Single propeller airplane minimal flight speed based upon the lateral maneuver condition

Abstract

This paper presents the application of the previously presented general analysis method to determine the safe flight boundaries of the asymmetrically loaded airplane within the terminal flight phases as applied to the case of inherently asymmetric single propeller airplane. As the lateral control surface design is done for the flight conditions out of the terminal flight phases, the key objective is to improve the flight safety of the asymmetrically loaded airplane by introducing the lateral flight controls verification at the low flight speeds. The concept of the authority of control surfaces presenting their capability to generate the forces and moments needed by the airplane to perform required maneuvers is the basis of the analysis. Control surface authority is the function of the control surface aerodynamic properties, structurally available flight control displacements and dynamic pressure. The analysis method scope is based upon the requirement to supplement the safe flight boundaries of symmetrically loaded airplane within the terminal flight phases, with the lift coefficient observed as the function of the angle of attack being at the linear limit. Control surface demands are lateral maneuver execution and asymmetric load and lateral wind compensation, the method scope permitting them to be addictive. Thus defined, the method is based upon the comparison of the available control surface authority and demands. For the defined flight conditions, the analysis is reduced to the comparison of the demanded and structurally available flight control displacement. The method combines the simple roll dynamics model, the stationary equations of the airplane lateral-directional motion and several numeric analysis procedures to obtain the results. This new combination possesses synergy properties and is implemented as the computer program. The method is applicable for any combination of airplane asymmetric loads and can be used throughout entire airplane life cycle. The contemporary trend of downsizing training and light combat airplane types with the rising number of the introduced medium and high power single propeller airplane types increases the significance of the method application in the design procedure.