Landing gears Flashcards
Function of landing gears
support the aircraft on the ground enable the aircraft to move whilst in contact with the ground absorb landing loads
Landing gear anatomy
steering actuator shock absorber/strut hinge point retraction actuator main gear lock links side stay unlock actuators internal locks withing the retraction actuators
Shock strut
prevent damage to the structure due to the high vertical loading on touch down and braking absorbs impact energy and dissipates it safely without causing rebound
Side stay
transfer lateral loads into the airframe
Retraction actuator
retract and deploy the gear
Unlock actuator
disengage lock links before retraction
Lock springs
engage lock mechanism when deployed
Total energy
Shock strut types
liquid spring oleo pneumatic
Liquid spring
movement of oil within the cylinder acts as a damper and spring generally compact but heavy
Oleo pneumatic
inert gas acts as a spring oil as a damping medium
Factors influencing configuration
type of layout type of truck tyre sizes and axle dimensions aircraft attitude for landing and take off aircraft centre of gravity types of retraction types of steering flotation requirement
Factors influencing layout
centre of gravity range and location aircraft MTW mission requirements turning circle requirements
Tricycle layout
relatively level fuselage for ground operations good stability during braking tends to produce nose down pitch on landing more logical steering improved pilot field of vision
Retraction
aims to reduce drag results in increased mass, structural complications, power and actuation factors and cost
