Full Scale Wind Tunnel, NASA history collection

As noted in Smith DeFrance's NACA TR No. 459: "The tunnel is of the double-return flow type with a 30 by 60 foot open jet at the test section. The air is circulated by two propellers 35 feet 5 inches in diameter, located side by side, and each directly connected to a 4,000-horsepower slip-ring induction motor. The motor control equipment permits varying the speed in 24 steps between 25 and 118 miles per hour. The tunnel is equipped with a 6-component balance for obtaining the forces in 3 directions and the moments about the 3 axes of an airplane. All seven dial scales of the balance system are of the recording type, which permits simultaneous records to be made of all forces." (p. 291)
NASA Identifier: L4934