The Six Types of Aircraft Propellers
The propeller, an essential part of an aircraft, is a device that converts rotational energy from the engine into propulsive force. Though the propeller is a relatively straightforward piece of machinery, it comes in many different variations depending on the performance requirements of a given aircraft. Here are the six most common types of aircraft propellers and their unique characteristics.
- Fixed Pitch Propellers
A fixed pitch propeller is a propeller that features a blade angle that stays in a fixed position, meaning it cannot be moved or altered. They are generally one solid piece made from aluminum alloy or wood.
- Ground-Adjustable Propellers
A ground-adjustable propellers operate similarly to a fixed pitch propeller, but their blade can be changed when the propeller is not in motion. The blade is held in place by a clamping mechanism and this clamp must be loosened before adjusting the angle.
- Controllable-Pitch Propellers
A controllable-pitch propeller features a blade that can be adjusted mid-flight while the propeller is still in motion. This is highly advantageous because it provides pilots with the means to adjust their propeller to meet changing flight conditions. Despite this, the number of pitch positions is limited. The propeller blade will typically have a minimum and maximum angle with settings in between.
- Constant-Speed Propellers
Constant-speed propellers adjust to the changing load exerted on the engine to maximize efficiency. The propeller speeds up when the aircraft is in a dive and slows down when it is climbing. This type of propeller features a mechanism known as a propeller governor which senses the aircraft engine’s speed and alters the blade angle to maintain a specific rpm independent of the aircraft’s operational conditions.
- Feathering Propellers
This type of propeller is found in a multi-engine aircraft. In the event of a single engine failure, these propellers ‘feather,’ changing the blade angle up to 90 degrees. This reduces the drag being exerted on the aircraft and allows it to maintain flight without full engine power.
- Reverse-Pitch Propellers
Reverse-pitch propellers, as their name indicates, are propellers capable of operating with negative blade angles during flight. The purpose of a negative blade angle is to produce thrust in the opposite direction. They are called into action after the aircraft has touched down to help it come to a complete stop.
Share
