Balancing Props Against the Other 3 Props

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I have been flying single propeller RC planes for many years so I know the advantage and necessity of balancing props. But coming from the plane world, I don't have much experience in the way of multi-rotor aircraft. I follow the same steps that I always have where I sand until the one side of the propeller is perfectly balanced to the other (less worry about the hub, but I do check that too from time to time).

A question for those that have flown multi-rotor aircraft for a while, is it necessary to balance the propeller against the other three? If you are sanding a fine amount off of one, it now has a slightly different weight and shape than the rest. Do this put extra stress on one of the motors (or the other three) and does this affect flight or the camera at all? I have not noticed any issues thus far and quite frankly the Phantom itself is not exactly balanced itself (which I assume is what the IMU calibration determines)...
 
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The balance is for one rotor. You don't have to balance each rotor to the other rotors. You are thinking too hard about this.
 
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Honestly, that doesn't even make sense. How would you know how much to shave off the other rotors?
 
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DEFINITELY way over thinking this, but that is what the mind does at the wee hours of the night.

That is why I am curious about it. If you were to hang a 200g whatever on one of the arms, the sensors would increase thrust to that motor and it's two neighbouring motors to compensate (so with not accurate numbers just for example with 70% being the normal baseline: heavy arm would be running at 90%, the two neighbours at 80%, and the opposite at the standard 70%). Now the motors have less power to give when moving, but also will constantly be recompensating. With how sensitive those sensors are, does a fraction of a gram actually make a difference? Unless it was a severe difference it would not be noticed by the user, but does it put any extra stress on the motors or internals. Than again, when you slice through a few flies do you now have to worry about those splatters doing the same thing.

This is all hypothetical and getting into decimals, but the effects could be real when the weight is off and the airflow around a prop is now changed. If this was a precise machine it would of course actually mean something, but this could also be contributing to the "jello" effect that some people are seeing...
 
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So... you want to attach smth to your drone. Not a smart move if you have P3P. I liked one guru message uphere, stating "Do not attach anything to your Phantom - it is not a quacopter, it looks like quadcopter, but it is not. It is just flying camera with 4 propellers". P3 is already balanced.

I am pretty sure you have to visit self made drone forum, not a Phantom one to get a proper answer. Phantom it is a magic out of the box - do not touch it and it will work excellent.
 
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Motors make up for any weight differential
 
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Hmmm. New to the drone thing but I am into total tinkering, so matching weight prop to prop makes total sense to me...
 
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As long as all 4 props are individually balanced ... the Flight Controller will detect any attitude / thrust difference and compensate.

There is no need to balance props against each other.

Of course technically - its nice if they are all same weight / pitch / diameter etc. to reduce work of FC .

Nigel
 
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I use the packing tape method. Tiny sliver of clear tape to the inner section of the prop until it balances. Works like a champ and no sanding.
 
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As long as all 4 props are individually balanced ... the Flight Controller will detect any attitude / thrust difference and compensate.

There is no need to balance props against each other.

Of course technically - its nice if they are all same weight / pitch / diameter etc. to reduce work of FC .

Nigel
Ok, that's what I'm focussing on as I'm looking for any area to improve flight time efficiency. Thx Nigel!
 

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Ok, that's what I'm focussing on as I'm looking for any area to improve flight time efficiency. Thx Nigel!
I don't see how these things can hurt...
...however I don't know how you'd tell it made a difference either, so if you enjoy the tinkering- then that's all that matters!
 
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I don't see how these things can hurt...
...however I don't know how you'd tell it made a difference either, so if you enjoy the tinkering- then that's all that matters!
You most likely cannot tell difference unless you correct a large differential. Then you would likely see a better average flight time ... less vibration .... maybe smoother / better response.

Trouble is as we are human - if we do something - our 'perception' is the machine acts better.

Bit like change the oil in the car and you think it drives better.

But with such as balancing all 4 props to each other - of course it will mean FC has less differential to compensate for and you should have better control - but how would you know ?

Nigel
 
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You won't get any noticeable flight efficiency time-wise from balancing props, that's not the purpose. The purpose of balancing is to prevent the drone from vibrating which causes cracks in the shell over time, which MANY have experienced in this forum. Severe vibration can cause jello in the video, but that's highly unusual with stock props that are undamaged. That much vibration you will definitely FEEL when you catch the drone, which should give you a clue. In those cases, 99% of the time you will have a damaged prop.
 
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You won't get any noticeable flight efficiency time-wise from balancing props, that's not the purpose. The purpose of balancing is to prevent the drone from vibrating which causes cracks in the shell over time, which MANY have experienced in this forum. Severe vibration can cause jello in the video, but that's highly unusual with stock props that are undamaged. That much vibration you will definitely FEEL when you catch the drone, which should give you a clue. In those cases, 99% of the time you will have a damaged prop.
Sorry but not actually the case.

Yes - reduction of vibration caused by unbalanced blades is a great benefit, but the gain in power efficiency of the motor is one important part of balancing.
Ask any RC aerobatics / 3D flyer why he balances his props .....

Unbalanced prop creates a vibration and in turn possible structural stress - but the vibration also robs power from the motor along with stressing the shaft bearings and mounts.

You may not notice the better efficiency and reduction of stress - but its a definite factor.

Nigel
 
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Sorry but not actually the case.

Yes - reduction of vibration caused by unbalanced blades is a great benefit, but the gain in power efficiency of the motor is one important part of balancing.
Ask any RC aerobatics / 3D flyer why he balances his props .....

Unbalanced prop creates a vibration and in turn possible structural stress - but the vibration also robs power from the motor along with stressing the shaft bearings and mounts.

You may not notice the better efficiency and reduction of stress - but its a definite factor.

Nigel
We agree, you won't notice any added flight time with balanced props. My point is the primary reason to balance props is shell crack prevention. If you develop a shell crack, you WILL notice it, and wished you had balanced your props. Generally speaking stock props are balanced pretty good, but you won't know that until you check them. I've had three that was unacceptable, out off about 30 that I've checked.
I guarantee you that DJI doesn't check each prop for balance.
 
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I balance all my props ........... habit formed over years ..... and especially that I fly Helicopters as well.

I have never found any prop to be fully balanced. Some are just better than others.

Nigel
 
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Balancing the blades of say a remote controlled helicopter is required to prevent vibration. However, it’s slightly different having four blades as they have the effect of cancelling each other’s inaccuracy in weight out.

If you have noticed vibration during flight then the chances are you have either previously crashed and bent something or the props are not attached correctly.

Also as others have said, the flight controller and ESC’s will distribute power as required thus ironing out any major issues.

Don’t get me wrong, balancing the props is never a bad thing and if anything could reduce the stresses on not only the motors but possibly on the shell too - also potentially reducing the known issue of random cracking around the motor bolts.

Just my two cents.
 

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