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Goodbye prop nut!

jyrc

Junior Member
#1
My friend and I went out today to maiden our electrohub-based "scratch-built" quad copter. Fired it up and "whoosh!" Off went a prop nut and the prop with it. The copter itself never left the ground.

We searched for half an hour with no success. Just spent $18 for another motor just for the nut. :( Lesson learned: Always use loktite!
 

pressalltheknobs

Posted a thousand or more times
#3
My friend and I went out today to maiden our electrohub-based "scratch-built" quad copter. Fired it up and "whoosh!" Off went a prop nut and the prop with it. The copter itself never left the ground.

We searched for half an hour with no success. Just spent $18 for another motor just for the nut. :( Lesson learned: Always use loktite!
That sucks.

Just in case you don't have it right...

In theory you should not need loctite if your prop rotation and motor shaft threads are correctly matched. A CCW (left handed/"normal") prop needs a CW (right handed/standard) motor shaft thread. A CW (right handed/R/reverse/pusher) prop needs a CCW (left handed) motor shaft thread. With this arrangement the inertia of the prop and the force of the air against its blades will naturally tighten the nuts as the motors spin.

If that was the problem you should switch your motors around so you have the correct match or it may happen again. Loctite will help for a while but eventually the props will work loose. If your motor shaft threads are all the same handed then locktite it is but you should check the nuts regularly.

$18 is a bit much. Most multi-rotor motors seem to have metric threads and you can usually find the correct size "normally" threaded metric nut at you local hardware store for a few cents a piece. If you are lucky they might have even have the left hand variety but left-handed metric nuts seem to be quite hard to find in the US so best to have some correctly threaded spare motor nuts on hand.