SpudFiles

You've done a great job on this cannon. 300 yds is an impressive softball shot....and a good clean build as well. The softball barrel is probably the ideal size for your cannon. The potato barrel is way short....but I'm sure you know that already.

Now that you have the propane thing down, maybe it's time for a fan and an air intake valve...and multiple spark gaps... While not obviously not necessary, these things do cause a noticable peformance jump.

Soooo, the LV cops haven't run you down at the park yet for disturbing the peace or some such rot-gut?

Don't forget the space occupied by the breech. That's more volume for the chamber, too.

Jeff

xpitxbullx wrote:Don't forget the space occupied by the breech. That's more volume for the chamber, too.

Jeff

...and somewhat of a choke point for your softball barrel.

BTW, how large and what type of rag are you using to sabo the softball?

Choke point helps build pressure. I use shop rags.

Jeff

The choke point builds pressure, but the pressure is immediately diffused to its original pressure, its like venturis effect, but when your barrel is the same size as the chamber the choke really has little effect on performance... and with the volume of the choke your C:B is more like 1.8:1...

No police trouble so far. It's not as loud with the softball as it is with potatos or tennis balls and I go shooting at a large soccer park early in the morning.

Oh, the size of the shop rags are 12"x12". I get them at Wal-Mart for a couple of bucks for a pack of 10. I'm going to try a chamois later.

Does anyone know the drag coefficient of a regulation softball? I'm trying to calculate why it flies as far as it does only having a 32" barrel. Hell, a potato or a tennis ball doesn't go as far.

Jeff

What PSI is the propane at?

why would you know that?

The psi for my setup is 36 psi for the softball barrel and 30psi for the others.

I'm trying to use that hybrid program to see what improvements I can make with my stuff. I can't get it to simulate my results and for proper max distance you can input the 'drag coefficient'

Jeff

daxspudder wrote: the choke really has little effect on performance...

i beg to differ because i have done this and it makes a huge differance. before the choke i got a small thud, shooting it many many times. after the choke "baffle in my case" i got a huge explosion every time since with the same amount of propellant.

Spuddin,

You get that softball barrel going on the Howitzer, yet?

Jeff

i think i leave the basball barrel on and modify my pneumatic mortar to shoot softballs.

xpitxbullx wrote: Does anyone know the drag coefficient of a regulation softball? I'm trying to calculate why it flies as far as it does only having a 32" barrel. Hell, a potato or a tennis ball doesn't go as far.
Jeff

A baseball averages around .3 but changes with velocity, not sure about a softball but I would think it's comparable but slightly higher. A tennis ball is in the .6 - .7 range. Golfball comes in around .25

The drag on a tennis ball and potato slug is going to be significant. There has been some speculation in the forum before regarding how much power it would take to shoot an unmodified tennis ball 1 mile. I contend that it can't be done because of the lack of mass and high drag. Visualize trying to shoot ping pong balls 1 mile...same problem albeit magnified.

You said "I MAY do a damage video for you destructive obsessive people. 3/4" plywood isn't cheap so I have to find something else. Plus it doesn't fit in my car."

Than you shoot a LCD screen.
Thats one very very nice cannon i love it, thanks for the video.

xpiC

Thanks. The LCD screen was not working anymore and heading for the garbage can anyways.

Jeff