I think we all had this problem once, or maybe twice.
Once you have put your propellers on the drone goes all over the place, or refuses to take off, it might even flip!
This is caused by 1 thing only! propellers that are not on the right arm.
Propellers are designed to generate thrust, not matter what kind of craft you are thinking of, if it is designed to fly, propellers are designed to gain upward or forward movement.
With drones we want upward thrust, but if the propellers are in the wrong place you won’t get upward thrust.
There are 2 sets of propellers needed on a drone, 1 set is designed to turn ClockWise, and 1 set is designed to turn CounterClockWise
In this picture you see a CCW propeller (white) and a CW propeller (red)
You should always keep in mind that the propellers needs to generate thrust, so if you look at the propeller you can already see which way the propeller needs to turn in order to generate that thrust.
In this picture you see that the white propeller needs to turn counterclockwise, and the red needs to turn clockwise.
The CW propellers go on CW motors, the CCW propellers go on CCW motors.
Some drones have the direction of the motor stamped on the arm.
This is an example of a CCW motor, with a CCW propeller fitted.
Others use A and B markings.
With A nd B markings there is a simple way of reminding how to put the props on.
The following line: BE RIGHT BACK says it all. Propeller B goes RIGHT BACK
Since front and back need 1 A and 1 B propeller it’s already clear after you put the B right Back.
the direction of the motors is NOT the same on every drone!
Here are some pictures to show this, I’ll use the right rear as reference.
On this drone, right rear turns clockwise, a clockwise propeller is fitted.
You can also see that the other CW motor is on the opposite side, this THE SAME on every drone
On this drone right rear turns clockwise, and has a clockwise propeller fitted.
On this drone, exactly the same.
However, on my Hubsan right rear turns counterclockwise! If I would mount the propellers in the same way as the drones above I would not generate any thrust at all.
So, before you start blaming everything for a drone that is acting strange, first check your propellers!
All of the above is not needed when you have a drone that has self locking propellers, these only fit in 1 way and you can’t go wrong on that. Self locking propellers lock themselves by movement of the motors. The CW motor has CCW thread, this makes the propeller lock to the motor.