Friday, February 20, 2004

HALLOWEEN Air Cannon
(Design from Bob Simons' Backyard Ballistics Page)



CAUTION
DO not use a CD or DVD for the diaphram as I have depicted in my photo...when overpressured these will shatter in to sharp shards and blast out the end of the cannon. I have found that the end of a grapefruit juice can (removed with one of those new can openers that doesn't cut the metal but only fold the crimp back) works perfectly without modification. When completed my cannon is wrapped with black stove pipe and held with hose clamps to help contain any pieces of the cannon that may be expelled if a failure occures. Always use a regulator or a pressure release valve on this type of cannon and keep your pressures as low as you can (I find 30lbs to be great). When possible use ABS instead of PVC as it will split instead of shatter upon failure. If using PVC, be sure to NOT buy "cellular core" type. It is not rated for pressure. Any PVC should have a pressure rating printed on its side. PVC cannons should not be used below 40degrees or above 100 degrees. Repeated firings may be an issue, as this pressure release cycling may tend to cool the cannon (this has not been experienced by me yet). Also, in an effort to lower the tone I increased the length of the center tube. This did lower the tone and reduced the volumn considerably. However, I found that adding a 45deg angle adapter on the end of the cannon actually increased sound output considerably (strange??). As an added benefit, the angle on the end of the cannon makes it impossible for this to lauch dangerous objects at any serious velocities. You can make this cannon any size. You will note that the spud gun directions show a longer gun with smaller pipe. Due to your reduced presure requirments 4" (and increased volumn requirements) the 4" seemed a good compromise. I'll add pictures to my finished version but in the meantime you can look at Cory Minions site for what he has built (and sells).
The information on this page is for information only. If you choose to build a cannon such as this one I take no responsiblity for its use in any way
Below are some pictures of my version of the Cannon
You can buy a "ready for action" and refined version of this from Cory Minion
[air cannon]
INSTRUCTION for the Backyard Ballistics pnuematic Spud Gun (air cannon)
Click this to see the prototype movie 1
Click this to see the prototype Movie 2
Click this to see hear high quality finished air cannon, audio (4meg)
Click this to see the finished air cannon work, Movie (12meg)
newdiaphram]
Diaphram to use (NO CD)
Circuit]
View6
[proto]
View1
[proto]
View2
[proto]
View3
[proto]
View4
[proto]
View5
[Final]
Final1
[Final]
Final2
[Final]
Final3
[Final]
Final4

Animation of how this Cannon works

This image taken from http://users.frii.com/bsimon/backyard.html


Link to Cory Minions AIR Cannon web page

To My HALLOWEEN Page Click Here
To My MAIN Page Click Here