HIGH BY-PASS RATIO TURBOJET ENGINE WITH COUNTERROTATING UPSTREAM AND DOWNSTREAM FANS

摘要

A turbojet bypass engine includes an upstream fan of a conventional type and also a downstream fan arranged to rotate in the opposite direction to the upstream fan and driven by a free turbine interleaved with the low pressure turbine which drives the upstream fan. The two fans are supplied by separpate overlapping and inverleaved air flow paths which are formed largely within the nacelle structure of the engine, giving the nacelle an ovoide shape which allows such engines with a high bypass ratio to be mounted below the wings of an aircraft.