I am dumb struck!!

I have a Bixler 1 and have been flying it for three to four months with no problems at all.

Have a bigger motor in and FPV gear on it. Last Thursday went to fly and something very strange happened. The Bixler nose-dived on its own, in stabilize mode. I did manage to save the bird, but 1 min later it did it again. But this time I could not save it as it was too low. I also did not have any telemetry connected.

Rebuilt it and went to the field Saturday morning. This time I had telemetry connected. I took her up and flew in manual mode for 3min, then switched to stab. It was not even 1min and it happened again. Saved her but the second time I could not. Crashed again !! I was busy turning (with the ail and elev) the nose just went down uncontrollably. I looked at the tlogs with Graham Dyer, what we could see is that the vcc was not very consistent at the time of the crash. Tlog attached named Saturday.

Rebuilt the Bixler AGAIN !!  I swapped the ESC too and reloaded the APM firmware (v2.68). Calibrated everything and tested it on the table. Sunday morning went out to the field. Once again took her up in manual and flew around for a while. Switched to stab and it went well for a couple of min’s. Then it happened again. Nose down 100% and whatever I did, did not help. CRASH NUMBER THREE !!!

We looked at the tlog and the power this time was 100%. But at the point of the crash there was nearly no input from ch2 but 100% output on ch2. Tlog is attached below, named Sunday

Rebuilt Bixler AGAIN !!!! Took out the APM 2 and swapped it for another one I had in my quadcopter. I went this morning and flew the Bixler again. It was much better but found something interesting, when I bank full ail the Bixler will tip over and dive, but this time it recovered after a second or two. Still very stressful to see. I tested this a couple of times, it loses control but gets it back again. Still not 100%.


Thursday I flew with 2.66 the rest was done with 2.68. I also loaded the default bixler.para from this site every time.


Please can someone look at the tlogs and give me some advice.

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It happens to me too.

One day everething goes more than awesome and the next day everething goes wrong... I lost 3 airplanes with reliability issues.

I was working for hours triying to find what goes wrong...

I was thinking in a Manual mode board that act as a bypass to have a real manual mode. because in my case the APM reinitializing is a recurrent cause of problems. and almost everytime ends in a crash.

Mine also had a couple of "re-initializing" sessions. But after I swapped the ESC I never had that problem again.

I have seen weird behavior like this on the bench even in the field just before flight but I've been fortunate so far in the air. I know that can change at any time so I am certainly not gloating. I have a few basic questions:

1) Are you using a 2.5 board with a 2.0 case?

2) Is the JP1 jumper in place and powering the board from one source?

3) what BEC are you using?

I have had success with an expensive castle creations UBEC and a very cheap turnigy UBEC 3a. No brown outs with these so far. I know that with a 2.5 board in a 2.0 case if anything taps the top it can trigger a reset and "initializing". 

I'm trying to find some basic common patterns in how we are configuring our systems that may reveal preferable set ups.

Exactly.. I had some resets with the case on the apm2.0 board, and I am convinced that the reset button was the culprit, so I removed the plastic button that came with the case..  

I am using 2.0 without a case.

Yes JP1 is in place

No i do not have a UBEC, getting power from ESC

I blame the first crash to power from the ESC.

and then flies a while without any incidents, but then, suddenly the plane reinitializes again and ends in a total loss of the airplane.

I notice the issue with the case the first time and solve it grinding the case to give more space to the button. we were lucky to notice that on the ground.

Hi Louis,

What FPV gear (camera model?) were you using? Also, are you using 433 3DR radio?

single power source it is wrong.

when the servo move out of the limits, power source is overloaded and brownout may occur.

I used a no name cheap cam, and HK tx & rx. The 500mw model

No i have the Xbee 9Pro radio

Yes single power is a problem, i have a UBEC now in my Bixler 2.

I am aslo getting the new APM 2.5 + today, so there i will also have ext power

Hi.  I know this is an old thread. 

I have had a similar situation.  Was flying quite happily in stabilize mode (ardupilot 2.5), practicing launches and landings.  Last flight of the day, launched plane as normal, it went straight up for about 30m, did a turn at the top and nose dived straight into the ground.  I had no control.  I noticed afterwards that the voltage on my transmitter was very low, I suspect it was sending bad data to the receiver.

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