The undercarriage is described in the Society's Glossary as “That part of the aircraft beneath the body intended for its support on land or water and to absorb shock on alighting.”

It is my intention to confine my remarks in this paper to undercarriages designed to support aircraft on land, that is to say, colloquially, “landing gears.” The reasons for this limitation are obvious; it is scarcely possible to compare even in a general manner the undercarriage problem of the land machine and the seaplane, and in the latter case the already wide subject has to be extended to consider float design.

The historical development of the undercarriage shows well-defined phases reflecting the performances and functions of the complete aircraft. In the early Wright machines, which were provided with a launching gear, the problem of alighting only required to be considered.