The present invention discloses an unmanned helicopter, and belongs to the technical field of unmanned aerial vehicles. The unmanned helicopter includes an air inlet system, an exhaust system, a cooling system and a dynamic balance system. The air inlet system is fixed on a second side; the exhaust system is fixed on a third side; and the cooling system is fixed on a first side, and the dynamic balance system is fixed on a tail. The airflow at the outside of the unmanned helicopter flows into the air inlet system smoothly, quickly and efficiently under the action of its own flow velocity relative to the unmanned helicopter, therefore the technical problem in the prior art that the air entering the fuselage with a unit volume is burnt insufficiently, which generates adverse effects on the normal flight of the unmanned helicopter, is solved.

An engine assembly including an internal combustion engine configured to be received in an engine compartment and a heat exchanger having a first conduit fluidly connected to a fluid circuitry of the engine and a second conduit fluidly connecting an interior of the engine compartment to its environment. The first conduit is in heat exchange relationship with the second conduit. The assembly further includes a forced air system operable in use to provide an air flow from the environment to the outlet via the second conduit of the heat exchanger and the engine compartment. The assembly further includes a selector valve configurable to selectively fluidly connect an air intake of the internal combustion engine with the interior of the engine compartment in a first valve position and with the environment in a second valve position. A method for supplying air to an internal combustion engine is also discussed.

An engine assembly including an internal combustion engine configured to be received in an engine compartment and a heat exchanger having a first conduit fluidly connected to a fluid circuitry of the engine and a second conduit fluidly connecting an interior of the engine compartment to its environment. The first conduit is in heat exchange relationship with the second conduit. The assembly further includes a forced air system operable in use to provide an air flow from the environment to the outlet via the second conduit of the heat exchanger and the engine compartment. The assembly further includes a selector valve configurable to selectively fluidly connect an air intake of the internal combustion engine with the interior of the engine compartment in a first valve position and with the environment in a second valve position. A method for supplying air to an internal combustion engine is also discussed.