What Are Major Types of Aircraft Propellers?

In the 116 years since the Wright Brothers first took flight, quite a lot has changed in the field of aviation. Airframes have changed from wood to metal alloys to composite materials; engines have become more powerful and efficient; and airplanes can now fly farther and faster than ever before. And yet, with all that change, one thing really hasn’t— the aircraft propeller. The propeller blades the Wright Brothers used are only about 5% less efficient than their modern counterparts. How?

Aircraft are able to fly as a result of “lift”, an upward force lifting the aircraft off the ground, generated by air flowing over and under the wings. The “airfoil” shape of the propeller and wings makes it all possible. And it was first designed by the Wright Brothers when they realized that when propellers had an “airfoil” like the wings, they could provide the proper propelling motion necessary for directed flight. Since 1903, there have been new types of propellers, but for the most part they remain fairly unchanged.

Fixed pitch propellers are designed as one single piece, typically with only two aviation industrial blades, and made from wood or metal. They get their name from the fact that they only have one pitch setting available.
Fixed pitch wood propellers are pretty uncommon nowadays thanks to the advent of metal propellers in the 1940s. They’re often found on business or personal aircraft and made with layers and layers of specially prepared and laminated woods like black walnut, black cherry, and yellow birth wood.
Fixed pitch metal propellers began to proliferate the industry in the 1940s, starting in the military. Typically, they are made of a durable, strong, and treated aluminum alloy made to withstand warping from the heat and cold. Nowadays, it’s rare to see propellers made from anything not metal.
Variable pitch propellers are, unlike fixed pitch propellers, able to change the pitch, allowing for more flexibility of movement and flight. In the past, when variable pitches were first introduced, they were changed manually before flight; now, they are changed automatically from a control panel.

Of course, as durable and strong as propellers are nowadays, they still need regular maintenance and repair. Because the propellers do depend on the airfoil to function properly, it’s important that their surfaces are relatively perfect to allow for proper airflow. This means regularly making sure they are in good working condition and free of bumps and dents.