Low-Noise Propellers for DJI Mavic 2 Zoom

[sar104]

I've seen your graphs @sar104, but I'm interested in your comment above ...
The quietness is due to the lower rpm rate in the hover. If the Mav' is using less rpm to hover, and the battery/flight duration is slightly better (as advertised) - wouldn't that imply that the MAS prop's are more efficient?

It would, but when I tested them they were using slightly more power, not less, making them less efficient. I should note one other variable here - I tested them at 7500 ft AMSL.

 

[Aerial-Pixel]

It would, but when I tested them they were using slightly more power, not less, making them less efficient. I should note one other variable here - I tested them at 7500 ft AMSL.

Hmmm, well that would go against MAS's claims... they claim increased power at higher altitudes. You understand this stuff way better than I do, It's nice having a ulta-techie-uber smart guy on the forum.

 

[sar104]

Hmmm, well that would go against MAS's claims... they claim increased power at higher altitudes. You understand this stuff way better than I do, It's nice having a ulta-techie-uber smart guy on the forum.
View attachment 92602

Interesting that they are claiming advantages at altitude, but they don't spell out what, exactly, that means. Props don't provide power, although they may more efficiently convert electrical power to thrust. But I would have expected to see lower motor power during hover at this altitude if that were the case. I'll do some extended tests to look at battery depletion rates as well as motor power.

 

[FoxhallGH]

Interesting that they are claiming advantages at altitude, but they don't spell out what, exactly, that means. Props don't provide power, although they may more efficiently convert electrical power to thrust. But I would have expected to see lower motor power during hover at this altitude if that were the case. I'll do some extended tests to look at battery depletion rates as well as motor power.

The 'altitude' claim may be due to the diameter & pitch of these prop's being a bit longer & a little coarser (1/10" more pitch I believe). If they are providing a bit more 'bite' into the air, for a lower rpm at sea-level, then perhaps that implies that they have a little more to give than the stock at service ceiling?
[DJI stock are 8743 and although it's not yet on the website - I believe I've seen it written that the MAS prop's are 8944]

 

[xspwhite]

They sound quieter, but they don't appear to be more efficient:

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This was my thought. The dji props sounded different and louder, but it also seemed that they were providing more chop and grabbing more air. The dji props would have better performance at a higher altitude where the air is thinner and harder to cut.

 

[FoxhallGH]

The dji props would have better performance at a higher altitude where the air is thinner and harder to cut.

Woah - can I correct you there please ... When the air is thinner - it's EASIER to cut! It's more difficult to get lift from the prop's at excessive altitude as they have to spin faster to get the same thrust as they do at sea-level (air-pressure decreases with height) ... The fact that the MAS prop's have a slightly coarser pitch than the DJI stock should tell us that for the same rpm, they will give a bit more thrust. You can see this in tests where the rpm registering on Go4 will be lower with MAS props during the hover, than with DJI stock props. If you hovered with the MAS props and then gave up-stick to increase rpm to the same as what the DJI hover at, then, of course, the Mavic will ascend.

 

[xspwhite]

Woah - can I correct you there please ... When the air is thinner - it's EASIER to cut! It's more difficult to get lift from the prop's at excessive altitude as they have to spin faster to get the same thrust as they do at sea-level (air-pressure decreases with height) ... The fact that the MAS prop's have a slightly coarser pitch than the DJI stock should tell us that for the same rpm, they will give a bit more thrust. You can see this in tests where the rpm registering on Go4 will be lower with MAS props during the hover, than with DJI stock props. If you hovered with the MAS props and then gave up-stick to increase rpm to the same as what the DJI hover at, then, of course, the Mavic will ascend.

When the air is thinner the prop has less to grab and bite on. So I would think that the thicker heavier prop would do better. After seeing the video I could tell just by the sound that the stock props are better.

 

[FoxhallGH]

When the air is thinner the prop has less to grab and bite on. So I would think that the thicker heavier prop would do better. After seeing the video I could tell just by the sound that the stock props are better.

I think I see what you are getting at. By "thicker heavier" - I guess you mean less flexible (stiffer), but in fact, the glass-fibre composite MAS prop's are stiffer than the plastic DJI prop's. If you hold a DJI prop blade at each end, you'll find that it's easy to twist it along its length. When the prop is actually in use, that lack of torsional stiffness means that the 'pitch' of the prop decreases as it spins faster. It's just the pressure of the air making the blade feather into the airflow. With a stiffer blade, the 'feathering' effect is either minimised or eliminated, and you find that the prop translates its rotation into thrust more effectively. You can see this best if you try carbon fibre prop's on a Mavic. Those guys just don't flex at all, and acceleration and stopping really is a different ball-game! The glass-composite MAS prop is a half-way house between the plastic used for the stock DJI props, and carbon-fibre as used by other 3rd parties.

I am wondering why you think that the sound makes the DJI prop's better??

 

[Aerial-Pixel]

I am wondering why you think that the sound makes the DJI prop's better??

I was wondering the same, seems like a backwards statement to me. The MAS props sound smoother, quieter and a lower frequency, so just going by sound alone and nothing else, I'd give the advantage to the MAS props.

 

[xspwhite]

The MS props sounded smoother, but the dji had more of a whip sound like more air was being grabbed.

 

[Aerial-Pixel]

The MS props sounded smoother, but the dji had more of a whip sound like more air was being grabbed.

Lower RPM at hover with the MAS means they are grabbing more air and quieter... Win-win in my book!

 

[Endeavor]

After owning a MA I have to say I like the more noise aspect as it make it easier to locate the drone on it's way home. I guess I am in favor of more noise props.

 

[mavic53]

just got the coloured ones. Very snazzy. No obvious flight differences.