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Rapid descent in RTL

Posted by Sandy Sound on March 30, 2015 at 4:00am

Hi guys,

I had a very heaving landing in RTL today - the descent was much faster than usual, it literally almost dropped out the sky. I suspect my battery failsafe is set too low and the voltage tapered off quickly as the battery ran out and that was that?

I think I have lowered the battery failsafe to 10.2, so I will put it back to 10.5 if it is a lack of voltage.

Could someone please view my log and confirm?

I am running a pixhawk 3dr quad 2014 kit stock with radio telemetry, 11 inch APC slo flyer props, tarot 2d gimbal with gopro3+ and taranis transmitter, 

Regards,

Sandy

63.BIN

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Replies

            • Andy Piper > Sandy Sound March 31, 2015 at 11:51am

              FWIW I have got a 3DR quad kit with similar setup and I use Turnigy 6000mah 4S 25-50c which gives me about 50% more time than the stock 3DR 4000mah 4S which I would imagine is still better than 4000mah 3S. The increased weight of the bigger battery does not seem to appreciably taper the flight time. They are more expensive however.

  • Kjetil Riisnes March 30, 2015 at 6:05am

    I had the same happen to me only in Loiter mode during descent today, I also have the failsafe set to 10,2 because it kept going into failsafe during load even though I had plenty to go on after landing. What battery are you running?

    Did you pull back the rear arms to make room for the 11inch props? Do you maybe have a picture of the quad I can see?

    • Sandy Sound > Kjetil Riisnes March 30, 2015 at 4:43pm

      Nope - 11 inch props fit on the diy kit just fine without any adjustments. I think it flys better on the 11's than the 10's they recommend. Just my opinion though! It wont take 12's without some modification.

    • Stuart Brookes > Kjetil Riisnes March 30, 2015 at 11:43am

      yup...battery too low...it gets down to 8.3 volts.way too low...I wouldn't trust that battery again if it were me. battery looks low right from start of flight.

      At the end some of the motor demands are maxing out to try and stay airborne. 

      Also your motor 3 isn't working as hard as the other for some odd reason, the demands to the others is a bit higher than i'd like if it were mine...maybe a fault...but it looks a little under powered......BUT that weakness may be due to the bad battery.

      • Sandy Sound > Stuart Brookes March 30, 2015 at 4:38pm

        yes it was my 2nd flight on that charge, was trying to sneak in a short flight... 

        I will reset my battery failsafes. I don't want that to happen again!

        Thanks for taking a look for me. I'm not too concerned about the lack of power to motor #3 as it flew fine today :)

        Cheers,

        Sandy

        • Stuart Brookes > Sandy Sound March 31, 2015 at 11:55am

          "I'm not too concerned about the lack of power to motor #3 as it flew fine today :)"

          Well the flight controller is amazingly good at masking issues....an attitude like that is asking for a crash, but hey ho....up to you.

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