Why are propellers designed to incorporate blade twist?

Propeller Design There is a twist along the length of a propeller blade because the blade speed is much higher at the tip than it is at the root. The twist is necessary to maintain a more or less constant angle of attack along the length of the blade.

Why are most aircrafts equipped with feathering propellers?

Most multiengine airplanes are equipped with “full feathering propellers” to minimize that yawing tendency. This is of particular advantage in case of a damaged engine, since further damage, caused by a windmilling propeller creates the least possible drag on the airplane and reduces the yawing tendency.

Why do propellers have 3 blades?

A 2-blade propeller produces two pressure pulses per revolution, whereas a 3-blade propeller will produce three smaller pulses per revolution for the same amount of total thrust. As a result, the 3-blade prop will be inherently smoother and therefore quieter.

Why are propellers shaped the way they are?

A Propeller “Lifts” an Airplane Forward Like a wing, it produces lift, but in a forward direction—a force we refer to as thrust. In cross section, a propeller is shaped like a wing to produce higher air pressure on one surface and lower air pressure on the other.

Why the mechanism of a feathering propeller would fail to feather the blades?

Usually, a propeller is feathered when the engine fails to produce the power needed to turn the propeller. Almost all small feathering propellers use oil pressure to take the propeller to a low pitch, while counterweights, springs, and compressed air take the propellers to a high pitch.

Why are feathers propelled?

The inflight feathering of the propeller, on an engine that has failed or has been intentionally shut down, greatly reduces the drag that would occur with the blade pitch in any other position.