Rethinking Heavy Lifting

Discussion in 'Cinestar 8' started by Chris Fox, Feb 14, 2014.

  1. Chris Fox

    Chris Fox Active Member

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    Is anyone using 4S motors with 16" props happily? Just rethinking the weight equation ... a setup like that would save about 1.6kg over a 6S setup when taking into consideration motor and battery weights ... and if you could run that size prop on a nice high KV motor ... 1.6kg is a lot of extra camera or glass ...

    Has anyone tried a U3 with a 16" prop on a test bench, or another 700kV motor?
     
  2. Jason Herring

    Jason Herring Member

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    That sounds like a good choice for smaller cameras
     
  3. Chris Fox

    Chris Fox Active Member

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    The recent sighting of a "snow dragon" looks to be running 4S batteries .... I have multiple 6S FF batteries, which all appear to be about 1/3 thicker than those shot in the video ....

    and a quick ecalc of something similar puts it in the realm of quite possible ...
     

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  4. Drew Kachurak

    Drew Kachurak Member

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    Chris - Tabb mentioned in the Snow Dragon post that he's flying dual 6S 9000mah batteries.

    Edit: after scrolling through the posts, I'm not seeing it. It may have been on the Red User forum.
     
  5. Gary Haynes

    Gary Haynes Administrator
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    The shots in the video were all from the Dragon. The copter you see in the video is carrying another RED Epic and it is a 4s machine. And the Dragon copter was 6s but you never see it in the film as it was the film ship.
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    I suspect the continued increase in motor efficiencies and prop design could yield much better performance from 4S setups. However, most of the new motors I’ve seen are only quoting performance numbers for 6S. I think that’s where the innovation is focused right now. But I agree with your premise.
     
  7. Chris Fox

    Chris Fox Active Member

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    It is going to be interesting to see, as my rough guess of of about 1.6kg difference between a 4S to 6S setup, also turns into a 2.5kg difference when using U7 motors .... and that is not considering the payload. So if they are all designed around carrying the same weight there is a big variation in AUW.

    Time to start looking at efficiencies, now that lifting the payload is sorted.
     

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  8. Dave King

    Dave King Well-Known Member

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    Chris I looked pretty hard at tigers motors and I don't see anything that's going to give you enough thrust to hover at target levels. Maybe Tabb is going to release a better motor with Synapse this coming year but as now I don't know what 4S battery is going to work at GAW's of 11kg or higher. I know that there's some new motors out there that claim a little better efficiency than the U series but they are all 6S. What I think you will see soon is that the size and weight of the 6S batteries will get better. What concern do you have with reducing weight? You got the U7's which can lift a small house. :D You also have to take into consideration that the MOVI will be much lighter than any home made brushless motor gimbal which will help keep weight down significantly.

    In my opinion its the U7's are just too large and heavy for most practical applications which is why I went back to the U5's. I'm going to be testing the U5's with the Tiger props as soon as the weather improves.
     
  9. Paul conto

    Paul conto Member

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    I currently have a X8 using 14" props on 4S setup, flying 16LBS at 5-8min.
     
  10. Brad McGiveron

    Brad McGiveron Active Member

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    ya at 16 lbs which is fairly light it should be no problem but I think Chris was referring to the 12-13 kg... 26-28 lbs department, where 4S batteries currently are just going to get destroyed over a short period of time.



    You can come up with a combo that works to some degree but any tests I tried just seemed to be pushing the lipos way to hard.
    Whats the point anyways... Just throw more power at more weight if you need it. If you don't need it then use less:)
     
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  11. Ozkan Erden

    Ozkan Erden Distributor

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    If you are looking for efficiency here, why don't you consider the motors around 100KV-135KV and 28-29" props?

    They will fly long time without stressing the batteries and ESCs. Only problem would be the size (even for X8) and the cost of the propellers.

    For instance:
    A copter loaded with Epic and Movi + 2 pieces 16A 6S battery + U8 motors (135 KV) and 29" props (AUW around 15kg) can fly around 20-25 minutes according to ecalc. I'm sure it will be more in real.

    My heavy lift is based on Avroto 3520. But I will be testing these low KV efficient motors. My only concern would be the perfomance in windy conditions.
     
  12. Steve Maller

    Steve Maller UAV Grief Counselor

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    Ozkan, with 29” props, doesn’t that mean you’d need 1 meter long booms or something crazy like that? Or are you talking about an X8 config? Ecalc assumes flat 8, and most measurements indicate 25%+ efficiency loss with X8. But I’m sure you know that. ;)
     
  13. Steve Maller

    Steve Maller UAV Grief Counselor

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    I also think we collectively need to separate ourselves from the 3D guys with respect to our needs. Quite frankly, if my copter was only capable of 15-20km/h max ground speed and a similarly slow rate of climb and/or descent, I’d be fine with that, as long as it flies smoothly and stays up for a decent amount of time. I ask you, don’t we all want that? If I need to chase a race car at 200km/h, my multi-rotor isn’t the right tool for the job, anyway.
     
  14. Ozkan Erden

    Ozkan Erden Distributor

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    Steve, you're right; with 29" props an X8 is a must. Even with an X8 config, those config will work pretty good I think.
     
  15. Chris Fox

    Chris Fox Active Member

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    In the video, it just shows a CS8, flying along with an Epic, Movi and HD downlink, running on 4S, and I'm guessing 16" props and 550mm booms ..... over water that nobody really wants to go swimming in .... so some folks are getting a reasonable payload on a lightweight system.

    Throwing more power at it is one way to achieve it, being smarter of the design is another. Its like having dome head rivets or countersunk rivet on plane .... they both do the job, one solution needs bigger engines, and the other needs more time to build but can get away with smaller engines ....

    I'm happy with the U7 build, after the issues I had with the 3515 (at my desired weight) The next steps are to chase done efficiency improvements.

    X8 with U8 motors and 28" props is the next build ;) the motors have been delivered, but the props are still outstanding.
     
  16. Brad McGiveron

    Brad McGiveron Active Member

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    Or they are trying to sell 4s batteries. ;)
     
  17. Chris Fox

    Chris Fox Active Member

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    maybe ... no 6S left in stock ;)
     
  18. Sebastian Meredith

    Sebastian Meredith Active Member

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    With the release of the GH4 - a cost effective, lightweight camera shooting highres with high frame rate - the rest of the camera manufacturers will be close behind ... 4K at 120fps from a camera weighing around 500 grams is only months away. The need for giant heavy lifters will be less important. There is still plenty of use for the 4S battery down the line. The REDs days in the lime light are dwindling! My 2 cents anyway ... ;)
     
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  19. Jason Herring

    Jason Herring Member

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    That is a very true statement , I work in Tv, Mike&Molly and the new Tv show the Millers and talk to our VC , they love the imagery that people are getting from the mark iii to the gh3 cameras, it's teaching DP, to get on board,
     
  20. Jason Herring

    Jason Herring Member

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    Paul,
    What size motors and batteries are you using on your x8?
     

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