Please select Into the mobile phone version | Continue to access the computer ver.
Prop broke for "no" reason. Ideas?
1164 32 2017-10-16
Uploading and Loding Picture ...(0/1)
o(^-^)o
ihackstuff
lvl.1
United States
Offline

Hi! First post! I love my Spark! It's really great. My first drone, and I'm really happy with it. So glad I didn't buy a knockoff. :-)

I was flying in sport mode, doing really wicked turns. I guess I was getting more confident and brave. I was in an open area about 1m off the ground, over very short grass, and I think the propeller broke and then the spark took a tumble across the grass. I was very happy that it was over grass and that I have my propeller guards on. It really was a "terrific" first crash. I say "I think the prop broke" because I'm pretty sure it broke which caused the spark to pitch into the ground, but I suppose something else could have happened causing the crash, and then the propeller broke on impact.

First, does the "propeller break" seem like the most logical cause for the crash? It did seem to dive motor-first when it crashed, which suggests the broken prop.

Second, could a bug or something have broken the prop? I've not flown much and do preflight checks to inspect everything and there was no prior damage to the prop. But it's the only thing I can think of.. a nasty beetle or something :-)

Third, if this happens when I'm up really high, will the spakr recorve with three good props, or will it drop like a rock? I think I know the answer, but I'm really hoping I could limp home if that happened somewhere not so nice.

Thanks for any clues. :-)

Johnny
2017-10-16
Use props
TheCyberKnight
lvl.4
Canada
Offline

Did a propeller break or is it one of the pins that lock the propellers in the motor?
Also, did you ever had a crash (even a light one) with these propellers before the incident?

I'm asking because there have been discussions around this. Hitting the propellers can create small damages to the locking pins, which can yield to critical failure during operation.

It is good practice to often check the propellers before flight. I often dismount them and lightly press against the locking pins to verify their integrity.

Once, a pin broke within my fingers, saving me of a possible in-flight failure.
2017-10-16
Use props
Javey
Second Officer
Flight distance : 503458 ft
United States
Offline

I once rammed a tree limb (very small) and my Spark took a 5 ft drop.  Broke one prop, but the rest was ok.  The props seem very fragile, probably broke on impact.
2017-10-16
Use props
ihackstuff
lvl.1
United States
Offline

TheCyberKnight Posted at 2017-10-16 08:38
Did a propeller break or is it one of the pins that lock the propellers in the motor?
Also, did you ever had a crash (even a light one) with these propellers before the incident?

The prop blade broke. The "connecting feet" are fine. I still had to press down on them to release them. But the blade snapped clean in half hallway between the widest part and the tip.

No, I never had a crash. The most that ever happened is we backed it slightly into a bush when we were learning, but it didn't make and terrible noises like the props hitting anything. No bush trimming occurred. :-)

That's good advice about the testing. Thank you!
2017-10-16
Use props
ACW
Captain
Flight distance : 12298924 ft
  • >>>
United Kingdom
Offline

Just to be clear - this is your first drone, you have not flown much and were flying in Sport mode at speeds of 31MPH doing wicked turns at 1M (3.3') above the ground with no obstacle avoidance and the prop guards on - crashed and you think it's because a prop broke? May be but more than likely you simply crashed it...
2017-10-16
Use props
hallmark007
Captain
Flight distance : 5467513 ft
  • >>>
Sweden
Offline

You could put your flight log up here might give you a better understanding of what happened.
Just click on link and follow instructions come back here and post your link.

http://www.phantomhelp.com/LogViewer/Upload/
2017-10-16
Use props
TheCyberKnight
lvl.4
Canada
Offline

ihackstuff Posted at 2017-10-16 09:28
The prop blade broke. The "connecting feet" are fine. I still had to press down on them to release them. But the blade snapped clean in half hallway between the widest part and the tip.

No, I never had a crash. The most that ever happened is we backed it slightly into a bush when we were learning, but it didn't make and terrible noises like the props hitting anything. No bush trimming occurred. :-)

The slight bush brushing may have created a very small dent in the propeller blade that caused its later failure. Sport mode is especially demanding on the aircraft.
Very hard to know for sure.

Glad your Spark is OK.
2017-10-16
Use props
EagleEyeUAV
Second Officer
Flight distance : 1242638 ft
United States
Offline

if you were to hit a bug the spark should have no issues cutting it in half more than likely if you hit something with the prop in clear open air it would be a bird. i have had my close calls with birds as they do tend to not like and chase rc aircraft including drones. could the drone have lost all power or to that specific motor? could somthing have loosened and caused a jam in the motor maybe a rock or somthing magnetic got in somehow?
2017-10-16
Use props
Sparky_17
Captain
Flight distance : 62349 ft
Canada
Offline

I've been lucky enough to have not broken a prop yet even after clipping a few leaves.  But I inspect my blades before launching my spark and checking to make sure the tabs are broken.
2017-10-16
Use props
LouisP
First Officer
Flight distance : 41952 ft
United States
Offline

Prop guards and sport mode don't seem to mix.  Others have had crashes doing that.   
2017-10-16
Use props
DJI Elektra
Administrator
China
Offline

Sorry for the accident. Any error message when you flew your spark? I would recommend you export the flight data for us to locate the problem.
2017-10-16
Use props
ihackstuff
lvl.1
United States
Offline

ACW Posted at 2017-10-16 09:29
Just to be clear - this is your first drone, you have not flown much and were flying in Sport mode at speeds of 31MPH doing wicked turns at 1M (3.3') above the ground with no obstacle avoidance and the prop guards on - crashed and you think it's because a prop broke? May be but more than likely you simply crashed it...

Yes, I was doing all the above. However, I have very good hand-eye coordination, and built up to flying like that after a few weeks of practice and lots of extra batteries. I kept the height locked at 2m, knowing that sport acceleration would drop my height to 1m at times. It was definitely NOT pilot error, unless the Spark is not capable of hard turns at sport speeds. But tight turning figure eights (an upgrade from my simple straight line back and forth at speed) seems well within the specs.
2017-10-17
Use props
ihackstuff
lvl.1
United States
Offline

hallmark007 Posted at 2017-10-16 10:00
You could put your flight log up here might give you a better understanding of what happened.
Just click on link and follow instructions come back here and post your link.

Definitely doing this. Thank you! I'll get that posted!
2017-10-17
Use props
ihackstuff
lvl.1
United States
Offline

TheCyberKnight Posted at 2017-10-16 10:30
The slight bush brushing may have created a very small dent in the propeller blade that caused its later failure. Sport mode is especially demanding on the aircraft.
Very hard to know for sure.

Thanks for the response. I'm glad it's ok too! I did back it into the bush in non-sport mode on day 2 when I was still trying to figure out forward and back. I guess we've all been there. But you may be right about the dent.
2017-10-17
Use props
ihackstuff
lvl.1
United States
Offline

EagleEyeUAV Posted at 2017-10-16 10:50
if you were to hit a bug the spark should have no issues cutting it in half more than likely if you hit something with the prop in clear open air it would be a bird. i have had my close calls with birds as they do tend to not like and chase rc aircraft including drones. could the drone have lost all power or to that specific motor? could somthing have loosened and caused a jam in the motor maybe a rock or somthing magnetic got in somehow?

It definitely wan't a bird. I was maybe 5 meters from the drone when it went down. You may be on to something with the motor powering down.. it all happened so fast. And maybe the blade broke on impact in the grass. I doubt it though because I crashed on the best possible place.. Thick, perfectly cut grass. The Spark didn't even make a sound. :-)
2017-10-17
Use props
ihackstuff
lvl.1
United States
Offline

LouisP Posted at 2017-10-16 13:24
Prop guards and sport mode don't seem to mix.  Others have had crashes doing that.

Very interesting. I didn't know that. It seems like prop guards are almost required for sport mode. That's when you need them the most! :-)
2017-10-17
Use props
ihackstuff
lvl.1
United States
Offline

DJI Elektra Posted at 2017-10-16 20:02
Sorry for the accident. Any error message when you flew your spark? I would recommend you export the flight data for us to locate the problem.
https://www.youtube.com/watch?v=ngEHdAlAh9A

Thanks for this info guys. I'm glad to know about assistant and all the features there. Here is the flight data and the black box. Is there a program I can use to look at this data myself?

Filedropper Link (.zip)

2017-10-17
Use props
JCStorbeck
lvl.3
Flight distance : 3106798 ft
United States
Offline

I imagine Props wear out.  I fly in Sport mode a lot and have noticed there is wear on the leading edge on all of the props.  Also found some small tears about midway along the blades on a couple.  I replace all the props after a tree branch bump and haven't had any crashes.   I wonder if I can add Props to my Amazon monthly delivery along with other staples...

Is their guidance on how many hours of flight before DJI recommends changing propellers?
2017-10-17
Use props
ACW
Captain
Flight distance : 12298924 ft
  • >>>
United Kingdom
Offline

ihackstuff Posted at 2017-10-17 06:04
Yes, I was doing all the above. However, I have very good hand-eye coordination, and built up to flying like that after a few weeks of practice and lots of extra batteries. I kept the height locked at 2m, knowing that sport acceleration would drop my height to 1m at times. It was definitely NOT pilot error, unless the Spark is not capable of hard turns at sport speeds. But tight turning figure eights (an upgrade from my simple straight line back and forth at speed) seems well within the specs.

You are aware that at 30MPH the VPS will not be effective and Sport mode turns off the OA - the drone can not therefore register it's position from the ground or avoid anything. Sport mode is not designed to be used when the drone is at 3.3' above the ground - read the warnings that pop up when you switch to Sport mode and I suggest reading the manual too - the slightest change in the gradient of the terrain and you'll crash at that speed - which you did. Prop guards also make the gains of the drone more susceptible to wind speeds and can drag the drone downward - at 3.3', flying at 31MPH with no VPS or OA whilst doing 'wicked turns' with prop guards on - no, the Spark is not designed for that - no DJI drone is. May be an FPV racer by an experienced pilot with years of practice.
2017-10-17
Use props
TranceMist
lvl.2
Flight distance : 1661591 ft
United States
Offline

Inspect your props regularly. I just found a small tear in one today and replaced it. A small tear under the stress of a strong turn could lead to failure...
2017-10-17
Use props
hallmark007
Captain
Flight distance : 5467513 ft
  • >>>
Ireland
Offline

ihackstuff Posted at 2017-10-17 06:40
Thanks for this info guys. I'm glad to know about assistant and all the features there. Here is the flight data and the black box. Is there a program I can use to look at this data myself?

Filedropper Link (.zip)

You need to put up your log from app to link I had given you,
2017-10-17
Use props
DJI Elektra
Administrator
China
Offline

ihackstuff Posted at 2017-10-17 06:40
Thanks for this info guys. I'm glad to know about assistant and all the features there. Here is the flight data and the black box. Is there a program I can use to look at this data myself?

Filedropper Link (.zip)

Please upload the data to dropbox, thanks for your support.
2017-10-17
Use props
ihackstuff
lvl.1
United States
Offline

hallmark007 Posted at 2017-10-16 10:00
You could put your flight log up here might give you a better understanding of what happened.
Just click on link and follow instructions come back here and post your link.

Wow! This is really really cool! Did you write this? Here's the link I had: http://www.phantomhelp.com/LogViewer/JP3OFIB9E0WDE8V0ZXKS/. Strange though, it doesn't show the crash. This is definitely the file though. The map view is absolutely correct, the path looks right, but the log just ends.

This is so cool. I'm checking out lots of logs! :-)

2017-10-18
Use props
ihackstuff
lvl.1
United States
Offline

DJI Elektra Posted at 2017-10-17 23:28
Please upload the data to dropbox, thanks for your support.

Sorry about that.

Here is the flight log: https://www.dropbox.com/s/wwt6og ... 8-01-34%5D.txt?dl=0

And the other files: https://www.dropbox.com/s/8rob6yg4gmf8qjp/Archive.zip?dl=0

Thanks!
2017-10-18
Use props
ihackstuff
lvl.1
United States
Offline

ACW Posted at 2017-10-17 09:59
You are aware that at 30MPH the VPS will not be effective and Sport mode turns off the OA - the drone can not therefore register it's position from the ground or avoid anything. Sport mode is not designed to be used when the drone is at 3.3' above the ground - read the warnings that pop up when you switch to Sport mode and I suggest reading the manual too - the slightest change in the gradient of the terrain and you'll crash at that speed - which you did. Prop guards also make the gains of the drone more susceptible to wind speeds and can drag the drone downward - at 3.3', flying at 31MPH with no VPS or OA whilst doing 'wicked turns' with prop guards on - no, the Spark is not designed for that - no DJI drone is. May be an FPV racer by an experienced pilot with years of practice.

I read the manual, and the warnings, but thanks for assuming I didn't. :-)

2m off the ground (I suggest you read my thread) in sport mode is perfectly reasonable over perfectly flat terrain, perfectly cut grass, all of which I said in this thread. I also mentioned in this thread that I accounted for wind speeds and "downward" drift, which is why I started at 2m. According to my flight logs, the aircraft never dipped below 4.5 feet during the entire session. Again, perfectly reasonable.

I understand that VPS and OA are not a factor, which is why I was in an open field with a near-perfect grass cushion and plenty of room and stopping distance.

And "I" didn't crash. A propeller broke, and the drone went down. Perhaps I wasn't clear in how I stated this, and sorry if I'm coming across as grumpy, but I figure if I'm going to be chastised in my first post, for not doing anything wrong, I at least have the right to defend myself.
2017-10-18
Use props
ACW
Captain
Flight distance : 12298924 ft
  • >>>
United Kingdom
Offline

ihackstuff Posted at 2017-10-18 06:48
I read the manual, and the warnings, but thanks for assuming I didn't. :-)

2m off the ground (I suggest you read my thread) in sport mode is perfectly reasonable over perfectly flat terrain, perfectly cut grass, all of which I said in this thread. I also mentioned in this thread that I accounted for wind speeds and "downward" drift, which is why I started at 2m. According to my flight logs, the aircraft never dipped below 4.5 feet during the entire session. Again, perfectly reasonable.

Well, you asked the question as to what is possibly the root cause and I gave my answer - whether you wish to accept it and learn from it or not is not my concern. Lets leave it there but in future, I wouldn't fly in Sport mode a such a low altitude - it's common sense more than anything else. From the manual: -
                                                                                                   [size=8.000000pt]S Mode (Sport): The aircraft uses GPS for positioning. As forward obstacle sensing is disabled, the aircraft will not be able to sense and avoid obstacles when in Sport Mode. Intelligent Flight Modes, Pano Mode and ShallowFocus are not available in Sport Mode.
                                         Note: Aircraft responses are optimized for agility and speed making it more responsive to stick movements.
                                         The 3D Sensing System is disabled in S Mode (Sport), which means the aircraft will not be able to automatically avoid obstacles on its route.
The aircraft’s maximum speed and braking distance are significantly increased in S Mode (Sport). A minimum braking distance of 30 meters is required in windless conditions. Descending speed is significantly increased in S Mode.
                                         The aircraft’s responsiveness is significantly increased in S Mode (Sport), which means small stick movements on the remote controller will translate into a large travel distance of the aircraft. Be vigilant and maintain adequate maneuvering space during flight.
                                 
                        
                 

2017-10-18
Use props
hallmark007
Captain
Flight distance : 5467513 ft
  • >>>
Ireland
Offline

ihackstuff Posted at 2017-10-18 06:29
Wow! This is really really cool! Did you write this? Here's the link I had: http://www.phantomhelp.com/LogViewer/JP3OFIB9E0WDE8V0ZXKS/. Strange though, it doesn't show the crash. This is definitely the file though. The map view is absolutely correct, the path looks right, but the log just ends.

This is so cool. I'm checking out lots of logs! :-)

Looking at your log although you say VPS was not on it was on you can’t turn off VPS   You can see when you were flying at times you were getting funny movements of aircraft rising on its own.
I will explain like this right at the end of your log you were throttling full down yet your spark was rising this is caused by VPS , while you say you were flying over perfectly mown grass this is no always the best type of surface for VPS . Vps needs perfect textured surface as well as perfect light if this is not the case it will cause your AC to jump slightly as yours done throughout the flight , when getting low to to the ground you can see your stick movements at 1.06 where you were throttling down your AC was actually rising.
Now as your log doesn’t show what happened at the end of flight, from the conditions you were flying in the speed you were flying at you were on track for something bad to happen , there is no possible way for a prop to break unless it was damaged before flight and aggressive flying made it worse or just one wrong move from you and as I said although VPs was on it was causing more problems for you as you will see throughout the flight.

You may need to rethink trying to fly under these conditions in sport mode as accidents can and will happen.
2017-10-18
Use props
ihackstuff
lvl.1
United States
Offline

ACW Posted at 2017-10-18 06:59
Well, you asked the question as to what is possibly the root cause and I gave my answer - whether you wish to accept it and learn from it or not is not my concern. Lets leave it there but in future, I wouldn't fly in Sport mode a such a low altitude - it's common sense more than anything else. From the manual: -
                                                                                                   S Mode (Sport): The aircraft uses GPS for positioning. As forward obstacle sensing is disabled, the aircraft will not be able to sense and avoid obstacles when in Sport Mode. Intelligent Flight Modes, Pano Mode and ShallowFocus are not available in Sport Mode.
                                         Note: Aircraft responses are optimized for agility and speed making it more responsive to stick movements.

I'm all about learning. that;'s why I'm here. But I'm not sure what I'm supposed to learn from the manual excerpt you posted, or from your comments. You seem to think I was flying too low for sport mode, that my prop guards had something to do with it, or OA, or something, but neither prop guards nor aircraft height are mentioned in this selection of the manual, only a bit about OA and braking distance. I have plenty of stopping room as my flight data shows and plenty of room in general as you can see from the map. I'm not trying to start trouble, especially not as the new guy, but I'm thankful for hallmark007 who is actually taking the time to assist. I'm learning a lot from him.
2017-10-18
Use props
ihackstuff
lvl.1
United States
Offline

hallmark007 Posted at 2017-10-18 07:14
Looking at your log although you say VPS was not on it was on you can’t turn off VPS   You can see when you were flying at times you were getting funny movements of aircraft rising on its own.
I will explain like this right at the end of your log you were throttling full down yet your spark was rising this is caused by VPS , while you say you were flying over perfectly mown grass this is no always the best type of surface for VPS . Vps needs perfect textured surface as well as perfect light if this is not the case it will cause your AC to jump slightly as yours done throughout the flight , when getting low to to the ground you can see your stick movements at 1.06 where you were throttling down your AC was actually rising.
Now as your log doesn’t show what happened at the end of flight, from the conditions you were flying in the speed you were flying at you were on track for something bad to happen , there is no possible way for a prop to break unless it was damaged before flight and aggressive flying made it worse or just one wrong move from you and as I said although VPs was on it was causing more problems for you as you will see throughout the flight.

WOW! A ton of good info here. I had to read it a few times and I'm still amazed. :-)

You said I was throttling down at 1.06. How can you tell? I'm sorry I'm asking dumb questions. I want to learn. I see the altitude going up, like you said. Is it the IMU altitude you're looking at?
2017-10-18
Use props
hallmark007
Captain
Flight distance : 5467513 ft
  • >>>
Ireland
Offline

ihackstuff Posted at 2017-10-18 08:07
WOW! A ton of good info here. I had to read it a few times and I'm still amazed. :-)

You said I was throttling down at 1.06. How can you tell? I'm sorry I'm asking dumb questions. I want to learn. I see the altitude going up, like you said. Is it the IMU altitude you're looking at?

Ok if you you download Csv file you will see all stick movements and a whole lot of other useful information. You will see it highlighted just under picture.
2017-10-18
Use props
ACW
Captain
Flight distance : 12298924 ft
  • >>>
United Kingdom
Offline

He knows a lot of info - his point in advising you to rethink flying under these conditions in Sport mode is especially prevalent.
2017-10-18
Use props
DJI Elektra
Administrator
China
Offline

ihackstuff Posted at 2017-10-18 06:32
Sorry about that.

Here is the flight log: https://www.dropbox.com/s/wwt6ogvrg1wlzej/DJIFlightRecord_2017-10-15_%5B18-01-34%5D.txt?dl=0

Thanks for your update. I would forward it to our engineers.
2017-10-19
Use props
DJI Elektra
Administrator
China
Offline

ihackstuff Posted at 2017-10-18 06:32
Sorry about that.

Here is the flight log: https://www.dropbox.com/s/wwt6ogvrg1wlzej/DJIFlightRecord_2017-10-15_%5B18-01-34%5D.txt?dl=0

Please export the completed flight data. You can follow the video to export the flight control data and the black box data.
2017-10-31
Use props
Advanced
You need to log in before you can reply Login | Register now

Credit Rules