After 12+ hours of work, I have finally created a working engine system using pistons. It does not use fuel, and since resizable wheels require a real engine part to turn I have incorporated the design into a paddle boat. Only has a top speed of around 7 mph, but I think it's the design and concept that counts. Directions: 1. Prime the engines by setting VTOL to +50%. Keep it in that position. 2. Activate bow and stern vertical pistons with Groups 1 and 3. Set throttle to 15-20%.3. Activate individual horizontal pistons with groups 2 and 4 when they are in optimal position. (Bow (2) piston should be just above the midpoint of the cycle, stern (4) piston should be just below the cycle. Vice-versa if you want to reverse). 4. Throttle up to 65-80%. Malfunctions may occur if the timings of activation were a little off. Turn with roll. Trim controls miniguns. 5. Enjoy! Post ideas in the comments and feel free to use the engine setup! (Although credit would be appreciated!)