Table 1

Parameters of aircraft

Fig.1

Aircraft hover mode configuration

Fig.2

Aircraft cruising mode configuration

Fig.3

Aircraft center of gravity in different modes

Fig.4

Design of variant mechanism

Fig.5

Variant mechanism of quadrotor hover mode

Fig.6

Variant mechanism of fixed-wing cruise mode

Table 2

Calibration accuracy of rod balance

Fig.7

Wind tunnel test model

Table 3

Wind tunnel test program

Fig.8

Longitudinal force test results of clean construction in cruise mode

Fig.9

Comparison of cruise mode lift-to-drag ratio between wing-foldable tail-sitter and traditional tail-sitter

Fig.10

Curves of trim state aerodynamic characteristics with angle of attack in cruise mode

Fig.11

Steady-state performance envelope of aircraft in cruise mode

Fig.12

Curves of aerodynamic characteristics with angle of attack of aircraft in hover mode

Fig.13

Curves of aerodynamic characteristics with wing folding angle

Fig.14

Curves of lift coefficient with angle of attack for different wing folding angles

Fig.15

Autopilot hardware layout diagram

Fig.16

Rotor arrangement and coordinate system definition of aircraft in hover mode

Fig.17

Curve of rotor control output in hover mode flight test

Fig.18

Definition of elevon direction when aircraft in hover mode

Fig.19

Curve of yaw moment coefficient with rotor yaw control input

Fig.20

Curves of yaw moment coefficient using elevon-rotor coordinated yaw enhancement control

Fig.21

Curves of lift coefficient and maximum longitudinal thrust with angle of attack

Fig.22

Curve of total lift with pitch attitude angle in hover mode

Fig.23

Flowchart of variant transition process control strategy

Fig.24

Schematic of variant transition process

Fig.25

Flight test model

Fig.26

Flight attitude of aircraft in hover mode

Fig.27

Flight attitude angle of aircraft in hover mode

Fig.28

Variant transition from multi-rotor to fixed-wing

Fig.29

Data curves for variant transition to fixed-wing

Fig.30

Comparison of vertical velocity during transition to fixed-wing

Fig.31

Flight attitude of aircraft in cruise mode

Fig.32

Flight attitude angle of aircraft in cruise mode

Fig.33

Variant transition from fixed-wing to multi-rotor

Fig.34

Data curves for variant transition to multi-rotor

Fig.35

Curves of rotor control outputs before and after variant transition

Fig.36

Curves of MIST-UAV variant command and rotor control outputs［19］