Low noise props

[SaigonDude]

I'm not clear how excess demand on the motors can actually improve flying time, as indicated in the DJI Store blurb. The physics just don't make sense to me. Any thoughts on this, or should we assume it's DJI marketing BS?

No, in this particular case, it is aftermarket marketing BS.

 

[Tander]

This video answers your question in great detail. Sounds like the new ESC design is the key upgrade that make the low noise props work efficiently to decrease battery consumption and extend flight time - not the props themselves.

DJI Low-Noise Props come Explained

This guy's videos are extremely informative, accurate and thorough. He's a real pro but the videos are long. In hindsight I've learned more from him than all other YouTube channels combined. He's a DJI fanboy but still remains objective. Worth browsing his library for sure.

What a find. I've subscribed to his channel. Thanks!

 

[Andre Levite]

No, in this particular case, it is aftermarket marketing BS.

In the particular case we are discussing [MP1 vs MP Platinum] the improved flight time is a fact - has been repeatedly demonstrated on YouTube. It is real. And proven. See the demo video below.

During a typical side by side comparison test the new props and motors add an average of 3 minutes flight time.

Improved Flight Time Demonstration of Mavic Pro Platinum over original MP

Not surprising at all that a modified motor and prop design could improve the efficiency of power consumption and thus increase flight time.

DJI has teams of excellent engineers and their marketers are not going to risk their brand reputation with false claims that are easily disproven. C'mon

 

[Dodge DeBoulet]

In the particular case we are discussing [MP1 vs MP Platinum] the improved flight time is a fact - has been repeatedly demonstrated on YouTube. It is real. And proven. See the demo video below.

During a typical side by side comparison test the new props and motors add an average of 3 minutes flight time.

Improved Flight Time Demonstration of Mavic Pro Platinum over original MP

Not surprising at all that a modified motor and prop design could improve the efficiency of power consumption and thus increase flight time.

DJI has teams of excellent engineers and their marketers are not going to risk their brand reputation with false claims that are easily disproven. C'mon

What sort of "modified motor" does an original MP have? I'm not arguing with the improvements seen with the MP Platinum; the improved ESC and other electronics would likely have a positive effect. But I've seen claims in this thread that the low-noise props cause additional stress on the motors while at the same time improving flight times for the original MP. That just seems to fly in the face of reason (pun intended) and I've yet to hear a good reason why.

And I know you're addressing the differences between the MPP and original MP in your response to @SaigonDude, but his post was in answer to my concerns about the claims made for the LN props on the original MP (as clarified here) ...

 

[Andre Levite]

What sort of "modified motor" does an original MP have? I'm not arguing with the improvements seen with the MP Platinum; the improved ESC and other electronics would likely have a positive effect. But I've seen claims in this thread that the low-noise props cause additional stress on the motors while at the same time improving flight times for the original MP. That just seems to fly in the face of reason (pun intended) and I've yet to hear a good reason why.

And I know you're addressing the differences between the MPP and original MP in your response to @SaigonDude, but his post was in answer to my concerns about the claims made for the LN props on the original MP (as clarified here) ...

This thread has been hijacked and misread enough times that it may be beyond clarification. But I'll try...

The power train improvement I referenced was related to the updated Electronic Speed Control for the MP Platinum motors (not the MP1). So we are actually on the same page there.

I was also the one who posted that my MP1 gave repeated "battery strain errors" when retrofitted with low noise props intended for a MP Platinum. Vibration issues have caused gimbal error for others as well.

But if you want to know exactly why that happens and how it effects the motors there's tons of replies on the MavicPilots Forum. Not sure other Spark others care about this topic

It became a moot issue for me once I put the standard MP props back on and all the performance issues went away. I may try Master Airscrew props next - they have much better reviews

 

[Gryphon962]

Given near-silent motors, the biggest factor contributing to noise is rotor rpm. Two quads of same weight, one with regular blades, another with more efficient ones, will show a clear difference in noise level as the regular blades have to turn faster to achieve same lift. Caveat - noise levels as perceived by humans are subjective: higher frequencies (high rotor rpm) are perceived as more noisy than lower frequencies (lower rpm) even if the db level when measured is the same.

Supersonic tip speeds are what limits the speeds of conventional helicopters (along with retreating blade stall). I havent done the math, but I very much doubt that tip speeds of any small drone are hitting 330 m/s or thereabouts. EDIT: I did the math (30,000 rpm = 500 rev/sec = 3142 rad/sec, so a 10 cm blade turning at 30 krpm would be at 314 m/sec tip speed and be transonic in forward flight at 15 m/sec).

So when it comes to aftermarket props, we have to start with the assumption that DJI picked the optimum airfoil for the stock blades such that at max collective the current draw equals the rating of the power supply system. If you fit props with airfoils that move more air, you will hover at lower rpm and expect lower noise levels (perceived) but will be able to overstress the power supply if you give it full beans. So, if your drone has aftermarket props and you get power warnings at full power, you should have a quieter drone in the hover than it was stock.

 

[Andre Levite]

So, if your drone has aftermarket props and you get power warnings at full power, you should have a quieter drone in the hover than it was stock.

Yes. The aftermarket props are quieter. In fact they are labelled as "low noise" right on the box.

But it's totally a moot point once the drone is a few hundred feet away because you can't hear it at all with either set of props.

It's difficult to explain the sphincter tightening effect of a "Excessive Battery Discharge" warning when you're 350 feet above water and 1000' from home point. The standard MP1 is pretty quiet right out of the box - much quiter than my Spark