Problem with props slipping when applying full throttle

[Louis van Zyl]

Hi there

I have a HMF550 Hex with sunnysky kv800 motors, 4S 16000 battery and 10x4.5 carbon fiber props. When I apply full throttle I can hear the props slipping and the craft momentarily loses a bit of power until I drop the throttle a little.

I get decent flight times. 4kg 20-25min with filming while flying. (Powering Gimble and camera as well.)

I have tightened the nuts with washers that holds the props in place to almost breaking point.
I have even tried some lock-tite to no avail.
Is there something that I can put in-between the prop and the motor shaft mount to prevent slippage as a result of torque?
Is there any other clever idea somebody had devised?

 

[Gator]

Try some o-rings between the top of the prop and under the nut. A little blue locktite on the threads just to hold the nut on. Just a drop is more than sufficient.

Hope it helps.

Mike.

 

[Chalagi]

That's a very heavy 550 copter

 

[moonpie57108]

Why do you think they are slipping?

I would be pretty surprised if a ten inch prop could produce enough torque to free spin if they bolts are half as tight as your suggesting.

 

[moonpie57108]

But if you want to add something, I might try an external tooth lock washer below the prop, it should do a decent job of locking the motor and prop together when you smash it with a nut over the top. Not sure an oring would produce the grip you need but you could try it first. The lock washer is going to bite into the prop and prop adapter to give you what you want.

I would wonder more so if the prop speed is a problem, that maybe they are stalling? At that weight for prop size, I am guessing your hover throttle is decently highly so you probably aren't moving very fast at full throttle so not a lot of fresh air for the props.

What are you getting for noise when this happens?

 

[Old Man]

Use a prop adaptor that uses through bolts. Any mount that functions via simple compression is prone to slippage. Happens with RC plane props too and why multi bolt hubs were created.