Eagle power UP40140 40 inch 2 Pairs 2CW/2CCW Carbon fiber Propeller

A 40-inch carbon fibre propeller, the Eagle Power UP40140, built for UAV airframes.

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.

Blade diameter sets the thrust and the current draw together, so a change of propeller changes what the motor pulls; step the diameter with the motor rather than in isolation.

Supplied as 2 pairs in matched CW/CCW pairs, which is how a multirotor needs them — counter-rotating pairs cancel torque. The CW and CCW blades are supplied together so a full set of counter-rotating propellers can be fitted from one order.