https://www.safran-group.com/products-services/comac-c919-nacelles
The nacelles manufactured by Nexcelle, the 50/50 joint venture between Safran Nacelles and Middle River Aerostructure Systems (ST Engineering), equip the CFM International LEAP-1A powered COMAC C919
It is composed of a single “O” shaped composite part (O-Duct), which replaces the traditional two-door “D” configuration. The new “O” design improves the aerodynamic performance of the aircraft and its fuel consumption (-0.5%, i.e. 300kg per flight) by increasing the efficiency of the thrust reverser.
