I have a non-racing question for the mechanically inclined.
My son is building a trebuchet (possibly several?) for a science fair project. He is guessing the weight will be 100-200 pounds, (outside chance of 300 lbs) and we are stuck on our fulcrum ideas. My trebuchets are simpler and smaller, so he is getting into construction details I am not readily familiar with. The payload he is throwing will likely be a softball or lacrosse ball.
Using some large iron pipe may work, but we thought a bearing would be a good idea. Where would I find a bearing that takes a strong iron tube or bar in the middle (or whatever you recommend for 300 lb load that moves), or what other easily pivoting ideas do you guys have?