This 1984 photograph is a close-up of the left wing of the F-4C in flight showing the tufting and the airflow over the wings upper surface. The nozzle from the Air Force and McDonnell Douglas test can be seen just below the "I" in Air Force in this photograph.

The McDonnell F-4C Phantom II was built for the U.S. Air Force and is a two seat fighter-type aircraft with folding wings and powered by two J-79-G.E.-15 Turbojet engines. An experiment to expand on some previous spanwise blowing testing, was proposed for this aircraft. The U.S. Air Force and McDonnell Douglas had conducted testing where J-79 engine high pressure bleed air from the compressor was piped forward along the inside of the fuselage, and expelled through a nozzle in the fuselage near the wing’s leading edge and just above the surface. NASA Ames-Dryden Flight Research Facility looked at extending the spanwise blowing by bring the engine air further out through the wings, and onto the upper wing surface.

Small pieces of strings, called “tufts” were taped to the upper surface of the wings. The “tufts” are photographed from a chase aircraft and provide a visual record of the boundary layer flow with and without span-wise blowing.