Stability and Control Results for Advanced Turboprop Aft-Mount Installations

An experimental investigation was recently conducted in the NASA-Langley Research Center 4-by 7- Meter Tunnel to explore the effects of aft-mounted advanced turboprop installations on the low-speed stability and control characteristics of a representative transport aircraft configuration. For the conditions investigated, the experimental results indicate that the longitudinal and directional stability of the configuration was not adversely affected by aft-pylon-mounted single-rotation tractor or counter-rotation pusher propeller installations. The results indicate that for the single-rotation tractor configuration the propeller induced aerodynamics are dominated by the interaction of the propeller slipstream with the pylon, and that the propeller contribution to the stability charcteristics for the counter-rotating pusher configuration is dominated by propeller normal forces. The longitudinal and directional control effectiveness, engine-out characteristics, and ground effects are also presented.