When ready to fly
When ready to fly, put on propellers by first putting on spacer that matches shaft. Make sure that you can read the numbers on the top of the propellers. Install the washer and then the nut. Tighten with pliers. (Figures 21A-D)
Spacer to match shaft
Numbers (circled in red) should be visible.
Note - Make sure the propellers are mounted to the correct motors and turning in the correct direction.
Nut should be tightened with pliers or nut driver (8mm).