Possible negative effect of raised lettering on props

[MS Coast]

I'm wondering about the effect on propeller aerodynamics of the raised part number lettering molded into the leading edge of each blade of the Mavic 2 propellers. (And presumably on other models.) It seems that the roughness would create unwanted turbulent airflow that could reduce the effectiveness of the prop and possibly increase noise.

Anyone have any thoughts? I know that having the CW and CCW props differentiated is essential, but it could be done with a non-raised mark. Anyone ever sanded the lettering off to check for an improvement? Any reason not to try that?

 

[dirkclod]

Have never messed with Mavic props but we used to sand them smooth on Phantom props experimenting. Some said it helped make them quieter but I never saw any difference one way or the other. Had to make sure and balance them afterwards though.

 

[old man mavic]

@MS Coast the lettering that close to the hub ,would have no noticeable effect on the props performance there is very little lift generated at that point ,and in a perverse sort of way the lettering could even help the air to leave the prop with less cavitation

 

[The Fat Controller]

Check the typeface because Bold would obviously weigh more, not to mention Italic because who knows what direction that would take your drone.

 

[Jeff A]

I'm wondering about the effect on propeller aerodynamics of the raised part number lettering molded into the leading edge of each blade of the Mavic 2 propellers. (And presumably on other models.) It seems that the roughness would create unwanted turbulent airflow that could reduce the effectiveness of the prop and possibly increase noise.

Anyone have any thoughts? I know that having the CW and CCW props differentiated is essential, but it could be done with a non-raised mark. Anyone ever sanded the lettering off to check for an improvement? Any reason not to try that?

I'll confess to dressing the leading edge of the props with ultra fine sand paper or crocus cloth. Part of my checks is to run a fingernail along the leading edge to evaluate the condition of the props, just checking for sand damage or any other kind of strike.

 

[sigi.stiemer]

I sanded the letters off and rounded the sharp leading edge. One might question the effectiveness, but it feels good ... certain things are soothing to one's mind.

 

[Meta4]

It's always interesting to see how drone fliers are so much smarter than DJI's propulsion engineers.
DJI's design team are very smart and know a lot more than most people about how propellers work.
Something as obvious as raised lettering won't have escaped their attention.

It could even be that the raised lettering is an intentional feature.
Airfoil design is a lot more complicated that many would imagine.
Look at the wing surface of real planes and some have rows of small fins (vortex generators) intentionally placed to improve the effectiveness of wings and control surfaces.

I'm sure that DJI's propulsion engineers know about such things and have a pretty good idea what they are doing.

Vortex Generators: Preventing Stalls At High And Low Speeds

You might have seen vortex generators - those little fins that protrude from the front of an airliner like the 737-800, or a Short Take Off and Landing (STOL) aircraft like this Top Cub.

www.boldmethod.com

Vortex generator - Wikipedia

en.wikipedia.org

 

[SkyeHigh]

It's always interesting to see how drone fliers are so much smarter than DJI's propulsion engineers.
DJI's design team are very smart and know a lot more than most people about how propellers work.
Something as obvious as raised lettering won't have escaped their attention.

It could even be that the raised lettering is an intentional feature.
Airfoil design is a lot more complicated that many would imagine.
Look at the wing surface of real planes and some have rows of small fins (vortex generators) intentionally placed to improve the effectiveness of wings and control surfaces.

I'm sure that DJI's propulsion engineers know about such things and have a pretty good idea what they are doing.

Vortex Generators: Preventing Stalls At High And Low Speeds

You might have seen vortex generators - those little fins that protrude from the front of an airliner like the 737-800, or a Short Take Off and Landing (STOL) aircraft like this Top Cub.

www.boldmethod.com

Vortex generator - Wikipedia

en.wikipedia.org

I wonder if there is a difference between the aerodynamic effects using Chinese characters or English. Maybe need to check which font would be best? Script seems more streamlined. [emoji41]

 

[The Fat Controller]

It's not just DJI engineers; drone fliers are also smarter than lawyers, CAA/FAA, local authorities, and just about everyone else. Joking aside though, there are plenty of knowledgeable people on this forum who frequently give accurate, sensible and dependable advice. It shines through in their posts. There are others who don't know their (Language Removed) from their elbow. It's usually not hard knowing what information to trust as fact and what can be safely ignored as mere opinion. It's the internet, it's a forum - plenty of room for diversity.

 

[The Fat Controller]

I wonder if there is a difference between the aerodynamic effects using Chinese characters or English. Maybe need to check which font would be best? Script seems more streamlined. [emoji41]

See post #4

 

[icecoldgin]

It's not just DJI engineers; drone fliers are also smarter than lawyers, CAA/FAA, local authorities, and just about everyone else. Joking aside though, there are plenty of knowledgeable people on this forum who frequently give accurate, sensible and dependable advice. It shines through in their posts. There are others who don't know their ( Language Removed) from their elbow. It's usually not hard knowing what information to trust as fact and what can be safely ignored as mere opinion. It's the internet, it's a forum - plenty of room for diversity.

Ahh, "The life of the law has not been logic; it has been experience" (US Supreme Court Justice Oliver Wendell Holmes, Jr.)

 

[Maviac]

It's always interesting to see how drone fliers are so much smarter than DJI's propulsion engineers.
DJI's design team are very smart and know a lot more than most people about how propellers work.
Something as obvious as raised lettering won't have escaped their attention.

It could even be that the raised lettering is an intentional feature.
Airfoil design is a lot more complicated that many would imagine.
Look at the wing surface of real planes and some have rows of small fins (vortex generators) intentionally placed to improve the effectiveness of wings and control surfaces.

Good points (especially about airfoil design and vortex generators, which seem counterintuitive but are effective). Though I do wonder if this is something added after the engineers get done with their design and, assuming it's run by them afterward, are like, eh, shouldn't affect anything.

For what it's worth, like some others, I lightly sand off the plastic flashing from my props (haven't really seen it on DJI ones but have on MAS ones). It seemed to make my Mavic Air props slightly quieter, though it could have been placebo. Didn't notice any difference on the M2P ones.

 

[dirkclod]

Hey we did it way back experimenting like we did everthing else.
How do you think we got to where we are now. Unless you try
to change stuff which works sometimes or not DJI wouldn’t learn
nothing ?

 

[Droniac]

I wonder if there is a difference between the aerodynamic effects using Chinese characters or English. Maybe need to check which font would be best? Script seems more streamlined. [emoji41]

?[emoji854]

 

[The Fat Controller]

There are others who don't know their (Language Removed) from their elbow.

Apologies for this. It's a common expression where I'm from, it wasn't my intention to be sweary. ?‍

 

[sigi.stiemer]

It's always interesting to see how drone fliers are so much smarter than DJI's propulsion engineers.
DJI's design team are very smart and know a lot more than most people about how propellers work.
Something as obvious as raised lettering won't have escaped their attention.

It could even be that the raised lettering is an intentional feature.
Airfoil design is a lot more complicated that many would imagine.
Look at the wing surface of real planes and some have rows of small fins (vortex generators) intentionally placed to improve the effectiveness of wings and control surfaces.

I'm sure that DJI's propulsion engineers know about such things and have a pretty good idea what they are doing.

Vortex Generators: Preventing Stalls At High And Low Speeds

You might have seen vortex generators - those little fins that protrude from the front of an airliner like the 737-800, or a Short Take Off and Landing (STOL) aircraft like this Top Cub.

www.boldmethod.com

Vortex generator - Wikipedia

en.wikipedia.org

You may be surprised: Quite a few engineers are smarter than others! Raised letters on an airfoil serve only one purpose: labeling. If one wants to intentionally create turbulence, commons sense would recommend to use special devices, not random letters.