S800 issue

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ProPilotWannaBe

Member
Thanks Serval! I will continue to be careful and watchful for the dangers that exist with this design.

By the way, for anyone interested, this weekend I saw a friend's setup and he had the IMU mounted underneath of the bottom plate. When I asked him about it he said it was DJI's recommendation after he had the FOD on a commercial shoot in front of the customer.
 

Parapyro

Parapyro

Precision Aerial Filmworks
I think what Serval is saying is that the anti vibration kit works SO well to keep the IMU from vibrating, that it masks the fact that the frame is still vibrating. And since the frame vibrating can cause a crash you wont have any warning with the kit installed. Its like if you were ill and the medication you are taking hides the symptoms, but doesn't cure the problem so you go on and get sicker and sicker. What I was trying to say was how do we address the vibration issue, without throwing the whole thing in the trash, and continue to fly safely?
 

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Serval

Member
ProPilotWannaBe said:
Thanks Serval! I will continue to be careful and watchful for the dangers that exist with this design.

By the way, for anyone interested, this weekend I saw a friend's setup and he had the IMU mounted underneath of the bottom plate. When I asked him about it he said it was DJI's recommendation after he had the FOD on a commercial shoot in front of the customer.
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Could believe me, i will never mount IMU underneath bottom plate ! :dejection:
It's feel DJI takes your friend for a fish or Beta tester... :shame:
Your friend must share his bad experience video on youtube, for all Pilots take care what could happen.
 

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Serval

Member
Parapyro said:
I think what Serval is saying is that the anti vibration kit works SO well to keep the IMU from vibrating, that it masks the fact that the frame is still vibrating. And since the frame vibrating can cause a crash you wont have any warning with the kit installed. Its like if you were ill and the medication you are taking hides the symptoms, but doesn't cure the problem so you go on and get sicker and sicker. What I was trying to say was how do we address the vibration issue, without throwing the whole thing in the trash, and continue to fly safely?
Click to expand...

Thanks you, you have traducted my means, my words.:02.47-tranquillity:
 

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pgodin

New Member
I'm new, this is my first response to any thread. I'm not associated to DJI or it's representative anywhere. I have purchase an S800 with all related products from DJI in Feb/2013. Initial flight showed a slight left drift with no gimbals. The Z15 is now attached, all software upgrades have been done. One motor overheating, this maybe an indication of an ESC issue. Also, flying a straight line and making a full stop causes a immediate and serious drift to the right. Flying backwards and making a full stop causes an immediate drift to the left.

If you have or have add this issue, please advise of any corrective measures that work. I have tried calibrating, compass degree corrections, software/firmware upgrade.
Many thanks
 

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Eggbeater

Member
I have a slightly diff angle on this vibration issue. All models will vibrate and at diff. frequencies. The S800 has more of it's share due to weaker arms than say a thick-walled 25mm CF tube (or alum). But the real danger and source of the irritation is the IMU internal dampening. A lot of heavy acoustic science goes into designing helicopters. That's why they are so expensive compared to planes and require such maintenance. The DJI IMU's in general seem to be on the weak side for handling vibrations. Too much dampening and they don't control as they should. Too little dampening and they vibrate apart eventually (FOD). The WKM is supposed to have better dampening than the NAZA (or higher grade internal components) and thus cost more money. At least you would hope that is the case. Most of us can't mess with all that but we can do some things. Keep wirings (or anything) from vibrating against the IMU sides. Some of these MR look like a big mess. No wonder they go down. Anchor stuff that hangs out (even wire bundles) so they don't flop around and add vibes. Balance anything you can such as props, motors etc. And last, experiment with diff. dbl sticky pads to adjust the IMU mounting. 3M is good but is it too hard? And if you start getting white lights from your LED, start thinking about not flying and replacing your controller. Godin, with a scratch built 1000mm Hex and WKM with latest firmware, I have noticed drifting shortly after stopping "forward" flight. But can't be of further help right now until my radio returns. Could be a week before I can experiment. Just make sure your overall aircraft is balanced in all directions testing all arms. Just a slight out of bal. can make for a drift.
 
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ProPilotWannaBe

Member
EGG, I have to say I agree entirely with your perspective. I work with and design equipment for real helicopters, including flight control systems, and your assessment of the impact of vibrations is more in line with my thoughts. Thanks for sharing!
 

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Eggbeater

Member
Vibes

ProPilotWannaBe said:
EGG, I have to say I agree entirely with your perspective. I work with and design equipment for real helicopters, including flight control systems, and your assessment of the impact of vibrations is more in line with my thoughts. Thanks for sharing!
Click to expand...

I'm picking up good vibrations (Beach Boys). There you go, folks. One dummy + One expert = One pretty good idea. Sure wish I could hang with you one day. Fascinated with "eggbeaters" all my life. To the Canadian gentleman, I just PM'd you. Change of heart. Probably ain't balance. Fix heat issue first. Swap like arms (CCW vs CW) and see if the heat follows the arm. That'll tell you if it's the esc/motor or the main hub. If you can afford a pre-soldered arm, get it. Replacing components is not for the squeamish. Thinking the drift is an IMU or compass orientation thing. Ref the PM. EGG
 

photobobga

photobobga

Member
Greetings,

In regards to isolating the IMU from vibrations I read that using a layer of MoonGel under it helps. It needs to be snugged down with two small zip nylon straps. I'm planning to use this on the IMU and Rx on my upcoming new hex.
 


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Eggbeater

Member
PhotoBob. Would like to see how that works out. I always wondered about using those zip ties on the IMU casing. Seems it could cause vibrations since they can't fasten tightly (or too tight). Small Velcro straps might be better if the sticky tape won't hold from the bottom by itself. But have seen many done with the zip ties so... I also heard of using the Align sticky pads which seem to be softer than good ol' 3M. That's what I'm trying next just to try to make the IMU internals last longer. EGG.
 

Parapyro

Parapyro

Precision Aerial Filmworks
HAHA, I have had those arm stiffeners on TWO separate S800's and although they help, they dont correct any of the issues I am having with these craft. There are HUNDREDS of aftermarket products made to correct issues that are inherent in the DJI S800 due to poor design, poor construction, and sub par materials. Maybe DJI should just FIX THE ISSUE!!!!!!! I have roughly $17,000 invested in these two aircraft. You would think they would at least return my emails.
 



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