newbie here

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
Mafia_Mike1321
Private
Private
Posts: 4
Joined: Sun Aug 20, 2006 1:42 am

Sun Aug 20, 2006 1:55 am

well so im trying to make my first combustion cannon.... im was messing around with some extra PVC i had lying around and i bought a grill starter....i have a 4 ft long 1.5 inch wide pipe and a cap on one end that u can screw on and off and i installed the grill started about 2 inches away from the screw cap...i loaded in a wad of cloth leaving about a foot left for a "combustion chamber" .. spritzed in 2 sprays of model nitro fuel (screwed the cap on) and when i fire it, it kinda goes FLOOMP and it onyl travels halfway down the barrel....so what am i doing wrong? i mean u guys are hurking these things a hundred yards lol dont flame me im new to this stuff
User avatar
VEGEMITEMODDER
Private 4
Private 4
Posts: 69
Joined: Sun Aug 06, 2006 8:21 am
Location: Australia Mate

Sun Aug 20, 2006 2:00 am

Have you tryed somthing like hairsprary of engine starter (eather)?

welcome to the forums
Mafia_Mike1321
Private
Private
Posts: 4
Joined: Sun Aug 20, 2006 1:42 am

Sun Aug 20, 2006 2:17 am

nitro fuel is MUCH more powerful than hairspray, its 15% model nitro from my hobby shop.......i was wondering, does it just need a better seal from the ammo to build up more pressure?
User avatar
VEGEMITEMODDER
Private 4
Private 4
Posts: 69
Joined: Sun Aug 06, 2006 8:21 am
Location: Australia Mate

Sun Aug 20, 2006 2:27 am

yes a tighter fit would help but not to tight
maybe you can just try hairspray or somthing like it just to see how it goes? or a chamber fan maybe
Mafia_Mike1321
Private
Private
Posts: 4
Joined: Sun Aug 20, 2006 1:42 am

Sun Aug 20, 2006 2:40 am

i actually did try hairspray and axe and the nitro lights better out of the three, and what is this about a chamber fan? ive heard about it but i'd liek to know more
jeracoo
Private
Private
Posts: 3
Joined: Sun Aug 20, 2006 4:45 am

Sun Aug 20, 2006 4:48 am

If you can't get it started on 15% nitro just build a simple pnemutatic all you need is a tubeless tire valve a .5 inch to 2 inch pipe one end cap a ball valve either plastic or metal and you can launch things preety far, its really easy.

I just use mortein to fire my combustion it works great mines 2 inch

Good luck with your current and furture projects
User avatar
killagorrila99
Sergeant 2
Sergeant 2
Posts: 1100
Joined: Tue Jul 25, 2006 2:35 am
Location: Australia.

Sun Aug 20, 2006 4:55 am

why dont u use oxy-aceteline? lol 8) anyway if u use potatoes it will work much better!
"I'm sorry, Mr.Bush cant come to the phone right now, He's playing cleudo with Mr. Cheney And he has him in the Cupboard with a broom stick" -White house receptionist.
User avatar
rna_duelers
Staff Sergeant 3
Staff Sergeant 3
Posts: 1739
Joined: Mon Sep 26, 2005 7:07 am
Location: G-land Australia

Sun Aug 20, 2006 5:37 am

Well if u have it from about 1' from the bottom the camber to barrel ratio is at 1:3,try having the rojectile about half way down because any combuston cannon with a 1:3 C:B ratio isnt going to shoot very well at all.
Image
User avatar
mark.f
Sergeant Major 4
Sergeant Major 4
Eritrea
Posts: 3637
Joined: Sat May 06, 2006 11:18 am
Location: The Big Steezy
Has thanked: 57 times
Been thanked: 57 times
Contact:

Donating Members

Sun Aug 20, 2006 6:56 am

Leave more of a "combustion chamber", and find a tight fitting projectile.

And when it does work, don't expect too much distance because you'll only be shooting out of a ~2' barrel.
Mafia_Mike1321
Private
Private
Posts: 4
Joined: Sun Aug 20, 2006 1:42 am

Sun Aug 20, 2006 8:37 pm

well ok one thing i discovered while i was tinkering with it was the fact that i just need to make a combustion chamber lol .... i cut the barrel down so that it was about 2.5 ft long and i just put in some wadding in the tip really tight....when it fired it actually threw the wadding about 15 ft or so and there was a loud crack from the air escaping...my next hardware store trip will be to get a reducer down to 1 inch so that my 1.5 inche chamber will work with it...hope it will work ive just been messing with it a bunch to try and make it work.....when i get some money saved up im going to make a proper cannon with a 3" x 2' chamber with a 2" x 4' barrel....... another question i have: is there another alternative to getting one of those caps you can screw on? cus on the cannon i tried making, i can hear lots of air wooshing out from there and i cant tighten it anymore by hand....oh yea and with my very first config. i found a propane bottle in the barn and i tried it and i got the same result, floomp and about halfway down the barrel....that or i hear air rushing out from where the cap is
User avatar
chosen_way
Specialist
Specialist
Posts: 106
Joined: Sun Jul 02, 2006 4:31 am

Mon Aug 21, 2006 4:04 am

go pneumatic, tons more accurate and alot more fun to shoot and you wont have any flames coming out that could burn you.
how do i put a picture here? woo i brought a signature and have nothing fun in it :(
jeracoo
Private
Private
Posts: 3
Joined: Sun Aug 20, 2006 4:45 am

Sun Aug 27, 2006 4:30 am

hey i already suggested that air is the way to go if your a newb
Benny
Corporal 4
Corporal 4
Posts: 844
Joined: Wed Apr 19, 2006 8:21 pm
Location: Tasmania, Australia.

Sun Aug 27, 2006 4:37 am

hey i already suggested that air is the way to go if your a newb
Hey, he was just backing up your comment.
And mark, try less fuel.
Join the spudshot forum!!!!!

F*ck the bunny... i got a fishy ><>
User avatar
Shrimphead
Corporal
Corporal
Posts: 509
Joined: Thu Nov 17, 2005 7:42 pm

Mon Aug 28, 2006 4:40 pm

Ya, you may be putting too much fuel in, which creates a less powerful explosion.
Controlled insanity = Genius
Life flies when you're being dumb.
User avatar
noname
First Sergeant 4
First Sergeant 4
Posts: 2698
Joined: Mon Apr 10, 2006 9:19 pm
Location: Bay Area, CA

Mon Aug 28, 2006 4:45 pm

You can put a ball valve on the back, always seals, easy to refuel.
Post Reply