Abstract
Poor lateral-directional stability due to the absence of vertical stabilizer is a great risk to the aircraft with flying wing layout. In this paper, an unmanned aerial vehicle with this kind of configuration is chosen as the research object. A three-dimensional model of the unmanned aerial vehicle is established, and then the sensitivity analysis is performed to obtain the effects of main aerodynamic shape parameters on lateral-directional flying quality. The results show that the roll mode and spiral mode of the aircraft meet the requirements of Level 1 flying quality in MIL-F-8785C. But the Dutch roll mode is generally divergent, which means that the flying quality of the aircraft is unacceptable. Thus it can be seen that the Dutch roll mode is the key to the dynamic stability of the aircraft. Further studies show that increasing the value of wing aspect ratio or decreasing the values of dihedral angle and torsion angle are useful for improving the Dutch roll mode. It is valuable to reveal the influence mechanism of aerodynamic shape parameters on lateral-directional flying quality for the design of flying wing aircraft.
Highlights
Flying wing configuration is considered as an important development direction of military aircraft and civil aircraft due to its potential benefits over conventional configurations in stealth capability, aerodynamic performance, and structural efficiency (Zhou and Liu 2015)
This paper studied how the aerodynamic shape parameters affect the lateral-directional dynamic stability of flying wing aircraft
The results show that the dynamic stability of the roll mode and spiral mode is better than that of the Dutch roll mode
Summary
Flying wing configuration is considered as an important development direction of military aircraft and civil aircraft due to its potential benefits over conventional configurations in stealth capability, aerodynamic performance, and structural efficiency (Zhou and Liu 2015). The lateral-directional stability of such aircraft is often at a disadvantage, which poses a great challenge to the designers for this kind of aircraft. One of the methods is making a large winglet at the wingtip of the aircraft, which produces the same effect as the vertical stabilizer (Snyder and Weisshaar 2013). This method is always used in civil aircraft, such as referenced in Zhang et al (2012a)
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