Blade Test Results- DJI vs CARBON FIBER

[niki]

Except for the chap whose Inspire 2 fell out of the sky is an expensive manner when his T Motor prop failed

I don't know about chap and his situation, what you mean by fail, did the prop break off at the hub, shatter to pieces or it flew away? Usually a prop failure can happen to everyone, it's a matter of proper maintenance. I'm just telling that the good CF props do not shatter and after collision and breaking part of it one can still produce lift and bring the quad back or land it.
The CF props must be checked before every flight for any scratches and smooth edges. All of the cases that I've heard with aftermarket prop failure where caused by mounting adapters and not the prop itself. The adapters are another story, there are pretty good and safe ones as well.

 

[dannybgoode]

I don't know about chap and his situation, what you mean by fail, did the prop break off at the hub, shatter to pieces or it flew away? Usually a prop failure can happen to everyone, it's a matter of proper maintenance. I'm just telling that the good CF props do not shatter and after collision and breaking part of it one can still produce lift and bring the quad back or land it.
The CF props must be checked before every flight for any scratches and smooth edges. All of the cases that I've heard with aftermarket prop failure where caused by mounting adapters and not the prop itself. The adapters are another story, there are pretty good and safe ones as well.

Yes it looks like there was a structural failure in this particular case.

That said I am not averse to the idea of 3rd party props assuming they are decent ones. After all that is what we had to use on our home brew drones and in the RC heli world nearly everyone uses aftermarket ones.

In the case of DJI though I’ll just stick with the OEM ones - they do everything I need them to and the price is reasonable. With the FC being so optimised I would rather stick with what the coders and product developers had in mind when designing and speccing the FC and associated electronics.

 

[Quad808]

I have both the Mavic Pro and the Platinum and have used 4 different props:
Stock DJI
Low noise DJI
CF
Master Air Screw
If you want more "responsiveness" out of your craft, use the 3rd party props. You can tell the difference, since both the Master Air Screw props and the CF are stiffer than the DJI props.
The CF props need balancing. Build quality is not top notch, but once balanced, they work great.
My favorites are the Master Air Screw props. They are slightly more responsive than the stock low noise props, since they are thicker and don't flex as much as the stock ones. The CF props are even more responsive. There is a big difference in response going from CF to stock low noise DJI props.
Sound - the Master Air Screw props are basically about the same volume as the stock low noise. Maybe a tad lower pitch. More pleasant to my ears.
The best sounding are the CF props. Much lower pitch, so they sound even better and are quieter. Low noise is important to me, since I don't like to bother others when I fly. I only use the Master Air Screw props now.
The good thing about the stiffer props is the improved response, but this is also a bad thing if you just film all the time. You will need to adjust your stick control slightly to compensate.
Balancing and screws...the Master Air Screws were perfectly balanced out of the box, so are the DJI props...either standard or low noise.
The CF needs balancing, AND as someone else said there is a chance the screws can back out, so I use loctite blue on them. I adjust all props to swing out easily. There is no need to use loctite on the Master AIr Screw props...they are put together differently.
Bottom line? Use what ever props are best for your flying style. No harm in trying different props IMO.

 

[rickw]

FYI,master airscrew are not cf,they are fiberglass

 

[FoxhallGH]

I have done a Flight Duration Test today to compare DJI Stock prop's to Carbon Fibre versions. So - here is the equipment, method and results:

Equipment
Drone: Mavic Pro Platinum [MPP]
Prop's flown: Hensych 8331 carbon-fibre (exact copy of stock DJI 'quiet' prop for MPP) - compared with DJI stock 8331 'quiet' Platinum props.
DJI Stock on left, Hensych CF on right.
Both prop-sets are 8.3" (210.8 mm) in diameter, with a pitch of 3.1" (78.7 mm)

Objectives
Carbon Fibre [CF] prop's are stiffer and typically show lower rpm readings on the DJI RC Controller. Is flight duration improved when using CF prop's over the stock DJI prop's of the same shape/profile?

Method
Low battery alert was set at 15%, and critical battery at 10% ... I used the auto-takeoff button on the DJI Go 4 app' to allow the MPP to start, and ascend to 1.2 metres without any further control intervention for both prop tests. I then immediately set 'Terrain Follow' mode to maintain height and override any height changes requested by RTH etc. I turned on video record prior to takeoff and ran that for the duration of the flight (as an alternative confirmation of flight time if needed). The MPP was then just left to hover above the take-off point with no control inputs until the battery got to critical and the Drone landed itself. RTH and low battery warnings were ignored in Go 4 - and the MPP just left to descend when it wanted to.
There were some light cross-wind gusts during the tests, but these would have been less than 2 metres/sec. max.
Flight logs were exported to DJI Flight Log Viewer - Phantom Help and the resulting tables were used to determine the exact time that the MPP provided RTH warning, and then when it touched down (i.e. the exact logged flight-time it attained minimal IMU Altitude).
The two batteries used were manufactured in December 2017 with one having 9 charge cycles and the other having 11.

Results
Hensych 8331 carbon-fibre prop's
[Using my battery # 3 ... 9 cycles]
Go 4 popped RTH notifications at 22 minutes 51.5 seconds into the flight
Minimum IMU altitude was recorded at 25 minutes 48.3 seconds into the flight
Motor rpm was observed on the controller to be varying between approx. 464 and 473 prm x10 during the hover

DJI stock 8331'quiet' prop's
[Using my battery #2 ... 11 cycles]
Go 4 popped RTH notifications at 24 minutes 30.5 seconds into the flight
Minimum IMU altitude was recorded at 24 minutes 49.3 seconds into the flight
Motor rpm was observed on the controller to be varying between approx. 497 and 513 prm x10 during the hover

Observations
1) The first test using the CF prop's ended differently to the second using stock DJI. Although the MPP had issued critical battery warning's during the first test, it continued to hover for about a minute after the warning was given, and the Go 4 app' showed --/-- battery remaining while it was in the hover. The second test was different in that the critical battery warning was given and the MPP then landed within seconds afterwards.
2) For the reasons in 1) above, it may be more indicative to use the "The remaining battery is only enough for RTH. Return home now." warning points for the purposes of comparing flight duration.
3) Stability while hovering was slightly but perceptibly better with the Hensych 8331 CF prop's. The presence of a cross-wind during the test made this more apparent, and while vertical movement on the video footage taken during the two flights is minimal, the flight with the stock DJI prop's shows MORE sideways movement as the drone was buffeted through yaw and roll. This movement is apparent on the video for both tests, but is more 'violent' and ranges further when the MPP is flying stock DJI prop's.
4) Based on the point at which the logs show "The remaining battery is only enough for RTH. Return home now." - the stock DJI 8331 prop's are providing the best flight duration (this warning came about 2 minutes later than when flying the CF prop's).
5) A second test run would be wise, swapping the battery/prop combination - to ensure that battery 'difference' is not a factor in this test.
6) No sound measurement [dB] tests were carried out, but the CF prop's have a lower frequency 'hum' than the stock DJI in the hover, and therefore sound quieter then the 'quiet' DJI prop's.

Conclusions
Earlier observations showed a lower rpm reading on the RC controller when the MPP was being flown on Hensych 8331 carbon-fibre prop's. The combination of the lower rpm, and the slightly shorter flight duration seen in these tests, seems to prove that the carbon-fibre prop's are making the Mavic's motors work harder, and therefore they draw more current from the battery - and consequently decrease flight duration.
It was outside the scope of this test, but improvement in stability appears to be a trade-off against flight duration when flying carbon-fibre prop's.
Ideally - both test flights should probably be carried out using the same battery to ensure that there are no issues in the test that are effected by a difference between batteries. However, battery charging time will introduce a significant delay between the two tests, that could lead to comparison issues due to weather and other atmospheric effects.

 

[old man mavic]

I have done a Flight Duration Test today to compare DJI Stock prop's to Carbon Fibre versions. So - here is the equipment, method and results:

Equipment
Drone: Mavic Pro Platinum [MPP]
Prop's flown: Hensych 8331 carbon-fibre (exact copy of stock DJI 'quiet' prop for MPP) - compared with DJI stock 8331 'quiet' Platinum props.
View attachment 55568 DJI Stock on left, Hensych CF on right.
Both prop-sets are 8.3" (210.8 mm) in diameter, with a pitch of 3.1" (78.7 mm)

Objectives
Carbon Fibre [CF] prop's are stiffer and typically show lower rpm readings on the DJI RC Controller. Is flight duration improved when using CF prop's over the stock DJI prop's of the same shape/profile?

Method
Low battery alert was set at 15%, and critical battery at 10% ... I used the auto-takeoff button on the DJI Go 4 app' to allow the MPP to start, and ascend to 1.2 metres without any further control intervention for both prop tests. I then immediately set 'Terrain Follow' mode to maintain height and override any height changes requested by RTH etc. I turned on video record prior to takeoff and ran that for the duration of the flight (as an alternative confirmation of flight time if needed). The MPP was then just left to hover above the take-off point with no control inputs until the battery got to critical and the Drone landed itself. RTH and low battery warnings were ignored in Go 4 - and the MPP just left to descend when it wanted to.
There were some light cross-wind gusts during the tests, but these would have been less than 2 metres/sec. max.
Flight logs were exported to DJI Flight Log Viewer - Phantom Help and the resulting tables were used to determine the exact time that the MPP provided RTH warning, and then when it touched down (i.e. the exact logged flight-time it attained minimal IMU Altitude).
The two batteries used were manufactured in December 2017 with one having 9 charge cycles and the other having 11.

Results
Hensych 8331 carbon-fibre prop's
[Using my battery # 3 ... 9 cycles]
Go 4 popped RTH notifications at 22 minutes 51.5 seconds into the flight
Minimum IMU altitude was recorded at 25 minutes 48.3 seconds into the flight
Motor rpm was observed on the controller to be varying between approx. 464 and 473 prm x10 during the hover

DJI stock 8331'quiet' prop's
[Using my battery #2 ... 11 cycles]
Go 4 popped RTH notifications at 24 minutes 30.5 seconds into the flight
Minimum IMU altitude was recorded at 24 minutes 49.3 seconds into the flight
Motor rpm was observed on the controller to be varying between approx. 497 and 513 prm x10 during the hover

Observations
1) The first test using the CF prop's ended differently to the second using stock DJI. Although the MPP had issued critical battery warning's during the first test, it continued to hover for about a minute after the warning was given, and the Go 4 app' showed --/-- battery remaining while it was in the hover. The second test was different in that the critical battery warning was given and the MPP then landed within seconds afterwards.
2) For the reasons in 1) above, it may be more indicative to use the "The remaining battery is only enough for RTH. Return home now." warning points for the purposes of comparing flight duration.
3) Stability while hovering was slightly but perceptibly better with the Hensych 8331 CF prop's. The presence of a cross-wind during the test made this more apparent, and while vertical movement on the video footage taken during the two flights is minimal, the flight with the stock DJI prop's shows MORE sideways movement as the drone was buffeted through yaw and roll. This movement is apparent on the video for both tests, but is more 'violent' and ranges further when the MPP is flying stock DJI prop's.
4) Based on the point at which the logs show "The remaining battery is only enough for RTH. Return home now." - the stock DJI 8331 prop's are providing the best flight duration (this warning came about 2 minutes later than when flying the CF prop's).
5) A second test run would be wise, swapping the battery/prop combination - to ensure that battery 'difference' is not a factor in this test.
6) No sound measurement [dB] tests were carried out, but the CF prop's have a lower frequency 'hum' than the stock DJI in the hover, and therefore sound quieter then the 'quiet' DJI prop's.

Conclusions
Earlier observations showed a lower rpm reading on the RC controller when the MPP was being flown on Hensych 8331 carbon-fibre prop's. The combination of the lower rpm, and the slightly shorter flight duration seen in these tests, seems to prove that the carbon-fibre prop's are making the Mavic's motors work harder, and therefore they draw more current from the battery - and consequently decrease flight duration.
It was outside the scope of this test, but improvement in stability appears to be a trade-off against flight duration when flying carbon-fibre prop's.
Ideally - both test flights should probably be carried out using the same battery to ensure that there are no issues in the test that are effected by a difference between batteries. However, battery charging time will introduce a significant delay between the two tests, that could lead to comparison issues due to weather and other atmospheric effects.

first of all thanks for doing the test and shareing the results to me props are to UAVs what tyres are to cars you have the choise of putting the recomended ones that came when the car was new they have been optimised by the car maker to suit that car and give the best grip and wear or as most of us do when cost is a factor aftermarket ones the only difference between tyres and props, is cars dont generally fall out of the sky if the tyres fail

 

[Floater]

... The problem is that Mavic props are flexible enough to twist along their length...

Do you have data on this? I only mention this as in the 40's NACA did a great deal of research on propellers and this issue was considered. Now high power airplane propellers are wood and aluminum (now fiber reinforced plastics too) but they are much more highly loaded. The tip speed on the Mavic is about 150 ft/sec while airplanes are Mach limited and run up to about 800 ft/sec. Sorry about the obsolete units, just an old engineer. The difference is even more than the these numbers indicate as both the aero and inertial forces ratio with the square of the speed. The point is that after a lot of work, gluing little mirrors on propeller blades, and cleaver high speed photography it was determined that inertial and aero force generated blade twist was neglectable.

 

[pdegenkolb]

Its basic stuff though, that if you can move an airfoil through the air at a lower speed and get the same lift from it, it's got to be more efficient! That ain't rocket science!

Actually, if you want to talk efficiency, look at hover time on a battery (ore measure battery voltage before and after a fixed time flight). Efficiency for an airfoil is mostly about lift vs drag.

 

[FoxhallGH]

Do you have data on this? I only mention this as in the 40's NACA did a great deal of research on propellers and this issue was considered. Now high power airplane propellers are wood and aluminum (now fiber reinforced plastics too) but they are much more highly loaded. The tip speed on the Mavic is about 150 ft/sec while airplanes are Mach limited and run up to about 800 ft/sec. Sorry about the obsolete units, just an old engineer. The difference is even more than the these numbers indicate as both the aero and inertial forces ratio with the square of the speed. The point is that after a lot of work, gluing little mirrors on propeller blades, and cleaver high speed photography it was determined that inertial and aero force generated blade twist was neglectable.

I calculated tip-speed on the 8331 prop's based on a diameter of 8.3 inches and rotational speed of 5,100 rpm. That comes out as 56.24 m/sec (or 184.51 ft/sec) at the tips. I've got no methods of photographing or testing the torsional blade twist, but have based my statement purely on the observed rpm drop when the stiffer carbon-fibre [c-f] prop blades are used. I've also observed that it takes VERY little torsional force to twist a stock DJI prop to reduce the pitch to zero at the tips. In comparison, the c-f prop takes significantly more force to distort it. Based on the fact that the weight of the c-f prop is similar, and the blade shape and pitch are identical, the only factor that can be reducing rpm when the c-f props are flown, is the stiffness of the c-f material maintaining the pitch angle along the prop-blade length.
The inability of the stock prop to maintain pitch along the complete length of the prop' blade (as well as a reduced longitudinal stiffness compared to c-f), COULD be seen as a good thing, because it turns the prop' into a shock-absorber to soak up a bit of movement in the drone due to turbulence - and in theory - turn it into a more stable camera platform. However, I did observe during my fight tests, that the effects of a gusty cross-wind were dampened out a little more effectively by the c-f prop's - which could be due to them being more responsive to motor control commands?.

 

[FoxhallGH]

Actually, if you want to talk efficiency, look at hover time on a battery (ore measure battery voltage before and after a fixed time flight). Efficiency for an airfoil is mostly about lift vs drag.

True - but - efficiency for a propeller, is actually more about 'power in V's thrust out'. There are a lot of similarities as well as differences between an aerofoil (wing) and a propeller. The biggest of course being that the propeller hits the air at a different velocity at every point along its length. What you are suggesting is pretty much what I was trying to test in my post above, however, I found that the batteries themselves have a big part to play in the test! I did want to get a 'practical' feel for how long I could keep the Mavic Pro in the air on these prop's too.

 

[Butterfingers]

I run both the Master Airscrew and the DJI Mavic Platinums on my MP1. Both seem quieter and seem to have extended my flight time noticeably, not by a major factor but noticeably. My MA set is the orange color which really helps with visibility and orientation.

Just bought a couple of sets of MA props for my MP1. One test flight so far - definitely quieter than the ML low noise and 45rpm slower spin. Still have to run and dndurance test.

 

[Quad808]

I have done a Flight Duration Test today to compare DJI Stock prop's to Carbon Fibre versions. So - here is the equipment, method and results:



Conclusions
Earlier observations showed a lower rpm reading on the RC controller when the MPP was being flown on Hensych 8331 carbon-fibre prop's. The combination of the lower rpm, and the slightly shorter flight duration seen in these tests, seems to prove that the carbon-fibre prop's are making the Mavic's motors work harder, and therefore they draw more current from the battery - and consequently decrease flight duration.
It was outside the scope of this test, but improvement in stability appears to be a trade-off against flight duration when flying carbon-fibre prop's.
Ideally - both test flights should probably be carried out using the same battery to ensure that there are no issues in the test that are effected by a difference between batteries. However, battery charging time will introduce a significant delay between the two tests, that could lead to comparison issues due to weather and other atmospheric effects.

From my flying observations and using CF props for a while now, the conclusions you have reached are spot on. For my flying style, I will take the improved stability - which I chalk up to improved responsiveness, and the overall improved response to stick input. Slightly lower flight times are ok with me, as is any slight strain put on the motors. I am sure they can handle it. DJI uses good components.

 

[old man mavic]

Been watching this post since it began just choose the props you are happy with and that fit your style of flying not a lot more to be said on the subject been very interesting though

 

[Beachboy]

Agree with “old man Mavic” been interesting all these prop tests, I’ll just stick with the DJI. Also interesting how many “You Tubers” keep trying to push the limits of the MA in distance, keep seeing some try to go more than lineof sight. Guess it keeps some of you prop heads busy.

 

[Robert Droner]

View attachment 54994

I use these, never had an issue. Commercial flights included.
https://www.amazon.com/RCGEEK-Plati...w+noise+carbon+fiber+propellers+for+mavic+pro

 

[FoxhallGH]

I use these, never had an issue. Commercial flights included.
https://www.amazon.com/RCGEEK-Plati...w+noise+carbon+fiber+propellers+for+mavic+pro

Looks like these pop up in various guises on both sides of the Atlantic. They are my standard prop-set. Beware when they get 'Drone World' logo's painted on them tho' as that ups the price by about $50!!

 

[FoxhallGH]

I got my MP Platinum some Master Airscrew prop's for Christmas (we now have a European distributor! Yay!!). I AM SOLD ON THESE PROP's!! ... Lovely sound in the air, lower rpm, duration seems to be extended slightly, and the MPP is so rock-steady!