Would like the official 'Andy' sign off?

Discussion in 'Cinestar 8' started by Ben Freedman, Jan 29, 2013.

  1. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    Howdy...

    Just finished building my new Cinestar 8, after trading up from my Draganfly X6. I've currently had 2 flights on the bird, with the gimble attached and a small handycam loaded.

    Andy, could I persuade you to take a look at my GPX files from the first 2 flights, and see if they meet with your approval? No weird anomalies, good temps and currents, etc... We built the ship according to your rather good DVD, so it'd mean a lot to have a diagnosis from you...

    Your time is extremely valuable, so if there's somewhere I can make a donation, or just buy you a Starbucks Card, I'm more than willing...

    Thanks!

    Best,

    Ben

    Benjamin Freedman
    PrimeImage Media
    480-399-0000 - direct
    480-240-9270 - office
    866-549-6051 - fax
    ben@PrimeImageMedia.com
    www.PrimeImageMedia.com

     

    Attached Files:

  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Happy to do so just because you asked nicely! :)
    I'm in the middle of something right now, but happy to have a look in an hour or so.

    Andy.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    On your first flight, motor 8 seems to be consistently drawing less current See the text summary of the first flight below.
    I used MK_GPXTOOL to get this summary. Not quite sure what to make of it, but using the blade tips of the props, spin adjacent motors around and make sure that the prop blade tips line up vertically.

    Here's the sequence:
    1. Spin Motor 1 and 2 to line up the blade tips. Check they are vertically at the same height above the bench.
    2. Then spin only motor 1, so that the other blade comes around and check the line up.
    3. Then spin only motor 2, so that the other blade comes around and check.
    4. Then repeat for motors 2 and 3, 3 and 4 and so on.

    The goal is to ensure that the motors are absolutely vertical and not introducing some yawing motion.

    If you have Xbee Wifi, you can also do this using the Balance Window in MK Tool while the copter is flying.

    On flight #2 everything looks the same as flight #1 -- all good except the question as to why Motor 8 is not pulling more or less the same current.

    I see you were testing altitude hold, position hold, and carefree. I presume you didn't see any problems there. Be very careful with Carefree Mode...it can lead to some crashes. Personally, I don't like to use it, but that's an individual pilot's decision.

    All other opinions welcome folks.

    Andy.

    -----



    Summary of flight #1
    MK Version: FC HW:2.1 SW:0.88n + NC HW:2.0 SW:0.28p

    Flight time: 10:24:45 AM - 10:34:14 AM (569 secs, 00:09:29)
    Total: 568 secs, 00:09:28
    Elevation(GPS) : 0 7.58 15.859 m
    Altitude(Barom.): 0.9 11.48 20 m
    Vertical speed : -2.54 -0.02 4.81 m/s
    Max speed : 24.2 km/h
    Max target dist.: 4.9 m

    Sats: 9 13 14 (min/avg/max)

    Voltage: min. 13.6, max. 16.4 V
    Current: 6.3 51 125.1 A
    Wattage: 89 773 1701.36 W
    Capacity: 8092 mAh

    Motor1: 0.5 7.9 12.6 A Temp: 21 66 82 °C
    Motor2: 0.6 6.9 12.4 A Temp: 26 66 83 °C
    Motor3: 0.5 7.1 11.1 A Temp: 26 50 64 °C
    Motor4: 0.4 5.0 11.0 A Temp: 22 45 61 °C
    Motor5: 0.5 6.8 11.4 A Temp: 19 45 59 °C
    Motor6: 0.6 5.4 10.7 A Temp: 15 38 57 °C
    Motor7: 0.8 6.7 11.7 A Temp: 14 45 59 °C
    Motor8: 0.2 3.2 6.2 A Temp: 17 52 75 °C

    Magnet Field: 105 107 111 % (ok)
    Magnet Inclination: 54 58 65 deg

    Errors / warnings:
    FC-Flag "LowBat" (5) occured 8 times!

    Summary of flight #2
    MK Version: FC HW:2.1 SW:0.88n + NC HW:2.0 SW:0.28p

    Flight time: 10:40:42 AM - 10:49:12 AM (510 secs, 00:08:30)
    Total: 508 secs, 00:08:28
    Elevation(GPS) : 0 18.11 69.648 m
    Altitude(Barom.): 0.95 19.53 71.05 m
    Vertical speed : -3.67 -0.01 3.38 m/s
    Max speed : 24.2 km/h
    Max target dist.: 6.7 m

    Sats: 12 12 13 (min/avg/max)

    Voltage: min. 14.4, max. 16.5 V
    Current: 0.5 52 75.2 A
    Wattage: 7 800 1143.04 W
    Capacity: 7448 mAh

    Motor1: 0.7 7.9 12.0 A Temp: 20 70 85 °C
    Motor2: 0.5 7.0 10.3 A Temp: 23 70 88 °C
    Motor3: 0.2 7.4 10.5 A Temp: 21 56 75 °C
    Motor4: 0.1 5.3 9.7 A Temp: 20 50 65 °C
    Motor5: 2.7 7.2 12.1 A Temp: 17 49 61 °C
    Motor6: 2.3 5.6 12.1 A Temp: 13 42 55 °C
    Motor7: 1.6 6.9 9.8 A Temp: 13 48 62 °C
    Motor8: 0.2 3.2 5.4 A Temp: 16 53 73 °C

    Magnet Field: 105 106 109 % (ok)
    Magnet Inclination: 55 58 67 deg

    No errors found ;)
     
  4. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    Thanks for that. I could see why a motor could draw MORE power if it was misaligned, but I'm having trouble seeing why a single motor would draw less. Do the temps see in-line to you? I'm a little worried about when it hits 115 here in summer. I've ordered some of the aluminium head sinks from QC...

    Finally, you mention CF leading to some crashes. Is this because of pilot-error/confusion/disorientation? Or some systemic issue with CF?

    Best,

    Ben
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    The temps seem in nominal. What was the ambient temperature where you are flying?
    If you're talking about 115F/46C, then definitely get the heat sinks. (At 115F you should be inside drinking a cool one!)

    CF causes disorientation especially if let the bird go overhead and behind you. Perhaps Steve Maller can comment on his experiences and the merits of CF. As I say, it's a very personal decision but to me, CF is up there on my list of things to avoid right below yellow snow. :)

    Andy.
     
    Shaun Stanton likes this.
  6. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    So, 2 thoughts...

    1) Could the lower draw from the 8 motor be caused by a non-centered center of gravity? ie. Perhaps the CG is tilted 'away' from boom 8, making it prone to rise up in the air, and therefore it compensates by not creating as much thrust? Feel free to destroy this theory..

    2) So CF doesn't work like it does on the DJI system, where pulling the stick back always returns the heli to you, describing an arc if the heli has drifted left or right? If you fly overhead, and turn yourself around, the heli would now fly away from you with rear-stick? I can see how that'd be confusing... Do I have this right?

    Best,

    Ben
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    That could certainly cause it, but the good news is that if you can use the MK Tools "Balance" window, it will show you (a) where the C of G is and (b) whether there is a yaw component that the FC board is "fighting."

    For my research on the forthcoming DVD "A Rather Good Beginners' Guide™ to MK Tool," I think I may have been able to reduce the MK CF mode down to three rules -- I'd welcome comments from anyone as to whether this is correct (the German/Germlish documents were a little confusing and take five separate diagrams to do what I've tried to distill below). Artificial Boom #1 is the reference line used for the roll axis (so if you roll left, you're rolling about this reference line).

    Rule 1: If Copter is on the ground and nose out from you:​
    Turn on Carefree (regardless of Teachable or not),​
    And then start the motors​
    Then: Artificial Boom #1 is original nose out all the time​

    Rule 2: If copter flying and > 20 meters away and Teachable CF is enabled​
    Switch CF off and on sets Artificial Boom #1 along bearing from you to the copter​

    Rule 3: If copter flying and < 20 meters away and Teachable CF is enabled​
    Switch CF off and on sets Artificial Boom #1 in direction of Actual Boom #1.​
    I can't speak to the DJI system as I don't know it, but the MK System seems like it might be confusing. (Note: That's British Understatement from a confused Brit. :) )
    Hope you're good at accurately estimating 20 meters. <evil grin>
    Andy.
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
  9. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    Here's my rule...

    NEVER turn CF on unless you are sure the current orientation of the heli is nose-out from you, regardless of whether it's in the air, on the ground, close or far.

    I believe if you follow that one rule, you'll be fine... CF is not for getting you out of trouble if you've lost orientation... Rather, it's for allowing you to fly the heli without regard to orientation so you can focus more on single-op camera work.

    Concur?

    B.
     
  10. Steve Maller

    Steve Maller UAV Grief Counselor

    Joined:
    Oct 30, 2012
    Messages:
    3,979
    Likes Received:
    807
    In theory, that sounds right. But in practice, many of us are skittish about using it. IMHO it's a crutch, and if you can fly the copter properly, there's no need for it.
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Imagine:
    1. You're facing North.
    2. The copter's boom #1 is nose out and therefore also facing North.
    3. You turn on CF so Artificial Boom #1 is facing North.

    Now you take off and fly off 100 meters away, to the North. Then either you fly it or the wind drifts it so that the copter is due East of you. You turn East to face it.

    You move the right hand stick to the right.

    Don't think about this now -- just react as you would have to in real life: In which direction will the copter fly?

    And that's why I'm concerned. :)

    Andy.
     
  12. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    Ah... your mistake was to turn to the east! There's no Mecca for CF users!

    Maybe it should be like DJI, where in CF mode, the heli flys an arc around you, so the nose is ALWAYS out....

    Best,

    Ben
     
  13. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    Here's the DJI video explaining their system:



    Best,

    Ben
     
  14. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    Howdy...

    So, Andy... Here's another GPX from today's flight. Something odd to me is that while motor 8 is indeed drawing less amps, it has the same temps as the other motors...

    I used MKTools 3D mode during the flight, and the 'yaw' element was off to the right by just a couple of degrees. Very slight. Also, the 'balance' screen showed a green dot in the center while on the ground. In the air, the dot moved around the middle a bit, and sometimes changed to a yellow dot. It never made it to red, or to the outside of the screen...

    Thoughts? GPX Attached for your reference.... :)

    Best,

    Ben
     

    Attached Files:

  15. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    By the way, here's a quick 360 pan from 160ft on my 2nd flight. I'm amazed at how stable the camera is. No post processing here... This is with a CX550...



    Best,

    Ben
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Hi Ben:
    What's with this cloudless sky thing? :) You're just trying to make me feel envious aren't you?

    I'm starting to wonder whether the issue is the reporting of the motor current rather than the actual motor current.
    Do you have time and inclination to do a simple test? Swap over booms 8 and 6 and see if the "low current" moves to boom 6.

    If it does, then everything is fine--its just that the brushless control (BL-Ctrl) for #8 is under-reporting the current draw and you'll just live with it! :)

    If it moves to boom 6, then it's likely to be the motor....and you may need to talk to your dealer.

    Let me know what you find.
    Andy.
     
  17. Shaun Stanton

    Shaun Stanton Active Member

    Joined:
    Oct 27, 2012
    Messages:
    748
    Likes Received:
    127
    I would suggest to make sure teachable carefree should be activated. Andy can correct me if I am wrong, teachible carefree allows you to bring the copter back to your position by pitching back. One the dangers of using carefree is inadvertently shutting it off then turning it back on not knowing where your front boom is pointed. Luckily if you have teachable carefree selected in MK tools and you are beyond 20 meters from the launch point it will orient the copter to the lunch point so if you pitch back the copter should make a b- line towards your original launch point no matter where the copter is in space.

    Warning//// not a good idea to use unless you have reliable GPS. Last ditch effort is Return Home but should be a last resort IMO.

    I am with Andy I do not like CF. I do not fly it on my Cinestar. I only use it on my DJi hex so I can give my cam op control of the yaw axis while I maintain orientation of the a/c
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    That depends on how far away the copter is. More than 20 meters, yes. Less than 20 meters, no. (Hope you can judge 20 meters accurately. :) ) See Rules 2 and 3 above in Message #7.

    Andy.
     
  19. Ben Freedman

    Ben Freedman Member

    Joined:
    Jan 11, 2013
    Messages:
    119
    Likes Received:
    1
    ...or follow my 1 rule from message #9! :)

    B.
     
  20. Shaun Stanton

    Shaun Stanton Active Member

    Joined:
    Oct 27, 2012
    Messages:
    748
    Likes Received:
    127
    I suppose I should have read the rest of e posts I missed that one, you covered it ;). I agree hard to judge 20m w/o telemetry or FPV. IMO never take the copter beyond video transmitter. My camera op and I practice a loss of orientation recovery on the dji where I have the cam op always point the a/c towards us and I disengage carefree an fly forward until I have a good visual orientation. I removed it from the CS after a near bad experience. I did the rookie mistake of taking off with on an lost orientation immediately after I yawed it. Luckily Return Home saved my SSS, but was not a comfortable feeling knowing I lost control. After that I disabled it on the CS and only use it on he bird because it is 2 axis gimbal.
     

Share This Page