suggestions on fuel source and mixtures

[Jlowe]

I saw a you tube video of (bobs golf ball cannon ) and couldn't live without making one . He used oxy and act to fuel his . I desire a more consistent charge to achieve accuracy. I am a long range rifle shooter, and machinist by trade . I have worked on my protect for close to a year and just finished it except for the fuel source . For ignition I am useing a grill igniter and a spark plug . The entire gun is built of steel . The chamber is 4"X 4" square 1/4 wall tubing . 1/2 thick end plates welded in both ends of chamber . Barrel is 1/4 wall pipe . I tapped the side of the chamber 3/8 NPT for the fuel source . My barrel has a snug fit for a golf ball .

I want to charge the gun and remove the fuel source . All I want left on the gun is a ball valve and a male air Chuck fitting .

I will calculate my chamber volume and measure the barrel lenght tomorrow . As I know that is the first question I will be ask.

I'm open to all suggestions to power my gun .

[matti]

You posted this to hybrid discussion area, but I'm not sure if you are talking about hybrid or combustion because you didn't mention anything about burst disc or pistonvalve.

Second thing is that a square tubing is very bad for pressure use. I would not use it with hybrid mixtures.

And for the fuel, propane is most used here because it's good, safe and cheap.

[Jlowe]

I'm new to all this and don't fully understand burst disk or piston valve systems .

[matti]

I'm new to all this and don't fully understand burst disk or piston valve systems .

Combustion launchers use chamber that is open to barrel all the time so they burn gas mixture in atmospheric pressure. Hybris are quite similar but they use a valve system between barrel and chamber so that you can have the gas mix pressurized in the chamber before ignition. This pre ignition pressure makes hybrids much more powerful then basic combustion launchers but are more complex to build and fuel etc.
Pistonvalves and burst discs are the most used valve types in hybrid cannons.

We normally talk about pre ignition pressures in hybrids as "4x mix" or "10x mix" etc. where for example the number 4 means that you have 4 times the gas i the chamber then what you would have in atmospheric system. 1x mix is a combustion (atmospheric) and anything above that we call a "hybrid".

Hope this helps!

[Jlowe]

Thanks for the help

[jackssmirkingrevenge]

Consider using a large syringe to meter butane or propane:

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