SPACEPHOTOS

NASA 834, an F-14 Navy Tomcat, seen here in flight, was used at Dryden in 1986 and 1987 in a program known as the Variable-Sweep Transition Flight Experiment (VSTFE). This program explored laminar flow on variable sweep aircraft at high subsonic speeds. An F-14 aircraft was chosen as the carrier vehicle for the VSTFE program primarily because of its variable-sweep capability, Mach and Reynolds number capability, availiability, and favorable wing pressure distribution. The variable sweep outer-panels of the F-14 aircraft were modified with natural laminar flow gloves to provide not only smooth surfaces but also airfoils that can produce a wide range of pressure distributions for which transition location can be determined at various flight conditions and sweep angles. Both gloves are seen on the F-14 in this photo. Glove I, installed on the upper surface of the left wing, was a ''cleanup'' or smoothing of the basic F-14 wing, while glove II was designed to provide specific pressure distributions at Mach 0.7. Laminar flow research has continued at Dryden. A later research program used the NASA 848 F-16XL in a laminar flow experiment involving a wing-mounted panel with millions of tiny laser cut holes drawing off turbulent boundary layer air with a suction pump.