if u shoot at night, and you see flames coming out of your barrel, tou are using too much fuel.
in a perfect world, the chamber should run out of fuel at the same time as the "potato" leaves the barrel.

too lean, and you get a vacuum before the projectile leaved the barrel.
too much fuel, and you ...

I would personally go for a 12v fan, with a mixing tube.

But i guess both solutions work, just make sure u mount the 5v fan so its easy to replace if u burn it with 9v , but its usually not a problem.

Meh... i still have some trouble with the design of the breach design.

Making a combustion, with a quick and hassle free, airtight seal on the barrels is not that easy.

A frontloader design is not a option

thanks peeps ... my mind will be occupied a few days now

Hi peeps...

Its winter, and i am planning a new spud build, and i want a "double spud gun with two shots, like a side by side shotgun.
The thing is, i want to reload it the same way as u would normally load a shotgun.
But i am not able to think out a reload design that is fast and safe at the same ...

the ignitor from USG can be connected directly to a battery ( at least from the one i got from USG ), if you do, it will continue to ignite untill the battery is empty.


So the first drawing Jack made will work (at least it works on my gun), and i would suggest u get a 9v battery connector, to make ...

The leak u have sounds like your gas valves are not 100% tight.

second thing that hits me, it sounds like u have not ventilated the chamber with fresh air before loading in a new potato. so the gun works the first shot, but then all the air is used, and only co2 left for the next bang.

i guess ...

regulators usually do not like liquid gas, but you already said you tried different angles.
Have you made sure the gas flow goes the right way trough the regulator ? usually they only work one way, and there is small arrows on the regulator telling wich way the gas should flow.


( just eliminatin ...

best solution is to have a mixing pipe (a pipe inside the chamber with a little fan in the end), that way u can pull out CO2 from the bottom of the chamber, and u fill up with fresh air pretty quick while u reload.
it also gives a wery good fuel mix

The reason your gas temperature is so cold, is probably due to the propane coming out of your can in liquid form. try to hold the cannister vertical when u measure the gas.
The other thing that strikes me, is that the measuring pipe u have there looks a bit large, what preassure do you use when ...

DYI wrote: Your idea is sound - no "cop"ing of heads here... That's actually how the very first hybrid ever posted on SGTC worked.

Really ?... must be a smart dude making that one.. hehe

Guess its a nightmare to calculate pressure etc... lol... so guess its not really a improvement

hmmm...just some brainstorming here... dont cop my head of if im wrong... but how about a combustion/pneumatic hybrid spudgun ?

Ignite the chamber to get up the pressure, then release the pressure with a valve, like a controlled burst disc

atm i don think the problem is getting a big enough bang, or using exotic fuels, but getting a bang that dont destroy the potato.
Maybe looking at the construction, and the way we think when we think combustion spudgun must go back to the drawing board.

what about two bangs ?. one explotion to ...

u got the camera up and going i see. nice shots

are u satisfied with the camera so far ?

Nice cannon, as mentioned before here, only concerne is the bolts going in to the chamber.