Smoke generators and yarn tufts are used for flow visualization studies on an F/A-18 flown by NASA's Dryden Flight Research Center, Edwards, California, in its High Alpha Research Vehicle (HARV) program. The aircraft is at about 25 degrees angle of attack in this photo. The aircraft was modified with a thrust vectoring system to further investigate high angle of attack flying. The program was conducted jointly with NASA's Langley Research Center.