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Max Wind Speed Resistance

Discussion in 'General Discussion' started by licensed pilot, Mar 22, 2016.

  1. licensed pilot

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    Before I get beat up; I searched for this term before posting this thread...:confused:

    What, exactly does this mean "Max Wind Speed Resistance", the specs state the value for the Inspire 1 Pro at 10 m/s.

    I'm guessing it means the max. wind velocity at which the bird will hold its position (GPS mode) ??
     
  2. The Editor

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    Basically yes. It constitutes the maximum wind speed DJI recommend flying the aircraft in.
    It is roughly half its rated power.
     
  3. licensed pilot

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    Thanks.
     
  4. eldorado

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    Until the power conservation routine kicks in! DJI indicates this occurs with batt temp below 16ºC but I have seen this message well above 20ºC. Mystery logic.
     
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  5. damoncooper

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    Roughly: core battery temp below about 14C or above about 45C and propulsion output will be limited.
     
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  6. eldorado

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    Thanks Damon!

    I fly in Canada winter/summer. 12 March was warmest day this year, started off about +5ºC.

    AC had battery insulators installed. I got the error at 44ºC while ambient had risen to about 10-12ºC! The following week started flying in -4ºC and had to calibrate compass with a starting battery 20ºC. By the time ready to fly the bat had dropped to 13.25ºC and got warning to warm to 25ºC before flying.

    So is the actual safe operating temp for the battery is 25ºC to 44ºC?

    Do we need to start figuring out onboard cooling? I hit 53ºC last summer.

    Damon, do you know what percentage drop in power is dropped by? This will of course change max wind resistance...
     
  7. damoncooper

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    Optimal battery core temp discharge range (aka "The Goldilocks Zone") is 20C - 40C (68F -120F).

    Not sure how much power is limited when core temp reaches the extremes AND voltage drops but one way you can fight this is to

    1) carefully monitor your battery temp and cell voltage during flight

    2) start with core battery temp at around 25C (car heater on the windshield dashboard for 5 min will do it).

    3) wear a battery compartment blanket (only) when ambient air temp is < 0C (32F)

    4) add chemical warners to the battery compartment blanket (only) when ambient air temp < -15C (5F).

    5) See point #1.

    I should add that it's not just temp range that triggers the propulsion governor, but the combination of temp range AND voltage.

    So, at the risk of sounding like a broken record, using a battery mod with external lipos can help keep voltage from sagging to the point where the propulsion governor is triggered.

    Note that the heavier the workload on the battery, the higher chance you'll get a sag at extreme temps outside the Goldilocks Zone. Pro units for example, draw more power due to a heavier camera and more powerful motors. Hence, the more care that must be taken to watch the battery temp and voltage on these aircraft.
     
    #7 damoncooper, Mar 23, 2016
    Last edited: Mar 23, 2016
  8. eldorado

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    Thanks!

    Great rules to live by Damon!

    Perhaps we need DJI to add the Temp to the display as it is now a critical performance measurement?

    I monitor battery via C2 toggle but preferred when that was dedicated to map view instead.
     
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