Radio brownout - Lost another pair of underwear (and confidence in the plane)

[njswede]

I keep having issues with my 104" AJ Slick. This time I had a radio brownout/loss of power/something. Lost all control for about 2 seconds and got it back just in time to save the plane and brought it in for a twitchy but successful landing. And now I have zero confidence in the plane.

The biggest problem is I can't reproduce the problem. I spent an hour tugging on wires and tapping on things, with no glitching or loss of power. I even started it up and taxied around the field. Still no glitches.

So now I have a big expensive plane I don't feel confident flying. What would you experienced lads do?

Here are some hints:

1) After I landed, the plane was quiet. No buzzing from the servos. Once I grabbed the plane, it came on again, but was twitching.
2) The engine stayed running, so I can't have been a full loss of electric power. The ignition is powered from the regulated 5V, while the servos are running on unregulated 2s LiPo.
3) The failsafe is set to ignition off, so the radio link must have been up.

Everything is powered through a SmartFly from dual 2s 3600 Pulse batteries.
Savox 1270TG all around, except throttle, which is a Savox 1272SG.
DLE 120 on cans.

Please help! The plane is a boat anchor until I can figure out why it's messing with me.

 

[njswede]

Oh, and one more crucial piece of information: Receiver is an AR10000 with three satellites and the tx is a DX9 Black Edition.

 

[camss69]

Were the lights flashing on the satellites/receiver or on steady after you landed?

Do you have a flight log checker to check the receiver?

Have you flown other planes with your DX9 with no issues?

Which smartfly device are you using? The smart fly is where I would start it's a single point of failure and if you have fail safe set to cut the ignition then you must have lost power and not signal. Personally I would eliminate the smart fly and use a power safe receiver. This cuts your single points of failure in half.

If you can't find anything on the ground, and you can fly other planes with your DX9 I would send the receiver in to Horizon and have it checked. I would also send the smart-fly in and have it checked if you don't want to swap to a power safe receiver.

Do you have the telemetry module so you know the receiver voltage?

That's where I would start...

 

[Phil.Griffin]

I keep having issues with my 104" AJ Slick. This time I had a radio brownout/loss of power/something. Lost all control for about 2 seconds and got it back just in time to save the plane and brought it in for a twitchy but successful landing. And now I have zero confidence in the plane.

The biggest problem is I can't reproduce the problem. I spent an hour tugging on wires and tapping on things, with no glitching or loss of power. I even started it up and taxied around the field. Still no glitches.

So now I have a big expensive plane I don't feel confident flying. What would you experienced lads do?

Here are some hints:

1) After I landed, the plane was quiet. No buzzing from the servos. Once I grabbed the plane, it came on again, but was twitching.
2) The engine stayed running, so I can't have been a full loss of electric power. The ignition is powered from the regulated 5V, while the servos are running on unregulated 2s LiPo.
3) The failsafe is set to ignition off, so the radio link must have been up.

Everything is powered through a SmartFly from dual 2s 3600 Pulse batteries.
Savox 1270TG all around, except throttle, which is a Savox 1272SG.
DLE 120 on cans.

Please help! The plane is a boat anchor until I can figure out why it's messing with me.

I am no expert on electronics, but I had a similar thing happen on my 91" EF Extra. Had a several seconds long "disconnect" of some sort on a 45 degree downline on flight 316, that reconnected about 3 seconds before impact. This plane was directed by a JR 921 receiver and my 11X. I could not reproduce the problem either. I ended up replacing the switches, receiver (upgraded to X protocol Powersafe) batteries, and the kill with a Tech-Aero IBEC. Over-reaction? Maybe. But the plane is back to flying problem free now. If you can't isolate the problem, I'd start replacing stuff.

 

[Phil.Griffin]

Were the lights flashing on the satellites/receiver or on steady after you landed?

Do you have a flight log checker to check the receiver?

Have you flown other planes with your DX9 with no issues?

Which smartfly device are you using? The smart fly is where I would start it's a single point of failure and if you have fail safe set to cut the ignition then you must have lost power and not signal. Personally I would eliminate the smart fly and use a power safe receiver. This cuts your single points of failure in half.

If you can't find anything on the ground, and you can fly other planes with your DX9 I would send the receiver in to Horizon and have it checked. I would also send the smart-fly in and have it checked if you don't want to swap to a power safe receiver.

Do you have the telemetry module so you know the receiver voltage?

That's where I would start...

And I didn't want to say that, but as camss says, the power distribution systems really aren't needed. I'd remove it if it were mine.

 

[njswede]

OK, I have a powersafe receiver sitting in a plane I'm not flying right now, so that would be an easy swap. BUT... it doesn't solve the problem! If I replace it without reproducing the problem, I still won't know if it's fixed. I don't want to experience those two seconds again. It's going to give me nightmares.

What do you guys do when you can't reproduce the problem? Just replace the most likely component and pray?

 

[Phil.Griffin]

I did just that. Replaced all the major components that I felt might have caused the problem. I realize this solution isn't for everyone, but it worked perfectly in my case.

 

[Phil.Griffin]

I sent the 921 back to Horizon for a check up, explaining to them what happened. The receiver came back with a clean bill of health. I'll keep it around to use as a test receiver in the shop. The rest of the stuff I threw away.

 

[Judge]

And I didn't want to say that, but as camss says, the power distribution systems really aren't needed. I'd remove it if it were mine.

Plus one on this point. I am amazed at how popular they have become. I have always seen them as an eloquent solution to a non-existent problem. Why introduce another potential failure point, added weight and complication to solve a "problem" that exists only in the minds of the people who market these devices.

 

[njswede]

So there's basically two things that can cause a loss of unregulated power without loss of regulated power: One is a faulty power distro and the other is a short in a servo or servo connection, provided that the SmartFly has some kind of over-amp protection on the unregulated rail (does it?).

So I guess the plan is to toss the power distro and put in a PowerSafe receiver. I was going to replace the elevator servos anyway due to slop. I don't think the IBEC is to blame, as it's on the 5V circuit which I don't think failed.

I stupidly shut everything down before checking the telemetry. Does anyone know if it keeps some kind of log somewhere for older flights?