An Investigation On Stability And Control Of Joined-Wings

The joined-wing is a kind of the non-conventional configurations. They have many advantages, such as lighter structure, more strength, more rigid structure, lower drag and larger lift than conventional configuration, as well as the ability of direct force control. It is important to investigate the characteristics of the stability and control for joined-wing airplanes. In this paper, we review the joined-wings difference between conventional airplanes and the joined-wings and discuss the advantages of the joined-wing configuration in chapter one. In chapter two the comparisons are presented for analysis methods evaluating the stability and control characteristics of the joined-wing configuration. The advantages and disadvantages of these methods are pointed out. The comparisons indicate that Vortex Lattice Method (VLM) is the ideal method to analyze the characteristics of stability and control of joined-wing airplanes. We explain the basic concept and principle of the VLM. In chapter three a general purpose VLM program is developed using MATLAB. The VLM program is able to compute aerodynamic force, moment and stability characteristics. The stability characteristics of the seventy configurations defined by Central Composite Design (CCD) was computed by the program. According to the computing results, the relations between the he stability characteristics and the configuration parameters of joined-wing airplanes were obtained. Furthermore, we analyzed the effects of changes of center of gravity and angel of extroversion on the stability characteristics for some large aspect ratio joined-wing airplanes. In chapter 5, this paper expatiate the concept and method on direct force control of joined-wing airplanes in details. It indicates that it is feasible for direct force control.