ArduPilot failsafe RTL in case of out of RC range

Hello,My new board has arrived (thank you Chris) and is working fine. I am an FPV flyer at the first place and automatic RTL mode is so tempting for me... Arduilot doesnt want to cooperate with my Corona RP8D1 in case of loosing RC signal. I added two little friends to the wire mess inside my small FPV platform.This is one of them:

First one is added between IN CTRL of ArduPilot and RC Rx. Second one between CPD4 RMT and Rx. This way I am not afraid of loosing the airplane during long runs.I think most of todays RC transmitters would benefit from such setup.
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  • 5ghz video TXs are really poor, even with diversity their range is limited and multipath is bad, not worth the cost. 900Mhz I agree with but I feel Michael is in the UK if he is on 35Mhz and hence 900Mhz is not legal even for radio hams.

    I'm also planning to use the Ardupilot as a RTL for some of my FPV aircraft but awaiting 2.1 so as I don't need the FMA co-pilot. I can't praise this project enough, it's just excellent.

    On one of my FPV aircraft I currently have the RVOSD which has a RTL "autopilot", it needs a stable airframe as it has no means to level the aircraft, I mention this because their solution to the failsafe on the spectrum is to program the throttle failsafe to a level you would never use in normal flight,say 130% throttle. If the OSD sees this throttle level it knows the link has been lost and it takes control of all channels.
  • Developer
    Yes, you can't use 1.5ghz because you will screw the GPS, the way to go is 900mhz (better range) or 5ghz (expensive) for video txs.
  • Yes Jordi I know about Spektrum advantages. But I have 2.4GHz video downlink onboard already. I have to stick to 35MHz since I have 4channel diversity receiver and a few transmittersfor 2.4GHz
  • Developer
    And you can program spektrum to save the failsafe parameters, for example throttle 50% and RTL is my default.....
  • Developer
    Any spektrum can do that, without extra hardware... Mine does.
  • The reason I modified my platform is that Corona (+lenghtened antenna to 3.04m) is really great Rx due to its glitch free behaviour. Thats why I want to stick with this receiver . My previous RC receiver HFD-06MN didnt even passed antenna down range tests. Another thing is that Hitec Rx didnt cooperate with ArduPilot in case of signal loss as well.
    Corona have its built-in failsafe but it is limited somehow (sometimes it falis to turn on the MUX).

    I dont know why but till now the only bullet proof device that could properly switch MUX and CPD4 on is the small failsafe from the first photo. It could be preprogrammed to hold desired state after RC signal is lost. I connected them between Rx and CPD4 / Rx and ArduPilot.

    It can be confusing indeed. But I wanted to post the solution to problems with some of the RC receivers since it could be vital for FPV pilots.
  • Ok, so this is a Spektrum specific issue, and not a problematic Corona Rx. Then the two failsafe units are just the right thing for Michal.
  • When Spektrum RC loses signal, it keeps last values for all channels except throttle, which is cut down. Also autopilot toggle channel keeps last value (probably manual mode). This would result in plane crash.

    Assuming Ardupilot can read all RC channels, possible detection of signal loss would be checking is throttle is down, and other channels not moving for certain time (e.g. 2 seconds).
  • In my case, my 9 channel Futaba Rx will just do exactly what both failsafe units of Michal are doing (autopilot and Co-Pilot on). But since he seems to have trouble with his Rx failsafe, he uses separate units. If I were Michal, I would probably change the Rx for one with working failsafe.
  • 3D Robotics
    I'm still confused by how the failsafe works. On all of our RC systems, the Rx traps the signal loss and generates its own pre-programmed failsafe command (usually cuts throttle). What does yours do?
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