Eagle power UC2896B 28 inch Carbon Fiber Composite (2 sets in CW/CCW/set)

Eagle Power UC2896 — a 28-inch carbon fibre propeller from the UC range.

Carbon fibre is used for these because it is stiff for its weight: a stiff blade does not flex under load, so the thrust the motor produces goes into lifting the aircraft rather than into deforming the propeller. The rigidity also keeps the blades from flapping, which sets the practical diameter limit on a given airframe.

The propeller has to be matched to the motor KV and the cell count, since the load a blade places on the motor is what determines whether the power system runs within its ratings.