Register Now

heliaddx · 09-08-2012, 07:21 PM

This happened to me twice already.

My beautiful Align T600 ESP which was smooth as butter before I installed the AceOne, and have have been flown without a single crash or part that needed to be replaced for over a year since it was put together, crashed because of a malicious input to the cyclic of the AceOne.

First incident was when I tried to land it with the AceOne in cruise mode. After touching down, the heli all of a sudden flipped to the right smashing the blades to pieces, stripping the gears, bending the FB, main shaft, feathering shaft and giving the boom a big dent from the blade hitting it.

My first instinct was to put on the throttle hold but the blades just kept on spinning. I didn't realize it at the time that the AceOne needed to be switched to Manual Mode before the throttle hold can work because AceOne controls throttle during the Atti and Cruise Modes.

To see my beautifully tuned never-been-crashed chopper do this was gut wrenching. It was brutal.

I have since only landed in Manual Mode and never in any of the auto modes.

After the crash I replaced almost all of the mechanical components including the main shaft bearings. Everything except the FB rotor head and the blade grips.

Even after all these changes, with the AceOne still installed, I never got the heli as smooth as it was before.

Just to clarify, smoothness was based on the amount of vibration and jello present in the video taken by a GoPro hard mounted with foam and secured with velcro straps.

I replaced the FB head with a FPL head and started to get acceptable results with the video. But the AceOne didn't seem to like the FBL head and the heli would fly around like it was drunk - all wobbly. There was an extreme difference between the flight characteristics of the FB head and the FBL head with the AceOne.

Nevertheless, the video was pretty smooth -still not as smooth before the AceOne Installation and Crash, but acceptable enough.

The heli was flying drunk but I have flown it successfully several times.

The second time the AceOne crashed my T6 was just yesterday. This time I was flying low over some tall grass looking for a fellow flyer's plane which had crashed and was missing.

I had flew around 200 meters out in my first pass and was heading back, when at around 160 meters over the tall grass, the heli which was flying even more drunk then usual, all of sudden flipped over in mid air and crashed into the tall grass.

I was like 'Oh shit! Now my heli is lost in the tall grass trying to look for a lost plane." I was pissed.

The tall grass was in patches of land in between streets of this undeveloped gated village. From the video I remember that the heli crashed around 3 streets out from where we where, so we took the car and drove there.

We couldn't find it.

I drove back to the base camp and took my video goggles, and looked for the heli by occasionally looking into the goggles and seeing if there was signal from the video tx. It worked and we were able to find the heli, which had crashed into the tall grass missing the pavement by only about a foot.

The beauty of it was the heli was unscathed, the only casualty was my home made gimbal, my gopro lens which crashed into the clay and the battery which got pierced. Apart from that the heli had no stripped gears, and the blades were scratch free.

I'm a bit weary of flying the AceOne now till I find out what the cause of the crash was.

Why would it all of a sudden flip like that for no apparent reason?

Here are the particulars surrounding the flight:

- New field
+could be RC interference although I highly doubt it as the area is undeveloped
+also the AceOne was set to RTH in the event of radio link loss.

- A little higher altitude than normal as the field itself is elevated on top of a hill over looking the bay.
+Could it have been a barometer malfunction

- Tall grass had cat's talis on the ends of it

-Heli was flying more drunk than usual
+Usually the heli flies as if it had 5 beers but yesterday if flew like it consumed around 8 beers.

Any ideas would be appreciated.

FSAMedia · 09-09-2012, 01:09 AM

If the issue isn't simple gain settings, it sounds as if the imu location isn't set correctly or you have a faulty gps. Try a firmware update and triple, quadruple check you imu location settings and cg settings.

Titusx · 09-09-2012, 01:56 AM

The drunk behavior is related to the mounting position of the IMU and GPS.
Check it a couple of times if it is set right, I have a hard time with it, as they do not use the standard space coordinates, Z is vertical and Y horizontal. Also colours in the graphics are reverse. Red for positive and green for negative.
Also check for straight line flight, if it tends to go right or left with only elevator stick input (in atti or cruise mode), you have to compensate rotating the GPS to the opposite direction. Remember to recalibrate each time you rotate GPS, just in case.
Adjusting the GPS orientation reduce a lot of the drunk effect.

I could not get rid of all the drunk behavior, but it flight way smoother now. Here is a vid.
[ame]http://youtu.be/_rhgymt9eJA[/ame]

Regarding the flip over, I think it has to be related to the system check in Ace One Assistant. You may have one set reversed. Also check it twice as the assistant first levels the swashplate and then do the motion. So sometimes you could get confused.
Loosing Tx signal could be the cause of the flip over. When trying to come back home and having one control reverse, it try to level it inverted.

I am really happy with my Ace One, it do what it is supposed to do, and had paid itself.
A couple of month ago, I was flying over a lake and lost Tx signal. Fortunately I had set the TBH and did not lost my heli.

Exposure · 09-09-2012, 02:35 AM

"If the issue isn't simple gain settings"

"You may have one set reversed."

Ever get the idea you asked the question in the wrong place ?. I wonder how you managed to fly around previsouly if either of these were true.

This is what DJI support should help you with : did you get any joy from them ?.

Titusx · 09-09-2012, 03:42 AM

Quote:

Originally Posted by Exposure

"If the issue isn't simple gain settings"

"You may have one set reversed."

Ever get the idea you asked the question in the wrong place ?. I wonder how you managed to fly around previsouly if either of these were true.

This is what DJI support should help you with : did you get any joy from them ?.

He was asking for ideas, and we are trying to help.
If you have a better idea of what is happening, please tell him.

Exposure · 09-09-2012, 07:22 AM

I did. I said he should ask DJI customer support because he is being sent on a wild goose chase here.

""Better to keep your mouth closed and be thought a fool than to open it and remove all doubt"

R_Lefebvre · 09-09-2012, 07:38 AM

My guess is that you have a vibration somewhere.

This sounds somewhat like a problem we have with Arducopter. It will fly the helicopter very well, but as soon as a bearing starts to go, it's game over. I've had it tip over into the dirt right on take-off a few times. The problem is it is more sensitive to vibration than a human is, so it's hard to detect the problem.

Every flight controller is sensitive to this, some of the others that are built into FBL controllers will detect the problem, and kick themselves out of stabilize mode with little or no warning, which can have pretty nasty consequences too.

In my experience, at least for our system, it is much more sensitive to very high frequency vibration than it is on low frequency stuff. Blade tracking, blade imbalance, don't seem to cause a problem. But if the bearings are going on the tail drive shafts, it's done.

This is why it's so difficult to detect. Most of you guys are used to sorting out all the lower frequency vibrations that you can feel by hand, or see in the video. But if a bearing is going, you might miss it. The only thing you can do is simply take it all apart, and feel every bearing by hand, and be super picky. If it's not *perfect*, throw it out.

I think I should just get a Pez dispenser for tail drive bearings.

I've tried many types of vibration damping systems for the IMU, but nothing seems to work. Anything that is soft enough to stop the high frequency vibration, can cause control oscillation on the pitch/roll axis.

I should also say, that the vibration that can screw up the IMU will NOT screw up a tail gyro. So again, it's why heli guys aren't used to looking for this.

Something I'm curious about with the DJI, is the magnetometer calibration. You guys talk about rotating the GPS mount, what you're really doing is realigning the mag that built into the GPS puck. This really shouldn't be necessary. I assume you've done a ground calibration? The problem is that electric helis generate their own magnetic field when running, both from the DC power wiring, and from the batteries themselves.

We developed an in-flight calibration routine to compensate for it. Fly around manually while collecting data, land, and then run a routine which uses the power of your PC to generate a field compensation. Then the mag is more accurate in flight with all these Mag fields in effect. Does DJI do anything like that?

Titusx · 09-09-2012, 08:40 AM

DJI's IMU has its own dampeners inside the box, so you do not need to use any foam on it. Also it has some led status on the GPS/Compass where you can see if the vibration level is ok or not. one or two white leds flashing means that the vibration level is more than it could handle.

Regarding magnetometer. You are right. We do field calibration, but as you said it has some deviation when in flight. So realigning GPS/Compass solve this problem.

Bob O · 09-09-2012, 09:57 AM

Quote:

Originally Posted by Exposure

"If the issue isn't simple gain settings"

"You may have one set reversed."

Ever get the idea you asked the question in the wrong place ?. I wonder how you managed to fly around previsouly if either of these were true.

This is what DJI support should help you with : did you get any joy from them ?.

Please use the quote function properly so we know who and where you grabbed them from without having to search for it.

Quote:

Originally Posted by Titusx

He was asking for ideas, and we are trying to help.
If you have a better idea of what is happening, please tell him.

Yes, please try to be more helpful.

Quote:

Originally Posted by Exposure

I did. I said he should ask DJI customer support because he is being sent on a wild goose chase here.

""Better to keep your mouth closed and be thought a fool than to open it and remove all doubt"

Please don't disrespect your fellow members like you've done here. A remark like that was uncalled for. If your only help is that the OP should contact DJI customer support, then great. The other guys will continue helping him out.

splitboarder · 09-09-2012, 10:47 AM

Not a DJI fanboy, but how can you say it wasnt a servo that went bad? It sounds like a bad servo. For a heli to be flying in ff and then roll over sounds like either the aileron or elevator servo going out or loosing signal

splitboarder · 09-09-2012, 10:55 AM

Not a DJI fanboy, but how can you say it wasnt a servo that went bad? It sounds like a bad servo. For a heli to be flying in ff and then roll over sounds like either the aileron or elevator servo going out or loosing signal

I will agree with you on the 'drunken sailor" description though. I think the DJI is a long way from a commercial use flybarless controller

Goldenhour · 09-09-2012, 11:05 AM

Quote:

Originally Posted by Exposure

I did. I said he should ask DJI customer support because he is being sent on a wild goose chase here.

""Better to keep your mouth closed and be thought a fool than to open it and remove all doubt"

Better to remain silent and be thought a fool then to speak up and remove all doubt.-Abraham Lincoln

I love that quote. Pertains to me more times in my life than I'd like to admit. I'm probably "speaking up" right now

helicek · 09-09-2012, 11:15 AM

Hi heliaddx,
I am sorry it had happened to you. It must be very annoying to experience something so fatal and not knowing why it had happened.
What you have experienced sounds very much like "glitch". Do you do range check?(while motor running, camera recording and downlink transmitting)
I agree with Exposure. You should contact DJI and see if they come up with a sensible solution. Yo may need to record flight log and send the "zipped" file to DJI. I had to do that for my faulty GPS module and they eventually replaced it, but you have to be very determined and some how let them realize that. Terry was the name of the person who took care of all that for me.
Good luck,
Ahmet

terry.wan@dji-innovations.com
Dajiang Innovation Technology, DJI
http://www.dji-innovations.com
http://www.dji-hobby.com
Tel: 086-0755-26656677 ext:203
MSN: terry.terrific@hotmail.com
Skype: terry.one

R_Lefebvre · 09-09-2012, 02:49 PM

Quote:

Originally Posted by splitboarder

Not a DJI fanboy, but how can you say it wasnt a servo that went bad? It sounds like a bad servo. For a heli to be flying in ff and then roll over sounds like either the aileron or elevator servo going out or loosing signal

I will agree with you on the 'drunken sailor" description though. I think the DJI is a long way from a commercial use flybarless controller

Really? The Ace One doesn't fly well? I assumed like most things DJI it was very good. Is it just a matter of FBL not flying well? What about FB?

I have to say that it's much more difficult getting a heli to fly really well on autopilot than it is for a multi-rotor. Not entirely sure why.

splitboarder · 09-09-2012, 04:57 PM

As a flybared controller it is rock solid. I do like mine. I myself could never get it to my liking in the flybarless mode. But there are several people using it as a flybarless controller in both ap and scale, I just couldnt get it dialed in

hellafilming · 09-09-2012, 07:45 PM

What type of radio are you using? are you on spectrum?

heliaddx · 09-09-2012, 10:46 PM

Thanks for the overwhelming response guys.

There are just a few points I need to clarify with my post to give a clearer picture of the events.

My first crash happened when I first installed the AceOne, which was a few months ago in March.

The second one happened just this weekend.

The first crash happened after I landed and the skids were already on the ground (AceOne was in Cruise Mode). The second one was in the air flying low around 15 to 20 feet off the ground around 160 meters away.

The first crash was with an FB head and the second one was with an FBL head.

Between the first and second crash I had been flying it both as an FB and FBL unit.

As an FB unit it was rock solid and amazing in it's position hold both on X and Z and its Y axis. The heli flew like it was on rails - but the video was full of vibration, which no amount of heli tuning could fix. I suspect the Main Rotor Head might have been slightly bent on the first crash.

As an FBL unit the video was acceptably smooth although the heli flew like it had a few beers.

I have flown the unit in all sorts of conditions and elevations, from valleys to mountains, from really windy days to really calm days, early in the morning and late at night. Never flew in the rain and have no plans to. I've flown over lakes, grass, trees and many different terrain without any problems.

I fly mostly FPV with this aircraft although I do also fly it LOS, and the AceOne unit flew great in between the two incidents.

As an FB unit it was perfectly dialed in including the RTH, it flies straight and true back to home whenever I switched it to RTH on my Tx or during the one time where I lost Tx signal. RTH was luckily set that day as failsafe and it performed flawlessly.

So the unit was working well apart from these two incidents. That is why I am very much confused and a little wary of flying it again.

The last incident was so random, although the heli did show signs of flying more drunk then usual.

I had flown it about two weeks prior on August 25, again without a hitch. In fact if I remeber it well the heli performed really well flying less drunk than it had been before.

Do you guys land in the auto modes without a problem?

I have ceased to land in auto mode ever since my first crash.

After the second crash, since the heli and the unit itself had no visible damage, after a thorough pre-flight check I strapped on new batteries and it flew flawlessly again. This was a few minutes after the crash, and the only thing I replaced was the main batteries.

Again it just seemed so random that the heli flipped like that without a reason - hence my hesitation to fly it again.

@FSA
I don't think it's the gain settings, since the heli had been flying flawlessly in between the two crashes.

@Titusx
My mounting for the unit as an FB controller/autopilot seems correct since it flies really well as with an FB head. The problem arose when I changed my head from FB to FBL - that is when the 'drunk behavior' came about. Do you think the mounting of the AceOne unit should be different between the two types of heads?

I left the mounting parameters, both hardware and software, same for both. The things that I changed in the software when I migrated to FBL was to switch on the FBL option in AceOne Assistant and I also had to tune the autopilot settings. But I've been flying FBL since May with acceptable results.

@Exposure
You are right in your deduction of the unit flying previously and I am taking your advise and contacting DJI as right after I type here. Thanks.

@R_Lef
I have tuned the heli mechanically over and over and there is still some form of high frequency vibration that can be seen as jello in my hard mounted GoPro video. Unlike before I installed the ace one. Although the unit had been performing well prior to the two freak incidents. I have two Cameras on the unit a GoPro and an FPV Cam.

The FPV Cam is mounted simply with a an L shaped aluminum flat bar which is stuck to the front of the heli with double sided tape. So the FPV cam is about as 'hard mounted as it gets with no dampeners between the heli's body an the camera apart from the double sided tape. The FPV cam shows no vibration whatsoever. So vibration, is at the bottom of my list in terms of suspects for the crash.

@splitboarder
After the crash I checked all swash servos and tail servos and they seemed to run perfectly well. I was able to fly a whole pack in both manual and atti mode after the crash for a whole battery pack. But this could be an issue. I test my servos by first checking their range without load and then with load (by applying some pressure with my finger and checking for clicks as a sign of stripped gears) - how do you test yours?

@Ahmet
Thanks for the suggestions and sharing your experience. Would you have an idea what caused the glitch and whether it's a preventable occurrence? How do I record a flight log? Is there a feature in AceOne Assistant to do this or would you need a separate logger such as Eagletree?

@hella
My RcTx is a Hitec Aurora 9 and my Vtx is 5.8ghz 500mw.

helicek · 09-10-2012, 04:29 AM

heliaddx

"Would you have an idea what caused the glitch and whether it's a preventable occurrence?"
Any component on the heli that transmit some sort of RF can cause glitch. It can be difficult to track down since it only happens once in a while. I would do a range check with reduced tx power while every thing is on and running. I would definitely remove the main blades while doing that.

"How do I record a flight log? Is there a feature in AceOne Assistant to do this or would you need a separate logger such as Eagletree?"
You need a micro SD card. Just insert it in the slot on the main unit and fly. It starts recording when ACEONE is switched on and stops when it is swithed off.
You can open the files in simple text edit but it won't tell you much

So you need to have DJI take a look at the file.
Good luck,
Ahmet

Flying Tivo · 09-11-2012, 02:05 PM

It really sounds like a static discharge to the rx side servo cables. Make sure you have grounded the tail boom to the frame and the frame to the Negative of the battery. If using a belt for the tail drive lube it up silicone or wd-40. If a torque tube drive, check your bearings inside the tail boom.

Felipe

heliaddx · 09-11-2012, 08:37 PM

Thanks FlyingTIvo.

Guys, is it safe to land in the atti or cruise mode? I've been landing in Manual Mode since my first crash due to landing in cruise mode - which made DJI flip the heli.

@Helicek
Thanks - I don't remember the slot for the microSD but I'll look for it - I might have placed a card there already from when I first set it up way back in March.

09-08-2012, 07:21 PM	#1 (permalink)
heliaddx Registered Users Join Date: Jul 2011	DJI Ace One Flip of Death FOD This happened to me twice already. My beautiful Align T600 ESP which was smooth as butter before I installed the AceOne, and have have been flown without a single crash or part that needed to be replaced for over a year since it was put together, crashed because of a malicious input to the cyclic of the AceOne. First incident was when I tried to land it with the AceOne in cruise mode. After touching down, the heli all of a sudden flipped to the right smashing the blades to pieces, stripping the gears, bending the FB, main shaft, feathering shaft and giving the boom a big dent from the blade hitting it. My first instinct was to put on the throttle hold but the blades just kept on spinning. I didn't realize it at the time that the AceOne needed to be switched to Manual Mode before the throttle hold can work because AceOne controls throttle during the Atti and Cruise Modes. To see my beautifully tuned never-been-crashed chopper do this was gut wrenching. It was brutal. I have since only landed in Manual Mode and never in any of the auto modes. After the crash I replaced almost all of the mechanical components including the main shaft bearings. Everything except the FB rotor head and the blade grips. Even after all these changes, with the AceOne still installed, I never got the heli as smooth as it was before. Just to clarify, smoothness was based on the amount of vibration and jello present in the video taken by a GoPro hard mounted with foam and secured with velcro straps. I replaced the FB head with a FPL head and started to get acceptable results with the video. But the AceOne didn't seem to like the FBL head and the heli would fly around like it was drunk - all wobbly. There was an extreme difference between the flight characteristics of the FB head and the FBL head with the AceOne. Nevertheless, the video was pretty smooth -still not as smooth before the AceOne Installation and Crash, but acceptable enough. The heli was flying drunk but I have flown it successfully several times. The second time the AceOne crashed my T6 was just yesterday. This time I was flying low over some tall grass looking for a fellow flyer's plane which had crashed and was missing. I had flew around 200 meters out in my first pass and was heading back, when at around 160 meters over the tall grass, the heli which was flying even more drunk then usual, all of sudden flipped over in mid air and crashed into the tall grass. I was like 'Oh shit! Now my heli is lost in the tall grass trying to look for a lost plane." I was pissed. The tall grass was in patches of land in between streets of this undeveloped gated village. From the video I remember that the heli crashed around 3 streets out from where we where, so we took the car and drove there. We couldn't find it. I drove back to the base camp and took my video goggles, and looked for the heli by occasionally looking into the goggles and seeing if there was signal from the video tx. It worked and we were able to find the heli, which had crashed into the tall grass missing the pavement by only about a foot. The beauty of it was the heli was unscathed, the only casualty was my home made gimbal, my gopro lens which crashed into the clay and the battery which got pierced. Apart from that the heli had no stripped gears, and the blades were scratch free. I'm a bit weary of flying the AceOne now till I find out what the cause of the crash was. Why would it all of a sudden flip like that for no apparent reason? Here are the particulars surrounding the flight: - New field +could be RC interference although I highly doubt it as the area is undeveloped +also the AceOne was set to RTH in the event of radio link loss. - A little higher altitude than normal as the field itself is elevated on top of a hill over looking the bay. +Could it have been a barometer malfunction - Tall grass had cat's talis on the ends of it -Heli was flying more drunk than usual +Usually the heli flies as if it had 5 beers but yesterday if flew like it consumed around 8 beers. Any ideas would be appreciated.

09-09-2012, 07:38 AM	#7 (permalink)
R_Lefebvre Registered Users Join Date: Nov 2010	My guess is that you have a vibration somewhere. This sounds somewhat like a problem we have with Arducopter. It will fly the helicopter very well, but as soon as a bearing starts to go, it's game over. I've had it tip over into the dirt right on take-off a few times. The problem is it is more sensitive to vibration than a human is, so it's hard to detect the problem. Every flight controller is sensitive to this, some of the others that are built into FBL controllers will detect the problem, and kick themselves out of stabilize mode with little or no warning, which can have pretty nasty consequences too. In my experience, at least for our system, it is much more sensitive to very high frequency vibration than it is on low frequency stuff. Blade tracking, blade imbalance, don't seem to cause a problem. But if the bearings are going on the tail drive shafts, it's done. This is why it's so difficult to detect. Most of you guys are used to sorting out all the lower frequency vibrations that you can feel by hand, or see in the video. But if a bearing is going, you might miss it. The only thing you can do is simply take it all apart, and feel every bearing by hand, and be super picky. If it's not perfect, throw it out. I think I should just get a Pez dispenser for tail drive bearings. I've tried many types of vibration damping systems for the IMU, but nothing seems to work. Anything that is soft enough to stop the high frequency vibration, can cause control oscillation on the pitch/roll axis. I should also say, that the vibration that can screw up the IMU will NOT screw up a tail gyro. So again, it's why heli guys aren't used to looking for this. Something I'm curious about with the DJI, is the magnetometer calibration. You guys talk about rotating the GPS mount, what you're really doing is realigning the mag that built into the GPS puck. This really shouldn't be necessary. I assume you've done a ground calibration? The problem is that electric helis generate their own magnetic field when running, both from the DC power wiring, and from the batteries themselves. We developed an in-flight calibration routine to compensate for it. Fly around manually while collecting data, land, and then run a routine which uses the power of your PC to generate a field compensation. Then the mag is more accurate in flight with all these Mag fields in effect. Does DJI do anything like that? __________________ -Rob Former Managing Director of Maxxum Robotics Inc.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

09-09-2012, 01:09 AM	#2 (permalink)
FSAMedia Registered Users Join Date: Oct 2010	If the issue isn't simple gain settings, it sounds as if the imu location isn't set correctly or you have a faulty gps. Try a firmware update and triple, quadruple check you imu location settings and cg settings.

09-09-2012, 01:56 AM	#3 (permalink)
Titusx Registered Users Join Date: Jun 2010	The drunk behavior is related to the mounting position of the IMU and GPS. Check it a couple of times if it is set right, I have a hard time with it, as they do not use the standard space coordinates, Z is vertical and Y horizontal. Also colours in the graphics are reverse. Red for positive and green for negative. Also check for straight line flight, if it tends to go right or left with only elevator stick input (in atti or cruise mode), you have to compensate rotating the GPS to the opposite direction. Remember to recalibrate each time you rotate GPS, just in case. Adjusting the GPS orientation reduce a lot of the drunk effect. I could not get rid of all the drunk behavior, but it flight way smoother now. Here is a vid. [ame]http://youtu.be/_rhgymt9eJA[/ame] Regarding the flip over, I think it has to be related to the system check in Ace One Assistant. You may have one set reversed. Also check it twice as the assistant first levels the swashplate and then do the motion. So sometimes you could get confused. Loosing Tx signal could be the cause of the flip over. When trying to come back home and having one control reverse, it try to level it inverted. I am really happy with my Ace One, it do what it is supposed to do, and had paid itself. A couple of month ago, I was flying over a lake and lost Tx signal. Fortunately I had set the TBH and did not lost my heli.

09-09-2012, 02:35 AM	#4 (permalink)
Exposure Registered Users Join Date: Jul 2006	"If the issue isn't simple gain settings" "You may have one set reversed." Ever get the idea you asked the question in the wrong place ?. I wonder how you managed to fly around previsouly if either of these were true. This is what DJI support should help you with : did you get any joy from them ?.

09-09-2012, 07:22 AM	#6 (permalink)
Exposure Registered Users Join Date: Jul 2006	I did. I said he should ask DJI customer support because he is being sent on a wild goose chase here. ""Better to keep your mouth closed and be thought a fool than to open it and remove all doubt"

09-09-2012, 08:40 AM	#8 (permalink)
Titusx Registered Users Join Date: Jun 2010	DJI's IMU has its own dampeners inside the box, so you do not need to use any foam on it. Also it has some led status on the GPS/Compass where you can see if the vibration level is ok or not. one or two white leds flashing means that the vibration level is more than it could handle. Regarding magnetometer. You are right. We do field calibration, but as you said it has some deviation when in flight. So realigning GPS/Compass solve this problem.

09-09-2012, 10:47 AM	#10 (permalink)
splitboarder Registered Users Join Date: Sep 2008	Not a DJI fanboy, but how can you say it wasnt a servo that went bad? It sounds like a bad servo. For a heli to be flying in ff and then roll over sounds like either the aileron or elevator servo going out or loosing signal

09-09-2012, 10:55 AM	#11 (permalink)
splitboarder Registered Users Join Date: Sep 2008	Not a DJI fanboy, but how can you say it wasnt a servo that went bad? It sounds like a bad servo. For a heli to be flying in ff and then roll over sounds like either the aileron or elevator servo going out or loosing signal I will agree with you on the 'drunken sailor" description though. I think the DJI is a long way from a commercial use flybarless controller

09-09-2012, 11:15 AM	#13 (permalink)
helicek Registered Users Join Date: Jul 2005	Hi heliaddx, I am sorry it had happened to you. It must be very annoying to experience something so fatal and not knowing why it had happened. What you have experienced sounds very much like "glitch". Do you do range check?(while motor running, camera recording and downlink transmitting) I agree with Exposure. You should contact DJI and see if they come up with a sensible solution. Yo may need to record flight log and send the "zipped" file to DJI. I had to do that for my faulty GPS module and they eventually replaced it, but you have to be very determined and some how let them realize that. Terry was the name of the person who took care of all that for me. Good luck, Ahmet terry.wan@dji-innovations.com Dajiang Innovation Technology, DJI http://www.dji-innovations.com http://www.dji-hobby.com Tel: 086-0755-26656677 ext:203 MSN: terry.terrific@hotmail.com Skype: terry.one

09-09-2012, 04:57 PM	#15 (permalink)
splitboarder Registered Users Join Date: Sep 2008	As a flybared controller it is rock solid. I do like mine. I myself could never get it to my liking in the flybarless mode. But there are several people using it as a flybarless controller in both ap and scale, I just couldnt get it dialed in

09-09-2012, 07:45 PM	#16 (permalink)
hellafilming Registered Users Join Date: Oct 2011	What type of radio are you using? are you on spectrum?

09-09-2012, 10:46 PM	#17 (permalink)
heliaddx Registered Users Thread Starter Join Date: Jul 2011	Thanks for the overwhelming response guys. There are just a few points I need to clarify with my post to give a clearer picture of the events. My first crash happened when I first installed the AceOne, which was a few months ago in March. The second one happened just this weekend. The first crash happened after I landed and the skids were already on the ground (AceOne was in Cruise Mode). The second one was in the air flying low around 15 to 20 feet off the ground around 160 meters away. The first crash was with an FB head and the second one was with an FBL head. Between the first and second crash I had been flying it both as an FB and FBL unit. As an FB unit it was rock solid and amazing in it's position hold both on X and Z and its Y axis. The heli flew like it was on rails - but the video was full of vibration, which no amount of heli tuning could fix. I suspect the Main Rotor Head might have been slightly bent on the first crash. As an FBL unit the video was acceptably smooth although the heli flew like it had a few beers. I have flown the unit in all sorts of conditions and elevations, from valleys to mountains, from really windy days to really calm days, early in the morning and late at night. Never flew in the rain and have no plans to. I've flown over lakes, grass, trees and many different terrain without any problems. I fly mostly FPV with this aircraft although I do also fly it LOS, and the AceOne unit flew great in between the two incidents. As an FB unit it was perfectly dialed in including the RTH, it flies straight and true back to home whenever I switched it to RTH on my Tx or during the one time where I lost Tx signal. RTH was luckily set that day as failsafe and it performed flawlessly. So the unit was working well apart from these two incidents. That is why I am very much confused and a little wary of flying it again. The last incident was so random, although the heli did show signs of flying more drunk then usual. I had flown it about two weeks prior on August 25, again without a hitch. In fact if I remeber it well the heli performed really well flying less drunk than it had been before. Do you guys land in the auto modes without a problem? I have ceased to land in auto mode ever since my first crash. After the second crash, since the heli and the unit itself had no visible damage, after a thorough pre-flight check I strapped on new batteries and it flew flawlessly again. This was a few minutes after the crash, and the only thing I replaced was the main batteries. Again it just seemed so random that the heli flipped like that without a reason - hence my hesitation to fly it again. @FSA I don't think it's the gain settings, since the heli had been flying flawlessly in between the two crashes. @Titusx My mounting for the unit as an FB controller/autopilot seems correct since it flies really well as with an FB head. The problem arose when I changed my head from FB to FBL - that is when the 'drunk behavior' came about. Do you think the mounting of the AceOne unit should be different between the two types of heads? I left the mounting parameters, both hardware and software, same for both. The things that I changed in the software when I migrated to FBL was to switch on the FBL option in AceOne Assistant and I also had to tune the autopilot settings. But I've been flying FBL since May with acceptable results. @Exposure You are right in your deduction of the unit flying previously and I am taking your advise and contacting DJI as right after I type here. Thanks. @R_Lef I have tuned the heli mechanically over and over and there is still some form of high frequency vibration that can be seen as jello in my hard mounted GoPro video. Unlike before I installed the ace one. Although the unit had been performing well prior to the two freak incidents. I have two Cameras on the unit a GoPro and an FPV Cam. The FPV Cam is mounted simply with a an L shaped aluminum flat bar which is stuck to the front of the heli with double sided tape. So the FPV cam is about as 'hard mounted as it gets with no dampeners between the heli's body an the camera apart from the double sided tape. The FPV cam shows no vibration whatsoever. So vibration, is at the bottom of my list in terms of suspects for the crash. @splitboarder After the crash I checked all swash servos and tail servos and they seemed to run perfectly well. I was able to fly a whole pack in both manual and atti mode after the crash for a whole battery pack. But this could be an issue. I test my servos by first checking their range without load and then with load (by applying some pressure with my finger and checking for clicks as a sign of stripped gears) - how do you test yours? @Ahmet Thanks for the suggestions and sharing your experience. Would you have an idea what caused the glitch and whether it's a preventable occurrence? How do I record a flight log? Is there a feature in AceOne Assistant to do this or would you need a separate logger such as Eagletree? @hella My RcTx is a Hitec Aurora 9 and my Vtx is 5.8ghz 500mw.

09-10-2012, 04:29 AM	#18 (permalink)
helicek Registered Users Join Date: Jul 2005	heliaddx "Would you have an idea what caused the glitch and whether it's a preventable occurrence?" Any component on the heli that transmit some sort of RF can cause glitch. It can be difficult to track down since it only happens once in a while. I would do a range check with reduced tx power while every thing is on and running. I would definitely remove the main blades while doing that. "How do I record a flight log? Is there a feature in AceOne Assistant to do this or would you need a separate logger such as Eagletree?" You need a micro SD card. Just insert it in the slot on the main unit and fly. It starts recording when ACEONE is switched on and stops when it is swithed off. You can open the files in simple text edit but it won't tell you much So you need to have DJI take a look at the file. Good luck, Ahmet

09-11-2012, 02:05 PM	#19 (permalink)
Flying Tivo Registered Users Join Date: Jun 2004	It really sounds like a static discharge to the rx side servo cables. Make sure you have grounded the tail boom to the frame and the frame to the Negative of the battery. If using a belt for the tail drive lube it up silicone or wd-40. If a torque tube drive, check your bearings inside the tail boom. Felipe

09-11-2012, 08:37 PM	#20 (permalink)
heliaddx Registered Users Thread Starter Join Date: Jul 2011	Thanks FlyingTIvo. Guys, is it safe to land in the atti or cruise mode? I've been landing in Manual Mode since my first crash due to landing in cruise mode - which made DJI flip the heli. @Helicek Thanks - I don't remember the slot for the microSD but I'll look for it - I might have placed a card there already from when I first set it up way back in March.

Register Now

Log-in