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Arducopter 2.0.25 - High altitude visit

Posted by Helldesk on June 28, 2011 at 5:30am


I decided to see how high I would have the nerve to fly today.

 

Started in Simple mode, default PID values. Motor to motor distance of the quad is 64 cm, Turnigy Plush 18 A ESCs, DT750 motors, 1045 EPP props. When I tried to start descending I hit a snag - lowering the throttle in Altitude hold mode seemingly did nothing! If I'm reading the log right, the descend did not start until I switched to Simple mode. I increased the throttle before I did that so I didn't sink like a rock. Still, all's well that ends well.

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  • Helldesk June 28, 2011 at 2:34pm

    Right, I figured on today's last flight that it simply takes its time and comes down gently when using alt hold. It was impossible to eyeball that movement 114 meters up and tens of meters off to the side! ;)

     

    RJBK: I don't know the AUW of my quad, sorry - I'll have to find a scale. Come find me on the chat one of these days and ask if I've had the time for that. I do think it is around 1.5 or between that and 2 kg, though. I find I need to apply a bit over half throttle to achieve lift. Interesting, if bigger props shorten the flight time for you. All I care is for efficiency - I want nicely behaved, boring and uneventful flights - unless I choose to spice it up.

  • Developer
    Jason Short June 28, 2011 at 12:41pm

    Bless you for posting the log! Here is the alt hold section of the data:

    3692230907?profile=original

    Gorgeous! You can click to view larger. It looks like you got a little impatient on the decent. It was starting to go down at the end. You can see the control input to go down only lasted 4 seconds.

    3692230884?profile=original

  • mc_don June 28, 2011 at 10:56am

    sorry helldesk.. I mean who about the flying thrust :) (sorry for my bad english)

    the Max thrust: of D750 is 1000g

    i have use this motor to. my qc auw is about 1.5kg. include 3700mAH 3cell.

    but if i use 10x45 props, my QC is feels heavy to fly.

    and if i use 12x45prop, was light to fly. sort flying time :( just about 8minit.

     

    can you tell me your QC auw? (in kg)

    thank's


  • Helldesk June 28, 2011 at 9:20am
    So far I have never seen amp draw higher than 30 A (that was on this flight). The Turnigy power analyzer that I fly onboard most often tells me the peak was about 28 A, which would mean 7 A per motor, and overall flight time out of a 5 Ah (5000 mAh) 3S lipo might theoretically be 15 minutes. One of the motors feels sluggish though - at some point I'll try swapping it out to see if it has a bent axle that could make it draw slightly more power. The DT750 is rated at 18 A.
  • mc_don June 28, 2011 at 8:55am
    how the power using DT750 motors+1045 EPP props

    becouse i have bad power in 1045 EPP props, and have good power in 12x45 props
  • Helldesk June 28, 2011 at 8:45am

    Oh yes, I was well aware I was four versions behind and I have been impressed with the speed of the new releases. However, 2.0.25 had functioned well on several flights so I did not want to change a working formula. Looks like I just stumbled on something! Judging by the few change logs I managed to find, the changes appeared to be non-critical, and one version possibly introduced a new problem, so I judged it best to fly once more with 2.0.25.

     

    Just out of curiosity: was this some known issue I simply had missed?

  • 3D Robotics
    Chris Anderson June 28, 2011 at 8:02am

    Please upgrade to the latest code (you're four versions behind). While we're in the beta period new code versions and bug fixes are shipped every day. You should always update to the latest code before flying and do a reset/setup process again. What we're looking for from beta testers (you are all beta testers during this period!) is feedback on the latest code, not reminders of bugs caught several versions ago. It's safest for you and most helpful for us if you remember to check for updates before flying.

     

    Once we come out of beta, code updates will happen less often and reset/setup will typically not be required. But it's still always a good idea to check for the latest code.

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