Prop balancing

[Offroader]

Anybody in Las Vegas area have equipment to balance P3A props?
I have some jello effect and it seems cyclical, as if a couple of props create harmonic vibration then goes away for a second then comes back and repeats until I change directions or velocity or even tilt the camera.

 

[Fly Dawg]

Prop balancers are cheap and easy to use. I use this one. No need for anything fancy.

https://www.amazon.com/Dubro-Produc...530389945&sr=1-2&keywords=dubro+prop+balancer

 

[solentlife]

Or the ODay version ...

Well worth having it ...

Nigel

 

[FLDan]

I have found DJI props to be well balanced, on the other hand I have purchased carbon fibers from Amazon that were crazy out of balance.

 

[solentlife]

I am always amazed with this subject .... sorry if I appear to be rude ... that is definitely NOT my intention.

Props may appear to be near balanced ... fine but making sure is kinder to all the other components in your airframe.
A prop this near balanced will be fine at xxxx rpm - but can create vibrations at another rpm that electronics and even structure are subjected to.

Balance the props and be kind to your gear ... it only takes a few minutes, gear costs about same as a set of props ... there really is no excuse.

I don't care what props you have ... please do them a treat ... get a balancer ... the O'Day is cheap enough and as good as the Dubro ... etc.

Nigel

 

[3putts]

Prop balancers are cheap and easy to use. I use this one. No need for anything fancy.

https://www.amazon.com/Dubro-Produc...530389945&sr=1-2&keywords=dubro+prop+balancer

Same one I have, invaluable!

 

[rkingsb353]

Prop balancers are cheap and easy to use. I use this one. No need for anything fancy.

https://www.amazon.com/Dubro-Produc...530389945&sr=1-2&keywords=dubro+prop+balancer

In the pass I had order the Dubro Prop Balancers for my P3A but found when I went to balance there was no way the prop could be attached to balance. I checked further and find that I needed to order another bar. Is this what you also had to do?

 

[Fly Dawg]

Is this what you also had to do?

Not that I recall. Iv'e had it a long time. It came with the correct size rod as best I remember.

 

[Steve7777]

In the pass I had order the Dubro Prop Balancers for my P3A but found when I went to balance there was no way the prop could be attached to balance. I checked further and find that I needed to order another bar. Is this what you also had to do?

Maybe some get lucky (as above) and have it included - but others may have to buy the rod separately. The two I just found on Ebay don't come with an additional rod for self-tightening blades.

I made my own balancer - something along the lines of this one

.
The main thing is to make sure that you get a nice fine precision point to reduce friction as much as possible. Mine seems to work well and is consistent.

 

[FLDan]

I purchased my balancer on Amazon, it offer as an option a rod that fits my P4 props. The props just slip in snuggly.

 

[solentlife]

In the pass I had order the Dubro Prop Balancers for my P3A but found when I went to balance there was no way the prop could be attached to balance. I checked further and find that I needed to order another bar. Is this what you also had to do?

Its a strange item ... the ODay has a rod with slide on bush that is a snug fit to the P3 prop ... and I believe the Dubro should have same. I read that some people buy a special rod for P3 props ... but why if the bush and rod supplied works ?

The Dubro and ODay balancer requires the long rod for ALL balancing jobs whether closed hub as P3 or not. If its not in the box .. how does anyone use the unit ?? Doesn't make sense.

Nigel

 

[solentlife]

Maybe some get lucky (as above) and have it included - but others may have to buy the rod separately. The two I just found on Ebay don't come with an additional rod for self-tightening blades.

I made my own balancer - something along the lines of this one

.
The main thing is to make sure that you get a nice fine precision point to reduce friction as much as possible. Mine seems to work well and is consistent.

This I have been posting about for long time but some people just do not believe a simple nail or cross point screwdriver can do the job. As you say - as long as you have a well defined pivot point - it works. The closed hub is a dome affair and the point centres into it ... the prop then sits and finds its balance ... simple and works.

Nigel

 

[Steve7777]

Its a strange item ... the ODay has a rod with slide on bush that is a snug fit to the P3 prop ... and I believe the Dubro should have same. I read that some people buy a special rod for P3 props ... but why if the bush and rod supplied works ?

The Dubro and ODay balancer requires the long rod for ALL balancing jobs whether closed hub as P3 or not. If its not in the box .. how does anyone use the unit ?? Doesn't make sense.

Nigel

I think that people are referring to the 'special' (separately purchasable) rod with the left-hand thread on one end and the right-hand thread on the other. Prop Balance Rod - Speedy Prop Balance Rod (for DJI Phantom 1,2 or 3, DJI 945... | eBay Some people say the special threaded rod works better but others have said that the threading on the rod was done poorly, so it's not so good. I don't have either model but I would think that if the push-in-option rod bush (supplied) is inserted snugly and accurately, then it should (as you say it is) be quite OK.

Since the latest question was asked on this thread was asked I have been watching a few YouTube vids on the subject. Some users have criticised the quality of machining of the aluminium discs of the cheaper ODay balancer but say that they been able to improve the finish by careful sanding, which seems a bit 'iffy' to me.

One thing to bear in mind with almost all types of balancer is that you may well have to balance the rod and retaining cones before you can even think about balancing props. It's explained here (at 4m:11s):-

If I was going to purchase a prop balancer, which I might do at some time as I have several other drones with non-self-tightening props, I'd probably go for a 'magnetic model', but would ensure that I balanced the rod and retaining cones on receipt.

 

[solentlife]

I have various balancers ... as i fly Helis / fixed wing and quads / multis.

The magnetic are in fact no different in result to the shaft placed on steel / glass edge - just less supposed friction.

My shaft / cones simple device - I have two L steel plates screwed to a wood block. The L plates spaced for the shaft to sit astride. It works as good as the magnetic one I have. But of course neither are any good for a DJI prop.

The problem we have here is that the DJI prop has a closed dome topped hub. So no shaft for balancer can pass all way through. It can only be inserted into and up against the top of the internal dome.

I have compared needle point vertical balancing to my over counter ODay push in rod bush and its fine. There is no discernible difference ...

nigel

 

[solentlife]

"Some users have criticised the quality of machining of the aluminium discs of the cheaper ODay balancer but say that they been able to improve the finish by careful sanding, which seems a bit 'iffy' to me."

Yes .. very 'iffy' ... the discs are only there to provide a low friction suspension point ... years ago - SLEC in UK produced a prop balancer using same discs principle - the discs were plastic. It worked fine.
The main point to be sure of with any disc system - is to make sure they can rotate freely. If anyone was to sand the faces of the discs - that would IMHO be bad idea as you are now introducing a scarred surface where it needs to be face smooth ...

I would suggest reason for any poor movement of discs is not due to need for sanding - but maybe disc axles or casing.

Nigel

 

[rkingsb353]

The Dubro comes with a rod that doesn’t have any threads to attach the P3A propellers. I did not want to pay additional $17 so I sent it back to Amazon.

 

[Steve7777]

The Dubro comes with a rod that doesn’t have any threads to attach the P3A propellers. I did not want to pay additional $17 so I sent it back to Amazon.

Too late now but as solentlife has already stated in post #11, both the ODay and Dubro models come with a rod and fixing bush which would have done the job.

 

[solentlife]

I have to say that when I got my ODay ... it confused me for about 2 minutes ... How was I going to balance P3 props ... the whole point I bought it for.

Then it dawned on me ... the bush ...... Bingo. Perfect.

Nigel

 

[REL]

If you already have the Dubro balancer (or a similar one) you can just buy the threaded 6mm rod.
The one listed in the earlier post includes the 6mm threaded rod. This is the rod only:

https://www.amazon.com/gp/product/B...ZXSF765RTEPT37XF&pd_rd_w=jBQJU&pd_rd_wg=hJzfp

 

[Offroader]

Just out of curiosity, I weighed a set of props and found the CCW props were about 12.610g and and varied by about .030g and the CW props were about 12.660g and varied by about .005g. I have a few other sets I can weigh, but I know there are a couple that have sustained damage. The ones I weighed are brand new.

Anybody else make this observation?