The effects of primary and runback icing and frost formations on the drag of an 8-foot-chord NACA 651-212 airfoil section were investigated over a range of angles of attack from 2 degrees to 8 degrees and airspeeds up to 260 miles per hour for icing conditions with liquid-water contents ranging from 0.25 to 1.4 grams per cubic meter and datum air temperatures of -30 to 30 degrees F.

Measurements of lift, drag, and pitching moment of an NACA 0011 airfoil were made in icing using two types of pneumatic de-icers, one having spanwise inflatable tubes and the other having chordwise tubes. Ice remaining after inflation of the spanwise-tube de-icer increased airfoil section drag 7 to 37 percent for 0 to 4.6 degrees angle of attack over the ranges of airspeed, total air temperature, liquid-water content, and cycle times covered. This drag increase became constant after a few de-icing cycles. Drag increases due to ice remaining on the chordwise-tube de-icer were similar to those for the spanwise-tube de-icer. Minimum airfoil drag in icing (averaged over a de-icing cycle) was usually obtained with a short (about i min) de-icing cycle.

The thermodynamic and transport prorerties of high-temperature air are found in closed form starting from approximate partition functions for the major components in air and neglecting all minor components. The compressibility, energy, entropy, the specific heats, the speed of sound, the coefficients of viscosity and of thermal conductivity, and the Prandtl numbers for air are tabulated from 500 degrees to 15,000 degrees K over a range of pressure from 0.0001 to 100 atmospheres. The enthalpy of air and the mol fractions of the major components of air can easily be found from the tabulated values for compressibility and energy. It is predicted that the Prandtl number for fully ionized air will become small compared to unity, the order of 0.01, and this implies that boundary layers in such flow will be very transparent to heat flux.