摘要 :
Small, fixed-wing unmanned aircraft often encounter gusts that disturb their motion and stress the airframe. A positive wing dihedral angle provides indirect roll stiffness to help meet lateral-directional stability requirements, ...
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Small, fixed-wing unmanned aircraft often encounter gusts that disturb their motion and stress the airframe. A positive wing dihedral angle provides indirect roll stiffness to help meet lateral-directional stability requirements, though it also reduces lift efficiency. By varying this angle, the aircraft may tune its stability characteristics to ambient conditions. Moreover, fast variations in the dihedral angle allow direct control of vertical lift for gust rejection and improved flight path control. These observations suggest a design trade-off between the potential performance benefits and the cost of implementing and using the mechanism. Considering a hinged servomechanism which can vary the outboard dihedral angle, the system performance and cost are affected by the spanwise location of the hinge. This paper describes analysis to predict the effect of such an adjustable dihedral mechanism on lateral-directional stability and on the capacity to reject vertical gust disturbances.
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