Self-tightening prop balancing solution!!

PhantomFan · Nov 20, 2013

One picture says a thousand words. Already own a magnetic prop balancer and didn't want to buy a second one, so I devised this method for balancing the DJI self-tightening props that ended up working brilliantly. Glass rods (if you don't already own some) or facsimile such as polished metal rods of suitable diameter will work just as well.

God knows I've spent a fortune on quad-related stuff, so getting this task done without spending a dime was a relief! Build up the end of a glass rod with electrical tape so it is a snug fit into the prop. Place the prop "lollipop" perpendicular to two other glass rods as shown. The friction is about ZERO. Use your favorite method to correct any imbalance. Glue, tape, paint, or sand. Personally, I sand the heavy side. You can see the result for yourself.

PF

Dave Pitman · Nov 20, 2013

Nice. I don't think I have any glass rods in the closet though.

Using a Dubro, you can do this:

Watch Video

PhantomFan · Nov 20, 2013

I know, but I don't have one of those. It was THIS video on motor balancing that gave me the idea of the glass rods. The idea of the glass rods came to me while I was driving. Couldn't wait to get home to try it. It worked, so I put the principle out there in case anybody else wanted to copy or Rube Goldberg their own variation.

http://www.youtube.com/watch?v=UYqtwd4x ... e=youtu.be

PF

Dave Pitman · Nov 20, 2013

PhantomFan said:
I know, but I don't have one of those. It was THIS video on motor balancing that gave me the idea of the glass rods. The idea of the glass rods came to me while I was driving. Couldn't wait to get home to try it. It worked, so I put the principle out there in case anybody else wanted to copy or Rube Goldberg their own variation.

http://www.youtube.com/watch?v=UYqtwd4x ... e=youtu.be

PF

So, PF, what are the rods really for?

PhantomFan · Nov 20, 2013

Stirring martini's, of course! Hey, I'm 60 years old...I'm over the legal drinking age!

PF

Dave Pitman · Nov 20, 2013

PhantomFan said:
Stirring martini's, of course! Hey, I'm 60 years old...I'm over the legal drinking age!

PF

Haha...I had envisioned the rods for some sort of Frankenstein electrical setup in the basement.

OI Photography · Nov 20, 2013

I thought they were the frame bars from his InvisiQuad 600X :lol:

ToddSmi · Nov 21, 2013

PhantomFan said:
One picture says a thousand words. Already own a magnetic prop balancer and didn't want to buy a second one, so I devised this method for balancing the DJI self-tightening props that ended up working brilliantly. Glass rods (if you don't already own some) or facsimile such as polished metal rods of suitable diameter will work just as well.

God knows I've spent a fortune on quad-related stuff, so getting this task done without spending a dime was a relief! Build up the end of a glass rod with electrical tape so it is a snug fit into the prop. Place the prop "lollipop" perpendicular to two other glass rods as shown. The friction is about ZERO. Use your favorite method to correct any imbalance. Glue, tape, paint, or sand. Personally, I sand the heavy side. You can see the result for yourself.

PF

Ah, well done! Thanks for sharing! I don't have those rods laying around, but I did get a tip on another forum about how to make the Dubro work properly so I will share below for others that may be interested.

ToddSmi · Nov 21, 2013

Dave Pitman said:
Nice. I don't think I have any glass rods in the closet though.

Using a Dubro, you can do this:

Watch Video

While I'm grateful for the author of the video getting the balancing going with a Dubro, the problem I had was when I was trying that method, I would get significant axial play between the shaft and propeller. So, based on a tip from someone in another forum, here's what I did that seems to produce a more consistent result.

Copied from my other post: I had to flip the main shaft of the Dubro around from its normal orientation to make everything fit, but doesn't seem like this should cause any balancing problems. The prop does feel more stabile now and less likely for axial play. Took a quick cell phone pic to show the setup for others to see. The only part you can't see is that I put the Dubro supplied fuel line onto the end of the shaft that goes directly into the prop. the yellow piece of fuel line you see is the same size as the Dubro provided one (3/32 inside diameter and 3/16 outside diameter). The final test will be on the flying field to see if the balancing makes much of a difference, but too windy today for a fair test.

Edit: For others considering this setup, I can't recommend it at this time. After more testing, I have found that this system is not properly balanced and give a different result depending on how the fuel line in the prop is rotated, so the result seems to have more to do with the weight of the fuel line than the weight of the prop...not good. My search for a good solution goes on...anyone have any other suggestions for prop balancing for the P2V? The above suggestion with glass tubes seems interesting and I may look into purchasing some of those as well to try.