NACA Technical Notes

The effects of existing frictional heating were analyzed to determine\ud the conditions under which ice formations on aircraft surfaces can\ud be prevented. A method is presented for rapidly determining by means\ud of charts the combination of-Mach number, altitude, and stream temperature\ud which will maintain an ice-free surface in an icing cloud. The\ud method can be applied to both subsonic and supersonic flow. The charts\ud presented are for Mach numbers up to 1.8 and pressure altitudes from sea\ud level to 45,000 feet