Development of a Whirlstand for Testing Jet Helicopter Powerplants

American Helicopter's new Air Force owned powerplant test stand can mount whirl arms with radii of 13 to 50 feet, and is capable of testing tipmounted engines weighing 600 pounds and delivering 1000 pounds of thrust at tip speeds to 700 feet/second. Outstanding design features are as follows: a) 630 horsepower driving engine to permit arm calibration and cold drag measurements. b) 500 horsepower absorption unit to eliminate drag plates and thereby minimize errors due to air contamination affects on rotor drag. c) Dual range torque gauges on main shaft, to eliminate data uncerainties due to losses in drive train. d) Electronic revolution counter to maintain rotor acceleration within allowable limits. e) Instrumentation to measure and record temperatures, strains, and pressures.