Tuning my quad was a challenging experience but a good one. It made me familiar with the settings and if I build another quad or hex or x8 it will so much simpler once we get familiar with what the rates do. A great learning experience. Now for two questions. Running 2.9.1b on a 5 pound quad. Four Avrotos turning 12.4.7 props. Flies great in stabilize. However, when switching to alt hold or loiter, it still simply sinks to the ground. So far I have reduces throttle rate P to 5 from the default of 5.8. How much lower can I go with this setting to get alt hold and loiter to work correctly? Second, when I did the calculations in ecalc, the internal resisitance on the motors is 100mohms. Is .1 or .01 the correct decimal representation, since it makes a difference in hover throttle percentage. At .01 the hover is 43%. I would then set the Throttle mid value to reflect that. With .1 its 53%, I would then set the Throttle mid value to 530. It may make a difference with alt hold and loiter. Thanks Roman

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  • Hi,

    I had the same problem in Alt Hold and all other modes which need Alt Hold. As pointed out in various threads, it is crucial to have minimum vibration on the Z axis accel. As soon as I eliminated the vibration by balancing props and motors and putting my APM on foam, everything turned out to be working well with the stock PIDs for Alt Hold and Loiter.

    I would suggest to turn on the RAW logs through Terminal mode in the Mission Planner, hover for a minute in Stab mode and see what readings you got for your Z Accel parameter. If it is not between -20 and 0, it is definitively a major problem. -15 to -5 should be ok as far as I recon. I do not know if there are "official" limits.

  • It sounds like you may have the Alt Hold/ Loiter P gain set to low. I would not worry about the Mid setting for throttle just yet as that is for the overall system performance. Try setting your Alt Hold/ Loiter P gain higher than stock (this will not affect Stab flight) and see if that corrects your sinking feeling. :)

    But to answer you question:

    100M ohm = 100,000K ohm= 100,000,000 ohm

    Megohms is the highest representation that normal people use, so everything compared to that would be in decimal value. 

    For example:

    100K = 0.1M 

    10K = 0.01M

    hope that helps!

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