Hi,
I doubt most on here are able to throw their projectiles with the same power as Timpa but I was looking at a youtube video of him and he showed a link to one of his websites where he shows his recorded speed of the sling projectile.
I use air rifles too and the legal limit in the UK is 12 foot pounds (12 ft.lb), any more and you need a fire arms certificate. Anyhow, there is a basic formula you can use to work out the "foot pounds" if you know the "feet per second" you are slinging your projectile, and its mass in grains.
Timpa states in one video he is slinging a ball bearing that is around 2.47 oz which equates to 69 grams or 1037 grains. He is slinging this thing at a very fast speed of 201 feet per second. The basic air rifle formula for gauging foot pounds is (speed * speed * mass ) / 450240 = foot pounds. The speed is in feet per seconds and mass is in grains (15 in a gram).
This means Timpa is achieving a whopping 93 foot pounds of energy ! It only takes 4 foot pounds to kill a rabbit. Legal air rifles come in at only 12 ft.lb and even a mighty strong Gamekeeper catapult (a youtube catapult wizard) only reaches 23 ft.lb!
This is some slinging power! Has anyone else done any chronography readings ? Especially a reading at around 20 yards would be useful - although difficult without destroying your measuring device.
Dont know what the actual foot pounds is to potentially kill a human (only as hypothetical example you understand!) but I think this could well be up there.
Timpa, your shots are way way powerful man.
Respect.
It was a heavy ball bearing which I myself have not used, but maybe some others on here have dont similar work ?
Move this to a relevant thread if its already been covered.
Roy.