Emergency Auto Landing - APM saves sUAV

by MyGeekShow | April 16, 2014 | (23) Posted in Just Fun

Mayday! Mayday! I tested the FPV system on the Raptor140B, with nearly disastrous results. Luckily, the APM was onboard to save the day!

I added the 400mw 1.3Ghz FPV transmitter to the 140B, and took it for a test flight. Right after take off I had significant control issues, and barely recovered the airplane. Thinking it may have been the flight controller, and wanting to determine the cause while the same circumstances were available, I double checked all connections and systems, and flew the aircraft again.

Again, it had significant control issues, even in manual modes. Luckily, the APM flight controller was able to safely loiter the airplane overhead while I determined that indeed the Turnigy 9x transmitter was no longer able to safely control the airplane.

This required me to create a mission mid flight, update the mission, update flight parameters, and attempt an autolanding, the first time I've tried this feature.

Watch the find out the results!

-Trent

- Find this article & others like it at www.FliteTest.com -

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COMMENTS

PaladinDG on April 16, 2014
AWESOME!!! Nice to see the abilities of the APM FC, but I think you got very lucky!!
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MyGeekShow on April 16, 2014
Totally agreed. Luck and a quick action saved the day.
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PaladinDG on April 16, 2014
I love your articles... always fun to watch!
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MyGeekShow on April 16, 2014
Thanks! I love making the show, not just building and flying, but the filming and editing are fun too. Just trying to tell the story is a challenge... Thanks for the feedback!
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Sirglider on April 16, 2014
One of the best Trent! ;)
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MyGeekShow on April 16, 2014
Thank you! This will go down as one of my favorite moments of the show I think.
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ikem on April 16, 2014
nice. I love my apm 2.6. I have it on a tricopter, but love the RTL and i configured the throttle cut button to auto land where ever it is at. Press it and it will slowly land. 1.3 and 2.4 shouldn't have much problem running together though. Were both of your antennas vertical? Maybe run one vertical and one horizontal? Just an Idea. Great video!
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MyGeekShow on April 16, 2014
Great tips. I'm trying adding filters and distancing the two. Hopefully that clears it up!
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ikem on April 16, 2014
I run my 5.8 and 2.4 about 6 inches away from each other. what wattage was the video transmitter?
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MyGeekShow on April 16, 2014
400mw. Mine are roughly 10in apart.
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TRXRacer on April 19, 2014
Actually the 2,4 Ghz freq of your TX and the 2,6ghz harmonic of the 1.3 vTx will most certainly have interference!! Its a known fact! you need a notch filter and a low pass filter!! This is normal for not using any filters and having those antennas as close as you do.
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JasonEricAnderson on April 16, 2014
(7:08) It looks like the RC RX is mounted right in the back of the of the jumble of your gear close to the motor mount (red ant. sleeve?) You might want to try and move it out to a wing tip to get it as far a way from your motor's EM field as you can. Also, if it's a single wire ant. think of it's field shape, with it positioned laterally across the wing your field torrid would have it's weak points facing each wingtip. Moving it out on the wiglet and pointing it vertical would move your field weak points up and down. This would make your signal pattern only weak when it was directly overhead and stronger when it's flying normally.

I'd try extending the FPV ant. out away from the box to put it at the other wingtip that way you can keep your GPS ant. centered in the main body to the front of the airframe.

Just my thoughts. Glad it all came out well in the end.
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MyGeekShow on April 16, 2014
Awesome suggestions. Thank you for the help! I'll be moving them apart and adding a filter asap. Like you said, I'm just happy it landed : )
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andre on April 16, 2014
That was very interesting to see. Have to done a range test since then?




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MyGeekShow on April 16, 2014
Not yet, I need a helper to let me know when it goes to failsafe. While I know this isn't a good configuration, I agree, it would be helpful to confirm it through a test. Thanks!
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andre on April 16, 2014
Regardless keep up the energy. Productions/videos are great.
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crlock on April 16, 2014
follow me feature???? care to elaborate on that?
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MyGeekShow on April 16, 2014
Is a feature of Arduplane and Mission Planner, in affect, you send live location data to the airplane, which in turn can follow a moving GPS device.
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Exhodus on April 16, 2014
About your range issues, if I see correctly the video Tx and the control Rx are quite close together and both equipped with linearly polarized antennas. Now, I know that 1.3 Ghz's second harmonic is not right at 2.4 as with 1.2 but its still damn close, and these Txs are tend to bleed signals all over the place.
So as I see it you having a 400 mW transmitter screaming right into the ear of your control Rx, which being a Turnigy 9x is roundabout 100 mW and not the most bulletproof protocol either (dont get me wrong I absolutely love 9x, its value for the money cannot be beaten), now there is your problem, to make things worst both are lineary polarized, so the signal can enter with full strength and you were sitting inside a car.. big no-no, that sheet of steel between you and the airplane is a serious violation of the frenell zone.
If you would take my advise on this, watch IBCrazy-s fvp tutorial videos, and take his points to heart, than you will have a good time flying fpv.

I had smilar issues in the past, Vtx 1.2 control 2.4, it basically reduced the range of my 9x to less than a 100 meters, and I had waay bigger separation than you do, also move the antennas away from soruces of noise like ESC, Motor, and power wires.
If you wanna stick to 1.3 you will need 433 Mhz or 35Mhz for control, I've put an orange OpenLrs into mine 9x, and I love it, when combined with ER9x you can set up everything, the possibilities are endless!
If wanna stick with 2.4 control than move to 5.8 for video, those two has no interference whatsover, no matter how close they are, but the range is much-much less than with 1.3 and 433, also with 5.8 circular polarization is an absolute must!!
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MyGeekShow on April 16, 2014
Thank you for the info! I was not aware of the bleed over and resonance. I'm watching IBCrazy stuff right now.

I have a EZUHF I'll be implementing on this set up, I was going to wait, but not anymore! Full speed ahead on that!

Thank you for the info and tips!
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JamesWhomsley on April 16, 2014
Oh my gosh dude, this was hilarious! I hope you find out and fix the issues you had, but yeah, man, your video was incredibly entertaining! Keep it up :D
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MyGeekShow on April 16, 2014
Perfect! That is music to my ears : )

I love making the show, glad to hear others enjoy it too.
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JamesWhomsley on April 17, 2014
No problem! Well, you just earned yourself a new subscriber. :)
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Exhodus on April 16, 2014
Also watching the end of the video, you will never have a failsafe on a 9x, it just does not support it with the default module. Once again OpenLrs or an Frsky 2.4 will give you this capability and much more! You were lucky, that you have the 3DR radio telemetry, thats 900 Mhz, so its not affected by the 1.3 Ghz
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MyGeekShow on April 16, 2014
Very lucky indeed! I'm going with a 433 via EZUHF here shortly. Thanks for the tips!.
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TehMaxwell on April 16, 2014
Great video! Good quick thinking on your part, and what an amazing performance from the technology. Yes you may have got lucky, but that still goes to show the power of automation right now!
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RcDad on April 16, 2014
LOVE IT! Great job thinking on your feet!
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kpd on April 16, 2014
Amazing job! It was amazing when you turned your transmitter off! I cant believe it landed so well too!
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KJ4CCH on April 16, 2014
ready made RC sells a filter that plugs in between your vtx and your vtx antenna.I cant find a link right now because it seems like the website is down for them. But you will need that if that is what you are looking to run. Otherwise, look into another freq. I do the 72 mhz thing
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fabLAB Asturias on April 17, 2014
Try to change the FPV Channel. Perhaps you're getting an harmonic that resonates with the antenna on your RC receiver. It happened to me once, I totally lost control 10 meters away from the transmitter. Changing the FPV channel solved it.
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ChrisJ on April 18, 2014
Sounds like your receiver is frequency hopping to the strongest signal which is a sub hamonic of the 400mW FPV 1.3GHz Tx a metre or so away. That's the main reason why people use 5.8GHz for FPV, non of it's sub hamonics are on the 2.4GHz band.

With my 200mW FPV Tx and scew aerials I get well over a mile solid signal, double that with a helical directional aerial, but it does have to have line of sight at that kind of range, it's pretty much a moot point as my 2.4GHz Futaba Tx can't reliably reach that far.

Chris
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Hasersys on April 19, 2014
Not sure how 1.3-2.4 is, but my 433mhz ran with a strong, 1080 or 1.2 system has to be very far away from one another. I even get harmonics from my camera.
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markcross100 on April 24, 2014
I have had brown outs using that Turnigy transmitter while flying fpv. When it is not used in conjunction with fpv equipment it does just fine.
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pezplanesrc on June 2, 2016
Trent - I want to send a word of thanks for this episode. Yesterday I flew close to a radio tower and for some reason my EZUHF was completely out of service for the rest of the flight. I found out that the tower is sending 462mhz at 45 watts. The only option I had was to use the auto-land feature of the APM, which was inspired by this episode as telemetry was solid.

In my case the first landing almost landed me in a tree and I put the plane into RTL at the last moment. I should have used the "abort landing" feature, which I have also now tested.

In the end, I created a mission to land the plane and it landed it very well.

I was shaking the rest of the day. What a great hobby!


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Emergency Auto Landing - APM saves sUAV