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 87 users online :: 5 registered, 0 hidden and 82 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

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

The Team
Administrators
Global Moderators
global_moderators.png CS

Second potato gun, poor results

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

Second potato gun, poor results

Unread postAuthor: Stampede10343 » Sat Sep 04, 2010 8:04 pm

Alright so i made a few simple spray and pray guns and have been browsing this site for answers but i still have a few questions..

My first gun is a 3" T and a 2 1/2 ft 2" PVC barrel and shoots about 100 yards with hairspray as fuel. I wanted to make a more powerful gun, so i decided to use a 4" x 20" combustion chamber and a 2" x 48" barrel. My first test shot the potato went about 15 yards, with a 2" spray, it felt like a really slow ignition so i tried again with not much luck. I came back on here and read about mixing the gas so i put a plastic golf ball in the chamber and mixed it up and got the potato to go about 100 yards. So i was wondering how can i make this any better since 100 yards isnt that impressive for a gun of this size..

Thanks, Stampede
  • 0


Stampede10343
Private
Private
 
Posts: 3
Joined: Sat Sep 04, 2010 7:57 pm
Reputation: 0

Unread postAuthor: clemsonguy1125 » Sat Sep 04, 2010 8:34 pm

A couple things you can do
1.Add a fan, this will help with your fuel mixing problems even more
2.Fuel mixture, theres a good chance you fuel mixture is not the best, experiment with different amounts or hairspray to find the best mixture
3.Even better than playing with the hairspray mixture is metering propane, you can make a fairly simple propane meter, browse through the combustion showcase for good examples of advanced combustions, starmans triple thunder are great examples. To find the right meter pressure you can use burntlatkes calculator or how to on calculating meter pressures
Good Luck,
  • 0

User avatar
clemsonguy1125
Major General
Major General
 
Posts: 1485
Joined: Tue Jul 21, 2009 4:00 pm
Location: East Coast
Reputation: 1

Unread postAuthor: Stampede10343 » Sat Sep 04, 2010 8:54 pm

Thanks, i'll try using a fan and testing different mixtures and see where that goes.
  • 0


Stampede10343
Private
Private
 
Posts: 3
Joined: Sat Sep 04, 2010 7:57 pm
Reputation: 0

Unread postAuthor: jackssmirkingrevenge » Sun Sep 05, 2010 3:32 am

A simple syringe meter is an easy way to get the correct amount of fuel into the chamber, use one and you'll be impressed with the consistency and power increase.
  • 0

User avatar
jackssmirkingrevenge
Donating Member
Donating Member
 
Posts: 24225
Joined: Thu Mar 15, 2007 11:28 pm
Country: Holy See (Vatican City State) (va)
Reputation: 66

Unread postAuthor: metalmeltr » Sun Sep 05, 2010 7:35 am

shorten your combustion chamber, there is a calculator on burnt lakes site that can tell you the ideal chamber size for certain size barrel, there is also one to calculate meter pipe size if you decide to do metered propene, after i set mine up for propane i never went back to spray and pray
  • 0


metalmeltr
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 426
Joined: Thu Dec 18, 2008 3:42 pm
Location: united states
Reputation: 0

Unread postAuthor: Stampede10343 » Mon Sep 06, 2010 11:19 am

Well theres good news and bad news.. i got a fan in the combustion chamber, good news is that it is more consistent, bad news is that it seems to consistent.. No matter if i do 2" or 8" of right guard it still goes right around 100 yards.. what now?
  • 0


Stampede10343
Private
Private
 
Posts: 3
Joined: Sat Sep 04, 2010 7:57 pm
Reputation: 0

Unread postAuthor: Heimo » Mon Sep 06, 2010 11:27 am

Stampede10343 wrote: what now?

now you add metered propane to the setup
  • 0

The voices in my head may not be real, but they have some good ideas!
User avatar
Heimo
2nd Lieutenant
2nd Lieutenant
 
Posts: 242
Joined: Sun Oct 25, 2009 3:02 pm
Reputation: 0

Sponsored

Sponsor
 


Return to Combustion Cannon Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'