The largest weight penalties were incurred to maintain the clean stall speed, but all effects were small considering the conservative assumptions made in the analysis. The effect of underwing frost on transport aircraft takeoff and climb performance was studied. Underwing frost occurs when the lower surface of the wing is cooled by cold-soaked fuel in the wing tanks and frost accretes prior to takeoff. A two-dimensional test was performed in the NASA Langley Low Turbulence Pressure Tunnel on a typical high-lift airfoil with leading-edge slats and trailing-edge flaps. Frost was simulated on the lower surface using distributed roughness particles. The test was conducted at a Mach number of 0.2 and chord Reynolds numbers from 5 to 16 million. The effects of the frost were generally small with the largest effects occurring for the slat open case with the frost starting at 12 percent chord. In this situation the frost actually contaminated the upper surface boundary layer. The 2-D data were extrapolated to 3-D for a typical twin-jet and four-jet aircraft. Drag increases were converted into weight penalties to maintain clean aircraft climb angles, and maximum lift penalties were presented as stall speed changes.


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    Title :

    Effect of Underwing Frost on Transport Aircraft Takeoff Performance


    Contributors:

    Publication date :

    1993


    Size :

    97 pages


    Type of media :

    Report


    Type of material :

    No indication


    Language :

    English