Wheel well is the space where an aircraft's landing gear retracts when not in use, a recessed compartment that nests beneath an airplane and stores the plane's wheels. This landing gear compartment - known as the wheel bay or undercarriage - houses landing gear, hydraulic lines, and control components. The wheel well ensures smooth operations during takeoff and landing while maintaining the aerodynamic efficiency of the aircraft in flight.
Expert behind this article
Jim Goodrich
Jim Goodrich is a pilot, aviation expert and founder of Tsunami Air.
What is a wheel well on a plane?
A wheel well on a plane is the landing gear compartment, alternatively known as the wheel bay or undercarriage, where the landing gear retracts. The wheel well is a feature in aircraft design that is a recessed compartment in the underbelly of the airframe. Its purpose during flight operations is to house the landing gear so that, after take-off, the gear can be retracted and stowed away efficiently. When the doors close behind the wheels, the smooth external surface that results markedly reduces drag and enhances aerodynamics, allowing the aircraft to climb and cruise with lower fuel burn.
Because the cavity must survive the harsh conditions of high-altitude flight, wheel wells are designed to withstand the differential pressures and temperature swings encountered while keeping every part secure and functioning correctly. Within this confined space, warm hydraulic fluid, retained heat in the tires, and some radiant and conductive heat from adjacent systems create a slightly less hostile micro-climate than the surrounding atmosphere, yet as the plane ascends both temperatures and oxygen levels decrease dramatically.
Where is the wheel well located on an airplane?
The wheel well is located within the fuselage directly beneath the belly of the plane. In a commercial jet the same bay, alternatively called the landing gear compartment, wheel bay, or undercarriage, retracts upward after take-off so that the wheels disappear into the fuselage. On a rear-fuselage jet the aft pair of wheels likewise folds into a shallow well just behind the cabin, while the nose well sits forward under the flight deck.
What does the wheel well of an aircraft contain?
The wheel well of an aircraft contains landing gear, hydraulic lines, and tires. These elements are compactly arranged so that, when the gear retracts, the strut, wheel, and tire fit into the narrow bay under the belly of the plane. Heat from hydraulic lines and retained heat in the tires both give off warmth, creating a slight temperature buffer within an otherwise hostile space.
How big is the wheel well of a plane?
The dimensions of a wheel well vary with aircraft type, weight and landing-gear design. For a wide-body freighter, the overall footprint of the stowed assembly is 108 L x 70 W x 122 H. Special ground-clearance features provide 5.5 wheel-well door clearance. Nose-strut bays are proportionally smaller: most aircraft provide half the nose-wheel diameter to the strut, and the tire itself is only about 30 in diameter.
