Longitudinal drop-water response analysis of low-flat-tailed firefighting aircraft

The low-flat-tail conventional-layout firefighting aircraft produces the obvious longitudinal head-up response when the gravity water-drop system is used. In order to solve this problem, through the theoretical study of the aerodynamic characteristic change principles during the aircraft's firefighting, a rigid water body assumption method is put forward to simulate the effect of the water body on the aerodynamic characteristics of the firefighting aircraft, and the intrinsic mechanisms of the water body are preliminarily revealed. On this basis, the spatial flow field is analyzed, and the optimal vortex generator layout is given and theoretically verified. The water-drop trial flight verification results show that the installation of a vortex generator can effectively mitigate the head-up moment caused by the presence of water bodies and that the mitigation measure is a low-cost and high-efficiency aerodyna-mic mitigation measure, which significantly reduces the magnitude of the instantaneous pushrod force of the water drop and guarantees the safety of a firefighting aircraft's flight, providing a design and modification reference for the development of other fixed-wing firefighting aircraft.