Data Points of Carbon Fiber Quick Release Props

[wingbotics]

Hi,

I purchased from Amazon a set of 4 carbon fiber quick release propellers. In this weekend, I did an set of experiments and collected the following preliminary set of data. I brought them here to share with you. I may do a little bit more experiment in the future to quantitatively see the pros and cons of different props.
______________________________________________ ______ _________
Property Measurement(Hovering of 30 seconds) OEM Non-OEM

Propeller weight (g) 7.25 7.25

RPM 8ft above ground in door (average) 570 510

dB Measurement average 77.3 74.5

dB Measurement minimum 76.0 73.8

dB Measurement maximum 78.3 75.0

dB Measurement peak 79.6 76.5
Stiffness flex very hard
Battery life N/A N/A
_________________________________________________________________________

Besides, I also did live sessions with a total of 40 minutes of fly-time using the CF props with up to 3-4 miles of traveling. Some observations of the blades of the propellers:

• The finish of the CF propellers is substandard at best.
• Uneven of the blade on each side. (or so-called the rake)
• Vibration wasn't immediately clear to me so far.
• Functional level isn't a problem

I have yet to check out the balance of the blades closely.

That's all for now.

 

[wingbotics]

Why not compare to the low noise props? They have more lift than standard props (lower rpm).

To put inpropective, the props in the picture is what I meant.

 

[wingbotics]

I mean if you are comparing a aftermarket prop, why not compare it to the DJI low noise props that they started selling when they released the platinum?

Well, I’ll get there once I buy the oem low noise props. The reason that I went with after market was for the carbon fiber.

 

[RayOZ]

I thought the carbon fibre would be lighter. they weight the same? problem with 3rd party props is they might work fine the first few times, but they can wear out at the joints quicker and cause vibrations. it just creates instability and fails sooner. not worth the risk. you bought it just because it says 'carbon fibre'? sounds like marketing hype.

 

[caspian]

having had extensive experience with "carbon props" on other aircraft, I am wary of cheaply made junk just because someone touts it as having graphite in it. that's no longer a gauge of quality if it ever was.

 

[wingbotics]

I thought the carbon fibre would be lighter. they weight the same?

Yeah, I expected CF to weigh less. Disappointment for sure.

problem with 3rd party props is they might work fine the first few times, but they can wear out at the joints quicker and cause vibrations.

Well, time will tell. I do inspect them of potential weak points or cracks (likewise of the OEM) before each fly.

you bought it just because it says 'carbon fibre'? sounds like marketing hype.

Not exactly... I bought cuz I want to try something different even though I knew before hand that the quality was not good. That was why I called it substandard. Will I buy it again? .
Besides, this is a cheap experimental part to learn and share. I didn't have much contact with CF before so it was nice to check it out. Is this a real carbon fiber? How to prove? Beat me! Please enlighten me on this... If it turns out to be a fake CF, I can only laugh and move on. Not the end of the world!

 

[wingbotics]

that's no longer a gauge of quality if it ever was.

Right on!
The picture that I attached clearly shows the scratched mark about 40x4mm. Either they sold me a used or returned part; otherwise, I call poor quality.
Will it eventually break down? We shall see. Or should I perhaps just return 'em after this experiment.
Does 19 bucks worth my emotion to go through the hassle? Nah, it functions so far.

 

[RayOZ]

Right on!
The picture that I attached clearly shows the scratched mark about 40x4mm. Either they sold me a used or returned part; otherwise, I call poor quality.
Will it eventually break down? We shall see. Or should I perhaps just return 'em after this experiment.
Does 19 bucks worth my emotion to go through the hassle? Nah, it functions so far.

Depends on when it fails? When your mavic is 200ft in the air?

 

[ChipDjipro]

I run CF props and do like them. I have them 4 my Inspire as well.

 

[flight_tee]

well done for experimenting with this. No doubt good quality CF props are available, but how to find them among the low quality that floods the aftermarket?

tailwinds <3

 

[ChipDjipro]

Good CF props R not cheap. There R a lot of cheep ones out there. These R over 200. But you get what you pay for.

 

[caspian]

No doubt good quality CF props are available, but how to find them among the low quality that floods the aftermarket?

as a rough rule of thumb, if they're cheap they are rubbish. high price is certainly not a guarantee of quality, but good composites are never cheap.

I would be willing to try the Drone World ones ChipDjipro pictured above, they look well made.

Drone World

 

[wingbotics]

View attachment 33463 I run CF props and do like them. I have them 4 my Inspire as well.

I'd like to get a set of the drone world propellers and I can absorb a $49.

View attachment 33467 Good CF props R not cheap. There R a lot of cheep ones out there. These R over 200. But you get what you pay for.

The KopterMax? I don't find them online at all. Where did you buy 'em from?
But 200 per set of 4? What currency are you talking? How much in US dollars? If it is US$200, I will have hard time to justify.

 

[wingbotics]

Depends on when it fails? When your mavic is 200ft in the air?

Good point. Props are like tires of a car, aren't they?
Just curious on the durability of the props:
How many times (in miles or duty cycles) will the propellers be used before they will be disintegrated (due to stress or fatigue?)
I assume that CF and plastic must be different in their life cycles. Right? By what? Quantitatively at all? Excuse my ignorance. I am an SW guy and don't know anything about material science even though I could imagine.

 

[ChipDjipro]

I'd like to get a set of the drone world propellers and I can absorb a $49.


The KopterMax? I don't find them online at all. Where did you buy 'em from?
But 200 per set of 4? What currency are you talking? How much in US dollars? If it is US$200, I will have hard time to justify.

Florida drone supply has them. They are for the inspire drones they are foldable props. Yes they are $200 US.

 

[wingbotics]

Florida drone supply has them. They are for the inspire drones they are foldable props. Yes they are $200 US.

Yes, now I found their website. Thanks for the information and clarification.

 

[RayOZ]

I guess $49 for good quality ones might be good. Perhaps real CF is more durable than OEM plastic ones, and can take minor dings.
@wingbotics let us know how they pan out if you get them.
Does it actually increase top speed? I don't think they can claim that, cos I think DJI has made software changes that ease the tilt when it gets past the 65kph. My max ever recorded was 74kph (max 26kph wind gust recorded), a few firmware back. Recently, on a rather windy day (max 30kph wind gust recorded), I flew with the tail wind, and the max was 68kph. It actually slowed the RPM too.

 

[wingbotics]

Here is the data collection (by using the OEM battery fly time) with still the same CF propellers this morning for the records.
Notes:

1. Deviation existd between the beeping started and stopping the stop watch on the iPad. It could be up to 20+ seconds. So the actual time could be up to 20 seconds less.
2. The condition for the fly session on the OEM props was a bit windy so the time may be impacted.
3. I have been thinking whether the fly pattern/behavior (flying speed, climbing/decendding, etc) would change the fly time.

Tried to create tables here but it did not work; therefore, I used underscore and courier font to line up the numbers for visual readability. Please let me know if there is a way to edit tables here like Thunderbird.
Yes, I will order a set of the Drone Propellers for experiments. BTW, I also ordered the Powerextra battery from Amazon. I will check it out with the actual fly time as well.

______________________________________________ ______ _________
Property Measurement(Hovering of 30 seconds)__ __OEM_ _Non-OEM_
============================================== ====== =========
Propeller weight (g)__________________________ _ 7.25 _____7.25
RPM 8ft above ground in door avg 8ft from_MP__ ___570 ______510
dB Measurement average________________________ __77.3 _____74.5
dB Measurement minimum________________________ __76.0 _____73.8
dB Measurement maximum________________________ __78.3 _____75.0
dB Measurement peak___________________________ __79.6 _____76.5
Stiffness_____________________________________ __flex very hard
Battery Fly Time(takeoff to 30% beeps)________ _19:36 ____21.41

 

[FoxhallGH]

I mean if you are comparing a aftermarket prop, why not compare it to the DJI low noise props that they started selling when they released the platinum?

To answer your question ... I replaced the low noise DJI prop's on my MP Platinum with these Hensych 8331 carbon-fibre props: https://www.amazon.co.uk/gp/product/B07848LR4F/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
They are exactly the same shape, and perhaps a gram or two heavier - but without the coloured ends. My experience is that the drone is just as quiet, but a bit more responsive - because the prop's are a lot stiffer and therefore don't flex in flight ( the stock plastic prop's can flex both length and width-wise and therefore the drone can be following the prop's rather than going with them). I've done a hover test because I felt sure that due to the C-F prop's being stiffer, they would require a lower rpm to keep the MPP at the hover.
With my Mavic Pro Platinum hovering at 3 metres, I got the following results:
- Stock DJI low-noise prop's = fluctuating between 501 and 515 rpm
- Hensych 8331 carbon-fibre prop's = fluctuating between 460 and 475 rpm
[Unfortunately I don't have a set of stock DJI Mavic Pro props to do all 3 ...]
Though I have no audio recordings, it also seems (to my ear), that the Hensych prop's have less high-frequency buzz and therefore are even a little quieter than the DJI low-noise
prop's. So - there you are ... Less intrusive at altitude, and needing lower rpm to stay in the air ... must have its advantages!

 

[wingbotics]

I did not get a chance to purchase the oem quiet props myself. It is very nice of you to do so to fill in the missing data. The key here is the stiffness of the props. 60 x 10 rpm is significant in terms of power usage and wear as well. How is the visual quality of the Hensych 8331 in your case? The one that I got was not good though I had put in almost 16 hours of about 100 times with 120 miles of flight milage.

Thank you.

[/QUOTE]

To answer your question ... I replaced the low noise DJI prop's on my MP Platinum with these Hensych 8331 carbon-fibre props: https://www.amazon.co.uk/gp/product/B07848LR4F/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
They are exactly the same shape, and perhaps a gram or two heavier - but without the coloured ends. My experience is that the drone is just as quiet, but a bit more responsive - because the prop's are a lot stiffer and therefore don't flex in flight ( the stock plastic prop's can flex both length and width-wise and therefore the drone can be following the prop's rather than going with them). I've done a hover test because I felt sure that due to the C-F prop's being stiffer, they would require a lower rpm to keep the MPP at the hover.
With my Mavic Pro Platinum hovering at 3 metres, I got the following results:
- Stock DJI low-noise prop's = fluctuating between 501 and 515 rpm
- Hensych 8331 carbon-fibre prop's = fluctuating between 460 and 475 rpm
[Unfortunately I don't have a set of stock DJI Mavic Pro props to do all 3 ...]
Though I have no audio recordings, it also seems (to my ear), that the Hensych prop's have less high-frequency buzz and therefore are even a little quieter than the DJI low-noise
prop's. So - there you are ... Less intrusive at altitude, and needing lower rpm to stay in the air ... must have its advantages!