Not sure if this has been discussed, but I've conducted 6 test flights of my Y6B and after running for 10 minutes in Loiter each flight I've felt the motors and observed the upper motors are relatively cool and the lower ones hot enough to fry eggs on it. Why are the lower motors running hard than the upper one? Is there something I can do to ensure I don't burn up the lower motors? Uppers are running 10 x 4.7, lowers are running 11 x 4.7 propellers.
Appreciate some insights and recommendations on this topic.
Doug W.
Replies
so from the above image and this one
@Teddy and Emin, thanks guys - these are good info's. I'll try bigger props on my bottom motors tomorrow.
The fact remains that if you fit bigger props on the bottom of identical top and bottom motors, the bottom motors will be working harder swinging bigger props/pitch using more energy to generate the same speed as the top prop. So to start - use the motor prop spec on the bottom motor and move 10% smaller (pitch or length) on the top motor. Am I right with this?
I hope our wiki ninja is onto this.
Thanks again for sharing.
its normal bottom motors to be wormer..i would just have higher pitch on bottom,not bigger prop
if you want to go in detail about coaxial setup, there is many links around net
first this not very long thread
http://www.rcgroups.com/forums/showthread.php?t=1600584&page=3
here is some more
http://www.djaerotech.com/dj_askjd/dj_questions/contra-prop.html
http://aerospace.illinois.edu/m-selig/pubs/BrandtSelig-2011-AIAA-20...
http://terpconnect.umd.edu/~leishman/Aero/AHS2002_Griffiths.pdf
http://www.rcgroups.com/forums/showthread.php?t=1600584&page=3
Keppeler elaborated on this below. While in some instances it doesn't matter, It is making a marginal difference on Doug's setup. And please mind the caps.
after reading post upon post about Y6es I did the same as you did. Bigger props on the lower motors. Then I made some measurements on the amp draw of the motors. Guess what, the lower motors where working much harder then the upper ones. I am now running the same size on all props and the currents are close.
Regards,
Mike
That's the one thing I haven't checked is Amp pull comparision. I suspect the 11 inch may be the culprit.
For those curious, I ran with the 3D Robtic configuration recommendation from last winter but I have noted that they only sell their RTF's with 10 inch only.
Has anyone seen a handling/performance difference with all 10 inch props?
Hi Doug, I think you have answered your own question. Run all 6 with the same props and compare again. The lower ones labours as hard as the top motors, but have a heavier load to carry. Are they identical motors and esc's. Are the bottom esc's running warmer as well?
It could also be in the anatomy of the motor. On top the prop pulls on the bearing. At the bottom the prop pushes on the bearing - reaching, but might be worth while looking at. I run a Y6B with 10x4.7 on all motors with identical esc's(Afro's). They run the same temp except the one with vibration - slightly warmer, but I'll sort that over the weekend.
Cheers,
Antonie
Hi Antonie,
All the motors are 850 Kv motors. I also have same 20A ESC that 3D Robotics sells.
Several months ago, when I first purchased my Y6 I had one motor get really hot like yours (even the boom was too hot to touch). After talking to 3DR and switching ESCs around we determined it was a bad motor...they sent me a new one and its been fine ever since.
I would suggest:
1. Running through all the calibration test.
2. Switching esc's (to eliminate an esc problem) or motors if you have spares
If your motors are still getting hot contact your manufacture and try switching the motors out.
DIYDrones Y6 group:
http://diydrones.com/group/arducopter-y6-owners-group
Good luck
Chad
Doug, why are you running larger props on the bottom? If anything they should be on top. You should try using the same size for both. To be honest, I don't like the 6b setup. I have flown that configuration and found I had more wandering on yaw as opposed to the 6a configuration.
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