
Tricycle gear is a type of
aircraft
An aircraft ( aircraft) is a vehicle that is able to flight, fly by gaining support from the Atmosphere of Earth, air. It counters the force of gravity by using either Buoyancy, static lift or the Lift (force), dynamic lift of an airfoil, or, i ...
undercarriage, or ''
landing gear
Landing gear is the undercarriage of an aircraft or spacecraft that is used for taxiing, takeoff or landing. For aircraft, it is generally needed for all three of these. It was also formerly called ''alighting gear'' by some manufacturers, s ...
'', that is arranged in a
tricycle
A tricycle, sometimes abbreviated to trike, is a Human-powered transport, human-powered (or gasoline or electric motor powered or assisted, or gravity powered) Three-wheeler, three-wheeled vehicle.
Some tricycles, such as cycle rickshaws (for pa ...
fashion. The tricycle arrangement has one or more nose wheels in a single front undercarriage and two or more main wheels slightly aft of the
center of gravity. Tricycle gear aircraft are the easiest for takeoff, landing and taxiing, and consequently the configuration is now the most widely used on aircraft.
[Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 524. Aviation Supplies & Academics, 1997. ][Aviation Publishers Co. Limited, ''From the Ground Up'', page 11 (27th revised edition) ]
History
Several early aircraft had primitive tricycle gear, notably very early
Antoinette planes and the
Curtiss Pushers of the pre-World War I
Pioneer Era of aviation.
Waldo Waterman's 1929
tailless ''
Whatsit'' was one of the first to have a steerable nose wheel.
In 1956,
Cessna
Cessna () is an American brand of general aviation aircraft owned by Textron Aviation since 2014, headquartered in Wichita, Kansas. Originally, it was a brand of the Cessna Aircraft Company, an American general aviation aircraft manufactu ...
introduced sprung-steel tricycle landing gear on the
Cessna 172. Their marketing department described this as "Land-O-Matic" to imply that these aircraft were much easier to land than tailwheel aircraft.
Tricycle gear and taildraggers compared
Tricycle gear is essentially the reverse of
conventional landing gear
Conventional landing gear, or tailwheel-type landing gear, is an aircraft Landing gear, undercarriage consisting of two main wheels forward of the Center of gravity of an aircraft, center of gravity and a small wheel or skid to support the tail ...
or ''taildragger''. On the ground, tricycle aircraft have a visibility advantage for the pilot as the nose of the aircraft is level, whereas the high nose of the taildragger can block the view ahead. Tricycle gear aircraft are much less liable to 'nose over' as can happen if a taildragger hits a bump or has the brakes heavily applied. In a nose-over, the aircraft's tail rises and the
propeller
A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...
strikes the ground, causing damage. The tricycle layout reduces the possibility of a
ground loop, because the main gear lies behind the center of mass. However, tricycle aircraft can be susceptible to
wheel-barrowing. The nosewheel equipped aircraft also is easier to handle on the ground in high winds due to its wing negative
angle of attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a Airfoil#Airfoil terminology, reference line on a body (often the chord (aircraft), chord line of an airfoil) and the vector (geometry), vector representing the relat ...
. Student pilots are able to safely master nosewheel equipped aircraft more quickly.
Tricycle gear aircraft are easier to
land
Land, also known as dry land, ground, or earth, is the solid terrestrial surface of Earth not submerged by the ocean or another body of water. It makes up 29.2% of Earth's surface and includes all continents and islands. Earth's land sur ...
because the
attitude
Attitude or Attitude may refer to:
Philosophy and psychology
* Attitude (psychology), a disposition or state of mind
** Attitude change
* Propositional attitude, a mental state held towards a proposition
Science and technology
* Orientation ...
required to land on the main gear is the same as that required in the
flare
A flare, also sometimes called a fusée, fusee, or bengala, bengalo in several European countries, is a type of pyrotechnic that produces a bright light or intense heat without an explosion. Flares are used for distress signaling, illuminatio ...
, 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 prevent the blast of hot, high-speed gases from causing damage to the ground surface, in particular
runway
In aviation, a runway is an elongated, rectangular surface designed for the landing and takeoff of an aircraft. Runways may be a human-made surface (often asphalt concrete, asphalt, concrete, or a mixture of both) or a natural surface (sod, ...
s and
taxiways. The few exceptions have included the
Yakovlev Yak-15, the
Supermarine Attacker, and prototypes such as the
Heinkel He 178 that
pioneered jet flight, the first four prototypes (V1 through V4) of the
Messerschmitt Me 262, and the
Nene powered version of the
Vickers VC.1 Viking. Outside of the United States – where the tricycle undercarriage had solidly begun to take root with its aircraft firms before that nation's World War II involvement
at the end of 1941 – the
Heinkel firm in World War II Germany began building airframe designs meant to use tricycle undercarriage systems from their beginnings, as early as late 1939 with the
Heinkel He 280 pioneering jet fighter demonstrator series, and the unexpectedly successful
Heinkel He 219 twin-engined night fighter of 1942 origin.

The taildragger configuration has its own advantages, and is arguably more suited to rougher landing strips. The tailwheel makes the plane sit naturally in a nose-up attitude when on the ground, which is useful for operations on unpaved gravel surfaces where debris could damage the propeller. The tailwheel also transmits loads to the airframe in a way much less likely to cause airframe damage when operating on rough fields. The small tailwheel is much lighter and much less vulnerable than a nosewheel. Also, a fixed-gear taildragger exhibits less
interference drag and
form drag in flight than a fixed-gear tricycle aircraft whose nosewheel may sit directly in the propeller's slipstream. Tailwheels are smaller and cheaper to buy and to maintain. Most tailwheel aircraft are lower in overall height and thus may fit in lower
hangar
A hangar is a building or structure designed to hold aircraft or spacecraft. Hangars are built of metal, wood, or concrete. The word ''hangar'' comes from Middle French ''hanghart'' ("enclosure near a house"), of Germanic origin, from Frankish ...
s. Tailwheel aircraft are also more suitable for fitting with
skis in wintertime.
References
{{Aircraft components
Aircraft configurations