Help needed with upside down propellers for Y6 multirotor

[jezmy]

Hi everyone!

I have just built my first multirotor using an electrohub frame - it's set up as a "Y6". I am using an Eagletree Vector flight controller and the configuration software indicates that the top three motors should spin counter-clockwise and the bottom three motors should spin clockwise (as viewed from above). However, this raises some questions that are confusing me.

The motors on the top do not pose too much of a problem - they will all be counter-clockwise rotating, with "normal" (Left handed) propellers so air is pushed downward towards the motors, giving upward thrust. All well and good. The lower motors however, are mounted pointing downwards. This means that in order for them to spin in a clockwise direction when viewed from above, they need to be spinning counter-clockwise from the motors point of view, i.e. CCW motors - the same as the upper ones... The problem I have is that to have these motors provide thrust in the right direction (pushing air away from the motor body) I would need to use "right handed" propellers. The snag is that if I do that, the lower propellers will be spinning the "wrong" way - leading with the trailing edge; as propellers are actually shaped with an airfoil cross-section, this would not be efficient. Like trying to put a wing on a plane backwards and expecting it to fly well...

One solution is to mount the lower propellers on the motor shaft "upside down", but the motors I have (EMax 2213/935KV) have an 8mm "shoulder" on the (6mm) shaft which stops you doing that without drilling out the propeller to 8mm and using a spacing ring (sorry, they probably have a proper name but I don't know what) in the propeller to reduce the internal diameter to match the 6mm of the motor shaft. This method does work, but drilling accurately enough through a propeller is really difficult and is likely to lead to imbalances and hence bad vibration problems if the hole is even slightly out.

I'm sure I am not the first person to have come across this problem and would be interested to hear from anyone here who has solved it and what they did. Symmetrical cross-sectioned propellers would seem to be one way of tackling it, or maybe a different method for attaching the propellers to the motors (which would probably mean getting different motors).

I look forward to any thoughts and suggestions anyone here might have... Including any advice on where to buy any necessary kit!

Thanks for reading this

 

[Tritium]

You are overthinking things. All props are mounted with the letters facing up so your lower props will be fine with CW rotation as viewed from above.

Thurmond

 

[C0d3M0nk3y]

The motors on the top do not pose too much of a problem - they will all be counter-clockwise rotating, with "normal" (Left handed) propellers so air is pushed downward towards the motors, giving upward thrust. All well and good. The lower motors however, are mounted pointing downwards. This means that in order for them to spin in a clockwise direction when viewed from above, they need to be spinning counter-clockwise from the motors point of view, i.e. CCW motors - the same as the upper ones... The problem I have is that to have these motors provide thrust in the right direction (pushing air away from the motor body) I would need to use "right handed" propellers.

This is how you want it. You'll need to get standard props for the top motors and reverse props for the bottom motors. All of the props should be mounted with the writing pointing up.

 

[MrBlee]

Links to such DJI-style-pusher-props, pretty please?

Pixhawk Y6B (i.e. "new" Y6) config has all motors spinning CW (when viewed head-on, so bottom motors spin CCW when viewed from above.) Fine. But the DJI-style motor mounts of the Emax 2213 means you can't just flip the bottom props - you need the 8mm-to-7mm-flat-to-6mm shaft part of the prop to be up against the motor.