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Posted: 6/3/2008 2:53:27 AM EDT
answer1 = (velocity * (bulletweight + 1.75 * powderweight)) ^ 2
answer2 = 64.348 * weaponweight recoil energy in ft.lbs = answer1 / answer2 This one works for most rifle velocities. |
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Posted: 6/3/2008 3:55:16 AM EDT
Post the equations you entered in each cell.
The simplest method is to add an apostrophe in front of each equal sign to change the equation into text; '= A31*B25/C3 for example. I'm guessing you either made an error in converting a weight or speed. There are 7000 grains per pound; the rifle weight and the weight of expelled components must be in the same units of measure. Here are two of several on-line calculators - www.handloads.com/calc/recoil.asp kwk.us/recoil.html |
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Posted: 6/3/2008 12:52:54 PM EDT
Basic physics. Newton's First Law. Only the velocity of the powder mass depends on pressure at the muzzle, anywhere from 5500 ft/sec for a high powered rifle to 3000 ft/sec for a pistol.
Note, the product of the mass and velocity of the powder and bullet must equal the product of the mass of the firearm and its free recoil velocity. Knowing this free recoil velocity, one can determine free recoil energy. |
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Posted: 6/4/2008 3:05:35 AM EDT
AeroE: Thank you for providing the links. My numbers do match when I plug them into the links.
I was using some data to cross check my formulas out of Hatcher's Notebook and the numbers do not reflect what he had listed… I have to re-examine that, only I need to read both chapters thoroughly! That is what I get for doing something on the spur of the moment while watching TV! |
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Posted: 6/4/2008 3:25:26 AM EDT
If anyone is interested:
Cell Name - Input Wg = Weight of Fiream – pounds W1gr = Weight of Bullet – grains W2gr = Weight of powder – grains Vp = Muzzle Velocity – fps Vc = *Powder Charge Velocity - fps Recoil Velocity =(((W1gr/7000)*Vp)+(Vc*(W2gr/7000)))/Wg Recoil Energy =(((W1gr/7000)*Vp)+(Vc*(W2gr/7000)))^2/(64.348*Wg) *I am using 4,700 fps constant for Powder charge velocity at the moment. (this is one area I am still researching.) |
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