462
P. Liu
Fig. 7.20 Dutch windmill (1200)—torque principle
Fig. 7.21 Bamboo dragonfly and its flight principle
an upward lift. When the lift is greater than the weight of the bamboo dragonfly, the bamboo dragonfly can fly upwards. On the basis of this principle,
humans invented the propeller later (as shown in Fig. 7.22). The bamboo
dragonfly is also the predecessor of the helicopter rotor.
P. Liu
Fig. 7.20 Dutch windmill (1200)—torque principle
Fig. 7.21 Bamboo dragonfly and its flight principle
an upward lift. When the lift is greater than the weight of the bamboo dragonfly, the bamboo dragonfly can fly upwards. On the basis of this principle,
humans invented the propeller later (as shown in Fig. 7.22). The bamboo
dragonfly is also the predecessor of the helicopter rotor.