Propellers are divided into two categories: fixed pitch and variable pitch propellers.
① Fixed pitch propeller
Wooden propellers are usually fixed in distance. Its pitch (or blade installation angle) is fixed.
Fixed pitch propeller - suitable for low-speed blade installation angles that appear too small during high-speed flight; Similarly, the installation angle suitable for high-speed flight may be too large at low speeds.
Fixed pitch propeller - Therefore, fixed pitch propellers have higher efficiency only within a selected speed range and lower efficiency in other states. The fixed pitch propeller has a simple structure and light weight, and is widely used in light and ultra light aircraft with very low power.
② Variable pitch propeller
Large engineering ship propellers - In order to solve the contradiction between the high and low speed performance of fixed pitch propellers, variable pitch propellers have emerged during flight. The propeller pitch mechanism is driven by hydraulic or electric power. We started using a double pitch propeller.
Large engineering ship propellers - use high pitch at high speeds and low pitch at low speeds (such as takeoff and climb), gradually increasing the number of pitches to adapt to more flight conditions. Air conditioner large bulk propeller - a more complete variable pitch propeller is a constant speed propeller with a speed regulator.
The propeller speed regulator of a large engineering ship is actually a device that can automatically adjust the pitch and maintain a constant speed.
Large engineering ship propeller - The driver can change the engine and propeller speed by controlling the regulator and throttle, which not only adjusts the propeller tension but also keeps the propeller in optimal working condition.
Air conditioning large bulk propeller - In multi engine aircraft, when one engine malfunctions and stops, the air conditioning large bulk propeller rotates like a windmill under the action of oncoming airflow, which increases flight resistance and causes significant unbalanced torque, and may also further damage the engine.
56M engineering ship propeller - for this purpose, the variable pitch propeller can also automatically pitch, that is, the blades turn to the basic direction of the air flow to make the propeller stationary and reduce resistance. Variable pitch propellers can also reduce the pitch, generate negative drag, increase resistance, and shorten the landing roll distance. This state is called reverse propeller.
