F550 WKM Throttle Spike

[gmahan3]

A buddy and I were flying this evening and he was testing out some minor tweaks we had changed. I flew through a battery with no issues. I had been having GPS issues that after our tests were seemingly resolved.

We swapped lipos, recalibrated compass, acquired 9+ sats and he took off. It flew for 2 minutes in attitude mode with no problem and then it had a bizarre throttle spike. The bird up about 10 meters before he kicked it into manual to regain control. After a brief hover he engaged GPS to hover at altitude. There was an noticeable inconsistency in motors when GPS was engaged. He kicked it back into manual and pitched backwards to bring it towards our launch point. You'll see a drastic maneuver that puts the platform in the parking lot where attitude mode was reengaged and it preformed nicely and I was able to catch it out of the air.

You can see the video link to get an idea of what transpired. I have no idea what has gone on here; the fact it will fly in manual mode leads me to believe it is not a mechanical error but something in the FC or other flight electronics. I guess an argument could be made that there was a signal interference but we scouted the location and it had a successful prior flight in the same location.

Can anybody weigh in on this?

Gains:
View attachment 17924

 

[gmahan3]

My Gains are:

160-160-170-160
140-140

 

[gmahan3]

It happened again! This time a bit more violent. At the end of the flight there was a crash landing

But this time I lost M5 during the flight and upon inspection after one of the ESC cable had come unsoldered from the ESC. I'm confident that this wasn't a result of the crash due to the stress relief I had in place.

In an effort to try and diagnose what happened; is there any credit to an intermittent ESC causing the violent shot upwards seen?

 

[cootertwo]

Vibrations ???? sounds and looks like there is some buzzing going on.......... ?????

 

[gmahan3]

It'll fly fine and then begin to "buzz" and jump in elevation. It will stop freaking out and I'll regain control and being to back to earth. Then out of the blue it'll shoot up again.

A theory that my flying buddy and I came up with after the second insistence of the same issue is that an intermittent ESC was sending signals to the FC that an motor was out. When it would send the power adjustment to the motors to compensate for the loss of a motor the faulty ESC connection operational and it would shoot the platform up.

I'm trying to make sense of what would cause it to fly normally then act the way it is.

 

[JoeBob]

Same this - maybe.
But mine is a Naza M v2:

http://www.multirotorforums.com/showthread.php?19165-550-Motors-Pulsing

 

[Scott Drysdale]

I recall similar situations about a year ago with my modified Naza V2 with larger motors and props, MR motor arm extension etc.........
After much troubleshooting and being convinced that the FC was failing, I isolated the FC and RC Rx from MR airframe vibration with Kyosho Zeal Tape and the sudden throttle spikes disappeared.
Subsequently I was able to better balance the motors and props and eliminate the Zeal tape under the FC..... but left the zeal tape under the RC Rx as these are still inclined to fail eventually from vibration.

 

[gmahan3]

Joe, I checked out that Thread Link and did not see a video

 

[gmahan3]

Scott, I just bought a strip of that tape. Amazon should have it here tomorrow. Hopefully this will get me up and going.

 

[JoeBob]

Try this one:

Skip to 8:40 for the short version.

Thanks,
Joe

 

[cootertwo]

I think it's the vibrations in both of those that are causing the MC to go wacky.

I once put a normal flying Phantom back together, after having the top off, and when I took it out to fly, motors armed normally, but as soon as I touched the throttle, it went straight up, wide open, like it was in manual mode. The whole time, I had both sticks pulled back, trying to un-arm it. Luckily for me, and it, I have a big tree canopy that caught it, and pointed it at the roof of my mobile home. It did the funky chicken up there, till it worked it's way off the roof, and fell to the ground, finally dead. When I opened it back up, the only thing I noticed, was that the gray ribbon wire, had got twisted when I put the lid on, and was pinched between the Naza MC, and the bottom of the GPS puck. Straightened the wire out, so that there was no contact between the MC and GPS, and it's flown perfect ever since. My theory is that the pinched wire was allowing the frame/motor vibrations to buzz the MC, causing it to go nuts.:dejection:

 

[gmahan3]

Scott, why take off the zeal tape from the FC. Just to see if you'd balanced properly or is it not good long terms to have the tape under the FC



Here is my set up. Nothing jumps out at anyone?

 

[cootertwo]

Nice rig, killer motors. What batteries are you using, and what's your flight times? I had a set of those legs, and mine broke in the center, from flexing. A cross brace between the legs, on the bottom, will prolong their life.:nevreness:

 

[gmahan3]

I've got a MaxAmps 4S 9000 mAh 100C that I get 8 minutes with and a MaxAmps 4S 11000 mAh 40C that I get about 13 minutes out of when it's fully loaded.

 

[Tahoe Ed]

Please remove the Zeal tape and install the FC with the supplied thin double stick tape from DJI. The FC has internal dampening. All the Zeal does is vibrate the FC more and confuses the sensors. Nice copter I have one that is almost identical except that I am using the E300 propulsion system on 4S.

Scott, why take off the zeal tape from the FC. Just to see if you'd balanced properly or is it not good long terms to have the tape under the FC



Here is my set up. Nothing jumps out at anyone?