For those of you who saw the computer animation of the radial engine I published a few weeks ago, here is the original prototype - in action with a power drill. I did make three small changes to the files after making this. The first is a lengthening of the pushrods by 1/32." This allows whoever assembles the models to get tighter valve fits, with more realistic valve overlap. You will now set the valve clearance with a sander. I changed the location of the timing idler shaft for the reduction gear by 5 thousandths of an inch for a better fit, and I reversed the numbers on the cylinder. My engine was firing 1 - 6 - 4 - 2 - 7 - 5 - 3 - 1 instead of the typical 1 - 3 - 5 - 7 - 2 - 4 - 6 - 1 I described in the video. (I lied!) Now the numbers are correct, and the production kits will fire as advertised. I could also have changed the cam plate gear reduction from 6:1 to 8:1, reversed the direction of rotation from against the crank direction to the crank direction, and it would have fired properly without reversing the numbers. My change was easier!
