Low-Speed Investigations of 'Apex Fence' and 'Cavity Flap' Concepts on a 60 Degree Delta Configuration.
Abstract
This report describes low-speed wind tunnel investigations of 'apex fence' and 'cavity flap' concepts applied to a 60-deg. uncambered delta wing/body configuration. The upper-surface apex fences, hinged near the leading edges, are deployed vertically at low to moderate angles of attack (appropriate to approach and landing) to force a powerful vortex pair which augments suction over the forward regions of the wing planform. The resulting nose-up moment is balanced by means of trailing edge flaps, resulting in increased trimmed lift as well as drag for improved short-field landing capability of the tailless delta. The 'cavity flap' is a lower-surface hinged vortex flap whose deflection creates a frontal cavity underneath the leading edge. Above a certain angle of attack the flap vortex fills the mouth of the cavity, which helps the external flow to turn around the leading edge thus reducing the vortex lift at high angles of attack, and b) creates suction over the cavity frontal area which generates a side-force component. The potential of asymmetrically deployed cavity flaps for lateral/directional control at high angles of attack was of interest. These concepts were subjected to low-speed tunnel studies exploring the lee-side flow field through visualizations and pressure surveys, and measuring force and moment characteristics. Results are discussed which verify the basic aerodynamic of these concepts and assess their potential for trimmed-lift increment and roll/yaw control capability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1987
- Accession Number
- ADA183138
Entities
People
- Charles T. Mills
- Dhanvada M. Rao
- Keith D. Hoffler