Inlet Duct being lowered into the Altitude Wind Tunnel Test Section

An inlet duct lowered into the 20-foot diameter test section of the Altitude Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Engines and hardware were prepared in the facility’s shop area. The test articles were lifted by a two-rail Shaw box crane through the high-bay and the second-story test chamber before being lowered into the test section. Technicians then spent days or weeks hooking up the supply lines and data recording telemetry.

The engines were mounted on wingspans that stretched across the test section. The wingtips attached to the balance frame’s trunnions, which could adjust the angle of attack. The balance frame included six devices that recorded data and controlled the engine. The measurements were visible in banks of manometer boards next to the control room. Photographs recorded the pressure levels in the manometer tubes, and the computing staff manually converted the data into useful measurements.

A mechanical pulley system was used to raise and lower the tunnel’s large clamshell lid into place. The lid was sealed into place using hand-turned locks accessible from the viewing platform. The lid had viewing windows above and below the test article, which permitted the filming and visual inspection of the tests.