DOC AIRBUS | AMM A320FFAN ROTOR - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. Fan Rotor and Fan Case
(1) The fan rotor module has a low pressure ratio fan rotor located at the forward end of the engine. The rotor includes 20 fan blades with fan blade fairings located between each fan blade root platform to keep a smooth airflow between the blades. The fan rotor is supplied torque, but at a decreased speed, through the Fan Drive Gearbox (FDG) connected to the fan rotor by a gearbox front shaft. The function of the fan rotor is to supply the primary source of engine thrust through the initial compression of ambient air. Compressed air that leaves the fan rotor is divided by the Fan Intermediate Case (FIC) and flows through both the fan nozzle (secondary flow) and the Low Pressure Compressor (LPC) to the core of the engine (primary flow).
Fan Rotor AssemblyA. The PW1100G engine has a 20-blade fan with an 81-inch tip diameter.
(1) The blades are a hollow aluminum design that has a dovetail root that engages slots in the fan hub.
(2) The blade design (which includes a reinforced leading edge) decreases impact damage (birdstrike or Foreign Object Damage (FOD)) and noise.
(3) No mid-span or part-span shrouds are necessary.
(4) Front and rear lock rings hold the fan blades in their correct axial position in the hub.
(a) Composite under-root spacers beneath the fan blades provide a radial preload of the blades to reduce fan rotor vibration.
B. It is possible to replace fan blades in as assembled engine and in a fan rotor removed from the engine.
(1) Counterweights can be added to the outer rim of the fan hub when necessary.
C. The fan is driven by the LPC/LPT through the Fan Drive Gear System (FDGS), a gear reduction unit which decreases the fan speed.
(1) Because the fan speed is lower than that of the LPC/LPT, there is increased efficiency across the full engine operating range.
D. At the front of the fan rotor is the inlet cone and the inlet cone cover.
(1) These parts are made of composite material and keep the flow of air into the engine smooth.