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.

• Corporate Authors:

  NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTER

  ATLANTIC CITY, NJ  United States 

  Federal Aviation Administration

  Systems R&D Service, 800 Independence Avenue, SW
  Washington, DC  United States 
• Authors:
  • Garodz, L J
  • LAWRENCE, D
  • Miller, N
• Publication Date: 1974-11

Media Info

• Pagination: 100 p.

Filing Info

• 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