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.
Several early aircraft had primitive tricycle gear, notably the Curtiss Pushers of the early 1910s. However, many sources credit Waldo Waterman with the invention of modern tricycle gear for his 1929 tailless Whatsit .
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 propeller in the ground and causing extensive damage. As well, tricycle gear planes are much easier to handle on the ground and significantly reduce the possibility of a ground loop. 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 propeller and damaging it. In addition, taildraggers exhibit less form drag in flight, though this is irrelevant for airplanes with a retractable undercarriage.
