I can't avoid this potentialy embarassing (for me) question

[Cheshirecat]

OK thsi is probably Coax 101 type stuff but despite searching around and even watching other peoples videos in slow mo i can't quite get the definitive answer i am confident with.

On an X4 what is the correct rotaionional layout betwix top and bottom props :confusion:

I have figured that the high pressure side of each prop is always down and that the botton motor would rotate in the same direction, mechanically albeit upsidedown so counter rotating looking down on the rig, but the prop would have it's leading edge on the otherside (counter) so effectively it's lift is the same.
So in essence the top prop is the reverse of the bottom prop and the motors rotate (mechanically in relation to themselves) in the same direction.
Then would every other boom be the reverse of the previous boom setup. So Boom 1 say Top Motor CW Prop Bottom Motor CCW Prop - Then Boom 2 Top Motor CCW Prop Bottom Motor CW Prop????


Crickey :upset: i wonder how right or wrong any of this is, maybe i should use rockets instead.

 

[Bartman]

CC,

There has been a lot of discussion on this and it will always be possible that a particular flight control firmware has been specifically tuned for a set combination of motor positions and rotations. In general though, IMHO, it doesn't matter. There are theories about torques and other stuff but at the end of the day after trying lots of different stuff I just haven't seen any differences in performance or handling. So, having said that, I've settld on having all of my top motors turn clockwise (looking down at them) and all of the bottom motors turn counter-clockwise. The reason is that the clockwise (aka pusher) props are harder to come by and come in fewer diameter/pitch combinations. As top props they're less likely to get damaged so I don't have to worry about replacing them as much. THe bottoms are the standard rotation props so I can always get them if I'm running low.

I generally run a degree or two of pitch higher on the bottom although I've also run 1" diameter greater on the bottom. Both seem to help although I do the pitch trick more than the diameter trick as the larger diameter props will be heavier than the smaller ones making the torques harder to compensate for making it harder for the FC to maintain heading. THe FC's can do it but it just makes more work.

Hope that helps,
Bart

 

[Cheshirecat]

Thanks for the reply, this has helped a lot.
I haven't got the WK-M yet that i plan to use but have just downloaded the manual, now that you have put me onto the FC being felixible in this regard.
Maikes more sense now.....

Thanks Again.

 

[Bartman]

keep in mind, the rotation of the props does have to match the scheme in the flight controller. you can't just put the props on without making sure the flight controller understands what you're doing. Hoverfly has a set scheme that matches what I do, Mikrokopter can be manipulated in the Mixer Set-up, DJI may or may not be flexible so you'll have to see what they offer in pre-configured options or figure out how to do a custom mixer table for it.


i hope that didn't confuse you. a DJI owner may chime in to clarify what is possible with the WKM.

bart

 

[Cheshirecat]

Nope all very helpful thank you very much.
I am having a good thumb through the WK-M manual now and it is all making some sense, once i have my hands on the kit i will sense check it again. Not planning on rushing anything.

 

[DucktileMedia]

Also, as i am hearing it more and more, this is called an X8 not an X4.

 

[Lanzar]

+1 Bart
+1 IrisAerial

DJI stock x8 mixer uses same propelers . But you can have different ones(the same as mikrokopter) since DJI also has a custom mixer. I do not suggest it until you are an expert.

 

[SMP]

WKM recommends same pitch top and bottom and Kopterworx concurs - Barts been flying coaxials from the beginning. Your call

We run WKM w same pitch top and bottom and getting a bit of sinking.