Research On Floating Stability And Floating Characteristics Of Highwing Aircraft

As the aircraft fly offshore or across the sea more and more frequently,the requirements for ditching of civil aircraft are gradually clear.The floating characteristics of aircraft is an important part of the performance of ditching.It describes the floating process of aircraft on water,mainly including the floating condition of aircraft after ditching,and the sinking posture and sinking time of aircraft after structural damage caused by impact,and determine whether the floating time is enough for the crew to escape.As the most important component of the water landing performance,the floating characteristics are important factors related to the success of ditching.Good floating characteristics can ensure that crew and passengers leave the aircraft and board the life rafts.In this regard,Part 25 of China Civil Aviation Regulation clearly states:It must be shown that,under reasonable and possible water conditions,the floating time and balance of the aircraft can enable all crew to leave the aircraft and board the required life raft.Therefore,study the characteristics of aircraft floating on water is of great practical significance.Starting from the engineering background and combining the advantages of mathematical analysis method and numerical simulation method,this paper develops a fast method to estimate the floating characteristics of aircraft ditching.This method has low cost,short period and certain accuracy.In this paper,a certain type of high wing airplane is taken as an example,and the following contents are studied in depth and detail.First,The aircraft floating stability was studied.Based on the CATIA software platform,the restoring moment of the aircraft in different states was calculated,and the longitudinal stability and transverse stability of the aircraft were studied.Second,The floating characteristics under hydrostatic conditions were studied:Based on the CATIA software platform and combined with the self-programmed floating characteristic calculation platform,the floating condition,waterline position and floating time under different conditions of the aircraft under hydrostatic conditions are completed.Third,The floating characteristics under wave conditions were studied.This paper uses Aqwa software which based on three-dimensional potential flow theory to calculate the dynamic response of the aircraft in the wave,and then combines the stepwise regression analysis function of Matlab software and the floating characteristic calculation integration platform to finally calculate the static floating characteristics and dynamic floating characteristics in waves.