I was planning on making the first air powered engine on PowderToy, but got sick of the idea. What? Even the great Leonardo da Vinci gave up on some of his ideas didn't he!?!? Also, I was going to use it as the first analog input simulation. (Using vac, you can control the direction you want the spark to go, like moving your thumb on a control stick.)
Essentially, pressure from a direction send water to that direction and causes sprk on corresponding metal wing. Maybe you could use the idea to make such an engine, since I bet you'd do way better than I would have the patience or skill to do.
@cctvdude99 I conisder it a simulation because, you are right, it is using water. However, i consider the water to have absorbed the energy of the surrounding pressure and converted into electricity. (In my own little happy place, that makes sense.) Kinda like how your engines sometime use more than 1 spark to ignite the engine over an over.