Prop balancing on the folding propellers

[GriffDawg]

Will this still be possible? I can't think of how you could effectively balance them if they aren't perfectly inline with eachother.

 

[Advexure]

Valid discussion. DJI has been using folding props on all of the larger units for years and we've always found them to be near perfectly balanced from the factory and have never found them needing further balancing. Just found this discussion over on RCG that will provide some additional insight as well: do i have to balance a folding prop? and how? - RC Groups

 

[DefaultIT]

I've been thinking about this too...even found that same thread (which btw is about a slightly different kind of of folding prop...blades pivot on a different axis). The process would ordinarily be closer to that of RC heli blades, but is complicated by the fact that these are both riveted into the hub and aren't constant chord (can't be aligned on a straight edge).

I think it may ultimately be a project for some enterprising 3D printers if it turns out to be needed, and that we live with however good they are from the factory in the meantime.

 

[Advexure]

I really don't see that balancing will be a problem. We've had hundreds of flights between the S900, S1000 and M600 which all have folding props from DJI. Have always put them on a balancer when setting them up and have not found balance problems. Hopefully we'll find the same situation with the Mavic

 

[DefaultIT]

[...]Have always put them on a balancer when setting them up and have not found balance problems. Hopefully we'll find the same situation with the Mavic

Good to hear... Are you just straightening them by hand when you do that?

 

[Advexure]

Good to hear... Are you just straightening them by hand when you do that?

Correct. Judging "straightness" by the eye. You can see pretty easily how well the plastic shaft of the prop is lined up into the hub to ensure they are straight.

 

[Advexure]

Since folding props are new to most on this forum I will also mention that they straighten by centrifugal force as the props accelerate.

 

[Slat]

Since folding props are new to most on this forum I will also mention that they straighten by centripetal force as the props accelerate.

I'm sorry to contradict you, but this is the opposite one. Centrifugal is the inertial force directed away the center of the rotation movement.

https://www.google.com.uy/amp/amp.livescience.com/52488-centrifugal-centripetal-forces.html


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[Advexure]

I'm sorry to contradict you, but this is the opposite one. Centrifugal is the inertial force directed away the center of the rotation movement.

https://www.google.com.uy/amp/amp.livescience.com/52488-centrifugal-centripetal-forces.html


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It's been awhile since 12th grade Physics and I was going to look up to the two to refresh myself on which one is which but went with my gut feeling. Thanks for the correction.

 

[Slat]

Going back to the propellers, I think the only and best way is to perform a dynamic balancing.

Something similar they do with helicopters blades. And is not an easy task.

Another way is found a way to keep them straight and aligned, and use a fixed propeller balancer. Widely used on RC aircraft. Won't be perfect but may be useful to return to flight condition a slight damaged prop.

Only one final consideration: I would buy a new one no risking a really expensive craft. After all the propellers are not a expensive part.

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[Pedro]

I've tried albeit much larger folding props without a lot of success: Product Review ** DJI 1552 Folding Propeller"]Product Review ** DJI 1552 Folding Propeller

Size is obviously a major factor here so I don't imagine the small Mavic props will be an issue..

 

[kydroneman]

Will this still be possible? I can't think of how you could effectively balance them if they aren't perfectly inline with eachother.

They aren't worth the time to balance as they are pretty close to begin with. To effectively check them you would have to spin them like in a drill so they would spread like they do in flight and carefully check them on a good prop balancer like a du-bro. IMHO more trouble than they are worth considering the small mass.

 

[Dragonfly]

The thing to bear in mind is A) the small size and B) due to the blades been mounted on pivots and center by centrifugal force they kinda ballance themself.
The only thing that would make any significant difference is if one was shorter than the other causing a difference in weight from one side to the other.
In this case a new prop.

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[Motley]

Peter Homer on YouTube showed a video of how he did it by straightening using a drill first. This has been covered in a few other threads as well.

 

[Fanman]

 

[BerndM]

I found the simplest way to straighten the props is to remove them from the motor, and grasp each tip between your thumbs and index fingers and pull the blades apart. This will stretch the blades to their max length and should be the straightest they can be.

 

[TallPaul74]

I really don't see that balancing will be a problem. We've had hundreds of flights between the S900, S1000 and M600 which all have folding props from DJI. Have always put them on a balancer when setting them up and have not found balance problems. Hopefully we'll find the same situation with the Mavic

Do you have to balance split/2 piece Blade?

 

[Thomas B]

I’ve never

Do you have to balance split/2 piece Blade?

had a problem... use the time to fly instead. Most likely trying to balance will end up ruining a prop.