TABLE OF CONTENTS The shock absorber is the one item that is common to all current landing gears. Some do not have tires, wheels, brakes, antiskid devices, retraction systems, or steering systems, but all of them have some form of shock absorber. While the carrier landing has sometimes been called a "controlled crash," it would be a complete catastrophe without the shock absorber. Since this part is undoubtedly the most important component in the landing gear, this chapter will discuss it in considerable detail.
The basic function of the shock absorber, or shock strut as it is often called, is to absorb the kinetic energy during landing and taxiing to the extent that accelerations imposed upon the airframe are reduced to a tolerable level.
There are two basic types of shock absorbers: those using a solid spring made of steel or rubber and those using a fluid spring with gas or oil, or a mixture of those two that is generally referred to as oleo-pneumatic. The gas is usually dry air or nitrogen. Figure 5.1 compares the efficiencies and relative weights of the various shock absorber types.
In selecting the type, due recognition must be given to the simplicity, reliability, maintainability, and relatively low cost of the solid-spring shock absorbers. On smaller utility aircraft, the weight penalty is usually negligible and the noted advantages far outweigh the penalties in such cases. The de Havilland of Canada (DHC) Twin Otter aircraft uses rubber compression...
