Tricycle gear

A Mooney M20J with a retractable tricycle landing gear

Polish 3Xtrim 3X55 Trener with a fixed tricycle landing gear taxiing.

Tricycle gear is aircraft undercarriage, or landing gear, arranged in a tricycle fashion. The tricycle arrangement has one wheel in the front, called the nose wheel, and two or more main wheels slightly aft of the center of gravity. Because of the ease of operating tricycle gear aircraft on the ground, the configuration is the most widely used on aircraft.

Several early aircraft had primitive tricycle gear, notably the Curtiss Pushers of the early 1910s. Waldo Waterman's 1929 tailless Whatsit was one of the first to have a steerable nose wheel.

Tricycle gear is essentially the reverse of conventional landing gear or taildragger. Tricycle gear aircraft have the advantage that it is much more difficult to make them 'nose over' as can happen if a taildragger hits a bump or has the brakes heavily applied. In a nose over, the airplane's tail tips up and the propeller strikes the ground, causing damage. Tricycle gear planes are also easier to handle on the ground and reduce the possibility of a ground loop, though they can be susceptible to wheel-barrowing. This is due to the main gear being behind the center of mass. Tricycle gear also provides an advantage in visibility to the pilot as the nose of the aircraft is level and, unlike in aircraft with conventional landing gear, does not block the view ahead. The nose wheel equipped aircraft also is easier to handle on the ground in high winds due to its wing negative angle of attack. Student pilots are able to safely master nosewheel equipped aircraft more quickly.

Tricycle gear aircraft are easier to land because the attitude required to land on the main gear is the same as that required in the flare, and they are less vulnerable to crosswinds. As a result, the majority of modern aircraft are fitted with tricycle gear. Almost all jet-powered aircraft have been fitted with tricycle landing gear, to avoid the blast of hot, high-speed gases causing damage to the ground surface, in particular runways and taxiways. The few exceptions have included the Yakovlev Yak-15, the Supermarine Attacker, and prototypes such as the Heinkel He 178, the first four prototypes (V1 through V4) of the Messerschmitt Me 262, and the Nene powered version of the Vickers VC.1 Viking.

The taildragger configuration does have advantages. The rear wheel means the plane naturally sits in a nose-up attitude when on the ground; this is useful for operations on unpaved surfaces like gravel where debris could damage the propeller. The tailwheel also transmits loads to the airframe in a way that is less likely to cause airframe damage over time operating on rough fields. The simpler main gear and small tailwheel result in both a lighter weight and less complexity if retractable. Likewise, a fixed-gear taildragger exhibits less interference drag and form drag in flight than a fixed-gear aircraft with tricycle gear. Tail wheels are smaller and less expensive to buy and maintain and man-handling a tailwheel aircraft on the ground is easier. Most tailwheel aircraft are lower in overall height and thus may fit in lower hangars. Tailwheel aircraft are also more suitable for fitting with skis in wintertime.