"An investigation of the aerodynamic characteristics of a powered semispan tilting-shrouded-propeller configuration has been conducted in the 17-foot test section of the Langley 300-MPH 7- by 10-foot tunnel. The wing had an aspect ratio of 2.67 (based on wing span of 60 inches), a taper ratio of 0.67, and an NACA 2418 airfoil section with a 15-inch-diameter shrouded propeller mounted on the tip. The test results show that large nose-up pitching moments are obtained at transitional speeds of about 40 knots and duct angle of about 70°. Decelerating flight procedures further increases in the nose-up moment. Ground proximity reduces the nose-up pitching moments. The large nose-up moments can be trimmed by use of duct-exit control vanes. The results show that unloading the duct (shroud) by flying at a wing angle of attack of 15° reduces the power required by about 30 percent at 50 knots. Duct-lip stall produces large increases in power required. The results in general show that full-scale aerodynamic simulation can be made with small-scale wind-tunnel models if duct-lip separation at low Reynolds numbers is avoided."--Summary.

This report presents the results of an investigation conducted in the Langley 300 mph 7- 10-foot wind tunnel for the purpose of determining the aerodynamic characteristics of a model wing-propeller combination, and of the wing and propeller separately at angles of attack up to 90 degrees. The tests covered thrust coefficients corresponding to free-stream velocities from zero forward speed to the normal range of cruising speeds. The results indicate that increasing the thrust coefficient increases the angle of attack for maximum lift and greatly diminishes the usual reduction in lift above the angle of attack for maximum lift.