Prop Balancing for the H

[Joneshd3488]

I'm sure all you longtimers know the value of prop balancing, so I'll direct this primarily to the lesser experienced to our sport/hobby. I myself go back to the very early days of analog RC, even late 60's so prop balancing is not only good, but essential to performance and the life of our very investment we put in the air. The slightest unnecessary vibration (can't get rid of it all) induces frequencies of all the vibration spectrum into our circuitry and airframe. And if you think Yuneec's props are any better than 40 years ago, think again. I just balanced all 10 of my H props and only 2 were actually in balance, only one other was close. All the rest were considerably out.

That said, multirotor props can present a new challenge in that the shaft holes, threads, and mounting hole sizes vary wildly from RC propeller aircraft as well as, not to mention various manufacturers of quad to quad, hex, etc. I just purchased the new DuBro Balancer (an excellent inexpensive balancer) last week expecting it to have a cone sizer on the propeller shaft like the old Hightpoint Precision Balancers after which Dubro modeled theirs, which of course is not included. No way the shaft fits or screws on to the larger diameter hole of the H props.So...

Easy fix for the H: get some 1/4 inch silicone fuel line (available at any RC hobby shop) and cut a half inch or so and thread it on each end of the balancing rod. I had feet of the stuff in my old RC box, but you may have similar lying around. Then, just press an H prop on to the very end making certain the shaft is at least flush with the other end of the prop.

My technique: I first clean and wax all my props then balance each prop using 100 grit paper to remove material from the mid to upper middle underside of the heavy blade. Avoid the tips as much as possible as they already flex considerably under load and I'm not comfortable removing even more material from that last 1/4 inch or so. I also use spray cleaning wax to seal the scratches after balancing, then check one last time. I'm sure any other wax product would work fine, just make sure to remove all excess. Perhaps I'm a bit anal about my balancing regimen, but the less resistance and vibration...the absolute better. Having flown planes, helicopters, ducted fans, and just about everything else with parts that can go round and round, I've grown to loathe vibration.

 

[eric bee]

i am with you that the best Flight you get without vibrations and of course Videos and pics. But i have find good results in balanced the props with tape on the backside.

 

[Paladin]

I am more or less a newb so please accept that before you think I am an idiot. ii

Do you think this is really as important these days? Back on the old RC copters I know it was because everything was analog. No computer control. It was in balance and spun or it wasn't in balance and spun less efficiently or downright dangerously.

The H has a computer in it that senses the motors spin and compensates for movement. I would assume if a prop is not 100% in balance the computer would compensate for that. Also the H motors are electric and spin in both directions, unlike the old copters. Would that require a balancing as much?

With that said I would think the more in balance the better, logically it makes sense, but is it really "needed" as much these days? Again I am fairly new to this so am just asking.

I would love to see a comparison of an H hovering with standard props and then a balanced set. See if it hovers any more stable.

 

[eric bee]

i can say for me its still important. I haves started with a DJI P1 without gimbal and have learned all whats needed to get nice Videos. Later with Gimbal it was also needed to minimize the Jellos.

Yes you are right its a flying computer, but there are no Sensors for vibrations. And there is no possibility to eliminate the vibrations of your unbalanced props by the electronic. The only way to stop the vibrations would be you stop the motor. And maybe you get a good result when you fly slow... but when you need the complete power of your multicopter and it works in full speed (because fast flying or stronger wind) then you get the risk your videos get shaky with Jello, sometimes the flightcontroller dislike vibrations too and you risk errors...and the hardware dislike too...
for me does it mean: for long save flights and good images... try all to reduce the vibrations on you craft

 

[Tolgademir]

I bought this one from amazon and it works great, it came with cones which fit H props
Du-Bro 499 Tru-Spin Prop Balancer https://www.amazon.com/dp/B0006N72Y8/ref=cm_sw_r_other_apa_FXiuxb91YF7KV

 

[Paladin]

Okay I admit, I am interested. I will read a bit more about it and what to do etc...
Honestly it is just for fun and I like anything involving "tweaking" things.

 

[eric bee]

a magnetic one is better, because no mechanical brake

Amazon.com: ZJchao Precision Prop Balancer for Quadcopter and Airplane Props: Toys & Games

 

[Joneshd3488]

Eric is completely right, Paladin... no amount of electronic compensation, prop reversing, etc. will change the fact that anything going round and round, especially at high rpm is transmitting any and all vibration directly into your frame, your electronics board, your camera. Sure it all works in spite of the vibration whether you can see it or not in your video, but it is about the life of your investment.

 

[Typhoon Charlie]

Reason balancing is essential in multimotor is because the flight controller users giros and accelerometers. Vibration can confuse them making for erratic flight, even fly aways. Giros are used for stability and accelerometers are used to detect motion both require low vibrations for proper operation. Most builders will mount flight controllers on a vibration isolation platform, I don't see one inside the H. Therefore motor and prop balance is important for best performance. Always balance the blades and the hub ,many YouTube videos on this.

 

[Typhoon Charlie]

a magnetic one is better, because no mechanical brake

Amazon.com: ZJchao Precision Prop Balancer for Quadcopter and Airplane Props: Toys & Games

I have tested both kind and have found magnetic type not to be as accurate.

 

[Paladin]

I see a business opportunity here. Someone should buy sets of rotors, balance them and resell them.

Man I don't know if I would have the patience to sit there and sand, measure, sand, measure... Sheesh.

Knowing me, I will mess them up. i i

 

[Typhoon Charlie]

Not that hard I don't sand I use tape on the light blade takes about one minute to do one once you get use to it.

 

[KBflyer]

I'm sure all you longtimers know the value of prop balancing, so I'll direct this primarily to the lesser experienced to our sport/hobby. I myself go back to the very early days of analog RC, even late 60's so prop balancing is not only good, but essential to performance and the life of our very investment we put in the air. The slightest unnecessary vibration (can't get rid of it all) induces frequencies of all the vibration spectrum into our circuitry and airframe. And if you think Yuneec's props are any better than 40 years ago, think again. I just balanced all 10 of my H props and only 2 were actually in balance, only one other was close. All the rest were considerably out.

That said, multirotor props can present a new challenge in that the shaft holes, threads, and mounting hole sizes vary wildly from RC propeller aircraft as well as, not to mention various manufacturers of quad to quad, hex, etc. I just purchased the new DuBro Balancer (an excellent inexpensive balancer) last week expecting it to have a cone sizer on the propeller shaft like the old Hightpoint Precision Balancers after which Dubro modeled theirs, which of course is not included. No way the shaft fits or screws on to the larger diameter hole of the H props.So...

Easy fix for the H: get some 1/4 inch silicone fuel line (available at any RC hobby shop) and cut a half inch or so and thread it on each end of the balancing rod. I had feet of the stuff in my old RC box, but you may have similar lying around. Then, just press an H prop on to the very end making certain the shaft is at least flush with the other end of the prop.

My technique: I first clean and wax all my props then balance each prop using 100 grit paper to remove material from the mid to upper middle underside of the heavy blade. Avoid the tips as much as possible as they already flex considerably under load and I'm not comfortable removing even more material from that last 1/4 inch or so. I also use spray cleaning wax to seal the scratches after balancing, then check one last time. I'm sure any other wax product would work fine, just make sure to remove all excess. Perhaps I'm a bit anal about my balancing regimen, but the less resistance and vibration...the absolute better. Having flown planes, helicopters, ducted fans, and just about everything else with parts that can go round and round, I've grown to loathe vibration.

Do you mind posting a picture of this homemade silicone fuel line add on? Somehow I find it real hard to believe once you add that to your balancing rod it still will be balance. I have even seen balance rods bought brand new that need to be balanced so adding a piece of plastic to a rod that is suppose to be true is not a good idea. You might be old school but I think you should go back to school.

 

[Joneshd3488]

I'm only talking a 1/4 to 3/8 on the end... which doesn't even cover the threads on the rod. But, whatever works for you as long as it's balanced...and mine are balanced.

 

[KBflyer]

Well I don't have the H yet, I will soon so I can't say one way or the other about the props being balance when they arrive. I can tell you that I have owned two Q500 quads and every one of the props that came with it where so close to perfect there was no use in screwing with them. I do own a DuBro Balancer also and take it apart after each use and put it away so dust does not get in the way so I know Yuneec props are pretty close to perfect.
Now like I said I do not have the H yet to check its props but I really can't imagine them being so far out of balance as you say. I would think they would stick to the same quality as the Q500 props.
So this is why I am calling BS on your plastic tube add on and you claiming so many props being out of balance. If its true its a wonder there are so many great videos without jello.

 

[glider]

I have access to a dynamic balancer we use at work and have used it on a few copters (yes, even T-Motor props come out of balance on occasion). It is extremely accurate but cumbersome to set up. However, there is a company that makes an inexpensive and from what I can tell a good solution to get to attain excellent balance results for props and motors.
Windows

 

[Paladin]

Okay you guys got me interested in doing this now. I have been watching video etc...
I completely see the need now.

I just ordered the Du-Bro 499. Is there anything else I need?
Also does the Du-Bro 499 have the correct shaft to fit the H props?
I don't even know the size shaft it has. 6mm? 8mm?

 

[Joneshd3488]

Okay you guys got me interested in doing this now. I have been watching video etc...
I completely see the need now.

I just ordered the Du-Bro 499. Is there anything else I need?
Also does the Du-Bro 499 have the correct shaft to fit the H props?
I don't even know the size shaft it has. 6mm? 8mm?

 

[Joneshd3488]

According to Tolgademir's post above, the 499 does.

 

[Tolgademir]

Du bro 499 has cones so it would fit a variety of shaft sizes. Props are pretty good out-of the box but I as well as another member here found that the side with the letter A or B is heavier. Check out that thread
Typhoon H Props out of balance