Order from DJI... Not too shabby! My experience this time around.

[RadioFlyerMan]

On April 26th I ordered a couple of batteries and two sets of props for my MPP from DJI. The package originated from China, and arrived on May 2. I thought that was pretty good timing, given the distance of travel from DJI in China to Honor, Michigan; with the virus thing, etc.

FYI, the batteries charged and worked great. Manufacturing date on the batteries is 12/2019.

The only issue is the new batch of props (8331F) are slightly more flexible than those I have purchased before, causing increased cavitation and motor current errors in high wind situations. Also, during some of those events, the front props will hit the shoulder of the arm as indicated by marks on the bottom of the prop and label tape placed on the shoulder. Also, the pivot pins are a lot tighter, but that's not causing any issues.

 

[Starz]

Interesting. Pictures of the new props and the package they were in please. I don’t think I’ve seen this kind of an issue with props direct from DJI.

 

[RadioFlyerMan]

Interesting. Pictures of the new props and the package they were in please. I don’t think I’ve seen this kind of an issue with props direct from DJI.

Sure. After receiving the props, I switched out my old ones. Then proceeded to fly about 2 flights in an 8 to 15 mph wind. That's when I started to get Motor Current Errors, a lot of them. Strangely enough, even when I was descending under very low power in Sport Mode. My MPP is set to descend at 22 mph in Sport... never had a MCE with such a maneuver.

I then inspected the props and "qualitatively" felt the flexibility between the old props and the new ones. My judgement is that the new batch was a little more flexible. I also saw the marks on the brand new props and decided to add the tape to observe a correlation between an MCE and the blade hitting the arm. There is NOT a one to one correlation with the blade hitting the shoulder and an MCE, so that's why I suspect a cavitation/resonance oscillation event due to prop wash under windy conditions. ( just a theory).

In almost 1200 motor starts/flights since August, 2018, I have a total of 16 flights that have MCE's, with most of them now due to the new props. It's not dirt or bad motors or such because I put the old props on, and with the same wind, same day, same maneuver and I get no MCE's.

That's my story!

Twin pack received from DJI...

Single Pair Box

Mark on bottom of front props

Indicator tape marks after MCE

 

[RadioFlyerMan]

UPDATE: Here's a more severe example of a windy day, and how the props hit the drone. This is one flight. I know it's a windy day, but I've flown in such weather lots of times with no problem. But these props are awful. I did not get any motor current errors in GO 4, but I need to check the flight record. This is so severe, I might re-post this issue under general discussions rather than under this obscure title.

 

[Starz]

I would wonder if the stock props would be better suited for the wind you are dealing with.

 

[RadioFlyerMan]

I would wonder if the stock props would be better suited for the wind you are dealing with.

Well I understand your point. However, with the hundreds of flights I've had, in winds up to 20 mph on the shore of Lake Michigan (it's consistent over water), with no MCE's nor prop scars using the 8331's since day one, I am convinced it's a bad batch.

I just completed some more research. The props that are bad were manufactured on 1/2019. I have two sets of 4. So today, I brought out some more new props manufactured on 4/2020. I just came in from a flight where I was fighting a 10 mph wind, sport mode and all, quick ascend/descend at 22 mph. No problems, no scars on my tape indicators, no MCE's. I say it's a bad batch, and I'm throwing them away. It's not worth it. I was amazed at how much the prop smashed into the arm in my previous post. Maybe it could snap a prop, I dunno. But for $26 versus $1000, (and as Remo said in the movie Casino...), "why take a chance?"

 

[old man mavic]

@RadioFlyerMan i am a little confused ,about the manufactured dates you mentioned,forgive me if i have got it wrong,when you received the props they were in boxes of two, a ccw and a cc is that correct so in total you had 4 boxes ,you mentioned the dates of 4/2020 as being ok,were all the new props you just received have the same date on them i ask because there is over a year between the manufacturing dates which seems odd

 

[RadioFlyerMan]

@RadioFlyerMan i am a little confused ,about the manufactured dates you mentioned,forgive me if i have got it wrong,when you received the props they were in boxes of two, a ccw and a cc is that correct so in total you had 4 boxes ,you mentioned the dates of 4/2020 as being ok,were all the new props you just received have the same date on them i ask because there is over a year between the manufacturing dates which seems odd

Yeah you're correct, my bad. My original post and thoughts were focused on my experience with DJI shipping, and I inadvertently mixed things up as to which order was which. Then on the same day, I figured I'd switch to new props as a preventative maintenance action. I picked up some brand new props from a previous order that was sitting around for a few months. That's when things went south! So then I was focused on my motor current errors and blade scratches and all that. It was that one flight today that was the last straw when I saw the big black marks on my tape. Finally I figured out which was which and installed the latest batch I got a few days ago to see if all the new props were screwy. Thank god the newest batch is OK. Then I went back to look at the manufacturing dates on the boxes, and thus saw the 1/2019 props were the problem. Confusing isn't it!

Bottom line... it's that older batch that is bad, not the new batch.

 

[old man mavic]

@RadioFlyerMan thanks for the reply ,and for unconfusing me ,never mind you still make the best amusing and interesting videos,and i always look forwards to seeing them