Abbreviated Full-Scale Flight Test Investigation of the Lockheed L1011 Trailing Vortex System Using Tower Fly-By Technique
NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTER ATLANTIC CITY NJ
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A brief flight test program was conducted at the National Aviation Facilities Experimental Center NAFEC to investigate the time-history characteristics of the vortex system of a Lockheed L1011 airplane in terminal area-type operations using a 140-foot high instrumented tower. Vortex rotational flow velocities were measured by hot-film anemometers, vortex flow visualization--as outlined by tower-mounted smoke granades--was deocumented, and meteorological data was recorded. In addition, data on aircraft track, performance, and configuration were gathered. The test results show that 1 the L1011 vortex system was more persistent and intense than that of other heavy jet transport 300,000 lb aircraft tested by NAFEC, but did not persist for more than 2 minutes 2 vortex dissipation was due primarily to vortex breakdown bursting 3 vortex core diameters were on the average about 5, 4, and 2 feet in diameter for the landing, approach, and takeoff configurations, respectively 4 peak recorded tangential velocities, were 126, 135, and 224 feet per second for these same respective configurations 5 vortex lateral movement in-ground effect was approximately pi6.6b, above ground level and 6 average vortex descent velocities approached 6 feet per second out of ground effect. Color illustrations reproduced in black and white.
- Civilian Aircraft