Propellers and Propeller System - Assignment Example

Wooden propellers were used almost exclusively both on personal and business aircraft that were used prior to world war two. The leading edge of most propellers has a nickel that reinforces them and gives them protection against rain, sand and small stones. In 1940, solid steel propellers came into the picture. The design is mainly for military use, Modern propellers, on the other hand, have fabrications from high-strength, heat-treated, aluminum alloy forgings. New composite materials for incorporation in applications consider mass and weight are very critical and, therefore, depend on how much a particular engine can handle efficiently.

Designing of propellers is typical of between two to six blades. Propellers also adhere to the aerodynamic laws that apply to wings as well but not in a horizontal plane. But in a vertical motion and so the thrust is created making the airplane moves forward reaching lift-off speed and gets airborne (Leishman, 2009). The blades of propeller vary in angle from the root to the tip. The angular speed of the blade is highest at the top and lowest at the root. Suppose the blade angle is constant the angle of attack of the relative airflow would vary across the propeller disc thus leading to the module being stalled.

The varied angle of the blade from the root to the tip ensures that the generated thrust is also equal from the root to the tip. At the time of propeller rotation, air flows past the propeller blade producing an aerodynamic reaction that gets resolution into thrust and propeller torque. The engine needs to create a force in order to rotate the propeller. Resistance to this rotation is propeller torque and when these two forces are in balance engine RPM is constant as well. Production of thrust occurs (Carlton, 2012).

Since fixed pitch blades cannot move but rotate, their blade angle is set as well though changes in blade angle are from the tip of the root.