Comparison of Predicted with Measured Aerodynamic Characteristics of the ATLIT Airplane

Flight test results are compared with predictions of the lift and drag of a light, twin-engine aircraft developed through the use of computerized analytical methods. Both lift and drag are higher than predicted at a given angle of attack. A rigging error of 1.5° could be responsible for the higher lift at α = 0. The experimental lift slope is 14 percent higher than 2π, an effect thought to be due to energetic propeller slipstreams which are not treated by the theory. Several interference and proturbance effects not included in the theory are thought to be responsible for the higher than predicted drag.