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We did a review on them, you can see them here:
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Master Airscrew
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IShouldBeWorking
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Alrighty, I got home from work late again tonight, but I decided to take the Mavic out back and film it in a hover so people could compare the sound of the MAS Stealths vs. the stock DJIs. I also took some dB and RPM readings. Hope this helps people who might be considering these. I'm pretty impressed. I'll be anxious to get out for a real flight with them when I can.
After some quantitative testing I'm not sure that the data support the conclusions so far from other reviews. A spectral analysis of the DJI and MAS props while hovering produced the following:
Most of the spectral peaks are lower for the MAS props, which is simply a result of a lower motor speed. That accounts for the overall lower tone of the MAS props. But integrating the spectral power with respect to frequency indicates a slightly higher overall sound level from the MAS props:
Looking at the actual motor characteristics:
The motor speeds are down for the MAS, averaging 5400 rpm vs. 5770 for the DJI props. However, the motor currents and overall motor power are up by around 3%, which will result in slightly shorter flight times. On balance I would say that the DJI props are more optimized than the MAS props, even though they subjectively sound louder.
Most of the spectral peaks are lower for the MAS props, which is simply a result of a lower motor speed. That accounts for the overall lower tone of the MAS props. But integrating the spectral power with respect to frequency indicates a slightly higher overall sound level from the MAS props:
Looking at the actual motor characteristics:
The motor speeds are down for the MAS, averaging 5400 rpm vs. 5770 for the DJI props. However, the motor currents and overall motor power are up by around 3%, which will result in slightly shorter flight times. On balance I would say that the DJI props are more optimized than the MAS props, even though they subjectively sound louder.
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How does lower RPM draw more Amps, are the motors working harder? I redid the hover test again swapping the batteries this time and the MAS props flight time was longer still by 1:18, not a lot again but longer. OEM landed at 9% MAS at 10%
Correct - the load on the motors is higher at lower rpm, as you would expect - you don't get something for nothing. You could think of it as equivalent to being in a higher gear. The difference in current is definitely above the error estimate for the data, so I'm not sure about your results. If you want to examine the flight DAT files then you can check how the motors were actually performing and why the flight times were different.
IShouldBeWorking
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This is some great concrete data! Thanks for sharing! As I posted above, I prefer the lower pitch of the MAS Stealths. But now I’m wondering if the resulting higher amperage draw will produce more heat and wear on the motors over time. I don’t need to shorten their lifetimes just for a subjectively more pleasing sound during fight.
The difference in wear is probably marginal. My guess is that MAS were focused purely on getting them to sound subjectively quieter, which is fine, rather than maximizing efficiency. Those are different, and potentially conflicting, design goals.
I suppose its only a matter of time before more run time tests are carried out. I see the analysis but at the same time when people are doing back to back tests and seeing a 1min+ increase in flight time it's either that they are using less power OR witchcraft. 
I suppose its only a matter of time before more run time tests are carried out. I see the analysis but at the same time when people are doing back to back tests and seeing a 1min+ increase in flight time it's either that they are using less power OR witchcraft.
Run time tests are poorly controlled, by their very nature. It will take a pretty large set of such data with controls for battery charge and other variables to make it statistically significant, as compared to the direct battery current measurements. That's why I suggest that those conducting the tests at least look at those data.
Hopefully aerial pixel will look at the data from their test runs and see what they get.
I remember back in my early phantom days (OG phantom!) and the props from the P2 came out (i think) they really did make a difference to battery life and even DJI acknowledged this.
I paid 9.99 for shipping to uk ... don’t know what the vat will be yet probably be not a lot based on the value.
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Noise reduction does not sell me. To be honest, many times I can hear my drone before I can see it. The fact that it might be quieter just means it will be harder for me to acquire it visually. After viewing @sar104‘s information, It’s clear to me DJI engineered a very good set of stock props. At twice the price of DJI’s oem props, and connsidering my type of flying (and I emphasize my type of flying) the new MAS props don’t provide much of a benefit.
When I was five years old, my father told me schizzle stinks. Nevertheless I had to find out for myself.
I’ll be ordering the props tomorrow.
When I was five years old, my father told me schizzle stinks. Nevertheless I had to find out for myself.
I’ll be ordering the props tomorrow.
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Price really isn't an issue, the MAS props are $25 for 4 (plus $4 shipping), DJI sells theirs for $15 per pair ($30 total) on their website. But you can get the DJI props for $24-$27 on Amazon for 4 of them. I really bought them to not draw attention, both at events and just out in public flying. The first wedding I filmed I had to bring my P4P down because it was so loud and distracting, the quieter the better IMHO. But I'm a VLOS guy so identifying at a distance isn't a big deal for me, I see what you mean there.
That app is way over my head LOL, Just tried the demo... I'm lost
Right - Igor Pro is not intended for casual use. It's a very powerful scientific data analysis package with a seriously steep learning curve.
I see your point...Prop noise could be a significant consideration for a 107 jock.
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