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Old Sep 23, 2013, 12:06 AM
Seattle, WA - USA
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Disco Brushless Gimbal Project

Once again I have modified my brushless gimbal (v4) to reduce weight and make it a little more compact. You can see my build notes below.

Brushless Gimbal Project

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Old Oct 17, 2013, 04:19 PM
Still learnin'
United States, GA, Alpharetta
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I have had the hardest time removing vibrations from my disco / brushless gimbal. Are those grommets standard "lowes" bin grommets? I did a very similar setup yesterday, but it's been raining all day today so I can't test. How are your jello levels?
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Old Oct 17, 2013, 06:24 PM
Seattle, WA - USA
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Originally Posted by 1eleven View Post
I have had the hardest time removing vibrations from my disco / brushless gimbal. Are those grommets standard "lowes" bin grommets? I did a very similar setup yesterday, but it's been raining all day today so I can't test. How are your jello levels?
Hey 1eleven,
Basically yes, they are hardware store grommets that are 3/16 x 5/16 x 1/16 size. If you click on the link above the picture then scroll to the bottom of my build pages there is a video which shows how much jello I get. This is on 720p at 60fps. On 30fps there is only a tiny bit and not much of the time.

Be sure to balance your props AND motors

Hope that helps!
Mark
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Old Oct 18, 2013, 09:28 AM
Still learnin'
United States, GA, Alpharetta
Joined Feb 2013
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I think I've wasted a weeks of my life in all the time I spend balancing. Last balancing session, I had each motor individually mounted to a fixture with a manual control to sweep the RPM range while metering vibrations in the seismometer app. I got the darn things as smooth as possible. At first, I thought you may be running a higher kv with a smaller prop, but you and I are almost alike. I am running 800kv SunnySky with 10x4.7 APC.

If it is a very calm day, it seems the jello is minimal and only in times when the copter seems to resonate. Add some wind or motion and the thing is more prone to jello. It almost seems that with 10" props, there is prop interference/wash between the props being so close together. I've been beating my head against the wall trying to get this disco to work, but today I started building a QAV type frame and I am looking at a fixture out front to hang the gimbal with isolation mounts. Moon gel arrives today, too. :-)

Kudos to you for getting such good video out of your rig. It looks great!

Oh - almost forgot...Looking at your build log, you and I both started with the RCTimer 2212 motors then moved to the iPower 2208's. Isn't the difference amazing!? I can't even bring myself to sell the 2212s to anyone knowing how bad they are.
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Old Oct 18, 2013, 12:27 PM
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I understand the journey on doing balancing. It took a while but I came up with a method that seems to work such that I can do four motors in about an hour and a half.

Here is how I do it - http://www.itsqv.com/QVW/index.php?t...otor_Balancing

Sunnysky motors are much nicer than what I started with so I would expect yours to be very smooth by now .

On the props, quality (and cost) make a huge difference here! For example, the worst props I have found in terms of vibration are anything GemFan, especially their woodies. Second to this are the RCTimer Carbon Fiber Graupner Clones. All these props are poorly made in that they have tip tracking issues and blade to blade inconsistencies that cannot be fixed with balancing. I really liked the way the GF Woodies looked and they made great thrust but the tip tracking was so poor I had to buy 8 props to get two that would test well. I could never get smooth video with them. The RCT CF props are just garbage. They cloned the Graupners to sell lots of props and it worked but they are very inefficient and poorly made. No video love here either!

The props that consistently work really well? Real Graupners, DJI (try the 10x3.8's), the new APCmr props, and the matched Xoar PJN's. Of this bunch, the Xoars are the quietest, the Graupners are the smoothest. BTW, I've always run 10" on my Disco since putting on the Brushless Gimbal without issue.

The other thing to watch out for (still on balancing) is a bent shaft or adapter. Balancing can't fix that!

Here is some info I threw together on prop comparisons recently:

http://www.itsqv.com/QVW/index.php?t...nch_Comparison

On the QAV frame I've almost pulled the trigger a few times as I really like this design and a buddies is awesome. He still had to do some balancing but I think his vids are sharper especially on 30fps. I will say, I like the way the disco flys over his QAV though, it just seems more "precise" in the tight stuff. I hope this works well for you.

On moongel, IMHO, don't hold your breath. If you want a good gel mount, the best out there is the Align PU Adhesive Gel. It is designed for mounting Heli Gyro's and therefore dampen a frequency range that covers what you are dealing with. The only issue is it is a bit too thick for a camera mount. If it was half as thick, say ~1/16", it would work better. this has to do with the cameras mass. Moongel is designed to dampen much lower frequency vibration and it is a pain to deal with but since it's on the way, give it a try! Here is a link to the Align Gel:

http://www.rcdude.com/servlet/the-23...ive-Gel/Detail

I used this on an HT-FPV frame that I could not get the Jello out of and it worked very well (until I got the Disco...) One piece will do 4 or 5 GoPro mounts, it is very sticky, leaves absolutely no residue and can be washed and "renewed with soap and water!

I originally changed to the iPower motors because I was on a serious mission to save weight and this worked well. Once I got them tuned however I did notice they are much smoother and quieter, waayyy nicer than the black pos's I took off

Good luck on your new build and thanks for the kind words
Mark
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