B-747 Vortex Alleviation Flight Tests : Ground-Based Sensor Measurements and Addendum

Details

• Creators:
  Burnham, D. C.
• Corporate Creators:
  John A. Volpe National Transportation Systems Center (U.S.)
• Subject/TRT Terms:
  • Wakes
  • Vortices
  • Flight tests
  • Laser doppler velocimeters
  • Takeoff
  • Landing
  • Aircraft wake vortices
  • Vortex alleviation
  • Laser doppler velocimeter
  • Vortex decay
  More +
• Publication/ Report Number:
  DOT-TSC-FAA-81-19 ; FAA-RD-81-99
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Corporate Publisher:
  United States. Department of Transportation. Federal Aviation Administration
• Abstract:
  In 1979, a series of B-747 flight tests were carried out to study the wake-vortex alleviation produced by deploying spoilers in the landing configuration. The alleviation achieved was examined by encounters of probe aircraft and by velocity profile measurements made by a ground-based Laser Doppler Velocimeter. For the first time these two types of measurements were analyzed in a way which allowed direct comparison; they showed reasonable agreement. The velocimeter measurements can be used to evaluate the vortex-induced rolling moment on any following aircraft at any separation. The spoiler alleviation was found to be insufficient to assure safe landings of small aircraft at reduced separation behind the B-747. The persistence of the alleviated vortices appears to be due to the wing-tip vortices which dominate the roll-up of the spoiler-alleviated wake. The addition of rapid roll inputs to the spoiler deployment produced much more effective alleviation, but at the expense of an unacceptable ride quality in the generating aircraft.
• Content Notes:
  Summary, Introduction, Test description, Data analysis, Results, Recommendations, References, Appendix
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/9405/dot_9405_DS1.pdf
• File Type:
  [PDF - 9.71 MB]
• Collection(s):
  Volpe Center
• Main Document Checksum:
  urn:sha-512:eb1a490f0605cc264c476b4003f99b8babea77c4d21959364a35c5935042b8886364731e5462131619ea050d91af0029c305d39e4812617bc0ca5b67f1b91585