My new MK heavy lift copter project

Discussion in 'Cinestar 8' started by Dave King, Jan 4, 2014.

  1. Chris Fox

    Chris Fox Active Member

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    Does it go something like, "I'm just about to do the dusting, and vacuuming all at once, just stand back while I start it up" ;)
     
  2. Chris Fox

    Chris Fox Active Member

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    G'Day Dave,
    I was thinking from your GPX file, the given you have got logging just the average motor currents for a lazy flight around the park should not be to far off the hover amps from eCalc, that is unless it is a howling gale, or you are going for an airspeed record.
    Is there a window in mk tool that shows amperage?
     
  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    Indeed, the GPX file is your friend. One of my last flights with the base 4S Cinestar I did just that. The first minute or so of level flight was just hovering (in PH and AH) and the GPX file gives me a very clear picture of the motor draws.
    Parallels Desktop-snap001.jpg
     
  4. Dave King

    Dave King Well-Known Member

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    Wouldn't hover gas be a good indication of what we want to look at? If hover gas is more than 60% it means its working too hard regardless of the current draw correct? But I imagine that they go hand and hand because if the motor is working very hard its going to draw lots of current.
     
  5. Chris Fox

    Chris Fox Active Member

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    Both are valid things, I've just been staring at amperage numbers the last week, because with higher amps, come higher temps, and high temps, let the smoke out of the wires, and no matter how much I google, I can't find how to put the smoke back in the wires ;)
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    It seems to me that hover gas % can be misleading. I agree with Chris that the actual voltage/current numbers are more significant. This is where MK shines, and why I’m sticking with them for now. This data is critical to tuning a system.
     
  7. Dave King

    Dave King Well-Known Member

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    Just came back from a flight with a 10 pound payload added. A added weight to my old 3 axis gimbal that was carrying the Sony 760 trying to simulate what it will be with the brushless motor gimbal and Scarlet on it. Todays fly weighed in at 24.5 pounds (11.1kg). So here's the data. I made one flight, it was 35 degrees outside and very little wind. I started bringing the copter in when the battery voltage was 21.6 volts and by the time it landed it reached 21.3 volts. Flight time was 20 minutes.

    Flight date: 1/12/2014 1:41:08 PM
    Flight time: 1:41:08 PM - 2:01:09 PM (1201 secs, 00:20:01)

    Elevation(GPS) : 0 22.28 53.88 m (min/avg/max)
    Altitude(Barom.): 0.2 26.87 58.55 m

    Vertical speed : -2.78 -0.02 2.49 m/s
    Max speed : 45.8 km/h
    Max target dist.: 16.6 m

    Sats : 7 9 12

    Voltage : min. 21.2, max. 24.8 V
    Current : 0.5 63 87.1 A
    Wattage : 11 1445 2072.98 W

    Capacity: 20983 mAh

    Motor1: 0.0 8.6 14.5 A Temp: 5 12 21 °C
    Motor2: 0.0 8.5 14.0 A Temp: 7 13 23 °C
    Motor3: 0.0 7.1 11.9 A Temp: 6 11 20 °C
    Motor4: 0.0 6.8 12.1 A Temp: 4 9 21 °C
    Motor5: 0.0 6.4 12.0 A Temp: 5 9 19 °C
    Motor6: 0.0 7.6 12.2 A Temp: 1 9 21 °C
    Motor7: 0.0 6.3 10.4 A Temp: 4 9 16 °C
    Motor8: 0.0 9.8 15.6 A Temp: 4 13 22 °C

    Magnet Field: 102 104 110 % (ok)
    Magnet Inclination: 51 64 79 deg

    No errors found ;)

    I have attached the GPX file, I add to zip it because its a 20 minute download.

    In the 20 minute flight I did several hovers, one hover was about 3 minutes long. The motors were definitely louder and working harder for sure. At this weight I think I need to increase the gyro d a little as its all bone stock settings right now except for GPS gain which is 90. Overall I am very pleased with the performance and I can't ask for anything more than 20 minute fly time in this cold weather. From my experiences with the 4S batteries I was getting about 2-3 minutes less flight time compared to 60-80 degree weather. I think 22 minute flights are definitely possible with this weight and combo. I can see this combo flying a 5D MKIII getting 23-24 minutes flight time in warmer weather.

    Here's a few minutes of the flight. Sorry its so blown out, my wife was filming and I was on manual Iris.
    http://www.youtube.com/watch?v=NO09s88MCYs
     

    Attached Files:

    Rick Chen likes this.
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    Holy smokes, Dave. 20 minutes at 24.5 pounds? That’s amazing. WOW. And those current numbers are just ridiculous. I guess now we know why everybody’s so nuts to go 6S, huh? :rolleyes:
     
  9. Howard Dapp

    Howard Dapp Active Member

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    Dave, amazing results and numbers! Congrats on the build!
     
  10. Chris Fox

    Chris Fox Active Member

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    Dave that is very impressive, as far as I can make out, you have doubled the predicted flight time from ecalc ..... (or am I entering the numbers incorrectly?)
     
  11. Gary Haynes

    Gary Haynes Administrator
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    Chris I was going to ask the same question. eCalc with those specs is showing a 75% hover throttle. Dave can you confirm, U5's, 15x5 Xoars, 2 QC 10000's? In your print out above it indicates that you used 20983ma. Something isn't computing...
     
  12. Dave King

    Dave King Well-Known Member

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    Gary see below I'm showing 67%. Could the MK calculations be off? Anything is possible but the flight time and the weight are correct so that kind of corresponds to the numbers at least for current. As for temps anything is possible but the motors were ice cold when I landed. I did fly in 35 degree weather after all not 85 degree 50% humidity. From what QC told me they got very good results with a HL they were testing using the new MK electronics with the 4012 motors and 1 battery. I believe they said they got 16 minutes with a 10 pound payload. I truly believe the U5 motors are more efficient than the 4012's so looking at the tests they performed with a lessor motor and one battery I believe I'm right on track.

    heavylift.jpg
     
  13. Dave King

    Dave King Well-Known Member

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    I"m seeing 12 minutes in the software but E calc but I don't think they can take into account every part of a setup. I attribute 3 things to the great flight time.
    1. The new MK electronics that puts the power back into the battery.
    2. The improved efficiency of the new U5 motors
    3. The efficiency of the 10,000 QC batteries.
     
  14. Gary Haynes

    Gary Haynes Administrator
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    Dave your throttle in the GPX file when not in AH is pretty high. It's running in the 75% range. For a couple of seconds you were in the mid-high 90% range. Something to consider. Totally masked since most of the flight was in AH.
     
  15. Chris Fox

    Chris Fox Active Member

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    Interesting experimentation when you vary the ambient air temperature on eCalc, the throttle settings at hover can change by nearly 15% just by a change in temperature. Cold temperatures and dense air are a good help as well.

    45 degrees C = hover throttle 72% (Port Hedland, Western Australia (only just on the map))
    25degrees C = hover throttle 67% (default, also a bit similar to Hobart (it is on the map ... honestly ;) )
    -1 degree C = hover throttle 60% (Sunny Pittsburgh area today .... I don't actually know if the sun is out .... Dave??)
     
  16. Dave King

    Dave King Well-Known Member

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    Gary the instance you were talking about was because I let go of the sticks for a second to see how it would respond and it dropped quickly so I recovered. I"m pretty sure that was the 90% range you saw but you also notice current didn't spike up really high. I went up and down the street with AH off and it felt like the sticks were pretty centered.

    I'll do some more testing with AH off.
     
  17. Dave King

    Dave King Well-Known Member

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    no sun all clouds.
     
  18. Dave King

    Dave King Well-Known Member

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    Gary can you tell me how you are calculating 75% throttle in the GPX file? I'm looking at it and just don't know how to calculate the numbers? Sorry for the stupid question.
     
  19. Dave King

    Dave King Well-Known Member

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    Here's the GPX file from my first flight I made on Saturday with no payload GAW of about 14.5-15 pounds.
    Sorry I had to zip it again because it was so large.
     

    Attached Files:

  20. Chris Fox

    Chris Fox Active Member

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    G'Day Dave,

    The throttle value is in the "RC Sticks" column of the data view, it is the fourth value in the comma separated list.

    It is detailed here http://www.mikrokopter.de/ucwiki/GPX

    Hope that helps.

    Cheers
    Chris
     

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