Experimental Study of Ground Effect on Horizontal Tail Effectiveness of a Conceptual Advanced Jet Trainer.

This research has provided the results for a static test of a conceptual advanced jet trainer (CAJT) aircraft in a low-speed wind tunnel within take-off and landing angle of attack limits. Test data includes longitudinal aerodynamic properties in take-off and landing phases. The analysis includes characteristics for lift and longitudinal stability, horizontal tail effectiveness, and studying the ground effect on the longitudinal aerodynamic properties. The tests have a Reynolds number of more than 1 million. Experiments were conducted in a low-speed, closed-circuit wind tunnel with a test section of 2.2 m width and 2.8 m height. The tests consist of measuring aerodynamic forces and moments using the six-component balance for strain metering. The slope of lift coefficient curve, lift coefficient value, and maximum aerodynamic efficiency value increase due to the presence of the ground. Also, the total aerodynamic center location moves backward as a result of the presence of the ground. It was observed by comparing the data for ground effect with those for out-of-ground effect that ground proximity significantly increases horizontal tail effectiveness as a component of pitching moment control. [ABSTRACT FROM AUTHOR]