It is going to be mega... and I will post details of it as it develops.
In the meantime, here is a 4 metre release height catapult you can build for £30 that throws a can of coke 60 metres easily. I designed and built these for a client to run a Science event on forces. Here is the catapult in use throwing a cricket ball (All the coke exploded after one throw!) about 45 metres easily. Unfortunately the moving speck which was the cricket ball doesn't show up well in the uploaded version but it reached half way up the bank at the end of the field they are on.
