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NEW U7 motor tmotor

Discussion in 'Cinestar 8' started by kjetil tønnesen, Nov 22, 2013.

  1. John Gore

    John Gore Member

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    Haha, got to love these comments. I can tell you that the kw12 motors are U7 with some differences. They are NOT identical to the U7 off the shelf. Please do not mix or use as replacement motors, they are not identical.

    You have linked to the facebook comment above, where I have already left my comment in response to this question from others:

    Jerry, you are welcome to buy any motors you feel suit your needs. Of course my comment above is tongue in cheek, but this time Kopterworx has decided not to let out what mods they have done to the standard u7 motors. I can fully respect that decision. We could have ordered standard u7 motors for our purposes weeks ago, but decided to rather wait for the Kopterworx version. So I guess that shows how we feel about supporting Kopterworx kw12 as the "better" motor for our needs than the standard u7.


    As you may have noticed, this multirotor industry has become the wild west, with just about everyone copying products either directly, or by launching very similar products. Things are advancing far too fast for the patent system or similar to have any effect here. Just look at the MoVi. More fake / copy MoVi gimbals were likely sold before the official MoVi was launched than actual MoVi gimbals were sold. Of course price and greed comes into it all, but you know where I am going. Kopterworx has been the "victim" of copying a number of times, and looses business after spending a lot of time and resources testing out products. So they are very resistant to sharing too much now after being burnt a few times. I can respect that.

    Kopterworx were one of the first to test out the U7 / U8 test motors, and find what really works for them. They then made special orders, and we have been in communication with them during this process. We waited patiently for the kw12 to be in stock, because in our minds they are better for our needs.

    However, as the price for kw12 and standard u7 420kv are the same, each buyer can make his own decision.

    PS: Even if they were / are identical in every way to the standard u7, we would still support Kopterworx because of their excellent service and attention to details. We buy from many suppliers and spend a large about of money over the last 2 years, and found Kopterworx to be one of the best suppliers for our needs. They may not stock as wide range of products as other shops, but generally they carry all the products we like to use, the more high end stuff. Very little of what they sell is junk.
     
  2. John Gore

    John Gore Member

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    We found exactly the same Howard. I still have some older MK stuff, and had it in an x8 config for a while over Oct-Nov for a project. The MK mixer likes custom mixing for the bottom to be a little faster.

    Howerver, I have not found this on the Wookong. We ran kw10 motors for 6 months now on our RED lifter, with 16x5 xoar, same mixer settings for top and bottom, and performance seemed great over hundreds of flights.

    One factor though is that with MK one can see the amp draw motor by motor (actually ESC), so it is easy to identify if the top and bottom motors are pulling the same amps / working as hard as the other. However, on Wookong we have no telemetry on a motor by motor basis, so its hard to know for sure if top and bottom are pulling the same time.

    The way to check then is to feel the motors temps after longer test flights, and see if top and bottom are heating up to the same degree. If top motors get hotter sooner than bottom, then top are working harder... but... this is not necessarily true as the cooling effect of an upside down motor is different to that of the normally mounted motor, so cooling can cause the difference.

    To share my findings thus far, on the new kw12 (u7) build, I have noticed all motors are room temp at landing after 5 min test flights, at 15kg AUW. But the top seem to be ever so slightly warm (bottom are less warm). I have put this down to the cooling fan effect that the motors have, but in time will try to investigate further. All ESC warm up equally, so amp draw seems to be identical or very very close. Flight is very stable, so we are so far very happy with the mixer.


    PS: Soon we will test with the Herkules III power system, and then we can monitor amp draw motor by motor, and identify if the top and bottom are pulling the same current more "scientifically". :)
     
  3. Michael Braun

    Michael Braun Member

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    John,

    what is your total flight time with U7 and Red on your new x8? Which battery packs do you use?
    What is your total Amp draw?

    Thanks for the answers :)
     
  4. John Gore

    John Gore Member

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    Sorry for slow reply, was away shooting for a few days, with very poor internet connection.

    We are making a number of changes, so flight times are not easy to compare as weight is also increasing.

    The goal is to improve on a number of things, and keep the 8min flight time we had on the pervious motors (kw10).

    In its current config, 14.5kg, with 17x6 props, we are getting 8min 30sec at altitude of 4400 meters. But we plan to make changes that will increase the weight, so should be close to the target 8min flight time we aim for.

    With 18x6 t-prop one would get about 1 min more flight time, but we prefer the wood and bit smaller props for our needs. :)
     
  5. Michael McVay

    Michael McVay Active Member

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    In the current config that gets 8.5 minutes of flight time, what are you using for batteries?
     
  6. John Gore

    John Gore Member

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    20Ah (2x 10000mAh 6s). It can easily take more battery if needed, for about 11min flight time, but will not be as nimble of course.
     
  7. Michael McVay

    Michael McVay Active Member

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    Thanks John.
     
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  8. Bryan Harvey

    Bryan Harvey Member

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    I just bought a set of the U7 490kv for my new HL build. Can someone recommend a motor mount for the U7 on the standard Cinestar carbon tube? I'm planning on converting my standard c8 frame to X8 and hoping this will be able to handle 18" props. Clearance wise it should not be a problem, but I'm unclear if the props vortices with disrupt my MoVI gimbal at this frame size. Any advice on this and recommended ESC's for this motor would be appreciated!
     
  9. Dave King

    Dave King Well-Known Member

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    Bryan

    You can use the CS054 motor mounts but you need to drill out the center hole a little bit for the center shaft clearance. I had them mounted to my CS frame in a flat 8 configuration and it seemed a little bit much for those motors because they are so big and heavy. With 18 inch props in a X8 config that thing is going to make some serious torque. Make sure you use metal clamps (32 of them) for the entire frame.
     
  10. John Gore

    John Gore Member

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    Agree! The frame is too weak for this kind of power. It will fly, but flight characteristics will not be great.
     
  11. Bryan Harvey

    Bryan Harvey Member

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    Interesting. So is there another frame that you would recommend to handle the U7 motors in X8 configuration?
     
  12. Patrick Thompson

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    There's a couple new offerings, designed specifically for U7 & larger motors, coming to the market in April. I'll post photos as soon as possible; feel free to contact me directly if you have any requests, such as payload or dimensional limitations.

    It's my hope that FF releases their M20 rig soon, so we can fully explore flight systems with larger imaging tools & optics.
     
  13. Michael McVay

    Michael McVay Active Member

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  14. Sam Fleishman

    Sam Fleishman Member

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    When is kopterworx releasing their x8 hammer frame?
     
  15. John Gore

    John Gore Member

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    Remember the history... The Freefly Cinestar frame was originally designed as a strong frame as replacement to the very weak Mikrokopter frame (using mk3638 motors which are tiny compared to the new generation of motors).

    Later some people simply added longer booms to the Cinestar frame in order to fit bigger motors and props. Some doubled up on the contemplates or used metal clamps in an effort to strengthen the frame.

    When using 2 motors per boom (such as x8 config), the frame needs to be at least 2x stronger than its design. When making booms longer this again increases the forces at work, so the construction needs to be stronger.

    Months ago Syndrones built an x8 frame that is ideal for such heavy lifting. We have been using 2 of these frames for our RED lifters, and they are rock solid performers. Gains can be pushed higher, because there is no flex in the frame even under harder flying. Bonus, although the quality and strength is very high, the frames are sold at fair prices.

    The hex version of the frame was launched 2 years ago to handle the big axi 4120/20 motors (bigger than u7, but less power and efficiency), and handles those motors very well as the frame is strong.

    As with a sports car, the chassis is a critical component to the design of a good performing multirotor.

    Most build light as possible, then strong enough.
    Syndrones design strong first, then light enough.

    The Syndrones frames are not light, because their focus is on strength and rigidity, using diamond weave and thicker carbon tubes, thicker plates. They also have a motor mount designed specifically for u7.

    Syndrones x8 heavy lifter frame.
     
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  16. Howard Dapp

    Howard Dapp Active Member

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    "design strong first, then light enough."

    Why we've always built our own frames.

    Any reason why they use G10 over CF other than cost?
     
  17. Steve Maller

    Steve Maller UAV Grief Counselor

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    Thanks for that thoughtful commentary, John.
    I can’t find pricing info for Jacques’ frames, or if they have a US distributor.
    Anybody know about that?
     
  18. Bryan Harvey

    Bryan Harvey Member

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    Great info John. I have inquired on the Syndrones site as to their pricing. I also found another interesting, very strong frame to consider:
    these from Gryphon Dynamics.

    http://gryphondynamics.co.kr/product-category/airframe/800-x8-octo-copterf-type


    Here's a guy in the middle of a build:

    http://gimb.al/gryphon-x8-day-3/




     
  19. Bryan Harvey

    Bryan Harvey Member

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    Dave, have you done this already? If not, do you think this would beef up the stock frame enough to solve the torque issues? Also, those aluminum metal clamps are $25 a piece on Quadrocopter vs about 3 bucks on HobbyKing that appear to be the exact same thing - times 32 is significant $$$ for some metal clamps. Any experience or thoughts about the HK version?

     
  20. Dave King

    Dave King Well-Known Member

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    Yes I have. Check out this video.

    I use all metal clamps on the hub and on the motors. My issue is that I had a hard time with these motors being compatible with the MK electronics. I didn't do any tweaking to the BL's to see if it could work as I just went back to the U5 motors and it appears to be enough power for me with 16 inch props. Carrying the frame around with the U7's just seemed like a lot of weight on the end of the booms and I could feel the frame flexing every so slightly. I think if you are going to run a straight 8 it might be ok, I didn't have enough data to support it though. I definitely think with a X8 it would be too much for the booms and stock cs8 center plates even with metal clamps.
     
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