Cinestar 8 Upgrade for Medium Heavy Lift (8-10kg)

Discussion in 'Cinestar 8' started by Steve Maller, Jan 3, 2014.

  1. Dave King

    Dave King Well-Known Member

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    You need to live here on the east coast where its 10 degrees and snowing. It cushions the blow when you can't fly.
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    HAHAHAHAHA no.
     
  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    Green lights are good. :D
    I’m now convinced that the first Double Quadro 2XL board I had was defective.
    I wired this one up in an identical fashion as the first one, and this one chirped happily to life. Started at 3S and 1/4 Amp just to be safe. Worked my bench supply up to 4S at 2A (although it was only drawing .5A) and ran some motor tests and other diagnostics.
    Eventually connected up one of the big 6S LiPo batteries, and it works great.
    So I await a replacement motor for the bum one.
    Stay tuned! :D
    IMG_8951.jpg
     
  4. Dave King

    Dave King Well-Known Member

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    Very nice!!
     
  5. Steve Maller

    Steve Maller UAV Grief Counselor

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    Tonight she flew!
    I was very concerned about this copter with all the new parts, so I was super methodical about testing, first with the bench supply at 15V and 2 amps, then with the 6S LiPos. I did a constrained engine run-up in my studio, and actually lifted it an inch or so off the floor whilst carefully monitoring current levels, etc.



    Then it was time to take her out and fly. I strapped a 5 pound dumbbell under her belly, and with that, I was at an AUW of 16.8 pounds (about 7.6kg).

    Unfortunately, as is often the case, I discovered it was already dark outside. But not to be deterred, I headed to my favorite flying park (a nearby baseball field). I put on a cheap set of CF props from Famous Hobby because I didn’t want to wreck any expensive props if I had a suboptimal landing. I’ll eventually use 15” Xoars or 15” Tiger CF props.

    The copter behaved beautifully on the 5 minute test flight (in the glow of my headlights). It was dead solid in the air, with no yawing or other weirdness. I saw on the GPX file that hover was right around 65 amps, which is really nice at that weight (basically the weight of the GH3 on my brushless gimbal). I carefully switched on altitude hold, then position hold, and both worked beautifully, too. I did one high-throttle climb (which was dangerous because the sky was dark and I don’t have my LEDs on yet!), and it felt effortless. And descending straight down at a decent clip was very smooth, too.

    The currents and temperatures were good, as you can see below. I’ve included the GPX file if you’re interested. Interestingly enough, this first flight was with 100% MK defaults. I didn’t want to assume anything with respect to tuning. And now I wonder if I’ll have to at all. My mixer setting is 64 for the top motors (1-4) and 67 for the lower ones (5-8). I think that looks pretty good, according to the current numbers.

    Flight date: 1/27/2014 5:49:41 PM
    Flight time: 5:49:41 PM - 5:53:47 PM (246 secs, 00:04:06)
    Batt. time : 261 secs, 00:04:21

    Elevation(GPS) : 0 2.47 15.85 m (min/avg/max)
    Altitude(Barom.): -0.4 3.44 17.45 m
    Vertical speed : -1.7 -0.03 4.05 m/s
    Max speed : 11.4 km/h
    Max target dist.: 0.9 m

    Sats : 7 8 10

    Voltage : min. 22.2, max. 25.4 V
    Current : 0.5 61 103 A
    Wattage : 12 1434 2286.6 W
    Capacity: 4223 mAh

    Motor1: 0.0 7.9 13.7 A Temp: 14 30 35 °C
    Motor2: 0.0 8.0 12.8 A Temp: 14 33 40 °C
    Motor3: 0.0 7.3 12.4 A Temp: 14 29 35 °C
    Motor4: 0.0 7.2 12.1 A Temp: 15 33 39 °C
    Motor5: 0.0 7.5 12.6 A Temp: 16 31 38 °C
    Motor6: 0.0 7.1 12.1 A Temp: 13 32 39 °C
    Motor7: 0.0 6.3 10.2 A Temp: 15 32 38 °C
    Motor8: 0.0 7.9 14.2 A Temp: 14 32 38 °C

    Magnet Field: 105 109 116 % (ok)
    Magnet Inclination: 58 61 66 deg

    No errors found ;)

    I’m encoding a video of the flight from both the ground and the GoPro on board. I’ll post it in a bit when it’s done.

    Thank you for watching! :D
     

    Attached Files:

  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    Here’s the video of the flight from a camera on the ground and a GoPro on the copter.

    But there’s a very funny story that needs to be told. As you may know, I had a meltdown of a power board a couple weeks ago, which has since been replaced. But I’ve been super paranoid about smoking another component. So imagine my disappointment when, after landing with no errors and no warnings, that the copter should smell of burnt electronics. “Damn it” I said (or something more strident), and I proceeded to crawl around in the dark with my flashlight sniffing all the motors, the power distro board...everything. I couldn’t find anything, but the smell was quite noticeable. So I decided to pack up the copter and bring it back to work where I could get a better view of things. But as I walked back to the car, I noticed that another car had parked right next to me. And in that car were two young men, smoking a joint. Which smelled remarkably like a burnt Mosfet. :eek: Mystery: solved!

     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Do you need papers if you're going to use MOSFETs?

    Andy.
     
  8. Howard Dapp

    Howard Dapp Active Member

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    Ahh totally missed this flight update. Congrats! She sounds and perfoms lovely. One thing that bothers me though, it's the exposed electronics...please get a dome or something, I tell you this from experience. Do you fly on humid days? All it takes is a single tiny drop of moisture to bring down that powerful beast.
     
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  9. Steve Maller

    Steve Maller UAV Grief Counselor

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    Howard, I have been looking at options for a cover. Conventional wisdom for Cinestar drivers has been that covering the electronics would result in more problems (primarily heat) than they’d solve (moisture, debris). But I have the new PDB from Mikrokopter with the integrated cooling fins, and I bet it’s going to run super cool. That said, a tiny 12V fan may eliminate that worry. So I’m going to go to TAP Plastics today and see if I can noodle out a hood of some sort. You might notice that because of the way I mounted the batteries on outriggers, I was able to consolidate the MK stack to the center of the copter (like the MK okto does). This will provide a smaller area that needs to be protected. Ideally I’d love to design some kind of spiffy Darth Vader-esque thing, but my 3D design skills are N/A.
     
  10. Steve Maller

    Steve Maller UAV Grief Counselor

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    I’ve heard a hollowed out apple will work, too. Or a hookah.
     
  11. Howard Dapp

    Howard Dapp Active Member

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    Got it. This is why I've always preferred to build my own frames instead of going with the standard MK/FF setup and that ESC layout. The perfect setup for day in and day out use, in my opinion, is esc mounted on booms with heatsinks wrapped in shrink tube, flt control completely covered & protected...in my case a plastic electronics enclosure with top access via removable lid. Escs are easily accessible and swapped out in case of any issues in the field. ESC overheating is not a concern. For me it's all about practicality and function over looks.
     
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  12. Dave King

    Dave King Well-Known Member

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    Steve it looks and sounds great. It seemed to handle very well in the dark. I can't believe you flew in the dark with no nav lights!! :eek:
    Time for the good props now and some load tests :D
     
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  13. Steve Maller

    Steve Maller UAV Grief Counselor

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    More flight testing today, with a little temporary setback when one of my booms loosened just enough for one pair of motors to twist. This obviously had a Very Bad Effect on the copter, but the good news is that I was only flying about 20 feet up, and I was able to wrestle it to the ground. There was no damage, thankfully. Just tightened up all those pesky screws, and was back in the air.
    IMG_9005 (1).jpg
    The first endurance test was interesting. The copter is hovering at about 60A and I landed after 16.5 minutes when I got the LEDs flashing with low voltage (nice feature). The BL temps were fascinating...not one was over 40°C, despite the fact that I spent most of the time hovering, and never really strayed from an area about 40-50 meters in front of my position, and altitude was generally about 10-20 meters. In other words, this MK Double Quadro 2XL "Cool" board definitely lives up to its name! This was at an AUW of about 17 pounds with cheap 15" CF (maybe) props and dual 8000 mAh 6S batteries.

    IMG_9001.jpg
     
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  14. Howard Dapp

    Howard Dapp Active Member

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    Awesome Steve! Taking it nice and slow is the way to go.

    Now, I've read your reasoning for using plastic boom clamps to secure the booms at the hub, which is a great reason but for pro heavy lifters that will eventually carry a hefty load, I don't think they are the best choice. You'll be lifting a fair amount of weight, now combined that with vibrations coming from two powerful motors mounted on a single boom, that's a heck of a lot of power and torque that has the potential to work those boom out of level while in flight. You want those booms fixed and immovable.

    I'm using plastic clamps to secure the 25mm boom landing gear legs on my brushless gimbal and I see that I can twist them out of position even when tightened to the max, this is nowhere as easy to do when using metal clamps. In the event of a big crash when fully loaded at a decent altitude damage will be severe regardless of what you use :)
     
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  15. Steve Maller

    Steve Maller UAV Grief Counselor

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    I believe I have now seen the light. Next step: disassemble hub and replace 4 pairs of boom clamps. The other 4 are holding the batteries and I don't think I need to upgrade those.
     
  16. Jason Herring

    Jason Herring Member

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    Steve,that bird looks amazing, I'm hoping my test flight goes as well as yours :) , what have you found to make sure all motors are vertical on the booms?
     
  17. Steve Maller

    Steve Maller UAV Grief Counselor

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    Funny you should say that. I just realized today that my workbench is not perfectly level. I have been using a bubble level across the motor mounts to level everything, but now I better level my table before I do that again!
     
  18. Steve Maller

    Steve Maller UAV Grief Counselor

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    The brushless gimbal and the Panasonic GH3 got their first ride on the copter! Worked like a charm. Flew an easy 15 minutes until it got too dark and I figured I proved my point. Can't wait to see what the video looks like! :D
    IMG_9014.jpg
     
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  19. Steve Maller

    Steve Maller UAV Grief Counselor

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  20. Howard Dapp

    Howard Dapp Active Member

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    Silky smooooth. Are any of the belt reduction guys getting these same results when simply hovering around?
     
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