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Recoil Calculator

A place to ask general spud cannon related questions.
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Recoil Calculator

Unread postAuthor: Moonbogg » Sun Jan 04, 2009 3:29 pm

I am designing a hybrid and needed to know recoil calculations and I found this. Many of you may already have something, I really don't know. But I wanted to share this. Its meant for shotguns, however, it can be used to give an idea of how your gun will kick. Leaving the powder grains at zero and enter the weight of the "Shot mass" "Gun weight" and "Muzzle velocity".

16oz equals 7000 grains incase you didn't know. I entered the data from my advanced combustion and it sounds like it would be about right.

http://www.zknives.com/bali/brcstgn.shtml
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Re: Recoil Calculator

Unread postAuthor: jonnyboy » Sun Jan 04, 2009 3:37 pm

wikipedia wrote:The backward momentum is equal to the mass of the gun times its reverse velocity.

Good ol mass times acceleration equals force. Reverse velocity is just projectile velocity I believe. Your answer will be in newtons so you may want to convert to foot pounds.
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mobile chernobyl wrote:I can shoot a Canuter Valve off my '82 Chevy Ram F150 AT LEAST 3/4 Mile with 'ma cannon made of soup cans duct taped together, then I just squirt some bacardi 151 in the chamber and hold up my cigarrete lighta and WHOOSH! That thing flies at least 3/4 mile
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Re: Recoil Calculator

Unread postAuthor: Ragnarok » Sun Jan 04, 2009 3:57 pm

Moonbogg wrote:Leaving the powder grains at zero

Disregarding propellant mass is poor practise - anyone who has ever dry fired a reasonably powerful pneumatic can tell you it will still kick, even without the projectile.
Indeed, on some cannons, it may be a majority of the cause of the recoil.

However, the problem at hand here is that the propellants used by spudders (air, propane/air, etc) have a different effect on recoil because they don't have the same velocities as smokeless powders.

@Jonnyboy: Certainly not. Recoil velocity is not projectile velocity, not unless you have an insanely heavy projectile.
Recoil momentum is the negative of propellant momentum plus projectile momentum - momentum being mass times velocity.

Recoil energy is then recoil velocity squared times half the mass of the launcher.

To both of you, I suggest a good read of my old article on the matter (actually my first post on these forums): http://www.spudfiles.com/forums/t-t11431.html
Unfortunately, it only works in an adiabatic consideration of a pneumatic, but it details most of the principles.

EDIT: Affect/effect confusion.
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Does that thing kinda look like a big cat to you?
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Unread postAuthor: Moonbogg » Sun Jan 04, 2009 4:35 pm

Alright i'm gonna go get a physics degree and i'll be right back.
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