An engine mechanic checks instrumentation prior to an investigation of engine operating characteristics and thrust control of a large turboprop engine with counter-rotating propellers under high-altitude flight conditions in the 20-foot-diameter test section of the Altitude Wind Tunnel at the Lewis Flight Propulsion Laboratory of the National Advisory Committee for Aeronautics, Cleveland, Ohio, now known as the John H. Glenn Research Center at Lewis Field. (August 25, 1949).
Looking down the throat of the world's largest tunnel. The scene is NACA's 40 x 80 foot wind tunnel at Ames Aeronautical Laboratory, Moffett Field, California, which when it was built was the world's largest. The camera is stationed in the tunnel's largest section, 173 feet wide by 132 feet high. Here at top speed the air, driven by six 40 foot fans, is moving about 35 to 40 miles per hour. The rapid contraction of the throat (or nozzle) speeds up this air flow to more than 250 miles per hour in the oval test section, which is 80 feet wide and 40 feet high.
The tunnel encloses 900 tons of air, 40 tons of which rush through the throat per second at maximum speed. Dwarfed by the immensity of the tunnel structure, the experimental model seen here is actually almost 50 feet long. Embodying a sharply swept-back wing suitable for supersonic flight, it is undergoing tests designed to improve the landing characteristics of this type of airfoil. Mounted on struts connected to scales under the test section, it is "flown standing still" while each element such as lift and drag is measured and air pressures occurring across the wing are recorded. Information gathered from such tests were made available to the nation's aircraft manufacturers by the NACA (now NASA), an independent agency of the U.S. Government. (1947).
Study of effect of twin-jet exhausts inclined toward the ground in simulation of take-off conditions for certain engine installations. Such an engine installation is useful for decreasing the takeoff distance of aircraft. This is one of many problems of operation under study at the Lewis Flight Propulsion Laboratory, of the National Advisory Committee for Aeronautics, now known as John H. Glenn Research Center at Lewis Field, Cleveland, Ohio. (July 7, 1949).
Technicians at Langley installing flaps and wiring on a flying-boat model, circa 1944.