66. Estimating Weight of Aircraft Electrical Wiring Systems

Paper

Abstract

There has long been the need for a practical method of estimating the weight of aircraft electrical wiring. This paper is presented in the hope that it will partially bridge the large gap between our present methods and our ultimate needs.
Electrical wiring is one item of appreciable weight in the present day aircraft which has been difficult to estimate accurately. The common methods of wire weight estimation by percentages, comparisons to similar aircraft, etc., are not practical due primarily to the fact that different airplanes rarely have the same electrical load requirements or voltages even though the airplanes may appear quite similar functionally and in other respects.
The present day aircraft electrical system is composed of from 10 to 40 percent in wiring; the wiring being responsible for 1 to 2 percent of the weight empty of the airplane. These are appreciable weights which in the past have been undetermined until comparatively late in the design stage. It is necessary, however, that the weight of electrical wiring, as well as other components of the airplane, be known far in advance of this phase of design in order to effect efficient weight control.
The method presented here is based on the electrical load requirements of the airplane, which is essentially the system used by the Electrical Design Section in determining actual wire sizes for the various circuits in the airplane at a later stage of design.