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Maskell's approach for performing drag integrals in far-field fully-developed three-dimensional wakes has been extended for near-field application. The extended theory has been applied to wake survey data at two traverse stations involving a stalled wing, and an idealized car model tested over a fixed ground at two yaw angles. As a spin-off, cross-flow velocity vector plots have been resolved into vorticity-driven and source-driven components, which give added insight into complicated flows. The new extension appears to work well in application to the test data, but correlations with balance measurements were compromised by fixed-floor flow problems. A limited review suggests that, while problems of wake definition may be soluble at zero yaw, changes in flow topology may negate comparable solutions with the model yawed. These difficulties are circumvented if a moving ground is employed.

This paper describes the comprehensive database developed by the Lockheed Aeronautical Systems Company which underscores (he critical mission needs for an Advanced Tactical Transport (ATT). A unique process was used to substantiate that an ATT must have the capability to: Deliver Army maneuver units and their fire support systems that weigh up to 55,000 lb. Operate on hot days, at night, or in bad weather from unpaved runways less than 2000 ft. In length at elevations greater than 4000 ft. Operate routinely within 20 nm of enemy Sines, and occasionally over enemy territory, and have improved survivability features. Accomplish multiple unrefueled sorties with total distances up to 1500 nm. Design implications, considering six specific alternative concepts, are discussed in terms of relative mission effectiveness, cost, supportability, survivability, technology and system programmatics.