Abstract: The ablation rates and effective heats of ablation were determined for a number of materials in supersonic ceramic-heated and electric-arc-powered air jets at stagnation temperatures ranging from 2,000° F to 11,000° F. The results indicated that the effective heats of ablation were from 7 to 40 times greater than the heat-absorption capacity of copper and increased with increasing aerodynamic heat flux. In addition, the results indicated that for the materials having phenolic-resin binders, the effective heats of ablation decreased with increasing resin content.