N1 (Fan) section speeds
Cymmon The Fan section is the slowest of the rotating members of an engine. For example, the Rolls Royce RB211-524 has three seperate rotating sections, all driven by their own turbines. They are N1 Fan (or Low Pressure Section), N2 Intermediate Pressure Section and the N3 High Pressure Section. The accesory gearbox is attached to the N3 section. At 100% RPM the speeds are as follows;
a. N1 3900 RPM
b. N2 7000 RPM, and
c. N3 10611 RPM.
Most of the thrust from the engine is produced by the "Cold Stream" airflow from the N1. In effect, the N1 is much like a ducted propeller, with a large proportion of the air from it being by-passed outside the "core" of the engine. And yes, the fan blades do have to withstand impact from FOD and are tested to measure how much they can handle.