SpudFiles

This is a proposed cannon that uses a carburetor and pump action to operate. It has the contriversial fuel, gasoline, and is technically an advanced combustion cannon. Probably more effective than metered propane.

Theory Of Operation

The cannon isn't much different from an internal combustion engine. There are three main differences however.

The first difference is the cannon does not have a compression or ignition stroke. It is theoretically possible to do so but it would be difficult to time a valved release of the pressure created during ignition. Because there is no compression or combustion stroke therefore cannon ignites at the bottom of the intake stroke. Since the ignition is at the bottom of the stroke, the piston can't move which eliminates the cannon to function as an engine.
The second major difference between an internal combustion engine and this cannon is created from the first difference. Instead of the energy being used for the acceleration of the piston, it is forced through the piston head into a "power tube" which leads to the barrel and doubles as the ammunition breach.
The final difference is the cannon has a manual intake and exaust stroke. This creates the "pump action" reffered to before. It however can be configured into a long travel bolt action.



If you see any design flaws that I'm not aware tell me. This design is still being configured. Otherwise just comment.

If you can pull it off then good luck

It looks like a hybrid, what with the sprung chamber seal, I'm assuming the angled pipe is the ammo feed.

How are you getting the carburettor to work?

Gasoline isn't as powerful a fuel as propane, but if that's what works for your design, then go for it.

Good luck getting the carburetor working properly.

Hotwired wrote:If you can pull it off then good luck

It looks like a hybrid, what with the sprung chamber seal, I'm assuming the angled pipe is the ammo feed.

How are you getting the carburettor to work?

You're correct on both accounts. It does look like a hybrid. But the thing about this one is my brain doesn't hurt looking at it. The carburetor works on creating a vaccum inside the chamber. This is created by moving the piston foreward toward the muzzle. The check valve will close off access to the air from the barrel end when creating volume inside the chamber forcing the carburetor to inject the fuel.

Nice concept! and a great job on the drawing. I have a couple of questions and comments.

I assume that's a PVC check valve inside and slides back on the "pump action". That's an awesome idea as I've been looking for an excuse to utilize those check valves in someway...give sort of a burst disk effect. I wonder though if it would allow full unimpeded flow to the barrel upon ignition...maybe next size bigger valve solves the problem if there is one.

Is that a lawn mower carburator and primer bulb on the backside. I'm not sure that will work very well as normally aspirated carburators for gas engines require the vacuum of the down stroke of the piston to pull air into the throat of the carburator. You won't have that action here. The most you might do is use the primer bulb to squirt some gas in there...OR...are you planning on using the pump action to suck air/fuel in through the carburator????? Intriguing idea...but you could do the same pump action using propane and a check valve air vent.

Which brings me to the next item...how are you getting fresh air into the chamber and exhausting the combustion gases?

I love the ideas here although I think I would dump the gas/carburator and just run with propane or Mapp, unless of course you're doing this as an experimental exercise.

EDIT: Somehow I didn't see the Theory of Operation Section at first. You answered about all my questions there.

starman wrote:Nice concept! and a great job on the drawing. I have a couple of questions and comments.

I assume that's a PVC check valve inside and slides back on the "pump action". That's an awesome idea as I've been looking for an excuse to utilize those check valves in someway...give sort of a burst disk effect. I wonder though if it would allow full unimpeded flow to the barrel upon ignition...maybe next size bigger valve solves the problem if there is one.

Is that a lawn mower carburator and primer bulb on the backside. I'm not sure that will work very well as normally aspirated carburators for gas engines require the vacuum of the down stroke of the piston to pull air into the throat of the carburator. You won't have that action here. The most you might do is use the primer bulb to squirt some gas in there...OR...are you planning on using the pump action to suck air/fuel in through the carburator????? Intriguing idea...but you could do the same pump action using propane and a check valve air vent.

Which brings me to the next item...how are you getting fresh air into the chamber and exhausting the combustion gases?

I love the ideas here although I think I would dump the gas/carburator and just run with propane or Mapp, unless of course you're doing this as an experimental exercise.

It is a lawnmower carburetor on the back. I plan to suck the air into the chamber by pumping the piston toward the barrel. This keeps the check valve closed forcing all air to pass through the carburetor. Meanwhile the breach closes. The exaust works by pumping the piston away from the barrel. This creates a small amount of pressure opening the check valve allowing the exaust to pass through the barrel. Meanwhile the breach opens.

OK I get the big picture now.....VERY nice. You've got me thinking now.

I think I'll let you run with the gasoline part of it. The pump and check valving system however, I may be able to use immediately.

Well thought out!!

--

Another thought... if you could somehow harness some of the combustion power enough to "auto pump" the chamber...you could automatically evacuate and aspirate the chamber...potentially setting up an auto-fire capability. Of course, PVC would never hold up to the heat build up of an automatic gun...have to do it with steel or aluminum.

Something to think about....

Ok the animation is up from this post on; for future references.

starman wrote:Another thought... if you could somehow harness some of the combustion power enough to "auto pump" the chamber...you could automatically evacuate and aspirate the chamber...potentially setting up an auto-fire capability. Of course, PVC would never hold up to the heat build up of an automatic gun...have to do it with steel or aluminum.

Something to think about....

Well congradulations you just thought up the internal combustion engine in a sense.

im just worried about the check valve choking flow

thespeedycicada wrote:im just worried about the check valve choking flow

If I need to I'll just make the barrel longer allowing more time for acceleration.

rcman50166 wrote:

thespeedycicada wrote:im just worried about the check valve choking flow

If I need to I'll just make the barrel longer allowing more time for acceleration.

And more time to choke the flow. sorry i could not resist.

You will be using a carb with reed valves right? You could still use propane, all you need is a propane carburetor from a small engine.