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Old Mar 25, 2012, 12:59 PM
Registered User
United States, AZ, Tucson
Joined Mar 2008
2,195 Posts
Help!
CRASHED my DJI F550 Hexacopter, don't know why. broke a blade but why?

I was just at the park hovering and crashed the hexacopter.
I'm pretty sure a blade broke and then broke my FPV TX antenna and another blade when it hit the ground pretty gently.
Luckily it was only a few feet off the ground when something happened.
I only have 19 hovers on this and maybe after a while the blades weaken.
I don't have the prop nuts too tight and besides they didn't break at the hub, they broke about 5mm past the hub. And I've never even dinged a prop before this. I balanced all the blades before I ever took the first flight.
I pretty much only hover so I don't think I've even had a big load on the blades.
I did have a gimbal and landing gear for about 3 of the flights that added a pound.

Please look at the video and I'd love suggestions as to why a blade broke.
I put 2 more blades on and it's flying great again but I'm just scared that what if it happens again and I/m high up. I am picking up my Graupners tonight and hopefully there won't be another mishap.
http://youtu.be/Nww9-BDEdjY


Here's also another video that maybe caused the blades to weaken or something.
When I was hovering high up yesterday and coming back down it was wobbling really bad on descent. Looking to see what that was happening also. Fast forward to 1:20 to see the wobbling.
http://youtu.be/YLnyo4Z5DAk
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Old Mar 25, 2012, 01:03 PM
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Joined Feb 2011
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Where you using the stock props? They are known to be bad. The graupners are very good.

So did it become uncontrollable with one broken prop?
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Old Mar 25, 2012, 01:04 PM
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Stock props? Well there's your problem. Switch to 10x5 Graupner E-props and never look back!
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Old Mar 25, 2012, 01:36 PM
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Las Vegas/Lake Tahoe
Joined Feb 2010
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Personally, I don't think that the stock props are that bad. I will condition that with the fact that I have one of the first F450 and F550 kits and I don't crash and burn often. If DJI changed the props since that time, I don't know. I have broken 5 of the 8" and none of the 10" I ran a 10" into a chain link fence and just bent it back into shape and continued to fly. Three of the 8"'s were because of crashes due to Rx issues and totally expected when you dirt dive. The other 2 were because I ran into a bush while flying between two buildings at night. Dumb thumb and totally my fault. I have never had a prop fail in flight without hitting something. There have been reports of failures that were the result of over tightening the base or putting loctight on the prop mount.

I am currently running Graupners of 8 and 10". They work well, sound different and man are they sharp. I cut my finger holding the prop while I tightened the nut. For $4/pair the DJI props are a bargain in my opinion. Graupners are a luxury at almost $10 a piece. I should know I have $250 of them mostly in 8's with some 10's and 11's.

Jasper, do you have pictures of the props and the bases on the motor? That would be helpful.
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Old Mar 25, 2012, 03:13 PM
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United States, AZ, Tucson
Joined Mar 2008
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Hopefully when I get the Graupners tonight I won't have any prop issues.
It didn't go violently out of control, if I was higher up I may have been able to bank yard left and land it.

Ed, I have never even had a prop strike with these props or even bumped them into a wall when walking through the house.
It's just weird how it all of a sudden it just broke.

Any solutions why I'm having bad wobbles on descent?
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Old Mar 25, 2012, 05:05 PM
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Las Vegas/Lake Tahoe
Joined Feb 2010
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If you are trying to come straight down, There will always be some wobble as you are descending in your own prop wash. A little forward motion will help. Some do a little falling leaf motion.
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Old Mar 25, 2012, 05:23 PM
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United States, AZ, Tucson
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Sounds exactly why its doing it.
Thanks a bunch.
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Old Mar 27, 2012, 09:37 AM
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United States, TX, Houston
Joined Jan 2012
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I had a prop break but it was right after I flipped it over. I checked for any prop damage but it was in soft grass and I didnt see anything. It help up till I hit the throttle then it ran across my yard and into my neighbors before I shut it down. Mine was related to the flipover, not sure what happened with yours.
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Old Mar 27, 2012, 09:44 AM
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Quote:
Originally Posted by Tahoe Ed View Post
If you are trying to come straight down, There will always be some wobble as you are descending in your own prop wash. A little forward motion will help. Some do a little falling leaf motion.
Yanno i haven't had this problem on any of my multis, but then again I'm using those waste-of-time reflashed escs instead of the 400hz winner turnigy plush/maytech
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Old Mar 27, 2012, 10:18 PM
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Las Vegas/Lake Tahoe
Joined Feb 2010
9,544 Posts
So TC as a sport flyer, you have never had a wobble coming straight down rapidly? You and your equipment are much better than I am. But then again I don't fly reflashed escs either. I have mostly used Turnigy Plush on my DIY multis. I only started to fly the DJI OPTO's because they came with the kit at a reasonable price.
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Old Mar 27, 2012, 10:26 PM
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Maybe you should give it a try, I heard even if it's a waste of time and scientifically unproven, it actually does work. Though I wouldn't recommend doing it on a DJI frame or you may find out some "small" design issues with it.
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Old Apr 08, 2012, 09:05 PM
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Joined Oct 2011
475 Posts
550 blade breakage

Yep I broke a prop tonight and it sounded just like that. I could hear the thing crack before it came down from 40 feet or so. Cheap DJI blades I guess.

Jerry

Quote:
Originally Posted by jasper7821 View Post
I was just at the park hovering and crashed the hexacopter.
I'm pretty sure a blade broke and then broke my FPV TX antenna and another blade when it hit the ground pretty gently.
Luckily it was only a few feet off the ground when something happened.
I only have 19 hovers on this and maybe after a while the blades weaken.
I don't have the prop nuts too tight and besides they didn't break at the hub, they broke about 5mm past the hub. And I've never even dinged a prop before this. I balanced all the blades before I ever took the first flight.
I pretty much only hover so I don't think I've even had a big load on the blades.
I did have a gimbal and landing gear for about 3 of the flights that added a pound.

Please look at the video and I'd love suggestions as to why a blade broke.
I put 2 more blades on and it's flying great again but I'm just scared that what if it happens again and I/m high up. I am picking up my Graupners tonight and hopefully there won't be another mishap.
http://youtu.be/Nww9-BDEdjY


Here's also another video that maybe caused the blades to weaken or something.
When I was hovering high up yesterday and coming back down it was wobbling really bad on descent. Looking to see what that was happening also. Fast forward to 1:20 to see the wobbling.
http://youtu.be/YLnyo4Z5DAk
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Old Apr 08, 2012, 09:30 PM
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Las Vegas/Lake Tahoe
Joined Feb 2010
9,544 Posts
I broke an MK prop today and barely touch the ground. I have only had one prop break in air and it was an APC at 25F. They do not like the cold. I have never broken a Graupner. You may want to try them.
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Old Apr 15, 2012, 09:59 PM
DJI Support
Las Vegas/Lake Tahoe
Joined Feb 2010
9,544 Posts
I crashed my WKM F550 big time today. 60 feet up and inverted down. 4 Arms and 5 Graupner props. I broke the top and bottom plates as well. It was not a DJI problem, the AR8000 bound but not the satellite. It was my fault for not paying attention closer. Oh well.
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Old Apr 15, 2012, 10:05 PM
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United States, MD, Frederick
Joined Aug 2010
394 Posts
Errr.... I'm not so familiar with Spektrum.... Did it switch diversity to the sat rx and then lose signal? Or just go beyond range?
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