun or crossbow. It releases a cocked spring. That spring pumps fuel into the chamber and causes a spark. I need to check the best way to cause a spark - classic grill sparker could work, but it also might be interesting to push a magnet through a coil and then run that through a small transformer.
Rifle
Most of the mechanisms will sit right behind the handle and trigger and the chamber will be in the butt. This will have the classic recoil mechanism - when the gun fires, some
Tennis Ball Launcher
This may be a better starting point. Instead of doing everything mechanically, do it electronically.
On trigger pull:
- Pump fuel and spark
- wait (~100ms)
- cycle air & load round
Need to take loading a clip into consideration. I like the idea of a sort of exposed chain fed system where you can see the tennis balls and can load them from the end. Or, taking that further, I could do a full chain feed system.