It happened again - prop failure #2...

[JamesT1950]

I changed over to carbon fiber props on my second flight and haven't gone back to the original props in over a year.

 

[WWI Flying Ace]

Once I get my bird replaced, I'll be happy to send you one of those rotors. I like the idea of a plastics/dye expert looking at these things. Part of me wondered if this was a dye issue.

I apologize for being unclear: 'Dye inspection' uses a colored dye to assist in visually detecting cracks in the hubs. It is true a good visual inspection under magnification, such as you are currently doing, can find cracks. As long as you're doing that and for what new rotors cost, it's probably the most cost effective course.

 

[jones4drones]

1"/pixel resolution, which puts us @ roughly 300' AGL. I used photo distance (not timing), 75/75 overlap. That said....

My typical shutter speed of 1/1600 pushes motion blur to roughly .2 or .3", which is very crisp. We try to keep motion blur < .6" at all costs.

Ironically, if I use default "Auto" camera settings, typically, software will close the aperture to f/5.6 (if memory serves), and sets ISO to 200(or 400?), and then sets shutter for (what I assume) to be an E.V. of 0. I can only assume this is to avoid lens and/or color aberrations (which isn't really an issue with the P4P camera for mapping photos), and set ISO to native. Ironically, this almost always drives motion blur into .7", which is unacceptable. Therefore, I never, ever, ever use auto settings. If it gets dark enough (due to clouds) that I have to slow shutter speed to 1/800, I'll raise the ISO to 200 so I can speed up the shutter. But that rarely happens. And FWIW, I always manually set color temperature, too, for GS Pro (because auto settings change WB all over the friggin' map). I do the same for Map Pilot, but unfortunately it usurps my manual WB setting, and only offers "sunny, cloudy or auto." So naturally I choose "sunny" or "cloudy." I never choose auto. Not only do these settings produce consistent results, but the photos are always crisp. My business partner (who does all the Pix4D stuff) REALLY appreciates the quality of the photos I provide.

D

Harleydude,
Thanks for the details on your manual settings. How do you calculate the motion blur?
- Jonesy

 

[Smokeywolf]

So your assertion is that propellers must be:

1) Held correctly
2) Torqued correctly
3) Operated within a tight, unspecified temperature specification
4) Not vibrated
5) and not sitting flat on the motor

on drones sold to the general public at Best Buy.

Yeah...no sale on that one, amigo. I'll give you a C for creativity, though.

D

Areo engineer 42 years bud
I deal in fact not fiction

 

[GVDD scout]

Hey doods;

So it seems it happened again...same problem, same conditions...

Deja vu for me....on a mapping mission this afternoon, I had a prop break mid flight. However, this time I have the prop. It seems this time, instead of the prop hub breaking, only one of the two rotors broke off the hub. So technically, I didn't lose a propeller. I only lost HALF a propeller.

Other than using my Phantom 4 an order of magnitude more than most guys, I'm doing nothing wrong.

So, once again I'm going to ask if any of you guys have seen prop failure. That's really the only information I can use at this point. Or if there are any plastics experts out there, perhaps they can look at the photos of the broken prop and share your thoughts.

Worth noting; the remaining 3 props remained essentially intact. One prop ejected upon impact. I know this to be true because the prop was a mere 8 feet from the drone (as opposed to 200' away had it ejected @ 300').

I've submitting an RMA to DJI. I purchased the Care Refresh for the replacement drone, which lasts a year from the purchase date mere weeks ago. The *warranty* ends May 10th. HA! So one way or the other, this will be replaced. Hopefully, sooner than later.

View attachment 98402 View attachment 98403

It's hard to believe this hasn't happened a second time...especially after DJI assured me it wouldn't.

Another thing worth noting, is that I notice the P4P props have the slightest amount of wiggle room on the hub. I can kind of rotate the prop 1° on the hub. They do the same on the Obsidian hub.

The Obsidian props, however, have zero tolerance. They are very tight on the hub. I think I'm going to purchase Obsidian props from now on.

D

Similar to you, but I've had the whole propeller come off 2 times. First was at 200' just into a mapping grid. right rear prop just came off, and down came the drone. Autopilot was fighting like mad and it landed on the side/one leg. Drone was OK to fly with new props. 2nd time was similar, straight up to 399' and just as it turned to go start the grid, off came one of the props. This time, terminal velocity and impact on asphalt destroyed the drone. Sent it off to DJI, no DJI care and out of warranty, in 2 days they agreed that it was a defect and sent a new drone/RC. I did not find out what they saw in the logs, but it was enough to convince them. That is one reason why I now hole the motors and slightly stress the props after installing them.

 

[WWI Flying Ace]

Areo engineer 42 years bud
I deal in fact not fiction

Every failed spaceflight was approved by an aeronautical engineer prior to lift-off. Jus' sayin'.......

 

[Erised]

You are flying your craft a lot harder than most of us, your speed and turning radius is constant so the forces are repeated over and over and fatigue takes it's toll. The hub has 3 sectors with a 2 blade prop, the prop that snapped at the hub was between the sectors hub joints. The one that didn't snap, the vertical web was in the center of the prop to hub mount. I wonder if your first prop fail would have been at the same place. Looks like one vertical web in the center of the prop was stronger (permited flex) and less prone to fail than the prop with 2 webs, 1 at each side of the prop mount. Her's a maybe without proof or data. The surviving prop has 1 web centered to the hub, the load would deform the hub (more) and some of the forces would be distributed in the hub, the prop that snaped had 2 webs, one on each side of the prop, the mounting in the hub would make this a stronger but stiffer triangulated mount, it may not distribute load as well in the hub and the repetition of the same type of loads caused fatigue and it tore off. Just saying that's what I see without having any more data.

 

[Smokeywolf]

Every failed spaceflight was approved by an aeronautical engineer prior to lift-off. Jus' sayin'.......

That's true lol !
Just like the old saying
"what goes up must come down"

 

[KB_Colorado]

Hi Harley, I had the exact same thing happen to me last year. DJI replaced the copter under the Care program, but didn’t seem concerned about the prop failure. I wish there was a fix to this issue, I am now out of warranty.

 

[The Phantom]

All props on my Phantom 4 (standard white props) has some play both horizontally and vertically.
Should i be worried?
I’m not sure swapping the props against new ones would lessen the play, since all 4 props has some play, and they all have about the same amount of play.

 

[Dan cutter]

Hey doods;

So it seems it happened again...same problem, same conditions...

Deja vu for me....on a mapping mission this afternoon, I had a prop break mid flight. However, this time I have the prop. It seems this time, instead of the prop hub breaking, only one of the two rotors broke off the hub. So technically, I didn't lose a propeller. I only lost HALF a propeller.

Other than using my Phantom 4 an order of magnitude more than most guys, I'm doing nothing wrong.

So, once again I'm going to ask if any of you guys have seen prop failure. That's really the only information I can use at this point. Or if there are any plastics experts out there, perhaps they can look at the photos of the broken prop and share your thoughts.

Worth noting; the remaining 3 props remained essentially intact. One prop ejected upon impact. I know this to be true because the prop was a mere 8 feet from the drone (as opposed to 200' away had it ejected @ 300').

I've submitting an RMA to DJI. I purchased the Care Refresh for the replacement drone, which lasts a year from the purchase date mere weeks ago. The *warranty* ends May 10th. HA! So one way or the other, this will be replaced. Hopefully, sooner than later.

View attachment 98402 View attachment 98403

It's hard to believe this hasn't happened a second time...especially after DJI assured me it wouldn't.

Another thing worth noting, is that I notice the P4P props have the slightest amount of wiggle room on the hub. I can kind of rotate the prop 1° on the hub. They do the same on the Obsidian hub.

The Obsidian props, however, have zero tolerance. They are very tight on the hub. I think I'm going to purchase Obsidian props from now on.

D

I’ve been bragging because I flew my P4 on same set of props for over 200 hours then recently it augured in due to prop hub failure. That’s what I get for bragging. Now I have the P4P with insurance. The prop tolerance is much tighter with no wiggle at all. I think over time UV and stress weakened those original props but this does not help you with a brand new drone.

 

[Ross Pearce]

Hey doods;

So it seems it happened again...same problem, same conditions...

Deja vu for me....on a mapping mission this afternoon, I had a prop break mid flight. However, this time I have the prop. It seems this time, instead of the prop hub breaking, only one of the two rotors broke off the hub. So technically, I didn't lose a propeller. I only lost HALF a propeller.

Other than using my Phantom 4 an order of magnitude more than most guys, I'm doing nothing wrong.

So, once again I'm going to ask if any of you guys have seen prop failure. That's really the only information I can use at this point. Or if there are any plastics experts out there, perhaps they can look at the photos of the broken prop and share your thoughts.

Worth noting; the remaining 3 props remained essentially intact. One prop ejected upon impact. I know this to be true because the prop was a mere 8 feet from the drone (as opposed to 200' away had it ejected @ 300').

I've submitting an RMA to DJI. I purchased the Care Refresh for the replacement drone, which lasts a year from the purchase date mere weeks ago. The *warranty* ends May 10th. HA! So one way or the other, this will be replaced. Hopefully, sooner than later.

View attachment 98402 View attachment 98403

It's hard to believe this hasn't happened a second time...especially after DJI assured me it wouldn't.

Another thing worth noting, is that I notice the P4P props have the slightest amount of wiggle room on the hub. I can kind of rotate the prop 1° on the hub. They do the same on the Obsidian hub.

The Obsidian props, however, have zero tolerance. They are very tight on the hub. I think I'm going to purchase Obsidian props from now on.

D

I'm pretty sure that you have balanced your propellers so as you said it seems to be a failure during manufacture if they are failing like that. I hope you sort it out before you loose a UAV altogether.

 

[BigRobs562]

What is DJI recommended time (hours) to replace the props on a P4? I'm asking for me, this doesn't have nothing to do with your post Harley.
Thsnks
BigRob
From
Los Angeles

 

[BigRobs562]

Thanks**

 

[msinger]

What is DJI recommended time (hours) to replace the props on a P4?

DJI has never made such a recommendation. Inspect them carefully prior to each flight and replace them once you notice any damage.

 

[RedDog7]

Does DJI mark it's props in any way, eg, have DJI printed or embossed somewhere on the prop. I just checked the few dozen props I got with a P3 and none of them have trade marks on them. Can I assume they're fakes? A few of them do have a direction of rotation in raised lettering, but no DJI logo. What should I be seeing if it's genuine please? By the way, I check all props for balance when I buy them, plus I check them for proper height. I've found a number over the years where one blade is higher than the other. An easy thing to check, but as yet I've never seen anyone doing similar tests on YouTube. One reason I won't store props where they're subjected to any pressure. EG. in the front pockets of backpacks. Add that pressure plus a good dose of Aussie sunshine and you'll end up with permanently bent props.

 

[msinger]

@RedDog7, where did you buy your props? Did they come in official DJI packaging?

There are lots of P3 props. Check the DJI Store for up-close photos of the props. You can find links to the various P3 props here.

 

[RedDog7]

msinger, I don't buy DJI props period. I've inherited a number of them when they come in package deals with other components, but I've never purchased any. I have however purchased a number of other props which have the same specifications as the DJI props and none have ever failed. As soon as any come into my workshop I balance them if that's required on a Blind prop balancer I designed and add them to my rather large collection of quad and plane props. I'm currently on my 4th shoe box, the other three are full of plane props.

Thanks for the links, but I'm sure I have enough and should I need any more I'll stick with the non-DJI props, my wife doesn't complain as much when I spend less. That's not being sarcastic, it's the way things work in my house. We live from pension day to pension day and money I spend on RC bits and pieces is severely restricted compared to when I earned a good wage. That's the reason I can't boast a squadron of DJI quadcopters. There's nothing I'd like more than to own a DJI Mavic, but that will never happen, the closest I. getting is a Phantom one I've managed to rebuild from parts I've scrounged from Ebay and Gumtree and hopefully a P2 on it's way from China a good friend sent me. all I had to pay was for shipping which was made possible by forgoing a new pair of shoes. Happy flying.

 

[ob1kanokie]

Hey doods;

So it seems it happened again...same problem, same conditions...

Deja vu for me....on a mapping mission this afternoon, I had a prop break mid flight. However, this time I have the prop. It seems this time, instead of the prop hub breaking, only one of the two rotors broke off the hub. So technically, I didn't lose a propeller. I only lost HALF a propeller.

Other than using my Phantom 4 an order of magnitude more than most guys, I'm doing nothing wrong.

So, once again I'm going to ask if any of you guys have seen prop failure. That's really the only information I can use at this point. Or if there are any plastics experts out there, perhaps they can look at the photos of the broken prop and share your thoughts.

Worth noting; the remaining 3 props remained essentially intact. One prop ejected upon impact. I know this to be true because the prop was a mere 8 feet from the drone (as opposed to 200' away had it ejected @ 300').

I've submitting an RMA to DJI. I purchased the Care Refresh for the replacement drone, which lasts a year from the purchase date mere weeks ago. The *warranty* ends May 10th. HA! So one way or the other, this will be replaced. Hopefully, sooner than later.

View attachment 98402 View attachment 98403

It's hard to believe this hasn't happened a second time...especially after DJI assured me it wouldn't.

Another thing worth noting, is that I notice the P4P props have the slightest amount of wiggle room on the hub. I can kind of rotate the prop 1° on the hub. They do the same on the Obsidian hub.

The Obsidian props, however, have zero tolerance. They are very tight on the hub. I think I'm going to purchase Obsidian props from now on.

D

Sorry such a late comer to this conversation, but it came back to memory after I just received a couple sets of the new "quieter" props. Anyone out there using sharp objects to remove the shrink-wrap that DJI puts on the prop hubs? Even a scratch in that area might be cause for a failure? Haven't a clue why they put that shrink wrap stuff on the hubs either. Over-kill? And sure could see someone using something like an exacto knife to take it off. Just a thought I had that might be worth passing on.

 

[KB_Colorado]

Hello HarleyDude, Yes I had the same exact failure, I saw the one blade fly off at about 30 ft. I have been checking props ever since. I flex them and look for cracks. And yes it was a genuine DJI prop.