Accession Number:

AD0617925

Title:

THEORETICAL AERODYNAMICS OF FLEXIBLE WINGS AT LOW SPEEDS. IV. EXPERIMENTAL PROGRAM AND COMPARISON WITH THEORY.

Descriptive Note:

Final rept. for Feb 64-Feb 65,

Corporate Author:

ITEK CORP PALO ALTO CALIF VIDYA DIV

Personal Author(s):

Report Date:

1965-02-15

Pagination or Media Count:

127.0

Abstract:

As Part IV of a general para ing study, low-speed measurements have been made of the aerodynamic characteristics of triangular one-lobed and two-lobed parawings of aspect ratios 1, 2, and 3 for comparison with the theory of Parts I and II of the study. It was found that this theory is adequate for determining the canopy shapes, the luffing boundaries, and the lift characteristics for parawings of low to moderate slackness ratio. The measured center of pressure positions are slightly forward of the theoretical position as a result, it is thought, of the presence of the leading-edge members. Also, the aerodynamic design of the leading-edge members is such that from 20 percent to 70 percent of the theoretical leading-edge suction is realized. The maximum lift-drag ratios appear to be adversely affected by trailing-edge flutter which in some cases is so intense as to preclude aerodynamic testing at angles of attack for maximum lift-drag ratio. A parawing of aspect ratio 8.5 with a taut trailing-edge cable exhibited no flutter, and when the tension was relieved the flutter was intense and the maximum lift-drag ratio actually increased. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE