Having trouble getting a tennis ball mortar to shoot

Boom! The classic potato gun harnesses the combustion of flammable vapor.
Xenophile
Private 2
Private 2
United States of America
Posts: 29
Joined: Sat May 07, 2011 10:16 pm
Has thanked: 6 times
Been thanked: 7 times

Hey guys. I have recently constructed a tennis ball mortar out of 3" diameter PVC pipe with two pringles cans lining the inside to act as baffles as detailed in the tennis ball mortar plans of the book "Backyard Ballistics". I use lighter fluid as my propellant an a piezoelectric lighter or long handled fireplace matches as my ignition source. Unfortunately, I have failed to get the tennis ball to fly out of the barrel. I know I am achieving ignition as I here a "whoosh" sound when I ignite the lighter. I also know I have achieved combustion as the tennis ball has a ring of carbon deposit when I remove it from the barrel to try again. What am I doing wrong? Any help/input would be appreciated. Thanks, you guys.
User avatar
Technician1002
Captain
Captain
Posts: 5189
Joined: Sat Apr 04, 2009 11:10 am

Too much fuel. Reduce it to go from whoosh or whump to bang.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26219
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 581 times
Been thanked: 347 times

Xenophile wrote:with two pringles cans lining the inside to act as baffles
Baffles? In a combustion chamber? Doesn't make sense to me...

If you want turbulence to encourage complete combustion, use a fan.
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
battlelava
Specialist
Specialist
Posts: 142
Joined: Wed Oct 26, 2011 9:13 pm

jackssmirkingrevenge wrote:
Xenophile wrote:with two pringles cans lining the inside to act as baffles
Baffles? In a combustion chamber? Doesn't make sense to me...

If you want turbulence to encourage complete combustion, use a fan.
The baffles are to hold the tennis ball and prevent if from dropping all the way to the bottom
Bowman wrote: If he uses propane it's a hybrid.
User avatar
jackssmirkingrevenge
Five Star General
Five Star General
Posts: 26219
Joined: Thu Mar 15, 2007 11:28 pm
Has thanked: 581 times
Been thanked: 347 times

battlelava wrote:The baffles are to hold the tennis ball and prevent if from dropping all the way to the bottom
One simple screw will do that without filling the chamber with rubbish :)
hectmarr wrote:You have to make many weapons, because this field is long and short life
User avatar
battlelava
Specialist
Specialist
Posts: 142
Joined: Wed Oct 26, 2011 9:13 pm

jackssmirkingrevenge wrote:
battlelava wrote:The baffles are to hold the tennis ball and prevent if from dropping all the way to the bottom
One simple screw will do that without filling the chamber with rubbish :)
Yea I wish I could find my copy of the book so I could post what its suppose to look like
Bowman wrote: If he uses propane it's a hybrid.
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

  • Similar Topics
    Replies
    Views
    Last post