How to reduce the Auto take off initial "drop" ?


During our last training session where we tried "Auto-Take off" (@1:25 min in the video) with the last Arduplane 3.3 version, I noticed a severe drop at the exit of the catapult. We tried to the minacc (was at 4m/s) , minspd (15m/s) and throttle delay (at 0,1) parameters to avoid that drop but without success so far.

The Talon is powered at 700Kv with a 13x8 prop on 4S, so it is certainly not underpowered.

Anyone advices on reducing the auto take off "drop" ?

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  • MR60

    As seen in my last blog published just now, we tried again an auto take off training session with perfect launch this time. The only difference we tried was to just put more tension in the catapult cable for a stronger throw. 

    • Sorry, I couldn't find that followup blog post of yours. Can you post a link?

      Thanks, Marc

  • Looks to me like it doesn't get pulled anywhere near as high by the bungee on the second launch.

  • Check that pitch angle for TAKEOFF mission item is greater than zero. I usually set it to 20 degrees, this gives good start.

  • Yes, the motor needs to be running at least 80% power during the launch.

    • MR60

      So I should maybe set THR_DELAY to zero ? There is to my knowledge no parameters allowing the engine to spin at 80% before minacc and minspd are reached or am I wrong ?

    • My Talon has the wing extensions, and 15 000 mAh worth of batteries in the nose.

      Even in "no wind " hand launches, it "almost" just flies out of my hand, @ 80% throttle.

      Should be more than adequate in your setup, with the motor running.

      I have no experience with Auto TO, but surely there must be some "motor on" command for the guys that use wheels ?

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