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Posted: Sun Dec 02, 2007 12:43 pm
by jimmy101
octane89 wrote:What I will end up doing is using a interchangable barrel system and record my data. Since my cannon will be the constant, the barrel will change lengths (and keeping the same C:B ratio) to see the varying results. I can also "match" spuds by their weight and hopefully I will finish this soon. I will record as much as I can: muzzle energy, projectile acceleration (using GGDT perhaps), distance, etc...
Excellent idea.

Even if you can't exactly match the spuds weights you can measure the spuds weight and then correct the results to a constant weight.

If you have the spud's weights you can also calculate the kinetic energy of the shot. This is probably a much better measure of the gun's performance than just the muzzle velocity.

Posted: Sun Dec 02, 2007 12:54 pm
by octane89
I found this-
http://www.ajdesigner.com/phpenergykene ... uation.php
I just need to enter the mass and velocity.

On a side note, I was thinking of using MAPP gas, and I don't think I'd encounter any different problems then I would with propane-sound like a safe bet?
I know I need to make adjustments for the 4.6% mix instead of 4.2, as well as 94psi of tank pressure.