Landing Gear

[Ref. Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25B Page 7-33, 7-34, Aviation Maintenance Technician Handbook–Airframe, Volume 2, FAA-H-8083-31A 13-4]

Landing Gear – its function?

Landing gear provide the support for an aircraft on the ground.


Composition of small GA landing gear – (2 main wheels + 1 front or rear wheel)

Most common type of landing gear on small GA is tricycle gear – consists of three wheels – two main wheels (one located on each side of the fuselage) and a third wheel positioned either at the front (i.e nosewheel) or rear (i.e tailwheel).


Nosewheels – Steerable v.s Castering

Tiller in Airbus

Steerable – nosewheels are linked to rudders by cables or rods ;
Castering – nosewheels are free to swivel – steering requires the pilot to combine the use of the rudder pedals with independent use of the brakes (differential braking)

Notes:

Small GA use rudder pedals to control the steerable nosewheels;

Heavy aircraft (e.g B777, A320) combines the use of tiller inside cockpit and hydraulic power to control the steerable nosewheels

 

Nosewheels advantages x3

  1. allows more forceful application of the brakes during landings at high speeds without causing the aircraft to
    nose over
  2. more directional stability during ground operation – since the aircraft’s center of gravity (CG) is forward of the main wheels. The forward CG keeps the airplane moving forward in a straight line rather than ground looping.
  3. better forward visibility

Fixed v.s Retractable landing gear

Further classification of aircraft landing gear can be made into two categories: fixed and retractable.

Fixed landing gear is attached to the airframe and remains exposed to the slipstream as the aircraft is flown – subject to parasite drag when the aircraft airspeed increases.

Retractable landing gear stow in fuselage or wing compartments while in flight. Although there is weight penalty, the overall efficency is improved for certain type of aircraft, such as heavy aircraft.

 

 

Read More –

Why bigger aircraft need Multiple wheels?

  1. Multiple wheels spread the weight of the aircraft over a larger area
  2. They also provide a safety margin should one tire fail

Heavy aircraft may use three or more wheel assemblies on each main gear – Triple-bogie-MLG

Leave a Reply

Your email address will not be published. Required fields are marked *