Im build a WW1 Howitzer replica for a history project and recently decided to mount a Potatoe gun on it to make it a working model, and so i can a demonstation outside.
Here what one looks like if your wondering

Now I know theres alot of different types and Im 15 so I want something simple or fairly simple. So if you guys could tell me which type is the best and which one i should build that would be great, i also need someway of calculating how far it will go, or a formula so i can figure out the angle, velocity, and weight of object i need to shoot the certian distance i want, understand that part?
Thanks guys