Landing Gear Information
Landing gear (also known as the undercarriage) is the integral component that provides a ground- or water-based interface for an aircraft when not in flight. Landing gear is specifically designed to allow the aircraft to land, take off, and taxi.
Airplanes are most commonly outfitted with wheel sets underneath each of the plane's main wings and one additional set of wheels either at the fore or aft of the plane (resulting in a 'tricycle' or 'conventional' landing gear arrangement, respectively). These wheels are frequently retractable to reduce drag while in flight. The wheels may also be modified by the use of skis to allow the plane to land on snow or ice. Replacing wheels altogether and supplying a plane with pontoons allows the vehicle to operate solely on aquatic surfaces. Similarly, helicopters may be outfitted with any of the aforementioned landing gear styles, but are far more likely to rely on a lone set of skids.
Landing gear supports the entire weight of the aircraft during landing and ground operations. It is attached to primary structural members of the aircraft. Regardless of the type of landing gear used, shock absorbing equipment, brakes, retraction mechanisms, controls, warning devices, cowling, fairings, and structural members necessary to attach the gear to the aircraft are considered parts of the landing gear system.
Types of Landing Gear
Landing gear configurations come in three basic types: tail wheel-type (aka: conventional gear), tandem landing gear, and tricycle-type landing gear.
- Tail wheel-type landing gear—The main gear is located forward of the center of gravity, which requires support from the tail of a third wheel assembly. Today’s aircraft are manufactured with a conventional gear.
- Tandem landing gear—Few aircraft are designed with the tandem landing gear. The main gear and tail gear are aligned on the longitudinal axis of the aircraft. Sailplanes commonly use tandem gear, some military bombers such as the B-47 and the B-52 use tandem gear, as well as the U2 spy plane.
- Tricycle-type landing gear—This is the most commonly used landing gear arrangement. It is composed of a main gear and a nose gear. This type of landing gear is used on large and small aircraft. The tricycle-type landing gear has many benefits. Typically, it allows for more forceful application of the brakes, which enables higher landing speeds. It also provides better visibility from the flight deck and also prevents ground-looping of the aircraft. The tricycle-type landing gear arrangement consists of many parts and assemblies such as struts, gear alignment units, steering systems, wheel and brake assemblies, retraction and safety devices, etc.
Video credit: mekanizmalar
Resources
Aeronautics Guide—Landing Gear Types
SlideShare—Aircraft Landing Gear
Images credit:
Dllu / CC BY-SA 4.0