I've been working on a catapult for my physics class for over a month now, and I'm not having much success. My idea was to use a leaf spring to power a lever arm to throw a baseball/tennis ball, but we can't seem to get it to work right. Is there something I can fix, or is it just a lousy?

-- Ben Russell (russ1982@hotmail.com), February 04, 2001

Answers

a leaf springs energy is best used at the middle of the spring!..where the axle rides......its difficult to determine the design flaw w/o seeing your device......but a coil spring would probably be better suited to the task, as its enegry is pretty much centralized at either end!.

-- imissher (milehiharley@hotmail.com), February 04, 2001.

A leaf spring also has a limited effective range. If you are pulling the launch arm against the spring and letting go, there may be enough initial thrust. However the swing arm may actually slowing down before the payload is launched...

A coil spring can give you the same force with a longer "acceleration" time.

-- Dan (bolden2@hotmail.com), February 04, 2001.

Have a look at trebuchet.com and go to the catapults message board. Some of the world's top catapult experts are posting there, and will be glad to help anyone who has taken the time to begin experimenting with a catapult. The site is owned and operated by Ron Toms, expert for the "Young Guns" team on the "Punkin' Chunkin" episode.

-- Waddy Thompson (cthomp3851@aol.com), February 04, 2001.