SpudFiles

Im sure these are on this site somewhere, but i havent exactly found what im looking for. does anyone know some links or formulas off hand that could help be predict piston force as well as projectile velocity or acceleration? I know the basic physics calculations with velocity/accel/distance/force, but i dont know how air pressure fits into all that since its constant force, instead of impact.

Any help or redirection is appreciated

As for the projectile questions, this is handy:
http://www.thehalls-in-bfe.com/GGDT/

For predicting piston force, what's wrong with finding the area of the piston exposed to air pressure and using that to figure out the force applied to it (force = pressure x area)? I'm sure you could calculate acceleration and what not as well if required (acceleration = force/mass) it wont be exact but it would do. Perhaps I've misunderstood.

Pressure is fLorem ipsum dolor sit amet, consectetur adipiscing elit. Cras nec placerat erat. Vivamus dapibus egestas nunc, at eleifend neque. Suspendisse potenti. Sed dictum lacus eu nisl pretium vehicula. Ut faucibus hendrerit nisi. Integer ultricies orci eu ultrices malesuada. Fusce id mauris risus. Suspendisse finibus ligula et nisl rutrum efficitur. Vestibulum posuere erat pellentesque ornare venenatis. Integer commodo fermentum tortor in pharetra. Proin scelerisque consectetur posuere. Vestibulum molestie augue ac nibh feugiat scelerisque. Sed aliquet a nunc in mattis.

Wow, thanks for the full explanation.
Also, very helpful calc MrCrowley

So if i have a 2.6lb piston in a 4" chamber and 1.3" stroke at 1000psi, that would be:
a = P*A/m, or 1000*12.56/2.6 = 4833 in/s^2 = 402ft/s^2

Then d=0.5at^2, or 1.3=0.5*402*t^2, so t=0.0804s

Then Vf= a*t, so 32.33ft/s

These last two might be unnecessary, but this is where i'm unclear. how is the impact force calculated? F=MA just gives me the initial force behind the piston, not the energy accumulated over its travel..

Can you then use this for the average energy accumulated over the pistons travel?

Yes! thats the equation i needed. it comes out to be 1359lbs, which sounds about right

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Cras nec placerat erat. Vivamus dapibus egestas nunc, at eleifend neque. Suspendisse potenti. Sed dictum lacus eu nisl pretium vehicula. Ut faucibus hendrerit nisi. Integer ultricies orci eu ultrices malesuada. Fusce id mauris risus. Suspendisse finibus ligula et nisl rutrum efficitur. Vestibulum posuere erat pellentesque ornare venenatis. Integer commodo fermentum tortor in pharetra. Proin scelerisque consectetur posuere. Vestibulum molestie augue ac nibh feugiat scelerisque. Sed aliquet a nunc in mattis.