SpudFiles

something hit me (like always)
i use an petrol engine with two cylinders and... the pic says it all.

questions: will it be worth to be the one and only in the world?
how do i ignite the mix?
how do i get the left piston to stay there until the mixture is ignited?(i was thinking to use a burst disk on the right cylinder between the barrel and cylinder then i add some pressure there and some pressure on the left cylinder to get it stay there)

any thoughts?

Other than as a Rube Goldberg approach to launching a projectile, what would the point be?

why don't you add a crankshaft and a spring fed magazine so you have a semi auto?

i actually thought of using and old rc airoplane piston assembly and just hook a barrel up to where the spark plug went and sliding bolt which is attached to the piston so when it moves down it allows a bb into the barrel and moves forward propelling the bb down the barrel oh and a motor attached to the crank shaft where the prop was

bluerussetboy: the crankshaft is there. don't you se?

and for d_hall the point is to do something unique that i can know for sure that no one has done before, not raw power. if i want more power i just use a 3cylinder engine and use a hybrid mix in the left and right and the barrel on the middle one. (my dad makes 1200cc snowmoblile engines but the cost is about 30.000 dollar so i would get 800cc of chamber)

if it is made (probably not as all of my ideas) it should be fun to hear the sound it makes. (i post stuff for others with to much mony to make)

the price tag of something like this is not worth it if i cant find a broken engine. if i find one there is an easy build.

spudfarm wrote:and for d_hall the point is to do something unique that i can know for sure that no one has done before,

Then I vote for a rocket-powered trebechet; the ultimate mixture of old and new technology!

funny dude 8)

You appear to be mixing two designs. Pick one or the other.

In the drawing, I don't see any reason for the pipe linking the first cylinder to the second. Movement of the first piston moves the second which ejects the shell. The performance will suck. The muzzle velocity will be basically the piston speed (which isn't all that fast) times the ratio of the cylinder to barrel areas.

Omit the second piston and just use the gases from the first cylinder to launch the projectile. The first piston functions basically as a burst disk. Performance will probably still suck.

the first cylinder will get some decent pressure on release out of the port so i add a longer barrel and that pressure it directed in the barrel for more performance.

also i will get a more controlled acceleration of the round.

Spudfarm: Have you considered a diesel type approach?

Why not have a combustible mixture in a piston with a burst disk to the barrel and ram a piston down to initiate the cycle?

If your dad makes engine blocks it should be no problem to borrow the mill for a bit and bore out a piston from some scrap metal.

hmm you got me on it:) burst disk on the barrel side and acetylene and oxy in the barrel cylinder then i ignite a 1x on the other side and hope it goes

Sorry to snub the idea, and I know I'm going to sound a little harsh, but to me, this is a horrific over complication.
If your plans are to try and achieve dieseling, then there are much simpler ways to manage that. Perhaps you should try something a little like a light gas gun's method of operation (obviously with changes).

A unique launcher is not necessarily a good thing. There are four main reasons why a launcher can be unique:
1) It's so new no-one else has yet been able to copy it.
2) It's so complex (or perhaps expensive) that it's nearly impossible to copy.
3) It's more than people want to copy, although they might like the concept (some of my ideas fit here, as well as a number of JSR's)
4) It's uniquely weird.
Or, paraphrased a little, those boil down to:
1) Too recent to have been copied.
2) Too hard to copy.
3) A bit fiddly to copy.
4) Not really worth copying.

No offence intended, I think this best fits category 4 - although it's got an element of #2 in there as well.

The old KISS (Keep It Simple Stupid) acronym should be considered - Can you manage to achieve all your aims with a simpler design? Can you find a way to cut out some parts?
I think both of those could be answered yes, so I suggest that you might want to spend a while simplifying the design.

Go for it if you want, but I think you should look here and consider alternatives - I'll never build anything complex without at least looking at a few other options:
http://en.wikipedia.org/wiki/Light_gas_gun
http://en.wikipedia.org/wiki/Combustion_light_gas_gun

note!
it says i am not going to build it, i put idèas on this site just for showing them of and for others to get interessed and may make it.

Ragnarok, you forgot reason number 5.

It's one of JSR's ideas and we just know that it won't work, because....

Hmm should I make fun of a sick man I wonder?

you guys are soo funny