Coaxial Cinestar...

Discussion in 'Cinestar Misc' started by Benjamin Rowland, Jan 26, 2013.

  1. Jason Toth

    Jason Toth Active Member

    Joined:
    May 11, 2013
    Messages:
    304
    Likes Received:
    45
    How are you liking the 16x5's? What motors / esc's are you using? Yeah the Xoar can get chipped/dinged easy.
     
  2. Justin John

    Justin John Member

    Joined:
    Jun 29, 2012
    Messages:
    54
    Likes Received:
    10
    Hello,

    This thread was very helpful for my latest Cinestar coaxial conversion. I utilized Brads custom DJI Mixing data. After a few successful flight tests I have run into some minor issues but I'm overall pretty happy. I listed some issues that I hope to get some input on. Has anybody experienced the same?

    Issues,
    - 3 Motors (2 bottom one top) are working harder than others and get extremely hot
    - Random YAWing when ending a flight movement and "braking".
    - When closely looking at motors during flight, motor vibrations are apparent.

    Solutions
    - *Completed - Lining up motors to be 90 Degrees
    - *Completed - Copter top and bottom completely balanced
    - Balance xoar blades
    - Re check wiring.

    Specs
    -3515 400kv
    -16 x5 xoars top and bottom.
    -2 x 6s 8000 MAH Zippys.

    Overall I'm extremely happy with the first couple of test flights.

    The benefits are:

    Longer flight times with the new motors - I get 8:30 mins of normal flight with a 8lb Red Weight. Batteries remaining at 3.75v / Cell
    Better wind resistance
    Smoother flight
    Ability to descend fast.
    Radians work much less because of the stability in the air.

    Any insight is greatly appreciated


    - Justin
     
  3. Justin John

    Justin John Member

    Joined:
    Jun 29, 2012
    Messages:
    54
    Likes Received:
    10
    I'm also looking to add some length between the gimbal and the octo. The two benefits are

    1. Avoid the blades from appearing in the shot. 2. Continue to utilize my retracting landing gear on the cinestar with my GH3 Zenmuse gimbal.

    I know of this solution http://forum.freeflysystems.com/index.php?threads/cinestar-8-quick-release-gimbal-system.803/

    But its rather expensive and my current Vibration dampeners are working really well with a few small modifications. I want to avoid the long process of tweaking antivibration mounts to achieve similar results.

    I'm thinking of getting some 50mm Standoffs but I fear that the weight of red will be too much. Does anybody know of other secure solutions? 3d Printed? I know Kopterworx has a unique solution using the oldschool wire dampening technique but I haven't located the product online so I'm assuming its custom.
     
  4. Jason Toth

    Jason Toth Active Member

    Joined:
    May 11, 2013
    Messages:
    304
    Likes Received:
    45
    Justin, your motors might be getting hot because the props. In eCal 16x4 props are just hitting its threshold so your 16x5's could be over. I'm running 14x6's up to 95 degree ambient and they run hardly warm. I have a bunch of props on order, you might want to put 16x4's on top and 15x5 on bottom. I'm going to try out 15x5's top/bottom and 15x5 top and 14x6 bottom and will report soon. Also I'm running the standard DJI top CCW and bottom CW and I have no issues with it - i do only fly in attitude mode with gains way down near 100 for all. Its a bit sloppy and perfect for filming - nice and smooth :) Also for me I noticed the arms vibrating at different RPM's (usually take off and landing) so I ordered additional top/bottom center plates to make the frame as rigid as possible - might order some custom 3mm arms also. X8 coaxial rock - everyone I have flown for are impressed right off the bat with its stability!
     
  5. Justin John

    Justin John Member

    Joined:
    Jun 29, 2012
    Messages:
    54
    Likes Received:
    10
    Hi Jason, thanks for your input. I know that Brad has been running this setup with no heat issues and it's ironic that I only have heat issues on a couple of motors. My gut says it is a motor alignment issue but I have been diligent with straightening as close to 90 degrees as possible.

    It is interesting that you are using the standard DJI x8 motor config, I've heard from others that the results vary. My attitude gains are at 100 for the most part. My basic gains are still up near 180 - 150 as per my usual flat 8 setup. Is your machine similar?

    I also noticed that the vibrations are only at certain RPM's but i'll need some more flight tests (hopefully tomorrow) to confirm this.

    Thanks again for your input, I'll go over my wiring, custom motor settings and motor alignment one more time and I'll make it an objective to balance my xoar blades, although in the past when balancing I've noticed that for the most part they are well balanced out of box.

    I do have 14x6's that I could try, but I'll leave that as a last resort. I like how the 16x5's have a 54% throttle hover point with the Red Epic weight and 46% with the 5D, this makes it easy to flip to manual if needed. I know others such as Brad have had success with the bigger blades. In fact he had mentioned using 16x7s in combination with the 16x5's.

    Jason do you use 6s or 5s batteries ?
     
  6. Jason Toth

    Jason Toth Active Member

    Joined:
    May 11, 2013
    Messages:
    304
    Likes Received:
    45
    I'm on 6S dual or quad 5100mah 65c depending on how I feel that day, adding the extra weight of the batteries only gives me a bit more flight time. I have only used 14x6's all around with the standard DJI and it works great. I would like to get some more efficiency out of it because my flight times are around 5 minutes with 10,000mah so hoping 15x5's will help. Will post results of 15x5's top/bottom and 15x5' top and 14x6 bottom next week. Maybe I'll try some 16x4's if I can find them and some more cash LOL.

    I'll post my gains next flight, off top of my head I think I'm Basic Pitch/Roll 140 - Yaw 120 - Vertical 100 - Attitude Pitch/Roll 100. If i go higher I notice even more bounce in the arms while taking off. Once up it goes away, hence why I'm adding center plates. I think all that weight (epic/cp.2/fiz/etc) just puts too much load onto the 4 arms & where it attaches. My vibrations are also at certain RPM's but mostly during take off.
     
  7. Jason Toth

    Jason Toth Active Member

    Joined:
    May 11, 2013
    Messages:
    304
    Likes Received:
    45
    Try allieddrones.com / Joshua Kornoff / info@allieddrones.com / 1 714 794-2811
    He is great, I have the Echo and works really well! I do not have retracts, looking at getting the Droidworx Coax version which comes with anti-vibration quickrelease: http://droidworx.co.nz/products/sho...g-gear-and-gear-rail-assembly-retractable-ti/

    Stand off should work fine as long as you have enough and they are on a antivibrations or something that has give so not to bent/snap during landing/take off. You could add another center plate or two to get the distance you need. The props do not bother us since we shot the Epic with CP.2 25mm at the wide end and only see when looking straight. If its an issue with client we push in with tighter lens.
     
  8. Guilherme Barbosa

    Guilherme Barbosa Distributor

    Joined:
    Jul 26, 2012
    Messages:
    140
    Likes Received:
    11
    Hi Justin, what retractable landing gear are you using?
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,351
    Likes Received:
    1,160
    Jason:
    I've been emailing with Josh (he's very responsive).
    What's your take on the Echo vibration isolation -- is it working for you?
    Also, when you add the quick release, what's the net weight increase? Josh suggests it's around 350 grams (about 12 ounces).

    Andy.
     
  10. Justin John

    Justin John Member

    Joined:
    Jun 29, 2012
    Messages:
    54
    Likes Received:
    10
    DJI Zenmuse - > GH3 Mod with Retracts
     
    Guilherme Barbosa likes this.
  11. Jason Toth

    Jason Toth Active Member

    Joined:
    May 11, 2013
    Messages:
    304
    Likes Received:
    45
    Hey Andy,

    The Echo is working great! It takes a little to get right, Josh helped me with a few suggestions. If I'm running the 5DMK3 I use the softest 2n's all around and tighten up then screws a bunch so it doesn't have play. If I'm running the Epic/CP.2/Dual Fiz I use the 5n's all around and crank the screws as well - otherwise you get bounce. I also have a custom rail assembly which has additional rubber grommets (15mm rails go into these grommets which are housed in a 16mm boom clamp), its like double anti-vibration I guess.

    The only issue with the Echo is you will want one for each camera set up because its a pain to get the little rubber grommet into place each different setup. I'm getting to the point I'm going to have a gimbal/echo for 5D/Epic/C500 to make my life easier :)

    I do not know the weight but around a pound sounds right (I'm rebuilding the rig next week and will take a measurement). The clamps weigh the most, I'm going to source different version of the clamps soon - but for know it works well. I did get different tightening which you can pull out to change where the lever is since it was hitting my frame and could not tighten fully. The rig is running great but I know I can trim a bunch a fat now its set up - like new QR clamps, shortening wires, losing repeating xt60/ec5 connectors, etc, etc.

    All in all its a great setup and you will be happy - its build like a tank!

    On a side note, I'm going to be making some extended legs for the gimbal (16in tall if anyone might want some) to get enough clearance for the C500 which has lame ergonomics for an aerial rig.

    Later, J
     
  12. Gary Haynes

    Gary Haynes Administrator
    Staff Member

    Joined:
    Jul 6, 2012
    Messages:
    5,211
    Likes Received:
    460
    Jason great writeup. Can you post what motors/props you are running on your CS frame?
     
  13. Jason Toth

    Jason Toth Active Member

    Joined:
    May 11, 2013
    Messages:
    304
    Likes Received:
    45
    I'm running:
    - X8 Coax 6S
    - 3515's (good for a flat but think the 4014's would be a bit more efficient for Coax + you can put on low profile carbons on)
    - 14x6 Xoar top/bottom (15x5's coming to test top/bottom & 15x5 top/14x6 bottom - hope to get 16x4's when I find them)
    - I'm doubling up the center plates to reduce flex with the 4 arms.
     
  14. daniel clarke

    daniel clarke Member

    Joined:
    Aug 9, 2012
    Messages:
    49
    Likes Received:
    5
    Hi all just thought i would put up a pic of my coax.
    cheers.
    flying cameras 1.jpg
     
  15. Chris Newman

    Chris Newman Member

    Joined:
    Oct 9, 2012
    Messages:
    200
    Likes Received:
    14
    Hey guys,

    I converted my cinestar to coaxial and followed all the mixers exactly etc. Using the 14" plastic props and it flew great for about 3 minutes until the battery wire become desoldered because it got to hot! Did I do something wrong, I flew it the same exact setup as my flat but with the mixer settings change and it got way hot. This happend the day before a shoot, so I hurried up and changed back to flat. Flew great, even over 1000 ft drop offs :)

    I'm also building a HL and trying out the octo x style. I love the stability and the size.
    These are my findings so far.

    - The top motor gets to be around 120F with no pay load, the bottom motor is around 100F. Is this normal?
    -ESC's get to be around 120-130F
    -1 lipo gets way to hot at 150F, 2 is way better at 110F.


    Does coaxial generally run hotter?
    I'm running AXI 4120/14's so they are huge and heavy, maybe flat style would work better for the larger motor? or should it matter?

    I appreciate any advice!
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,351
    Likes Received:
    1,160
    Can you post a GPX file, Chris?

    Andy.
     
  17. Brad McGiveron

    Brad McGiveron Active Member

    Joined:
    Jul 7, 2012
    Messages:
    396
    Likes Received:
    65
    Can you post the mixer you used?

    MK PDB and stack?


    Personally I would use a much lower KV motor and larger prop/pitch combo for a HL X config but in all honesty, if you are using the MK PDB you are probably going to get its limits pretty quickly.
    I did convert a stock CS8 MK over to X with the stock QC motors and it runs fine on 14" props and it has no unusual heat but generally this is a job for separate ESC's and larger motors if you plan on any real payloads.

    Also make sure your soldering and wiring gauge all match... I mean no 14 gauge on the PDB. If your lipos have 10 gauge then no less then 10 gauge to the connectors. :)
     
  18. Chris Newman

    Chris Newman Member

    Joined:
    Oct 9, 2012
    Messages:
    200
    Likes Received:
    14
    I don't have any GPX files. Sorry Andy!

    MK PDB and stack on my reg heli.
    It did fly fine in OCTO-x mode but with my regular payload it did not.
    My MK mixer setup is below.

    Note: I'm not planning on flying my reg mk setup in OCto-x, just thought i'd give it a try.


    My heavy lift has 85amp ESC'S and wookong M with the 4120 / 14's.

    What motors do you recommend and use with you HL setup Brad and what lipos do you use?

    I've tested it with a 8lb payload today in the octo-x setup and wrote down the temperatures. I'm going to convert to flat and then do the same and see if there is a big difference.


    --------------------------
    [Info]
    Name=Octo-X
    Version=1
    [Gas]
    Motor1=64
    Motor2=64
    Motor3=64
    Motor4=64
    Motor5=71
    Motor6=71
    Motor7=71
    Motor8=71
    Motor9=0
    Motor10=0
    Motor11=0
    Motor12=0
    [Nick]
    Motor1=64
    Motor2=-64
    Motor3=64
    Motor4=-64
    Motor5=71
    Motor6=-71
    Motor7=71
    Motor8=-71
    Motor9=0
    Motor10=0
    Motor11=0
    Motor12=0
    [Roll]
    Motor1=64
    Motor2=-64
    Motor3=-64
    Motor4=64
    Motor5=71
    Motor6=-71
    Motor7=-71
    Motor8=71
    Motor9=0
    Motor10=0
    Motor11=0
    Motor12=0
    [Yaw]
    Motor1=64
    Motor2=64
    Motor3=-64
    Motor4=-64
    Motor5=-71
    Motor6=-71
    Motor7=71
    Motor8=71
    Motor9=0
    Motor10=0
    Motor11=0
    Motor12=0
     
  19. Brad McGiveron

    Brad McGiveron Active Member

    Joined:
    Jul 7, 2012
    Messages:
    396
    Likes Received:
    65
    Hey Chris

    Ya that probably makes sense with your MK test X config. It cant haul the same payload without working a great deal more. That is the right mixer.


    I am using 4120-20's and also MT 3515's on my two WKM X setups. 2 X 6s 6600 45C's. I also use 16x5 on top and 16x7 on bottom with AUW at around 12 kg... give or take.

    Lots feel that DJI and larger disc speed is better but I don't think thats the case.
    Basically I think somewhere around 400 kv motors are suited better for bigger weight... but that's just my opinion and what I use.
     
  20. Brad McGiveron

    Brad McGiveron Active Member

    Joined:
    Jul 7, 2012
    Messages:
    396
    Likes Received:
    65
    One thing... since brushless mounts are now running so much better than servo driven ones, the whole reason I really switched over to an X config was for stability. Its very stable and far more than a flat but maybe it is not as necessary as it might have been 6-12 months ago. Other than the footprint which is clearly smaller, you can get just about the same footage with anything now.
    Just a though :)
     

Share This Page