Charlie's Catapult Seesaw

A playground seesaw built at 10x scale, with a ten-ton iron weight dropped on one end. Drive up the ramp onto the low end of the plank, stop on the red X, and hold still. The machine counts down from three on screen. Move faster than 0.6 m/s and the count goes back to three. Roll off the X and it goes back to three. Sit still long enough and the hook lets go. The weight falls 5.6 meters onto the far end, the plank swings through 15.5 degrees in four tenths of a second, and you leave partway through that swing at 42 m/s up and 8 m/s downrange at 154 km/h, almost all of it vertical. Then it resets itself. The winch reels the weight back up and it's armed again. How to use it Spawn it from the vehicle selector like any other prop, then drive a second vehicle up the ramp. It wants flat open ground: roughly 27 metres nose to tail, 14 to the top of the sign, plus clear sky and somewhere to come down. Gridmap and the airfields work well. Feedback and bug reports welcome.