Engine device for unmanned flying apparatus

An engine device for an unmanned flying apparatus, the engine device comprising:

• a first cylinder and a second cylinder respectively including a first piston and a second piston, the first and second cylinders being horizontally opposed to each other along an axis extending in a left-to-right direction of the unmanned flying apparatus such that the first and second pistons are each configured to advance and retract in opposite directions relative to each other;
• a first crankshaft and a second crankshaft respectively driven via the first piston and the second piston, the first and second crankshafts extending vertically between the first and second cylinders in a direction perpendicular to the axis such that the first and second crankshafts rotate in opposite directions relative to each other;
• a first centrifugal clutch and a second centrifugal clutch respectively coupled to the first crankshaft and the second crankshaft at positions above the first and second crankshafts such that the first and second centrifugal clutches rotate in opposite directions relative to each other;
• a one-way clutch coupled to the first and second centrifugal clutches so as to receive a combined rotational force from the first and second crankshafts;
• and
• a final drive shaft coupled to the one-way clutch so as to transmit the rotational force to a gear mechanism including a plurality of bevel gears each configured to rotate a propeller shaft.