According to Randy the know issue of altitude loss after a high speed run is at its heart a frame issue.This seems to me a very worthwhile discussion to have.Once the majority of us understand this, we will be less likely to muck up other threads.Take it away Randy...

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            • publishing them to Thingiverse is my suggestion http://thingiverse.com

              • Good idea. Thanks.

                http://www.thingiverse.com/thing:1309180

                • could you check the link, or give the name it is posted as please? that link gave an error

                  • Thing 1309180 is live.

                  • I just created a thingiverse account. They tell me that I have to wait 24 hours to publish anything. I didn't realize that at first. The link should work tomorrow. I'll check it. If it still isn't good, I'll reply with another.

                    Sorry about that.

              • Hi Chris!

                Did you test with the tube ending at the top of the past, without the plastic 'antenna'? 

                • Hi nicopter,

                  Not in this round of testing. As I've mentioned, I haven't been terribly scientific in my experiments. I did test with just an open tube, mounted in a similar location, in previous experiments. The result was a negligible improvement, if any, over the internal barometer.

      • Hi Richard,

        Thanks.

        I'm willing to try, though I suspect I would have the same issue as in previous experiments, wherein the inlet was still inside the airframe's pressure envelope and didn't accomplish anything. That's the reason for the tall mast. I also have the propeller flow-fields to contend with. There is a low-pressure gradient above each prop that changes with RPM. There isn't much room to work with on this airframe.

        I'll see if I can get in a flight with a shorter mast this week, but it may have to wait until the weekend.

        Cheers!

    • @Chris,

      you can easily correct and control altitude via a simple AltHold
      energy consumption test.
      Power meter can give you highly reliable energy consumption vs. altitude (air pressure) at AltHold chart, you can use to support EKF.

      If energy consumed by motors and hardware to stay in AltHold mode
      at altitude 10m is E10, so if energy consumption starts to grow suddenly you can can expect error in bar, GPS, IMU altitude calculations.

      Alt control via power consumption exactly resembles manual mode control with joystick.

      Saving power consumed data to logfile may give better insight into Drone Fly-away Syndrome, since if energy consumption is steady, all you can expect from your drone is a horizontal drift in Stabilize mode.

      • Hi Darius,

        Thank you for the suggestion, though I'm not entirely sure that I follow. Are you saying that I may be experiencing voltage droop to the IMU due to motor current surges? If that's the case, I'm pretty sure that my power supply regulation is good. If I had such a problem I would be seeing other issues as well.

        I am aware that I can tweak EKF_ALT_NOISE to gain a small amount of immunity to small altitude changes, but this isn't a good option for me as I am currently fighting vibration issues as well.

        Maybe I just don't understand what you mean.

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