Hi Guy's I had a crash today with my skywalker. It has never battered an eyelid at anything I have thrown at it and has flown many missions without a hiccup. Today I went for a fly at my usual haunt. I uploaded an auto flight with 4 waypoints (I have flown these waypoints before) and hand launched after waiting approximately 5 minutes for the GPS fix. I flew around for a minute or two whilst I positioned the goggles on my head and when they where on I flicked through stabilise to Auto. Once it went into Auto the engine reved up and the skywalker banked slightly to the left (to get on track) and pitched down violently, I tried to pull up but it did not respond at all, I went to Manual mode and by that time it was too late.

I did notice my airspeed went nuts but it was windy around 6 Knts variable. Also the HUD was not reflecting my pitched down angle, Also Ignore the Voltage on the screen, The Voltage has not been calibrated.

I have attached my .tlog, .log amd kmz file for everyone to look at. I have had a look but I can't decipher the logs. Also attached the FPV video as well as the Wing cam.

Another thing I noticed in the kmz file was showing I was flying in yellow stabilise but in actual fact I was in manual which should have been orange. the green in the middle of the yellow and blue reflects me going through Stabilise green to get to Auto black but the kmz shows me going into RTL which is blue. The OSD reflects me going into manual, taking off, flying then going through stabilise to get to auto, I never hit RTL ?

I hope it was something I have done because it was going so well and this was just unexpected.

Any info would be appreciated.

I will upload the Video's as soon as they get to youtube.



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But you can now Ron with you and me combined we can help anyone who wants to crash !!!

I have given the Skywalker to Ron. It can be fixed but I would rather buy a new SW and start fresh. I should have it in a month (payed monthly). I can start fresh and learn from the last SW and hopefully make this one better so it does not end up in pieces of little foam.

I will definitely be following the PID guide I was shown on the Wiki and I assume this is what you mean.

This one    http://plane.ardupilot.com/wiki/roll-pitch-controller-tuning/

I will follow method two which says its the better one of the two, and also I will calibrate my Airspeed.

Start with method one. It is easier and method 2 can induce high frequency oscillations that may result in loss of control or damage to your servos.
Method 2 will yield a more stable result and a bit smoother performance in turns, but method one has less risk of accidents and will also get your plane flying nice and responsive.

Look at the parameters for common airframes, I believe the SW is in there too and it will get you started just a little bit faster.

I will do that. You have actually raised a question, Is there a way to tell the APM to run a different frame rate for servos ? i.e., Digital or analogue. 

Deleted, comment already made.

Hi Pieter. Myself and Ron went to the field today for some tests on his skywalker. We did a erase on his APM and Radio, and installed Arduplane 2.74b and set the radio up with Manual and FBWA to start with.We flew the plane around in manual and trimmed by landing and adjusting linkages then went into FBWA to alter the Servo Roll Pid. it was originally at 0.400 and we adjusted it all the way to 1.000 with better results but we did not encounter any overshoot or ocilations we went as far as 1.300 with out any more luck (I am thinking the P does not work after 1.000) with the setting of 1.000 on the roll P we could not get the plane to move as "freely" or with as much Authority as in manual mode. I am thinking we need to extend the pushrod to the outer hole on the servo arm to speed up the movement and deflection (Although the deflection is great in manual mode) I thought We had better come back and ask some questions before proceeding as you asked. (this may stop us from making the same mistake twice)


You must repeat one of the two methods every time you adjust your airframe, or trim it.

After trimming, gain some more altitude and see if it flies well in FBWA mode. If it does, and you can steer it around with the same control authority as in manual, it will fly good in auto mode. if it doesn't, well, don't switch to auto mode, come back here and ask for help ;-)

My condolences for the crash ...

Shortly before switching to auto mode, your battery warning signals again, it may be that you had too little power? Greetings from Germany, Klaus

Hi Klaus, Guten Arbend Vighets ? ( god afternoon how are you I think ) The battery was ok. I did not have the Battery monitor set up correctly. Only recieved a few hundred Mah when charging. Cheers for Chipping in.

I would say its worth a try replacing your elevator servo. I had an HXT 900 on an aileron that would intermittently fail to full deflection. It caused two crashes with me thinking it was a brownout. 

Hi Ted, Ron here I fly with Adrian and he uses only the best of parts to build his models. He had some wiz bang expensive servos in his model while I use the cheaper emax stuff however even the best components can fail at times. In this hobby if it can happen it will happen.

Hi Ron,

If you are using the stock clamps for the SkyWalker 1900 for you elevator/aileron control rods then it might be worth looking at replacing those. I had a lot of trouble with the little grub screw on those slipping on the smooth wire during flight, with nasty results.

I found that putting a bit of CA on the wire and letting it dry then sanding it rough helped with the grip of the screw, but it still isn't ideal. Hot glue to hold it in place might be a better idea.

Cheers, Tridge

I do have lots of problems with those little grub screws, I can never find the allen key to fit them when I'm at the field. :-) but seriously I find them difficult when making fine adjustments, when I undo them the control surface moves and then I need to make a good guess of where to position it.

Next time I place an order with HK I am going to get some of those pushrods with the plastic clevis, remove the clevis adjust half-a-turn or so and your done. I'll make sure I use a piece of silicone on the clevis so it will not pop open in flight.


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