Balance for Measuring Skin Friction in the Presence of Ablation

: This report describes a skin-friction balance that is presently being used to measure shear stresses acting on the wall of an ablative duct. Tests have been conducted in the 3 Megawatt Arc Tunnel with a Mach number of 3, a stagnation enthalpy of 3000 BTU/lb, and a stagnation pressure of 20 atmospheres. The balance is a direct deflection measuring device in that balance arm rotation is measured with a linear variable differential transformer as the balance arm deflects due to shear loads acting on the end of the balance arm.