Tricycle undercarriage - Definition and Overview

A Cessna 152 with a tricycle landing gear

Tricycle gear describes a kind of aircraft undercarriage, or landing gear, arranged in a tricycle fashion. The tricycle arrangement has one gear strut in front, called the nose wheel, and two or more main gear struts slightly aft of the center of gravity.

Tricycle gear is essentially the reverse of taildragger or conventional gear. Tricycle gear aircraft have the advantage that it is (nearly) impossible to make them 'nose over' as can happen if a taildragger hits a big enough bump. In a nose over, the airplane's tail tips up, burying the propellor in the ground and causeing extensive damage. As well, tricycle gear planes are much easier to handle on the ground and significantly reduces the possibility of a ground loop. As well, 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. As a result, the majority of modern aircraft are fitted with tricycle gear.

The taildragger configuration does have a few advantages though. Having the rear wheel keeps the plane in a nose-up attitude on the ground which is useful for operations on non-paved surfaces (i.e. gravel) where one would be concerned about debris being sucked into the propellor and damaging it. As well, taildraggers exhibit less form drag in flight, though this is irrellevant for airplanes with a retractable undercarriage.