I am doing an experiment for my science class, in which I am studying what variables will make an ordinary playing card "fly" further. The problem is that I need something that can always throw the card the same way evrytime, unlike a human hand, as the slightest variation in original movement could throw off my data. Someone suggested that I take a tennis ball gun and modify it to shoot cards but I don't know how to do that, and don't have or know where to get one. Someone else suggested that I build a catapult of somekind, but it would have to grip the card and be able to release the card at just the right moment. Does anyone here have any suggestions as to what and how to build something like this?