Effect of Taper Ratio on the Low-Speed Rolling Stability Derivatives of Swept and Unswept Wings of Aspect Ratio 2.61
Abstract
An investigation has been conducted on a series of tapered swept wings in the 6-foot-diameter rolling-flow test section of the Langley stabilfty tunnel under conditions simulating rolling flight. The results of the tests showed that a decrease in taper ratio (ratio of tip chord to root chord) of a swept wing caused a small decrease in damping in roll at low and moderate lift coefficients; at high lift coefficients, decreasing the taper ratio caused a large reduction in the damping in roll and greatly reduced the increase obtained for the untapered wing prior to maximum lift. For an unswept wing, a decrease in taper ratio caused a small decrease in the damping in roll throughout the lift-coefficient range. The rate of change with lift coefficient of the yawing moment due to roll and of the lateral force due to roll were slightly decreased at low lift coefficients by a decrease in taper ratio. Available theory generally predicts the effect of change in taper ratio on the rate of change of the yawing moment due to roll with lift coefficient and on the damping in roll at zero lift more accurately than it does the effect of sweep. Tip-suction effects, not accounted for by the theory, may cause large errors in the theoretical values of the yawing moment due to roll and the lateral force due to roll. For a swept wing the yawing moment due to roll can be estimated by applying a correction to the available theory by utilizing the experimental value of the lateral force for an unswept wing of the same aspect ratio and taper ratio (the tip-suction force) and the geometric characteristics of the wing.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1951
- Accession Number
- ADA380454
Entities
People
- Jack D. Brewer
- Lewis R. Fisher
Organizations
- National Aeronautics and Space Administration