Anyone spent quality time with DJI carbon reinforced props?

Tony Cowan · Apr 3, 2016

Well I wanted black on black after getting bird painted. They sound sweet. I just took them on a 10k thrill ride. I'm still shock but I made it back safe.

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DefaultIT · Apr 3, 2016

dtokez said:
I still can't see the point in these. Speed and agilty are not really nessesary traits on a camera platfrom drone in my opinion. I would rather have a slow, smooth ride personally

Actually there is one other thing I didn't mention that is specific to shooting: they're less reflective. I noticed from some recent sunset footage that I have a few shots with props in the frame that you just can't see...I didn't even realize until the motor pod came into frame. With a long enough shutter speed, the black ones totally disappear

AlexSP · Apr 3, 2016

DefaultIT said:
Actually there is one other thing I didn't mention that is specific to shooting: they're less reflective. I noticed from some recent sunset footage that I have a few shots with props in the frame that you just can't see...I didn't even realize until the motor pod came into frame. With a long enough shutter speed, the black ones totally disappear

Yep, that's true. One more reason I use them at times.

AlexSP · Apr 3, 2016

dtokez said:
I still can't see the point in these. Speed and agilty are not really nessesary traits on a camera platfrom drone in my opinion. I would rather have a slow, smooth ride personally

Actually speed and agility means improved responsiveness, but not necessarily rough or sudden movements. In that regard, it's more about the expo than props themselves, and gimbal stabilization exists to handle the shaking and bumping anyway. Besides, there are situations when you need faster response even if that means a bit more zip than the usual smooth slow pan. I do a lot of sports and other fast action filming, sometimes in the wind, and speed and agility can be welcome, if props can help with that.

ihavesheetsforbrains · Apr 3, 2016

Compared to the standard props, are the CF ones higher or lower frequency sound?

Everyone says 'more quiet'. Some say 'the same'. Anyone do a dB and dBA measurement?

But what is the frequency of sound?

I'm wondering in the context of whether it can be heard from a distance. Lower frequency sound travel longer distances without appreciable energy loss so you'd be able to hear it further.

Msvet · Apr 4, 2016

Drone World sells 3rd party CF props. I don't believe they sell DJI CF props. Their price is like $50 bucks plus. DJI CF are $15 bucks for 2.

ryanmanchester · Apr 4, 2016

Many hours on the cf probes never had any issue.

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Tony Cowan · Apr 4, 2016

ihavesheetsforbrains said:
Compared to the standard props, are the CF ones higher or lower frequency sound?

Everyone says 'more quiet'. Some say 'the same'. Anyone do a dB and dBA measurement?

But what is the frequency of sound?

I'm wondering in the context of whether it can be heard from a distance. Lower frequency sound travel longer distances without appreciable energy loss so you'd be able to hear it further.

Quiet. Without measurement. 60 ft out you hear nothing. Props in video. I was going full boar on the flight. 36mph

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mrcrane2u · Apr 4, 2016

Just send my bird to neroguard to get a plasti bath in stealth black

Tony Cowan · Apr 4, 2016

mrcrane2u said:
Just send my bird to neroguard to get a plasti bath in stealth black

Really. How much did that run? Can you see mine above ?

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AlexSP · Apr 4, 2016

Carbon fiber props (not DJI's carbon fiber reinforced plastic but the 100% made from CF) are a lot quieter. I use them on my other quads like the racing ones, helis and planes, and the sound is very different and a lot more muted. OK the motors are also slightly quieter, but everyone can tell the difference immediately without instruments. The sound is related to prop pitch and stiffness mostly.

darthmogo · Apr 4, 2016

Wow...I must the the only one experiencing violent vibrations on take-on.

Originally the DJI CF props worked great, so I always flew them exclusively. No gain adjustments required.

I took a few months from flying when the FAA registration bs came out.

When I flew again in January, the P3P immediately started vibrating violently after take off with CF props.
I switched to the Plastic props and it was fine. I blamed the cold weather.

I tested again yesterday and saw the same violent vibrations with 2 different sets of DJI CF props - one older, trusted set and one brand new set. The P3P flew great with the plastic props back on.

This CF prop vibration behavior started after FW 1.5., and continues to occur in 1.6 and 1.7.
I've never adjusted the gains on this aircraft, so it doesn't makes sense that I need to start now.

Any suggestions or has anyone else found the need to change their gains?

Thanks

Tony Cowan · Apr 4, 2016

For sure have never seen any vibrations. Ever. That would be easily noticeable. And since I like to take off indoors. There is no doubt.

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Zzyzx · Apr 4, 2016

darthmogo said:
Wow...I must the the only one experiencing violent vibrations on take-on.
[...]
Any suggestions or has anyone else found the need to change their gains?

I've never had (even minor) vibration problems with the DJI CF props. Even before I balanced them (they weren't off by much). Just flew 4 batteries yesterday with them on all current firmware/software with no visible vibration and the video is nice and stable with no jello at all.

FWIW, I flew a battery with the original white plastic props on Saturday. Sound different for sure, the CF props have bit sharper sound and bit louder on max lift. Performance-wise it seems like the CF props might brake quicker/crisper (full forward to full stop), but I wasn't trying any specific A/B tests and it could have just been the way the wind was blowing a that moment or something.

I have updated gains and expos, but not to correct problems, just to adjust the feel to be more the way I like to fly, and not by very much (like 5% on a couple of gains, down to 0.30 on the yaw expo).

ihavesheetsforbrains · Apr 4, 2016

Tony Cowan said:
Quiet. Without measurement. 60 ft out you hear nothing. Props in video. I was going full boar on the flight. 36mph

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To be honest, I can't really hear my my standard props out 60 ft too the last time I tried, but mine is relatively windy area. Maybe in a super quiet place I could.