An engine device for an unmanned flying apparatus that provides good weight balance for the flying apparatus; cancels the gyroscopic effect; and has auto rotating propellers.
The engine device includes a first cylinder and a second cylinder arranged horizontally and opposed to each other, and pistons within the cylinders advance and retract in opposite directions to each other; a first crankshaft and a second crankshaft arranged in the vertical direction, driven by the first cylinder and the second cylinder, respectively, and rotate in opposite directions; a first centrifugal clutch and a second centrifugal clutch rotate in opposite directions to each other; a final drive shaft transmitting rotational force to a gear mechanism comprising orthogonal transform gears, to rotate a propeller shaft; a one-way clutch arranged between



the first crankshaft, the second crankshaft and
the final drive shaft, and driven by both the first crankshaft and the second crankshaft.