This paper was presented at the Twentieth National Conference of the Society of Aeronautical Weight Engineers at Akron, Ohio, May 15 – 18, 1961. The weight engineer’s standby --- the strength to weight ration --- has become almost obsolete in the construction of modern aerospace vehicles. This ratio should be implemented by a cost factor. The weight engineer must modernize his thinking with new factors and new materials. This paper presents a new factor that includes the interplay of strength, density, and cost. This factor is determined by dividing strength by the product of cost and density. When plotted against temperature, this factor rearranges the usual rankings of metals into various regimes and provides a way to compare the materials on a “value” basis.
This paper presents this ratio plotted versus temperature for metals which have shown promise for elevated temperature usage up to 2800 degrees F. In addition, a simplified formula for determining the cost per pound of weight savings is derived and several examples of its use are given.