Momentary loss of control - Aileron sensor out of range

[OnTheSnap]

I'll post a log later.

At a funfly this weekend I had 4 instances where the cyclic stopped responding and then came back a second later. It doesn't happen every flight. In the log I have observed one of 2 warnings in each instance - Cyclic ring active or aileron sensor out of range.

In all the failures, I gained control quick enough to just barely save the model.

I tried swapping the black sensor with a blue, but had the same issue again.

This is on a Goblin, Torq servos, WR BEC, 8.4V.

I had a ESC failure maybe 20 flights ago where a phase on the ESC failed that melted down the motor. Flames shot out of the motor and left some scorch marks on the front servo.

It seems reasonable that a momentary servo lock up could produce the above errors. Basically the swash won't move where commanded so the system maxes out it's input to the non-functioning servo which produces the cyclic ring message. However the aileron sensor out of range error makes little sense if the servo is at fault.

I have never seen checksum errors, antenna switch or rx packet errors and the model is 23 ohms from tail shaft to motor mount. I also tried swapping the sat wires to no avail. Again replacing the vBar sensor showed no improvement.

I'm thinking I could use a heat gun on the front servo and set pitch pump to 100. Then pump collective to see if I can get the servo to reproduce the failure on the bench.

Any other ideas or experiences?

[kachur779]

i had kinda similar issue yesterday i lost my all control of my tail for about 2 seconds on a huricane as it was flying towards me ..then the heli gained contol again just in time what a scary situation that was .My log has full of swtched antena errors ,i noticed my static wire was not getting a good connection so i replaced that just waiting to fly it again

[baui2000]

The same happened to me on my Mini Protos about 2 weeks back. All axes reported sensor out of range for about 2 seconds and the whole system went into failsafe. No idea what happened

[MrMel]

Sensor out of range = sensor working, but heli moves faster than 500 degree/sec
Meaning, not the sensor unless you get tons of this messages.

Something made the heli move fast, very fast, static hit is always a suspect in those cases, but a glitch in form of a bad cable or connection is doable also.

[kimmik]

I think if the Heli even momentarily hit 1.5turns per second you would have noticed the jerk. So I think the sensor out of range is either a sensor fault, or connection fault, or interference of some kind.

[MrMel]

Not if you are already at for say 360 degree turn (roll or other movement), a notchy servo is all that it takes, or a chafed cable.

OP has tested another sensor so that is not the case.

could be a broken servo port on the vbar main unit, wiggle each cable and see if servo dies.

[OnTheSnap]

I fixed the issue by dumping the BEC and using a RX pack. But now I have another interesting problem.

If I do full stick forward flips, the heli will do a couple, and then suddenly pause (while vertical usually) move slowly for a second and then recover to normal. It won't do this in back flps or aileron rolls. Just forward flips.

I don't see any binding issues, and the cyclic ring is at 100, but seems reasonable. So long as I don't do full stick elevator flips, it flies normally.

Seems like the possibilities are:
1) Servo problem. Although it flies great and it is just forward flips. I could swap out all the servos. :-/
2) Swash binding issue? Swash seems OK
3) My numbers are pretty high numerically for 8 degrees of cyclic. like 100 for cyclic, and 105 for cyclic ring. Maybe I should move the balls on the servo horn out by one to bring the values down into a normal range?

Pretty funky issue. Never seen anything like this.

[trickybit]

Yeah sounds like early-phase brain tumor.

[TdB]

TX issue maybe?

Tim

[MrMel]

Start with going in under Expert Cyclic and press Reset, then check if it still does it.

[OnTheSnap]

Brain tumor? LOL.

Thanks for the suggestions. The problem is finally solved and it was a setup issue. The elevator servo simply did not have enough throw. At full elevator plus near full pitch the swash would flatten out as the 2 front servos moved more than the elevator servo. The problem was solved by simply moving out a hole on the servo horns.

Seems trivial now but this issue was subtle and has given me some terrifying moments in the past few months. It manifested like a true radio lockout and even caused a small crash once.

[trickybit]

Wow, glad you found it, survivor.

What would the setup-check step be? Measure the full cyclic at full collective at 4 rotation angles?

(Can you tell I still haven't used my digital pitch gauge?)

Rock on.

[TdB]

Originally Posted by OnTheSnap

The problem was solved by simply moving out a hole on the servo horns.

I think the Goblin has a sufficient range as it comes to collective and cyclic pitch.
What's your Cyclic Throw value right now? (must be lower, right?)

I just can't imagine this being the right solution for your problem...

Tim