Over-Under Propane 1st Timer - Updated!!!

[sruggles]

This is my first serious attempt at a propane injected cannon.

It has a 80mm chamber fan which is actuated by a small switch just above and in front of the front grip.

The ignition system is a dual spark set up with a 100,000v stun gun for power. The stun gun's trigger has been relocated to the rear grip.

The gun was originally meant for static guard, so it has a 1.5 to 1 C:B ratio. It will launch a potato 250-300 yards and is really dependable. I know the design is not that uncommon. The first time I saw a gun of this design, I had to have one.

Ok I have taken some of your excellent advice and made some revisions which have really paid off.

First, as you can see, Bertha now sports a 7 ft 6 inch barrel to bring the C:B ratio to 1 to 1. I then moved the dual spark from the barrel side of the chamber to the cap side. I also wired another 9 volt battery in series to the fan so it is now an 18 volt system.

I made each change independant of the others so I could evaluate the increased performance of each change. All of them have made drastic differences but I'd have to say that the added benefits gained from the increase in fan rpms really shocked me. It now has a loud solid crack instead of a low, slow thump when let off, and although not measured yet, the distances and speeds appear to be much higher.

Has anyone else noticed a marked addition in performance after changing your fan or increasing the voltage/rpms of the fan?

[MrCrowley]

Thats a pretty awesome gun you have there. The design looks familiar. A longer barrel will do you wonders.(with a 7' golf ball barrel it will be even better)

[experament-u2]

i agree with mrcrowley a longer barrel would do u wonders

nice gun i like the ignition box

[Killjoy]

Looks like some sort of futuristic rocket launcher. love how clean the construction is.

[SpudBlaster15]

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[MrCrowley]

Joanna has a range calculator? Gimme!

Edit: http://bb.1asphost.com/sigmarhaven/SSpi ... orV2-2.xls

[spudthug]

wow this cannon is awesome....love the paint....and bertha..lol..well anyway darnit!!!mcrowley ur link doesnt work for me

[LGM]

Whoa, I just posted in the cannon you are making for your daughter, and you are really good at this. That gun looks like it has a big enough chamber to handle a 3" barrel too, you should install a threaded adapter to change barrels.

[VH_man]

Yeah, that loosk sweet. i wish my combustions looked that good. A longer barrel would increase performace though............

[sruggles]

agree with mrcrowley a longer barrel would do u wonders

Yes, the C:B is definfitely off for propane. I really want to set it up for innerchangable barrels, just haven't had time yet. It has a 264 cu. inch chamber, so it could power a much larger barrel.

I plugged appromixate values for this launcher into joannaardway's range calulator, and it shows that you are actually acheiving range closer to 175 yards. Still quite good none the less.

I was just estimating. I've been too lazy to measure them out. Thanks for the info!! I've been looking for a way to find the range on the Black Widow, as it fires too fast to even hope to follow the ball.

[Specialist]

cool gun, how many volts is your stun gun ignition? nice paint job on the black widow and this gun

[SpudBlaster15]

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[sruggles]

Yes it's 100,000v and thank you for the compliments on the paint.

[Tommy_TreeTop]

Wow that is a nice cannon. Im amazed by the whole propane thing and what not. Im still to chicken to play with Propane cannons. Anyways nice job!

Have a nice day

CwB

[lukemc]

too chicken? or too poor/not motivated/parents wont let you/too busy. chichen isnt realy much of an excuse because that are pretty safe when built right