The Bell X-5 swings its wings in this multiple exposure photograph. Variable-sweep wing technology later appeared on the F-111, F-14 and B-1.

NACA X-Planes on South Base ramp. Northrop X-4, Bell X-1, Bell X-5, Douglas D-558-1, Douglas D-558-2. Back row Convair XF-92A. March 30, 1952

Early NACA research aircraft on the lakebed at the High Speed Research Station in 1955: Left to right: X-1E, D-558-II, X-1B

This photo of the X-1A includes graphs of the flight data from Maj. Charles E. Yeager's Mach 2.44 flight on December 12, 1953. (This was only a few days short of the 50th anniversary of the Wright brothers' first powered flight.) After reaching Mach 2.44, then the highest speed ever reached by a piloted aircraft, the X-1A tumbled completely out of control. The motions were so violent that Yeager cracked the plastic canopy with his helmet. He finally recovered from a inverted spin and landed on Rogers Dry Lakebed. Among the data shown are Mach number and altitude (the two top graphs). The speed and altitude changes due to the tumble are visible as jagged lines. The third graph from the bottom shows the G-forces on the airplane. During the tumble, these twice reached 8 Gs or 8 times the normal pull of gravity at sea level. (At these G forces, a 200-pound human would, in effect, weigh 1,600 pounds if a scale were placed under him in the direction of the force vector.) Producing these graphs was a slow, difficult process. The raw data from on-board instrumentation recorded on oscillograph film. Human computers then reduced the data and recorded it on data sheets, correcting for such factors as temperature and instrument errors. They used adding machines or slide rules for their calculations, pocket calculators being 20 years in the future.

The Bell Aircraft Corporation X-1-2 aircraft on the ramp at NACA High Speed Flight Research Station located on the South Base of Muroc Army Air Field in 1947. The X-1-2 flew until October 23, 1951, completing 74 glide and powered flights with nine different pilots. The aircraft has white paint and the NACA tail band. The black Xs are reference markings for tracking purposes. They were widely used on NACA aircraft in the early 1950s.

From December 10, 1966, until his retirement on February 27, 1976, Stanley P. Butchart served as Chief (later, Director) of Flight Operations at NASA's Flight Research Center (renamed on March 26, 1976, the Hugh L. Dryden Flight Research Center). Initially, his responsibilities in this position included the Research Pilots Branch, a Maintenance and Manufacturing Branch, and an Operations Engineering Branch, the last of which not only included propulsion and electrical/electronic sections but project engineers for the X-15 and lifting bodies. During his tenure, however, the responsibilities of his directorate came to include not only Flight Test Engineering Support but Flight Systems and Loads laboratories. Before becoming Chief of Flight Operations, Butchart had served since June of 1966 as head of the Research Pilots Branch (Chief Pilot) and then as acting chief of Flight Operations. He had joined the Center (then known as the National Advisory Committee for Aeronautics' High-Speed Flight Research Station) as a research pilot on May 10, 1951. During his career as a research pilot, he flew a great variety of research and air-launch aircraft including the D-558-I, D-558-II, B-29 (plus its Navy version, the P2B), X-4, X-5, KC-135, CV-880, CV-990, B-47, B-52, B-747, F-100A, F-101, F-102, F-104, PA-30 Twin Comanche, JetStar, F-111, R4D, B-720, and B-47. Although previously a single-engine pilot, he became the Center's principal multi-engine pilot during a period of air-launches in which the pilot of the air-launch aircraft (B-29 or P2B) basically directed the operations. It was he who called for the chase planes before each drop, directed the positioning of fire rescue vehicles, and released the experimental aircraft after ensuring that all was ready for the drop. As pilot of the B-29 and P2B, Butchart launched the X-1A once, the X-1B 13 times, the X-1E 22 times, and the D-558-II 102 times. In addition, he towed the M2-F1 lightweight lifting body 14 times behind an R4

Stan Butchart climbing into B-47.