A Wing-by-Wing Approach for Biplane Static Longitudinal Stability and Control Analysis

This paper presents a theoretical model for the analysis of the longitudinal static stability and control of biplane aircrafts that take into account some effects neglected by the classical approach based on the concept of an aerodynamically equivalent monoplane. Adopting a different approach, the present study considers individually the effects of lift and drag of each wing and the influence of the horizontal tail drag. The study includes the determination of neutral and maneuver points under free and fixed stick conditions and the influence of them over aircraft longitudinal control. Through a practical example, it's shown that, depending on aircraft geometry, an analysis based on the present study can lead to results very different of that furnished by the equivalent monoplane analysis.