hector_quadrotor does not take off

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Hi, I am using ROS kinetic and since the tutorials on http://wiki.ros.org/hector_quadrotor/... is a littile bit out-dated, I followed the answer in http://answers.ros.org/question/24477... .

It did compile and roslaunch the demo successfully. I've checked the rostopic list and found there is actually a topic called /cmd_vel. I tried to use this command to let the quadrotor take-off

rostopic pub -r 10 /cmd_vel geometry_msgs/Twist  '{linear:  {x: 0, y: 0.0, z: 1.0}, angular: {x: 0.0,y: 0.0,z: 0.0}}'

But the quadrotor still stays on the ground. I used

rostopic echo /cmd_vel

to check if the message is sent to the topic correctly, and it does.

Does someone know what can be possibly wrong?