Airplane wheels are generally not powered for takeoff or landing. However, some aircraft utilize powered wheels for ground maneuvering or specific takeoff/landing systems. Here's a breakdown:
Wheel Powering Systems
While most airplane wheels are not powered in the traditional sense of driving the aircraft during flight phases, there are some specific systems and scenarios where wheels receive power:
-
Electric Taxiing Systems (ETS): These systems use electric motors integrated into the landing gear to allow the aircraft to taxi without using the main engines.
-
Power Source: The electric motors are powered by the aircraft's Auxiliary Power Unit (APU) or by batteries.
-
Control: Electronic power components control the power distribution to the motors.
-
Gearbox: A reduction gearbox typically connects the motor to the wheel, matching the motor's torque and power output to the wheel's requirements.
-
-
Braking Systems: Although not "powering" the wheels in a propulsive sense, braking systems use hydraulic or electric power to apply the brakes.
- Power Source: Hydraulic systems utilize pumps powered by the engines or APU. Electric brakes use electrical power.
- Function: These systems are crucial for slowing down the aircraft during landing and preventing it from rolling too far on the runway.
-
Experimental and Specialized Systems: Research and development are ongoing for powered wheels that could potentially assist with takeoff or landing in specific situations, such as short runways or adverse weather conditions.
Why Wheels Aren't Typically Powered for Takeoff/Landing
- Weight and Complexity: Adding a powered wheel system for takeoff and landing adds significant weight and complexity to the aircraft, reducing fuel efficiency and increasing maintenance requirements.
- Engine Efficiency: Aircraft engines are highly efficient at providing the thrust needed for takeoff and maintaining speed during flight. It's more practical to rely on the engines for propulsion.
- Control Issues: Coordinating wheel power with engine thrust during takeoff and landing could introduce control challenges for the pilot.
Summary
In most commercial airplanes, the wheels are not powered for takeoff or landing. They rotate freely. The engines supply the thrust required for takeoff and flight, and brakes (powered hydraulically or electrically) are used to slow the aircraft during landing. However, some aircraft are equipped with electric taxiing systems, which use electric motors to power the wheels for ground movement, and powered wheels are sometimes part of experimental or specialized systems.
