Flight tests were conducted in the fall of 1995 off the coast of Wallops Island, Virginia to measure characteristics of wake vortices at flight altitudes. A NASA Wallops Flight Facility C-130 aircraft equipped with smoke generators produced visible wakes at altitudes ranging from 775 to 2225 m in a variety of atmospheric conditions, orientations (head wind, cross wind), and airspeeds. Meteorological and aircraft parameters were collected from a Langley Research Center OV-10A aircraft as it flew alongside and through the wake vortices at varying distances behind the C-130. Meteorological data were also obtained from special balloon observations at Wallops Island. Differential GPS was used on each aircraft to obtain altitude profiles. Vortices were observed to rise at distances as close as 500 m behind the C-130. The wake was observed to be 150 m higher than the C 130 on one occasion at a distance of 11 km behind. The rising motion on this day was due to large vertical oscillations in the wakes. The atmospheric conditions were near neutral stratification with significant turbulence. There were several cases when the vortices did not descend after the first few minutes, and they remained near generation altitude in a variety of moderately stable atmospheres and wind shears. Excerpts of flight videos will be shown. The FAA Wake Turbulence Training Aid is currently under revision to incorporate some of the data from this research
The 8th Conference on Aviation, Range, and Aerospace Meteorology