Please select Into the mobile phone version | Continue to access the computer ver.
[Guide] How to check for prop wear.
12117 289 2020-4-30
Uploading and Loding Picture ...(0/1)
o(^-^)o
siowxsen
Second Officer
Flight distance : 1952359 ft
Malaysia
Offline

Thanks for sharing..
2020-5-14
Use props
Markforrester99
lvl.1
Flight distance : 43278 ft
United Kingdom
Offline

I have just fitted some carbon props to my mavic mini after getting fed up with the constant error messages since the last firmware update. They are solid and very robust. It took a while to get them to screw in properly due to the excessive use of loctite. First impressions are good but i haven't really pushed them hard yet. I have the Dat file for this test flight with alot of hovering but my CSV viewer refuses to work. Has anyone got an email address i can send the Dat file to so you can put it on the forum. Would be interesting to see the various motor RPMS with the carbon props
2020-5-16
Use props
Markforrester99
lvl.1
Flight distance : 43278 ft
United Kingdom
Offline

Markforrester99 Posted at 5-16 09:54
I have just fitted some carbon props to my mavic mini after getting fed up with the constant error messages since the last firmware update. They are solid and very robust. It took a while to get them to screw in properly due to the excessive use of loctite. First impressions are good but i haven't really pushed them hard yet. I have the Dat file for this test flight with alot of hovering but my CSV viewer refuses to work. Has anyone got an email address i can send the Dat file to so you can put it on the forum. Would be interesting to see the various motor RPMS with the carbon props

2020-5-16
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

Here's my latest graph after doing the new hover test, I'm using my original front props as rear props and a replacement set of props for the front.



I've gone ahead and re-pictured my current props using the new flat surface white background method.

You can see the replacement props on the front have the slight upward pitch to them while only one of my rear left props has it.
Let's take a closer look at the Rear

It's really hard to tell but I can make out a slight upward pitch on one Right Rear prop, the others to me look flat. The RPM information doesn't show an increase of RPM for the rear props dispute visually looking flat.


EDIT: Upon closer investigation and the help of photoshop Both Rear Left do have an upward pitch while my Rear Rights really don't look any better.


I want to re-run the above tests but on the original Rear props, try the smoothing technique and see if it's possible to "restore" a bad prop by smoothing and change the rears again for my last set of upward pitched props to see if any difference is made.

2020-5-16
Use props
bestaccountingh
lvl.1

India
Offline

All the details are in this post are very interesting & I will share this post with my all friends because all the details are in this post is brilliant. Fix QuickBooks Error H505
2020-5-16
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

Markforrester99 Posted at 5-16 09:54
I have just fitted some carbon props to my mavic mini after getting fed up with the constant error messages since the last firmware update. They are solid and very robust. It took a while to get them to screw in properly due to the excessive use of loctite. First impressions are good but i haven't really pushed them hard yet. I have the Dat file for this test flight with alot of hovering but my CSV viewer refuses to work. Has anyone got an email address i can send the Dat file to so you can put it on the forum. Would be interesting to see the various motor RPMS with the carbon props

I sent you a PM with a link to upload your DAT file. Really curious to see how those props do. Would you mind to share where you purchased them from, and what was the price?
While the material is of course better (and more expensive) than plastic, some no-brand CF props are actually worse, simply just because those manufacturers don't really possess the necessary knowledge to make good props.
2020-5-16
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

Zbip57 Posted at 5-14 18:15
I might have selected different option settings in CsvView. (See image)

I only replaced the props once.  Starting left-rear, then adding right-rear, then left-front.  The right-front are the only remaining original blades.

Agreed.  The props likely do not need to be replaced unless an actual Motor Speed warning is triggered.  Even then, if the props are only marginally bad they may continue to fly well and never trigger the same warning again.  But if you get repeated warnings, it's certainly worth paying attention to.  These graphs do illustrate that there is a measurable difference in the motor speed output when using fresh props compared to old props.

Exactly, well said. Some people fail to understand that it's not a black or white situation, where you have "good" and "bad" props... it's everything in between. The warning is just a threshold, you might hit it today and not tomorrow. And even if you get it, your MM might continue to fly well and never experience any real problems. But high RPMs tell you clearly that your motors have to spin faster than they should, which means your MM is not performing as it should.


We still don't know what threshold actually triggers the Motor Speed warning.  Is it just when the motor exceeds some finite number like 1600 rpm?  Or is it when some threshold difference is exceeded between the actual response of the motor versus what thrust the controller is commanding and expecting of the motor?

We can't say. It could be a sophisticated algorithm that combines RPMs and IMU data, or something simple like a threshold and a rolling average. I would assume it needs to take into consideration what the pilot is doing, as of course going full stick in S-Mode in turbulent air forces the motors to work much harder than C-Mode on a calm day.
Our basic indoor hover test in that respect is more accurate, and can detect under-performing props well before they trigger a warning, because it's done in repeatable conditions.
2020-5-16
Use props
Markforrester99
lvl.1
Flight distance : 43278 ft
United Kingdom
Offline

Hi, I have sent the DAT files to the two guys who asked for them. The reason i went for the CF props is that although they are more expensive and probably of dubious quality i can be alot happier that they wont deform in flight as much as the DJI ones. Having changed the props twice now and now fitted the CF props im hoping they will give some reliable sustained performance. It would be interesting to see what the motor RPM graphs show thats for sure. I got them from ebay uk and they were shipped from china. I think the full set was £15. The box is marked rcgeek.net
2020-5-17
Use props
Ralle
First Officer
Flight distance : 11289 ft
Finland
Offline

ABeardedItalian Posted at 5-16 11:01
Here's my latest graph after doing the new hover test, I'm using my original front props as rear props and a replacement set of props for the front.

[view_image]

2020-5-17
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline


Here's your hover graph:

Here's your graph from the other file:

And each part broken down:




I don't know what you were doing for the above but your hover test looks excellent, be careful with carbon props as I've read a lot about them not being balanced properly but your data looks good.

Here's the Dat files if anyone else would like to check them.
Dat #1 Dat #2
2020-5-17
Use props
GroTToFlyeR
Captain
Flight distance : 1148937 ft
United States
Offline

Thank you very informative
2020-5-17
Use props
Zbip57
Second Officer

Canada
Offline

Markforrester99 Posted at 5-16 09:54
Would be interesting to see the various motor RPMS with the carbon props

Import the csv file into Excel and average the motor speeds, not counting those under 8000rpm takeoff & landing,
=AVERAGEIF(FL2:FL3809,">8000")   In my spreadsheet the motor speeds are columns Fi,FJ,FK, FL.

Here's a comparison of the average motor speeds in hover.  The fresh DJI props hover at slightly lower motor speeds compared to the carbon fibre props.


120ccpm's Hover Test
# New Left Back props:
Right Front: 9582 RPMs
Left Front: 9386 RPMs
Left Back: 9431 RPMs
Right Back: 9960 RPMs

Zbip57's Hover Test
With fresh L.Front, L.Rear, & R.Rear blades.  R.Front remains original;
R.Front - 9756
L.Front - 9603
L.Back -  9974
R.Back -  9564

Markforrester99's Hover Test (@ Carbon props)
R.Front - 10814
L.Front - 10611
L.Back -  10820
R.Back -  10071
2020-5-17
Use props
Markforrester99
lvl.1
Flight distance : 43278 ft
United Kingdom
Offline

Zbip57 Posted at 5-17 07:23
Import the csv file into Excel and average the motor speeds, not counting those under 8000rpm takeoff & landing,
=AVERAGEIF(FL2:FL3809,">8000")   In my spreadsheet the motor speeds are columns Fi,FJ,FK, FL.

That's interesting so that means in theory it could make the power issue worse because the motors are working harder.

In terms of balancing there is a slight patch where the balance is out. When you transition from the props spinning on the floor to take off there is a slight vibration but once at idle speed all vibration has gone.
2020-5-17
Use props
Markforrester99
lvl.1
Flight distance : 43278 ft
United Kingdom
Offline

Thanks for looking at the files. Everytime i try to open them up i keep getting java runtime issues and even with the latest version it still says i haven't got it installed
2020-5-17
Use props
Zbip57
Second Officer

Canada
Offline

Markforrester99 Posted at 5-17 07:38
Thanks for looking at the files. Everytime i try to open them up i keep getting java runtime issues and even with the latest version it still says i haven't got it installed

I had a heck of a time trying to install the Java Run Time Environment on my Win-10 system.  The CsvView program kept popping up an error msg telling me I needed to install the Java RTE.  Clicking on the link provided in the error message brought me to the Java download link, clicked that, installed fine, still get the same error message every time trying to run CsvView.

Three days later I finally found a separate page where I could get the 64-bit version of the Java RTE, but it required registering a free account with Oracle.  Of course I can no longer find that page again.

Try here instead for the 64-bit version:  https://www.java.com/en/download/manual.jsp


2020-5-17
Use props
Zbip57
Second Officer

Canada
Offline

Markforrester99 Posted at 5-17 07:36
That's interesting so that means in theory it could make the power issue worse because the motors are working harder.

In terms of balancing there is a slight patch where the balance is out. When you transition from the props spinning on the floor to take off there is a slight vibration but once at idle speed all vibration has gone.

At hover the motors are running only slightly faster with those carbon props.  That seems to indicate that the carbon props are slightly less efficient at generating lift compared to a fresh set of original DJI props.   But that's still well below the 16000 rpm peak motor speeds we've seen with some deformed props.

If the carbon fibre props are stiffer and more resistant to being flattened and  deformed, by whatever mechanism causing that to happen to the original DJI props, then the carbon props are likely an improvement if they can hold their shape better over the long term.
2020-5-17
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

Markforrester99 Posted at 5-17 07:38
Thanks for looking at the files. Everytime i try to open them up i keep getting java runtime issues and even with the latest version it still says i haven't got it installed

Unless you already had Java installed for other reasons, I suggest you uninstall every version you ended up with, reboot, then use the offline installer. Here's the link to the 64-bit version, which is on the page Zbip57 mentioned above.
2020-5-17
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

Markforrester99 Posted at 5-17 07:36
That's interesting so that means in theory it could make the power issue worse because the motors are working harder.

In terms of balancing there is a slight patch where the balance is out. When you transition from the props spinning on the floor to take off there is a slight vibration but once at idle speed all vibration has gone.

Mixed feelings about your CF props. In a hover, they spin 500-1000 RPMs faster than a new set of DJI props. But they likely hold their shape much better than plastic ones, so at the end, in actual flight conditions, they might turn out being  a better choice (your second test looks good).
I don't like the vibration issue, though.
2020-5-17
Use props
Markforrester99
lvl.1
Flight distance : 43278 ft
United Kingdom
Offline

Thanks for the link to the 64bit installer. I might take the drone out for a proper flight tomorrow and get some sustained sports mode flying and see what happens with the motor rpms. What are the motors rated too?  Since I got the motor error after the last firmware update I've been reluctant to push the drone
2020-5-17
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

Markforrester99 Posted at 5-17 11:06
Thanks for the link to the 64bit installer. I might take the drone out for a proper flight tomorrow and get some sustained sports mode flying and see what happens with the motor rpms. What are the motors rated too?  Since I got the motor error after the last firmware update I've been reluctant to push the drone

MM motors are 2900kV, meaning that theoretically, under no load, they could spin up to ~24k RPM with a fully charged battery (8.4V). In reality, under load, they seem (very early indications) to max out well below that number. You can try new DJI props if you don't feel comfortable with the CF ones. Also note that some people got the Motor Speed error disappear by refreshing the firmware with DJI Assistant. If you have not done it yet, it's worth a shot.
2020-5-17
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

Here's some interesting data for you guy's, went out for a flight the other night and looking at the data I would think my Left Rear would be Suspect but from the hover and over tests show otherwise but those were controlled and not subject to wind like this flight was and when wind is involved the motor is working much harder and is close to triggering a motor speed warning. I was also flying into a cross wind and the Left Rear was working harder already to keep the drone flying straight. I flew up to 300 feet and went out about 3k feet before coming back and dropping and doing some close flying before landing.


If I understand the graph at 300' I was experiencing gusts up to 13mph and was getting high wind warnings well before at around 10mph, I need to check FRAP to find out when the errors came about but I had a few early on. You can see during the high points of wind the left Rear was really doing it's all and follows the wind, how little wind still has it's effects on it. After lowering altitude things got a lot better looking but with this information I'm going to replace the Rear Left again and retest when conditions are close enough. Since the Rear Left is my original Front Right  that while it's fared better being on a slower motor that when exposed to the stresses of the Rear it exaggerates the issue.
2020-5-17
Use props
itchyeyeballs
Second Officer
United Kingdom
Offline

Hi guys,

Posting some results after getting some prop strikes and an uncommanded descent whilst flying in a bit of wind (suggestion from 120ccpm in my original thread - https://forum.dji.com/forum.php? ... 1&extra=#pid2160120).

This test was in indoors, no control inputs, drone is two-three weeks old, all props as from factory (no accidents) apart from the front right which has one blade damaged from prop strike (why only one I wonder )

Average speeds using the quoted Excel formula:

Motor:Speed: RFront = 10071.57487
Motor:Speed: LFront = 10070.7655
Motor:Speed: LBack = 11816.18507
Motor:Speed: RBack = 9331.206051



I'll replace the back left and front right and try again when I have some time.
2020-5-17
Use props
itchyeyeballs
Second Officer
United Kingdom
Offline

itchyeyeballs Posted at 5-17 13:27
Hi guys,

Posting some results after getting some prop strikes and an uncommanded descent whilst flying in a bit of wind (suggestion from 120ccpm in my original thread - https://forum.dji.com/forum.php? ... 1&extra=#pid2160120).

ok, I changed the props

New values

Motor:Speed: RFront = 9731.233112
Motor:Speed: LFront = 10380.14529
Motor:Speed: LBack = 9367.782002
Motor:Speed: RBack = 9550.895361

2020-5-17
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

Let us know if you are still getting prop strikes on the Front Right, there has been reports in the past of the mini's Front arm's warping/deforming and that play's it's own role in the prop strikes but everything looks a lot better outside the Left Front that could be better but overall this looks much better.
2020-5-17
Use props
itchyeyeballs
Second Officer
United Kingdom
Offline

ABeardedItalian Posted at 5-17 14:04
Let us know if you are still getting prop strikes on the Front Right, there has been reports in the past of the mini's Front arm's warping/deforming and that play's it's own role in the prop strikes but everything looks a lot better outside the Left Front that could be better but overall this looks much better.

Will do

Strange how the left front is now out of whack, seemed fine in the first test, I guess it's due to the shifted balance with the new props on the other arms.
2020-5-17
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

ABeardedItalian Posted at 5-17 13:03
Here's some interesting data for you guy's, went out for a flight the other night and looking at the data I would think my Left Rear would be Suspect but from the hover and over tests show otherwise but those were controlled and not subject to wind like this flight was and when wind is involved the motor is working much harder and is close to triggering a motor speed warning. I was also flying into a cross wind and the Left Rear was working harder already to keep the drone flying straight. I flew up to 300 feet and went out about 3k feet before coming back and dropping and doing some close flying before landing.

[view_image]

I don't think you calculated your average RPMs for the hover test, but from the graphs it seems your motors were spinning a bit faster than mine (new props are in the 9400-9500 range).
Despite that, your Left-Rear in your recent flight was remaining below 16k, and it never triggered the Motor Speed warning, so we can assume it was within the limits.
Our little hover test is no substitute for real-world conditions, but so far we're getting some good indications out of it, so I still consider it valuable. Over time, we might be able to correlate Motor Speed warnings with hover averages, at ballpark. Something like: if you're above X RPMs in hover, those props are likely to trigger a Motor Speed warning.
2020-5-17
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

I got averages working in Open Office the Function is =AVERAGEIF(GK1:GKxxxxx;">8000") for those who don't have excel.

Here's my hover test graph again, original front props on the rear and new props on the front:

Right Front :10281
Left Front   :10366
Left Rear    :10478
Right Rear  :9936

So I got around to testing the Original Rear Props on the Rear motors again, I wish I would of just flown them as is from the last time I used them but I did give them a gentle massage first, visually they were flat again and any damage from bending was non visible. I have to make a video on how I massaged them but I made sure to follow the pitch and end with a little bend/bow/flick upward to give them there upward pitch look, I'm really surprised by these numbers as there almost the same as my previous setup. Remember these are the props I "Destroyed" and that were "Trash" to begin with if you listened to you know who... Still with the damaged tips and all they look almost better then my first tests though we weren't doing the hover test yet so I can't say for sure. I'm going to try flying these tomorrow to see if when under actual load that they don't re-deform under stress. I'm going to change them out once more for a complete set of replacements to see if I can't get closer to your 9500 avg.


Right Front :10285
Left Front   :10452
Left Rear    :10360
Right Rear  :10025
2020-5-17
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

If you already have a full set of fresh props, I would try that. But your numbers are not horrible and you're not getting any Motor Speed warnings for now, even in demanding conditions, so you're probably ok. I'm happy where I am with my MM, glad I did the test and spotted a weak Left-Rear, which has been replaced. I put extra care storing my MM and I might repeat this test in a couple months to see where I am... what's most important to me is to have a baseline, a reference point. Thanks to this thread, I think we have that.
2020-5-17
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

Went out for a small flight this morning testing my original Rear Props this morning, I never thought I could fly as well as it is on these props again after how much I had to bend them to cause my FC to lag out.

RF: 10450
LF: 10438
LR: 11260
RR: 11203
A high wind warning as I got closer to 400 feet and at 420 I had a max power load reached error which I wasn't expecting, I brought it down and tried to re-create the hover/fall I had but it was flying like a normal mini so I gave up after a few good tries.

Foggy this morning, It felt like I was flying through the clouds.

2020-5-18
Use props
zeb_
lvl.4
United States
Offline

Hi,
After having played with a friend's MM for a few weeks, I finally bought my own. And having followed all that prop story, I can report some stats made with a brand new MM.

  • I purchased the MM with the Fly more combo. The MM arrives already packed in the case. Props were maintained (very tightly) horizontally with paper bands and were stored in the case as pictured (albeit the fact the drawing is slightly incorrect, as reported before). I immediately took pictures of the props as shown below, before first flight.
    20200515_214724_m.jpg 20200515_215457_m.jpg 20200515_215601_m.jpg
    One can see that the LBack props look slightly more flatten than the other ones (in particular RFront, which is the same CCW prop type). Contrary to the others it does not have this slight pitch up at its extremity. This is less dramatic as reported by sean-newbie in this thread: https://forum.dji.com/forum.php? ... 172&pid=2155310 but looks similar to Ralle's picture at https://forum.dji.com/forum.php? ... 705&pid=2150960 (notice that Ralle did not have the motor speed error).
  • I used DJI Assistant 2 on a W10 PC to update the firmware. Assistant 2 indicated that the MM arrived with FW version 0400, and I could upgrade to 0500, which I did. Everything was fine and Assistant 2 showed that current FW was indeed 0500.
  • I installed DJI Fly (and checked server sync was indeed disabled), connected to the RC and linked the RC to the MM which I also registered. Interestingly, the DJI Fly app notified me that there was a FW update available. This was surprising and I went ahead anyway with the upgrade, which seemed to complete fine. After restart of the MM DJI Fly did not request to upgrade the MM anymore. I checked in Assistant 2 that the FW was 0500 and that there was no error. Must be a bug in DJI Assistant which fails to bump the version number read by DJI Flay maybe...
  • Inserting the 2 other batteries led to their upgrade too and everything went fine.
  • Maiden flight was done outside but with absolutely no wind. I auto took off and did the hover test: 2 times around 1 minute. No error shown. .DAT file was extracted from phone, used DatConv to get the CSV data and plotted data and calculated speed mean over 8000 rpm with an R script. Here is the figure:

    Hover

    Hover

    RFront: 8717.768
    LFront: 9585.989
    LBack: 9335.398
    RBack: 9018.147
    One can notice that all speeds are under 10K rpm. RFront is significantly lower, but LBack, which is often the culprit when it comes to the speed error, is not the fastest with 9.3K.
  • The day after I did a first test at low altitude outside with almost no wind. Did not go higher than 10 meters and was very careful and gentle with the MM, flying slowly around trees, using Mode P and C. Here are the results:

    Low altitude

    Low altitude

    RFront: 8906.579
    LFront: 9519.387
    LBack: 9355.405
    RBack: 9240.972
    Again very consistent results with the RFront and RBack slightly faster, which is expected when manoeuvering. No error.
  • In the afternoon I went in a countryside place clear of houses and with some woods. Low wind. This time I pushed it a bit more, going up to 30 meters, and piloting a bit farther and faster (Mode S at some point). Here are the results:

    Higher altitude

    Higher altitude

    RFront: 9141.595
    LFront: 9713.071
    LBack: 9741.867
    RBack: 9531.982
    As expected, motors go a bit faster on average, since the MM went faster and higher and in a more open space. But still no error and we never reach 10K on average. Highest rpm was around 13K with LBack and RBack at offsetTime 510, but this was very transitory and possibly while using the Mode S (I cannot ascertain this, is it shown in the logs?)
  • Conclusion: I am delighted with my MM. No motor speed error and it seems that even with a brand new MM it can be a miss and hit.  But I was really interested in the rpm data and here I show that despite the LBack props looking (slightly) more flatten the MM flies extremely well and the motor never reach 10K on average. These props have therefore suitable lift power and there is no outlier. We know from published graphs that the motor speed error is consistently linked to a high mean rpm. This means that the difference between props leading to high mean rpm and 'normal' speed may be small, and that an apparent flatten shape may not be a problem (to a certain point I suppose). Maybe other factors (such as plastic quality, flexibility?) play a role.


Voilà! Hope this helps.

2020-5-18
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

zeb_ Posted at 5-18 05:00
Hi,
After having played with a friend's MM for a few weeks, I finally bought my own. And having followed all that prop story, I can report some stats made with a brand new MM.

Very good post, thanks! Yes your Left Rear looks flat, but RPMs show you're actually good, which means you are. Enjoy your new MM and keep an eye on those props when you store it.
2020-5-18
Use props
zeb_
lvl.4
United States
Offline

120ccpm Posted at 5-18 06:54
Very good post, thanks! Yes your Left Rear looks flat, but RPMs show you're actually good, which means you are. Enjoy your new MM and keep an eye on those props when you store it.

Thanks. Coming back to the "flattiness" of the props. Maybe the point is not the upward pitch at the end of the tip, but also the overall shape. There is plenty of literature about propeller efficiency, with various theories and models with different level of detail or complexity.

Besides, if there are suggestions of 'experiments' I could do then I am happy to help. At least I think that I will analyse the .DAT files after every flight to have an idea of the performance changes on the long run.
2020-5-18
Use props
zeb_
lvl.4
United States
Offline

Another point: DJI's advice on checking props is very shaky: 'If the propellers are slightly misshapen, can straighten them out'. What does misshappen mean in this context? upward pitch? left to right shape? front to back shape? Which shape is good? What are the tolerances? Also, what is straighten them out? With which tool? Without a precise gabarit and tolerances this advice is extremely vague, if not hazardous.
2020-5-18
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

zeb_ Posted at 5-18 07:12
Another point: DJI's advice on checking props is very shaky: 'If the propellers are slightly misshapen, can straighten them out'. What does misshappen mean in this context? upward pitch? left to right shape? front to back shape? Which shape is good? What are the tolerances? Also, what is straighten them out? With which tool? Without a precise gabarit and tolerances this advice is extremely vague, if not hazardous.

Yes, I agree. We're seeing very clearly that one cannot really tell how a prop will perform by simply looking at it, yet DJI recommends to eyeball it... that's not really reassuring, considering how important props are on a drone.
2020-5-18
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

I finally changed the rear props to my last set of replacement props, and started doing testing and have found some interesting results.

Here's the 1st hover test with new Rear Props, the fronts have already been replaced and are to be considered "new" by myself.

RF: 10145
LF: 10367
LR: 10147
RR: 9376

Huh the Right Rear looks and is performing closely to your guy's "New" props, I wanted to be sure so I ran the test again.

RF: 9868
LF: 10529
LR: 10189
RR: 9496

Well the Rear Right is still performing better, but now the Right Front is performing better. I think a few hundred RPM is allowed for margin of error, but I was curious that it could be something to do with the screws so I repeated the above test after checking that all screws were tight.

RF: 10088
LF: 10427
LR: 9975
RR: 9499

I didn't run as long of a test this time as I was just double checking that the tightness wasn't a factor, so I decided to try changing the screws on the Rear Left to see any if at all difference that makes.

RF: 10100
LF: 10398
LR: 9808
RR: 9492

Just changing the screws had a 200RPM difference, when doing my replacements I've used the new included screws but now I'm wondering if I should try other screws on the other motors to see if I can't get a perfect balance or if I should leave well enough alone at this point. I think this is really as good as it's going to get unless I get a full replacement set and change all the props fully because the Fronts do have a little air time on them.
2020-5-18
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

Can't see why screws would be a factor, unless they are bent or worn out. DJI recommends changing props in pairs, but doesn't mention screws. Are you doing your tests indoor, no wind, same conditions? I really see no reason for screws to affect your numbers, but if you're doing the test outside, a bit of wind can make the RPMs go up.
2020-5-18
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

120ccpm Posted at 5-18 12:19
Can't see why screws would be a factor, unless they are bent or worn out. DJI recommends changing props in pairs, but doesn't mention screws. Are you doing your tests indoor, no wind, same conditions? I really see no reason for screws to affect your numbers, but if you're doing the test outside, a bit of wind can make the RPMs go up.

Inside, no a/c, no fans, what I can see from the used screws is the paint or anodizing has worn off and is bare metal. While all the new screws are solid black with a little blue thread locker on the end from factory, my guess is the added material but I'm not coming up with anything solid but repeating the test yielded similar results, I need to try going back to the new screws but I think we have good enough information for now. I want to do another high altitude wind test to check for max power load error and to see if these props get anywhere near 15k.
2020-5-18
Use props
ABeardedItalian
First Officer
Flight distance : 1063107 ft
United States
Offline

Rain cleared up but the wind didn't, was a bit more spicy out but I still put it through it's paces.

RF: 11032 Peak: 14577
LF: 11350 Peak: 15394
LR: 10961 Peak: 15347
RR: 10658 Peak: 14869

No max power load reached warning, plenty of high wind warnings. These numbers are just a shy slower then the previous high altitude test with the old setup, I went higher and experienced higher winds during this flight so while it's not a great margin of difference it's still an improvement overall.
2020-5-18
Use props
120ccpm
First Officer
Flight distance : 967441 ft
United States
Offline

ABeardedItalian Posted at 5-18 12:40
Inside, no a/c, no fans, what I can see from the used screws is the paint or anodizing has worn off and is bare metal. While all the new screws are solid black with a little blue thread locker on the end from factory, my guess is the added material but I'm not coming up with anything solid but repeating the test yielded similar results, I need to try going back to the new screws but I think we have good enough information for now. I want to do another high altitude wind test to check for max power load error and to see if these props get anywhere near 15k.

I doubt the finishing of the screws is thick enough to make a difference, compared to inevitable tolerances on the prop itself, but it could be. I think you have the best configuration you can have, and some good data points to base future decisions on.
2020-5-18
Use props
Occams Razor
First Officer
Flight distance : 303455 ft
United States
Offline

You really need to operate your drone in Sports Mode at maximum horizontal speed with full front pitch (30 degrees) if you want to see how your propellers are ultimately performing.   Below is a flight I took a couple of weeks ago.  There is greater separation at full elevator but at lower speeds the front propellers have a greater differential.  Also, in full reverse, the rear left propeller has lower speeds than the right.  FYI, these RPM's never trigger a Motor Speed warning.   Also, these are my original propellers that have been stored off and on in the Fly More Case for about 3 months.  

2020-5-18
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules