THE MEASUREMENT OF THE MCDONNELL-DOUGLAS DC9 TRAILING VORTEX SYSTEM USING THE TOWER FLY-BY TECHNIQUE
The results are presented of a series of low-altitude (approximately 200 feet above ground level) fight tests in which the trailing vortices of the McDonnell-Douglas DC9 airplane were investigated, using a 140-foot instrumented tower. Data presented consists of plots of vortex tangential velocity distribution, peak velocity as a function of time, airplane configuration and windspeed, vortex descent rates, and lateral transport rates. Principal findings were that: (1) Within the time period 30 - 100 seconds after vortex generation, the peak velocities within the vortices were bounded by the function V sub theta = 396exp(-.0347t), with a half-life of 20 seconds; (2) Vortex cores were uniformly small (1 - 2 feet) in both configurations tested (takeoff and landing), and little or no growth with time was found; (3) Vortex lateral transport velocities correlated well with the crosswind measured at 140 feet; and (4) The presence of a temperature inversion markedly retarded the vortex descent rates. The highest peak recorded tangential velocity was 120 - 130 feet per second, found to occur in both configurations tested.
NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTERATLANTIC CITY, NJ United States
Washington, DC United States
- Garodz, L J
- LAWRENCE, D
- Miller, N
- Publication Date: 1974-11
- Pagination: 100 p.
- Accession Number: 00080458
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: FAA-NA-74-28 Final Rpt.
- Files: NTIS, USDOT
- Created Date: Feb 27 1975 12:00AM