working out FT LBS TO FPS

[gtfreight]

ok thanks

but how do i find the Muzzle velocity
on a air rifle ?

thanks

If you don't know the muzzle velocity you can't work out the kinetic energy in ft/lbs.
I don't understand why you give a fps reading for conversion, then you ask how to find out how to get fps.
You can buy inexpensive chrono's (Combro) for about £40 that attach to the end of your muzzle and they will give you a read out in fps. They can also convert this into ft/lbs if you know the weight of your pellet.
Regards,
Gary.

[Simple]

Try this:-
http://www.1728.com/energy.htm

[Bronc59]

>>Muzzle velocity squared, multiplied by the weight of the pellet, divided by 450240

Spot on. Looks a bit weird but it's because of the units used - grains, pounds, and feet.

The kinetic energy of a pellet leaving the barrel is:

(pellet weight x (speed x speed)) / 2

This is nice and easy using SI units:

(Kg x (m/s x m/s)) / 2

i.e. (pellet weight in grams / 1000 x (speed in metres/second x speed in metres/second)) / 2

The result is the energy in joules.

It gets a bit messy in imperial because grains isn't a simple fraction of a pound. But the figure of 450240 is a simple way to convert grains to pounds and also apply the division by 2 in the formula. So, you put in feet/second and grains and out pops the energy in lb/ft.

[celticwar]

go here dude
http://www.theoben.co.uk/pages.php?pageid=5

[a88ott]

some good sites here people

thanks alot