Assembling and adjustment of the propeller

The electric motor driving the variation of the pitch is lodged in the central body of the hub.

The blades are inserted in the hub seat, toghether with the needle bearings.

The nut ring is screwed with fixed couple and the blocking screws on its top are tighten.

The dynamic balancing of the propeller is carried out.

To this purpose, the propeller is mounted on the balancing equipment with blades at neutral pitch and is putted in rotation at 800 rpm about.

The equipment allows the measure of amount and angular position of mass imbalance.

The balancing precision attained is 10 thousandth of millimeter.

This precision is better than the assembling precision due to the high quality machining of the hub base.

The balancing correction is carried out by injection of the needed weight of resin inside the blade core.

The mechanic adjustment of the propeller acts on the pitch range limits of the blades.

The adjustment is made by a protractor. The pitch is measured at (0,75*R) of the blade, being R the radius of the propeller.

The limit switch is activated and the current is shut off when the pitch reaches or the maximum or the minimum pitch value.Usually, the minimum pitch value is used for the take off of the airplane.

The maximum pitch value is adjusted for the condition (VNE at max rpm), where VNE is done as airplane characteristic and max-rpm is the full throttle point.