Lubrication..every 6 flights?

Posted by Dan McKenna on February 26, 2015 at 10:17pm

I seem to remember a discussion about the need to oil the motor bearings every 6th flight.

OMG!

I was on the phone with 3DR about another subject and when finished I said  "oh by the way"

blah, blah, need to Lube? and the answer was yes, I will send you the directions. 

I did not receive the information as of 2 weeks later.

How often to do oil the bearings?

with what oil?

and how?

Decades ago I built anemometers for a research project and calibrated them in a wind tunnel. I found that

it was better to run the bearings dry as it did not collect dirt as well. The bearings were very lightly loaded

so it seemed to work. It seems to me that when I fly and apply vigorous attitude adjustments the bearings are sufficiently loaded to require Lubrication.

Can I get a witness?

How about, how often and the technique.

Safe landings

Dan

 

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Replies

  • Erik Graham February 28, 2015 at 9:14am
    Whoa. We are supposed to oil our Iris+ motors?
    This is the first I've heard that. Looks fairly straightforward based on the video, but please update if or when you determine how often (every 6 flights seems a lot) and which oil to use.
    • Jimmy Oliver > Erik Graham February 28, 2015 at 9:34am

      I've never done it. This is the first I've heard of it but it makes sense. I will call and ask the company, stay tuned. 

    • Gary McCray > Jimmy Oliver February 28, 2015 at 10:13am

      Hi Guys,

      One topic that has been completely inadequately covered in this group is motor lubrication.

      We use tiny little bearings and in multicopters, the bearings used are not even actually designed for a thrust load.

      They are Conrad style pressed bearings which work best for a radial load, but are sub-optimal for end loads.

      And since our multicopters literally hang from these bearings, our primary load is a end / thrust load.

      And lubrication is a very individual subject, some of the brushless multicopter motors actually have "permanent" lubrication with side seals on the bearings.

      Basically you can't lubricate those even if you want to.

      Most of them use an ABEC or ABEC style / compatible bearing which are used in a whole variety of applications, the best are German or Japanese, and many Chinese ones are garbage.

      The correct lubricant is extremely important, and varies with load, rpm, bearing size and RPM.

      And there is almost no information available.

      Top quality synthetic lubricants are best, but viscosity and additives are also very important and vary greatly for each bearing, bearing size and bearing application.

      MOS2, Teflon (PTFE) additives and polymer based lubricants are probably best for our use.

      I use a bit of "SuperLube"  myself which is a thin greasy polymer based lubricant with PTFE additive.

      It can be applied with a toothpick and for our use you probably only need to do it once every 30 or 40 uses.

      Unless you are using it in wet or dusty conditions.

      Actually if you are using it in dusty or gritty conditions, you may need to actually clean the bearings with a gentle solvent and relubricate them periodically, our little bearings really don't like fine grit.

      Sadly, even this advice is woefully inadequate, way too little actual information is actually available in relation to the importance of this subject to us.

      Best Regards,

      Gary

    • Ben Norris > Gary McCray March 4, 2015 at 7:53am

      @Gary McCray "And since our multicopters literally hang from these bearings, our primary load is a end / thrust load." No they do not, the weight is taken by the magnets as you can see if you run a motor without the c clip.

    • Andy Windle > Ben Norris March 4, 2015 at 8:16am

      Good point Ben, with a half decent prop balance the bearings are just rolling along without much stress at all which answers why my rattly old cheap crappy motors are still running fine, theyve had play in the bearings for a year, if they had a fair operating load theyd have eaten themselves by now. Oh and I run them at around 16500 rpm.

    • steve > Gary McCray February 28, 2015 at 12:51pm

      I use this. You think it's ok?

      http://www.amazon.com/Inox-Lubricant-Injector-Bottle-60/dp/B00CC4AI...

    • Gary McCray > steve March 1, 2015 at 11:59am

      Hi Steve,

      That's some interesting stuff, but it isn't really made for ball bearings and might not have the film strength you need.

      This is Super Lube and it is definitely made for small high speed bearing use:

      http://www.amazon.com/Super-Lube-51004-Synthetic-Viscosity/dp/B000U...

      It is also available in a tiny injector bottle but is way more expensive and I prefer to buy it as a light grease:

      http://www.amazon.com/Super-Lube-Synthetic-Syncolon-Lubricant/dp/B0...

      And put it on with a toothpick (I also use it in the linear ball bearings and ball screws of my CNC machine).

      I also think that the heavier body of the grease helps it stay intact on the bearings longer.

      Top quality skateboard or inline skate lubricants should work well also.

      But you definitely want a top quality synthetic and with additives like PTFE and that lube you are using is organic and none of those.

      Best,

      Gary

    • steve > Gary McCray March 2, 2015 at 2:12pm

      Thanks for the recommendation. I just ordered some! First I will use alcohol to clean them up.

  • Jimmy Oliver February 27, 2015 at 9:25am

    I found this:

    http://www.rctigermotor.com/html/2013/spotlight_0904/6.html

    • Richard Jacobs > Jimmy Oliver February 28, 2015 at 5:33am

      That's good info, but it doesn't state what type of oil.
      WD40 can harm bearings; it's so thin it can wash-out existing oil. Higher viscosity oils can gum up, especially in the cold and collect debris.

This reply was deleted.