Battery powered vertical takeoff and landing(VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, mot...Battery powered vertical takeoff and landing(VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, motor and electronic speed controller, the power consumption model of propeller and the constant power discharge model of battery, an efficient method to estimate the hover endurance of battery powered VTOL aircraft was presented. In order to understand the mechanism of performance improvement, the impacts of propulsion system parameters on hover endurance were analyzed by simulations, including the motor power density, the battery capacity, specific energy and Peukert coefficient. Ground experiment platform was established and validation experiments were carried out, the results of which showed a well agreement with the simulations. The estimation method and the analysis results could be used for optimization design and hover performance evaluation of battery powered VTOL aircraft.展开更多
A mathematical model for system life and reliability of a multiple power takeoffs aeroengine accessory gearbox transmission is presented.The geometry model of gear train is distributed into several subsystems by diffe...A mathematical model for system life and reliability of a multiple power takeoffs aeroengine accessory gearbox transmission is presented.The geometry model of gear train is distributed into several subsystems by different transmitted powers.The lives of each component are combined to determine the units,subsystems and entire system lives sequentially according to a strict series probability model.The unit and subsystem interface models are defined to dispose the loads of common components.The algorithm verification is presented and a numerical example is given to illustrate the use of this program.The initial design could not fulfill the life requirement.A design modification shows that the gear train has a more balanced life distribution by strengthening the weak parts,and the overall life of entire system is increased above the design requirement.This program can help the designer to approach an optimal accessory gearbox transmission design efficiently.展开更多
文摘Battery powered vertical takeoff and landing(VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, motor and electronic speed controller, the power consumption model of propeller and the constant power discharge model of battery, an efficient method to estimate the hover endurance of battery powered VTOL aircraft was presented. In order to understand the mechanism of performance improvement, the impacts of propulsion system parameters on hover endurance were analyzed by simulations, including the motor power density, the battery capacity, specific energy and Peukert coefficient. Ground experiment platform was established and validation experiments were carried out, the results of which showed a well agreement with the simulations. The estimation method and the analysis results could be used for optimization design and hover performance evaluation of battery powered VTOL aircraft.
文摘A mathematical model for system life and reliability of a multiple power takeoffs aeroengine accessory gearbox transmission is presented.The geometry model of gear train is distributed into several subsystems by different transmitted powers.The lives of each component are combined to determine the units,subsystems and entire system lives sequentially according to a strict series probability model.The unit and subsystem interface models are defined to dispose the loads of common components.The algorithm verification is presented and a numerical example is given to illustrate the use of this program.The initial design could not fulfill the life requirement.A design modification shows that the gear train has a more balanced life distribution by strengthening the weak parts,and the overall life of entire system is increased above the design requirement.This program can help the designer to approach an optimal accessory gearbox transmission design efficiently.
