I have a phantom 4. How much play is acceptable in the propellers and when should the mechanism on top of the motor that locks them in be replaced

Well it is a good idea to regularly visually inspect both the mountings and the propeller hubs for damage or obvious wear. The spring forcing the propeller upwards should also not be damaged and free to function. Check to ensure that the screws holding the adapter onto the motor are not loose, do not mess with them they are fitted with locktight that doesn't like being loosened and retightened a lot. Otherwise the system is good. Rotational play should be minimal, if it is more then the reason is sure to be visible. I have lost propellers before but not with a DJI machine.

There is no need to change the propellers if obvious visual damage has not been found. I would recommend you to do a fully pre-flight checklist before take-off.

It should be close to zero unless you apply enough force to compress the springs.

If the springs are not keeping the props firmly locked in place then you can replace the plastic hub mounts + springs.  Better to do it sooner rather than after a prop flies off mid-air!

It is not common to have problems with P4 propellers though, they can last for years.

If the propellers have impacted something hard like a rock then consider replacing the mounts as well as the props, hitting soft grass doesn't require replacement unless there is visible damage.

Dockater Posted at 2017-11-5 11:20
Well it is a good idea to regularly visually inspect both the mountings and the propeller hubs for damage or obvious wear. The spring forcing the propeller upwards should also not be damaged and free to function. Check to ensure that the screws holding the adapter onto the motor are not loose, do not mess with them they are fitted with locktight that doesn't like being loosened and retightened a lot. Otherwise the system is good. Rotational play should be minimal, if it is more then the reason is sure to be visible. I have lost propellers before but not with a DJI machine.

Great advise.

m1shootr Posted at 2017-11-6 07:12
Great advise.

You are welcome, it is good to hear about someone who takes care themselves.

Dockater Posted at 2017-11-6 07:53
You are welcome, it is good to hear about someone who takes care themselves.

Thanks for the advice. I'm just going to go and change them again. I fly almost every day. The last time I change them the machine flow A lot quieter for quite some time.