Gap and Stagger Effects on Biplanes with End Plates: Part I

Document Type

Conference Paper

Publication Date


Publication Source

47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition


Modern flow diagnostics applied to a very old aerodynamic problem produced a number of intriguing new results and produced new insight into previous results. The aerodynamic performance and associated flow physics of the biplane with endplates as a function of variation in gap and stagger were analytically and experimentally investigated. A combination of vortex lattice method, integrated force measurement, streamwise PIV, and Trefftz plane Stereo PIV were used to better understand the flowfield around the biplane with endplates.

This study was performed to determine the configuration with the optimal aerodynamic performance and to understand the fluid mechanics behind optimal and suboptimal performance of the configuration. Part I specifically addresses experimentally determined differences in aerodynamic performance due to changes in gap and positive and negative stagger not predicted by inviscid codes and Munk’s theory. Downwash angles determined through streamwise PIV are used to better understand the individual contributions to lift of the upper and lower wings as a function of gap and stagger. The downwash data were subsequently used to calculate lift. This downwash calculated lift compared well to the force balance results except at large angles of attack for configurations with negative stagger.




Permission documentation is on file.


American Institute of Aeronautics and Astronautics

Place of Publication

Orlando, FL