Influence of design on cost of operating airplanes
This is a 1922 NASA technical report, compiled from the NACA-era aeronautical research record, on how airplane design choices drive operating cost; it was written for aircraft engineers and designers. The four charts plot percentage of total weight, pay load percentage, operating cost in cents per pound-mile and per passenger-mile, and initial rate of climb against speed and duration, with lettered curves for comparing design variants. A designer could take from them the clean, labeled grid layout and the lettered-curve convention for comparing several options on one plot.
