Analysis Of The Effects Of Boundary Layer Control On The Take Off Performance Characteristics Of A Liaison Type Airplane PDF Download

A performance analysis has been made to determine whether boundary-layer control by suction might reduce the minimum take-off distance of a four-place or five-place liaison-type airplane below that obtainable with conventional high-lift devices. The airplane was assumed to be capable of operating from airstrips having a ground friction coefficient of 0.2. The pay load was fixed at 1500 pounds and the wing span was varied from 30 to 100 feet, the aspect ratio from 5 to 15, and the power from 200 to 1300 horsepower. Maximum lift coefficients of 5.0 and 2.8 were assumed for the airplanes with and without boundary-layer control, respectively. A conservative estimate of the boundary-layer-control-equipment weight was included. The effects of the boundary-layer control on total take-off distance, ground run, and stalling speed were determined The analysis indicates that the addition of boundary-layer control does not reduce the absolute minimum total take-off distance that is obtained with an airplane having a low wing loading and a moderately low aspect ratio. The effectiveness of boundary-layer control in reducing the total take-off distance for a given maximum speed improves with increasing aspect ratio and, for wing loadings of 10 pounds per square foot or more and an aspect ratio of 10 or more, the addition of boundary-layer control results in a decrease in the total take-off distance. For a given maximum speed the ground run was reduced for all configurations by the addition of boundary-layer control. The reduction was negligible for aspect ratio of 5 but was 10 to 30 percent for aspect ratios of 10 and 15. The stalling speed for a given maximum speed was reduced 20 to 25 percent for all configurations by application of boundary-layer control. A reduction in the weight of the boundary-layer control equipment would result in an appreciable decrease in the total take-off and ground run distances, but would have a negligible effect on the stalling speed.