what is aircraft propeller reduction gearing?

Propellers are aerodynamic devices that change rotary motion from an airplane engine or other related power source into propulsive force, allowing the aircraft to traverse the sky with ease. They can be fastened directly on a crankshaft of a piston engine or powered through a reduction gear box (RGB) attached to a piston or jet engine. The RGB converts the high rotation speed of the engine into the appropriate speed for propeller operation.

what are opposed piston engines and their advantages?

Piston engine technology has a long history for automobiles and aircraft engine assemblies, ensuring the generation of thrust and propulsion through the combustion of fuel-and-air mixtures. Since their inception, various piston engine types have come about for aircraft and automobiles, examples being in-line, rotary, V-type, radial, and horizontally opposed engines. The opposed piston engine in particular is a more specialized type, featuring cylinders that have a piston on both ends and a lack of a cylinder head.