ABSTRACT
Synthetic fluids and lubricants have been used in aerospace equipment for many years. Aerospace applications are very demanding on fluids and lubricants. The major reason that aerospace applications are so demanding is that there is such a concern about the weight associated with aerospace systems. Since significant costs are incurred with flying every pound of an aerospace system, all elements of every system are the smallest, lightest available. This results in minimum volumes of fluids and lubricants used, the smallest heat exchangers possible, smaller reservoirs, smaller pumps, actuators, etc. The result is that fluids and lubricants in aerospace applications are required to withstand extremely severe levels of stress since small volumes are used and must operate at high temperatures generated in the application as well as at extremely low temperatures in which aerospace equipment is required to operate. In general, the synthetic fluids and lubricants are required for aerospace applications due to the wide temperature range over which they must operate. In comparison, nonaerospace applications, which are generally not so concerned about the amount of fluid used or the overall weight of the system, which permits the use of large heat exchangers, if required, do not put as much demand on fluids and lubricants. However, as nonaerospace applications become more sophisticated and the synthetic fluids and lubricants become less exotic and more readily available at lower costs, synthetics will be more widely used. Different classes of synthetics have been used for different aerospace application areas.
