Effects of Various Fillet Shapes on a 76/40 Double Delta Wing from Mach 0.18 to 0.7
Abstract
The objective of this experimental investigation was to understand the impact of small geometry modifications (fillets) at the juncture of a 76 degree sweep leading edge extension (LEX) or strake and a 40 degree sweep cropped delta wing (76/40 double delta wing). A sharp leading edge model was used to depict a generic fighter strake and wing configuration. These fillets were developed to control the shedding, trajectory, and subsequent breakdown of vortices to enhance aircraft aerodynamic performance at subsonic and transonic speeds, and at elevated angles of attack. Longitudinal, lateral, and flow field characteristics of the double delta wing were investigated with different sized linear, diamond, and parabolic shaped fillets. The investigation was conducted in the 7-by-10 foot High Speed Tunnel at the NASA Langley Research Center. The wind tunnel test was conducted from Mach 0.18 to 0.7; Reynolds numbers per foot were from 1.2 to 3.6 x 10(exp 6); angles of attack were from -4 degrees to 42 degrees; and there was zero sideslip. Force and moment, pneumatic pressures, pressure sensitive paint, and vapor screen flow visualization measurements were used to characterize the flow field and to determine longitudinal forces and moments. The fillets increased lift coefficient and reduced induced drag without significantly affecting pitching moment. Pressure sensitive paint showed the increase in lift is caused by an increase in suction and broadening of the vortex suction footprint. Vapor screen results showed the mixing and coalescing of the strake fillet and wing vortices causes the footprint to broaden. The presentation of the experimental results begins with a description of the aerodynamic characteristics of the baseline 76/40 double delta wing. With the baseline configuration as a basis for comparison, a discussion of the effects of the various fillets follows. (34 figures, 32 refs.)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2003
- Accession Number
- ADA419050
Entities
People
- Blair G. Mclachlan
- Gary E. Erickson
- Hugo A. Gonzalez
- James H. Bell
Organizations
- Naval Air Station Patuxent River