EDF Dynamic rotor balancing - Page 2 - RC Groups
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Aug 14, 2009, 09:22 AM
Ginger or MaryAnn ??
fh64_lucky's Avatar
All I can say is "WOW" Don balanced me a couple 64mm rotors,I installed one in my jet.Total difference in sound now,it is so smooth!Thanks Don for your help,that balancer is awsum! Joe
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Aug 14, 2009, 04:56 PM
Are you guys sitting down? Put the Astro flight meter on the 64mm fan unit..
Brand new Turnigy 4s2600 30c Lipo
60 amp Pentium esc
Wicked 4000
Started off at 700 watts and then settled down to about 650 to 670 watts at 43 to 45 amps. Ultra smooth running fan that sounds awesome too.
I think the balancing and using good batteries is taking this EDF thing to a whole new level!!
Don,looks like you really have got the hang of using that magic box!
Aug 14, 2009, 07:25 PM
Indoor Free Flight Modeler
Glad you guys like the smooth fans, they do sound so much better balanced

That is some serious power on them new lipos. Please be very careful on your WOT runs as you are in unchartered territory with that many settled watts. You will need to keep WOT runs short and allow cooling.

Aug 14, 2009, 09:08 PM
Will do Don!!
Aug 15, 2009, 04:18 PM
Registered User
Bob Blackburn's Avatar
At least with a balanced EDF more of the power the wattmeter shows will be moving air instead of vibrating and more air means a cooler motor.

It is win win
Sep 03, 2009, 09:29 PM
HighNear90's Avatar

This may be a stupid question, but can I order a balanced 64mm EDO fan without the motor?

I've already got a wicked 4000kv on 4s in my Freewing F-15 and I didn't balance the rotor. Kinda rough sounding as it is right now.

Let me know and I'll order right away.

Sep 03, 2009, 10:01 PM
Indoor Free Flight Modeler
No problem. I would suggest the original EDO fan over the newer version as I feel it is a little stronger especially for 4S.
Sep 03, 2009, 11:18 PM
HighNear90's Avatar
Originally Posted by The Don
No problem. I would suggest the original EDO fan over the newer version as I feel it is a little stronger especially for 4S.
Wonderful, just tell me what to order. And yes, I am around 500 watts static. Send a PM or whatever you prefer.

Thanks so much and by the way......I LOVE MY WICKED EDF 4000 Kv MOTOR !!!!!
Sep 07, 2009, 12:36 AM
Indoor Free Flight Modeler
I have had several people ask me how to use this device etc and here is how I balance a rotor. It is essentially what is spelled out in the manual but I will write exactly what I do.

1. Mark the blade with a yellow stripe from a paint marker near the center of the hub

2. Run the fan on a 2S lipo to about 1/4 throttle

3. Rotate the sensitivity all the way up (cw) then turn back ccw as low as it will go to get a steady single line. Note that position, say it is the 1 on a clock face, i.e. 1 o'clock position.

4. Add a piece of ballast to the rotor in line with the mark on the spinner

5. Spin it back up again but this time do not mess with the sensitivity knob, just observe where the new line is. Lets say it is at the 12 o'clock position.

6. Shut the motor off, then rotate the yellow mark on the spinner to the
position where the line was observed with no added ballast (step 3). In this case the 1 o'clock position.

7. From step 5 we know the observed ballasted line was in the 12 o'clock position so we want to add weight to the rotor 180 degree away from that which is the 6 o'clock position. So the yellow mark on the rotor is pointed to the 1 o'clock position, but we are going to add weight to the rotor at the 6 o'clock position.

8. Once you add the weight spin up the fan again. If you are close to being balanced you will see no flashing on the rotor from the strobe at all when you start it back up. This means the vibration is small and that the sensitivity knob has to be turned cw to increase the sensitivity level to see the lines again. Yo may have to add or subtract small amounts of weight to get the lines to go all around the spinner evenly. Sometimes it is very hard to do and I can get only 1/2 or 3/4 the way around but on the smaller fans I do, even that feels very smooth when you run up the fan.

One other thing I do is when I am very close I will move the weight clockwise or counter clockwise maybe 1/8" to fine tune it. I have found that sometimes I can be off in the exact location on the ballast location and 1/8" in either direction can suddenly make a big difference.

Last edited by The Don; Apr 24, 2010 at 10:19 PM.
Oct 03, 2009, 07:20 PM
Ok then
Thanks Don. I've been using the balancer for a while now. I'm not convinced that it works or maybe its damaged. Yes, it does show an imbalance or it strobes very well but after many hours of running I cannot get the equidistant lines even on the smaller fans. I've tried so many things until I'm blue in the face. I've even tried a Wemotec dynamically balanced fan (various types) and it shows that it is also out of balance. Would really appreciate your help.
Oct 04, 2009, 01:15 AM
Indoor Free Flight Modeler
Well I will say there is a little bit of black magic sometimes. I just spent the past few days balancing about 12 more setups and the best I can tell you is to keep at it as the unit does work. Take your sensitivity knob and turn it all the way up, then back off about 45 degrees. That is about the sensitivity I used to find the as is rotor position and the position with the ballast added. Once I know where to put the weight, I do not adjust the knob when adding ballast to the required position. I only add weight to the rotor then spin it up again. All of the sudden when you get the right amount, there will be no strobing effect at all in that knob position, that means you are very close and 95% of the time that is the correct amount as well. Then I turn the sensitivity up some more until I see the light again. At this point it may be all around equal spaced lines, or lines around about half the spinner.

If it is partially around then I add or remove very very small amount of weight then run up again to see if it makes it worse or not. It will be pretty obvious. If it seems to get worse when you add or subtract then I take the unit off the balancer and hold it in my hand to feel how smooth it really is when it is running. I am testing 60mm and 64mm fans so the power is not that high. I also test on a 3S lipo at this point instead of 2S. You may find holding it and running it up it is perfect except for one area of throttle range, then what I do is move the weight amount slightly clockwise or counterclockwise to try and fine tune it. I have found that sometimes the phase angle location can be off a bit no matter how hard I try to nail its location, so adjusting the weight either direction sometimes helps as well but that is a final fine tune step. So my actual final test is holding it in my hand to feel the smoothness.

Oct 04, 2009, 03:13 AM
Ok then
Thanks Don. Out of interest, do you find that the heavy spot (with weight added to datum mark) is at 9 or 3 o'clock position consistantly or does it vary from time to time?
Oct 04, 2009, 10:56 AM
Indoor Free Flight Modeler
It is different on every rotor and the position can be anywhere. Sometimes if I am having difficulties, I will relocate the datum mark and start again.
Nov 15, 2009, 12:32 AM
Like my Goat?
F7X's Avatar

I've got a Wicked Extreme. If I shipped it out to you, and purchased a Wicked EDF fan unit from you along with a dynamic balance service, could you put it all together for me and balance it? Thanks!

Nov 15, 2009, 12:41 AM
Indoor Free Flight Modeler
Yes sir!


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