Air curtain insulating system for aircraft cabin

An improved passenger aircraft insulating system, comprising

• a fuselage including a passenger cabin extending above a cargo compartment, both the passenger and cargo compartments including wall panels extending parallel to and spaced from an outer skin of the aircraft, forming at least one bay between the outer skin and the wall panels of the cabin and cargo compartments, wherein the at least one bay comprises an air space extending between outer surfaces of the wall panels of the passenger cabin and cargo compartment and the inner surface of the outer skin, and the air space permitting air flow through the bay;
• and
• means for introducing a stream of hot bleed air into the at least one bay for thermally insulating the passenger cabin from the outer skin while maintaining a comfortable temperature in the passenger cabin.

A method of insulating a relatively warm passenger cabin extending above a cargo compartment of a passenger aircraft from a relatively colder outer skin of the aircraft fuselage, comprising the steps:

• directing a stream of hot bleed air from an aircraft engine into a supply duct extending parallel to the longitudinal axis of the aircraft;
• and
• generating a flow of hot bleed air from the supply duct through a conduit network into an air space extending between an inner surface of the outer skin of the aircraft and outer surfaces of the wall panels of the passenger cabin.