The experimentally determined aerodynamic characteristics of the NLAM 78 airfoil section, a natural-laminar airfoil, over the Mach number range 0.6 to 0.85 and angles of incidence from -1 to 4 as well as the Reynolds numbers 8, 16, and 32 million, respectively. The airfoil section was selected as the basic airfoil for the hybrid laminar flow control airfoil study, which is described. The test was executed in the NAL two dimensional transonic wind tunnel with a test section of 0.3 x 1.0 m where measurements of the static pressure on the airfoil surfaces and the wake traverse were made. The test has shown that natural laminar airfoil characteristics are maintained for a flow condition of Mach numbers as high as 0.8 and angles of incidence up to 1 degree, and that the lift to drag ratio for the condition takes very high values of 72 to 85 depending on the Reynolds number. Also, it shows that for the flow condition, the drag divergence Mach number is about 0.82 and drag creep phenomena are rarely observed. Comparisons with the flight data shows quite satisfactory agreement. Also, comparison with some supercritical airfoil with almost the same thickness ratio as the present airfoil confirms the superiority of the aerodynamic characteristics of the NLAM 78 airfoil.
Investigation of a Two-Dimensional Hybrid Laminar Flow Control Airfoil at High Subsonic Flow. Part 1: Aerodynamic Characteristic of a Basic Airfoil NLAM78
1990
27 pages
Report
No indication
English
Aerodynamics , Fluid Mechanics , Aerodynamic characteristics , Airfoils , Boundary layer control , Laminar boundary layer , Subsonic flow , Two dimensional flow , Mach number , Reynolds number , Wind tunnel tests , Angles (Geometry) , Incidence , Laminar wakes , Subsonic speed , Transonic wind tunnels , Foreign technology
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