Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 39 users online :: 3 registered, 0 hidden and 36 guests


Most users ever online was 218 on Wed Dec 07, 2016 6:58 pm

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

need some help

Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
Sponsored 
  • Author
    Message

need some help

Unread postAuthor: konarider321 » Thu Jun 12, 2008 6:31 pm

just built my first spudgun and i am having some problems with blowby and partial combustion. im thinking making the barrel end pointed so the inside edge makes the spud fit smoothly. any suggestions would be much appreciated.
  • 0


konarider321
Private
Private
 
Posts: 2
Joined: Thu Jun 12, 2008 6:13 pm
Reputation: 0

Unread postAuthor: Darkside 6ix » Thu Jun 12, 2008 6:41 pm

Okay...what do you mean by blowby? Does it mean when the potatoe leaves the barrel? Some pics of the cannon would be pretty helpfull. And shaving away the inside tip of the barrel wont do you much good. I think that your having problems with the combustion. You said you had problems with partial combustion. If you could just give a tad bit of more information to let people know what are your problems, we would be glad to help you.
  • 0

"Dude, if all of the people on spudfiles got together with all of their cannons, we could take over china"
User avatar
Darkside 6ix
1st Lieutenant
1st Lieutenant
 
Posts: 298
Joined: Sun Apr 30, 2006 6:53 am
Location: United States
Reputation: 0

Re: need some help

Unread postAuthor: starman » Thu Jun 12, 2008 6:56 pm

konarider321 wrote:just built my first spudgun and i am having some problems with blowby and partial combustion. im thinking making the barrel end pointed so the inside edge makes the spud fit smoothly. any suggestions would be much appreciated.


Yeah that's a common performance hop up. Grind a small bevel on the inside edge of your potato cutter. That will cause the potato to cut slightly large and fit tighter in the barrel.

I assume by blowby you mean the spud isn't fitting airtight. This is more a problem with 2" barrels than 1.5" since you need a bigger spud for 2".
  • 0

User avatar
starman
Donating Moderator
Donating Moderator
 
Posts: 3041
Joined: Wed Dec 12, 2007 12:45 am
Location: Simpsonville, SC
Reputation: 0

Unread postAuthor: konarider321 » Thu Jun 12, 2008 8:22 pm

by partial combustion i mean not all the propellent is igniting and blowby i mean some of the blast is passing by the potato before it lanches. it is a 2" barrel btw. thanks again
  • 0


konarider321
Private
Private
 
Posts: 2
Joined: Thu Jun 12, 2008 6:13 pm
Reputation: 0

Unread postAuthor: BigGrib » Thu Jun 12, 2008 8:42 pm

ok well both problems go hand in hand my answer get bigger spuds. and yes unlike what pvcpsyco says beveling the inside edge of the barrel at the muzzle will help form a tighter seal
  • 0

Yea, that's definitely going to get you at least a tazer.

<a href="http://www.youtube.com/watch?v=AkMkGOpAF4s">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
facebook.com/biggrib
User avatar
BigGrib
Colonel
Colonel
 
Posts: 652
Joined: Mon Oct 01, 2007 11:43 pm
Location: TriCities, WA
Reputation: 0

Unread postAuthor: psycix » Fri Jun 13, 2008 5:00 am

I recommend a chamber fan to you for faster combustion.
It really increases performance ALOT.
  • 0

Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

Spudfiles steam group, join!
User avatar
psycix
Donating Member
Donating Member
 
Posts: 3684
Joined: Mon Jun 25, 2007 7:12 am
Location: The Netherlands
Reputation: 0

Unread postAuthor: jimmy101 » Fri Jun 13, 2008 1:46 pm

Did you bevel the outside of the barrel? A single outside bevel will give a good seal as long as the minimum diameter of the spud is greater than the ID of the barrel. If you can see any gaps between the spud and the barrel that'll screw up your mixture since the fuel will be leaking past the spud before the gun is fired. When fired, the gap will give significant blowby and reduce the gun's performance.

The double bevel will increase performance versus the single outer bevel but the single outer bevel should give an essentially airtight seal, assuming your spuds are big enough. It seams to me that finding spuds big enough for a 2" barrel is getting to be harder.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3129
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Sponsored

Sponsor
 


Return to Combustion Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'