Engine assembly with engine and cooler compartments

An engine assembly for a helicopter having a longitudinal axis extending from a front end to a rear end of the helicopter, comprising:

• a compartment having separate engine and cooler sections fluidly connected with each other through an opening defined through a wall extending substantially transversally to the longitudinal axis, the engine an cooler sections serially disposed in a direction of the longitudinal axis and located on opposite sides of the wall, the engine section having an air intake fluidly connecting an interior of the engine section to an environment of the engine assembly, an interior of the cooler section fluidly connected to the environment of the engine assembly via an inlet and an outlet;
• a compound engine received in the engine section and including a compressor in fluid communication with the environment of the engine assembly, an internal combustion engine having an inlet in fluid communication with an outlet of the compressor, and a turbine having an inlet in fluid communication with an exhaust of the internal combustion engine, the turbine compounded with the internal combustion engine, the compressor in driving engagement with at least one of the turbine and the internal combustion engine;
• a heat exchanger received in the cooler section, the heat exchanger fluidly connected to a fluid circuitry of the compound engine, the interior of the cooler section fluidly connected to the inlet of the cooler section via the heat exchanger;
• and
• a forced air system operable to drive an airflow, the forced air system in simultaneous fluid communication with a main flow path and a secondary flow path, the main flow path extending from the inlet of the cooler section to the outlet of the cooler section via the heat exchanger and the interior of the cooler section, the secondary flow path extending from the air intake of the engine section to the outlet of the cooler section via the interior of the engine section, the opening and the interior of the cooler section.

A method for cooling an internal combustion engine received in an engine compartment of a helicopter separated from a cooler compartment of the helicopter, the helicopter having a longitudinal axis extending from a front end to a rear end of the helicopter, the method comprising:

• expelling air from the cooler compartment to an environment with a forced air system to simultaneously create main and secondary airflows, wherein:
• creating the main airflow includes drawing outside air in the cooler compartment from the environment separately from the engine compartment;
• and
• creating the secondary airflow includes drawing additional air in the cooler compartment from the engine compartment through an opening fluidly connecting the cooler and engine compartments, the opening defined through a wall extending substantially transversally to the longitudinal axis, the cooler compartment and the engine compartment being serially disposed in a direction of the longitudinal axis and located on opposite sides of the wall.