8 REPLIES
dries_w
Commander Pilot

Re: balance blades


JohnnySuperDad wrote:

 . . . . . . . . . . 

Is prop balancing worth the effort? You bet it is . .  

 


No, its realy not. With propellors turning arround more then 7500RPM you wont see the difference between a 'balanced' prop or not. Your video shows Jello effect with a drone stressing the motors gaining higher altitude and the second part flying straight forward, that can not compared to take any conclusion. :-)

But anyone who has the urge to 'balance' there plastic fast turning props: be my guest.

EDIT:

Even after you put an other video (23 oct) to convince members like me, there is no need to balance four fast turning props.

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JohnnySuperDad
Master navigator

Re: balance blades

 

 

Here's the part I bought on Amazon to balance the two props without the center holes.

https://www.amazon.com/gp/product/B01B4PV6MA/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Here's the prop balancer I bought to do all blades with center holes.

https://www.amazon.com/gp/product/B0006N72Y8/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

 

Quick video:

https://www.youtube.com/watch?v=Cvcq20-taWg

 

Most Dremel kits come with cutoff wheels that you mount on a spline.

A small screw holds the cut off wheel to top of the spline shaft.

Drill out the screw hole just big enough to accept the rotor shaft and spin freely.

Using a cordless drill as a stand, I tightened the chuck on the drilled out spline.

Stick in the shaft protruding from the (repair part) rotor and the heavy blade should fall to the bottom.

If the prop does not freely spin, try tapping on the table like your playing bongos to get it to move. 

 

 

Here's a before and after video. Same drone, same location, same direction, same speed, same wind.

The only thing different is prop balancing.

https://www.youtube.com/watch?v=FdSXoCWm8sM

Is prop balancing worth the effort? I sure feel it is!

 

JSD

 

 

dries_w
Commander Pilot

Re: balance blades


NeeKniggit wrote:

I have a dial guage that I purchased for rebuilding my front differential on my car. They aren't very expensive anyway and they can measure differences up to 1/1000 of an inch. I found if I put the prop on a flat surface and then compare the blade tolerences of each blade I can at least get them all true under no load. Can't guarantee what happens once a load is put on them. Just an idea of another way to do prop checks.


If you measure a difference of 1 or 2/1000 of an inch, what will you do with that prop? Do you think that difference is noticeable with the very high speed of the flexible props? just curious :-)

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NeeKniggit
Navigator

Re: balance blades

I have a dial guage that I purchased for rebuilding my front differential on my car. They aren't very expensive anyway and they can measure differences up to 1/1000 of an inch. I found if I put the prop on a flat surface and then compare the blade tolerences of each blade I can at least get them all true under no load. Can't guarantee what happens once a load is put on them. Just an idea of another way to do prop checks.

dries_w
Commander Pilot

Re: balance blades

I'm glad it was not my question about balancing the props, nor my artikel in the link, pffff what a reaction :-)

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mountkidd
Commander Pilot

Re: balance blades

Ok, after reading the link in dries_w post I can't ***** my tongue anymore...

 

Static balance isn't going to do much for a prop that spins at 7000-10000 rpm.  Dynamic (spinning) balance is needed if any at all.  And of course this is very difficult to do as the B2 prop blades are somewhat flexible and may change shape under aerodynamic loading.  The motor gimbals may be more significant from an imbalance perspective.  This is all high-precision stuff, not likely something that can be done from the trunk of your car...

 

Sand the bottom of an aerodynamic prop surface?  OMG!

dries_w
Commander Pilot

Re: balance blades

In another post I saw a link about balancing blades to avoid jelly effect in video:

http://dronetechreport.com/reducing-jello-getting-​natural-look-aerial-video/ 

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PhilG
Commander Pilot

Re: balance blades

Good question.

 

A traditional prop balancing jig relies on a spindle through the prop which, of course, you can't do with 2 of the Bebop props.

 

You could make a prop holder on the end of a shaft but due to it having to be more than a fine spindle you could have potential balance problems with it, unless you are extremely accurate in it's manufacture.

 

In short, I don't know the answer.  However, I would always avoid non OEM props to minimise the risk of unbalanced props.  Also, if I damage them I replace them - they aren't particularly expensive.

 

It is easy of course to check for bends and other damage.  Stand the Bebop on a table, place a straight edge on the table against a prop tip and rotate by hand to see if all the tips are in alignment.

 

Phil

brwbier
Co-pilot

balance blades

Does anyone have a good way to check the balance of the blades?