This is an inline 4 piston engine that I built. The motor is designed for high torque/low speed and has a modular design, so you can quickly and easily adapt the motor to your needs. There are connection points on both sides of the engine that are directly connected to the crankshaft. The speed of the engine is controlled by the left VTOL slider. The optimum speed is reached at the second marker from the top. If you push the slider further up, the engine quickly reaches a critical range and stutters/cannot make a full revolution anymore. To start the engine, the left slider must be slowly pushed up. Unfortunately, the direction of rotation is random. have fun :)