Large aircraft landing gears – a brief overview

Abstract

The presentation provides a simple view on large aircraft landing gears. Following items are touched: Landing gear types, civil, military and special ones are shown with several examples of existing and past lay outs. The landing gear design objectives along with its constraints are given as well and discussed. Surprising is the large run time of aircraft on ground which is expressed by typical usage. An important item worth to mention is the weight relation of landing gears in relation to the total structure weight of an aircraft. A short view on the airworthiness requirements is made which also provides a view on the suspension modeling for design load determination which is briefly expressed. Landing gear overall structure components with their specific parts e.g. main fitting and shock absorber, braking system and retraction system are shown for nose and main landing gears. Tyre for landing gears and their characteristics are discussed. Since aircraft tyre data are insufficient supplied by the tyre manufacturer special test bench has been developed and are successfully applied for structure design data. Some data and results are discussed. Some of the landing gear structure loads conditions as are landing, braking and handling on ground are given. If time allows, some interesting videos will be shown, providing an impression of dynamic landing impacts with excessive deformation at wheels and structure which indicates the enormous load at landing gear and associated airframe structure.