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T-Motor U13 (100kV) + CF 29x9.5 3-blade prop REVIEW + THRUST TEST

Discussion in 'Member Drone Product Reviews' started by Skewp, May 9, 2016.

  1. Skewp

    Skewp Member

    47
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    Mar 31, 2013
    Estonia
    Posted by Skewp, May 9, 2016 #1
    I would have posted this review in the review sub-forum but unfortunately I am somehow unable to post in there. Since I am going to build a U13 based quadcopter, this sub-forum should be the next best thing for this review :)

    T-Motor U13 (100kV) & CF 29x9.5 3 -blade propeller in depth review

    There are big motors, there are huge motors and then there is T-Motor U13. This is the newest and most powerful brushless motor produced by T-Motor. I managed to get my hands on one along with their CF 29x9.5 Three-blade prop to test them out. Since I am not a simple man, I decided to go in depth – Let’s see what’s inside the motor, how does my testbench thrust data compare to the official test data and let’s take a look at the quality of the CF 29x9.5 prop.

    T-Motor U13 (100kV)

    The motor itself is truly massive. I had seen it on a picture but when mine finally arrived I was like „WOW, this is huuuuge“. I fly U7 rig daily and thought that U7’s are pretty big but they look like racer quad motors when compared to U13. The words themself are not worth anything without numbers so here they are:

    Motor diameter: 118,4 mm (4,66“)
    Motor height: 56,8 mm (2,236“)
    Shaft diameter: 17 mm (0,669“)
    Bearings: 30x17x7 mm EZO (2pcs)
    Cable length: 150 mm (5,91”)
    Weight: 1235 g (2,72 pounds)
    Bottom mounting holes: 4-M5 D50 (mm)
    Top mounting holes: 8-M4 D40, 4-M4 D25 and 4-M3 D23 (mm)

    [​IMG]
    Figure 1. T-Motor U13 (100kV) dimensions and mounting holes.

    Here are some images to show what You get for the price. I really like that there is a design touch on the package and the motor is not simply packed in a noname plain brown cardboard box. The box itself adds value to the product, it makes it seem more high-end.

    [​IMG]
    Figure 2. T-Motor U13 (100kV) package.

    [​IMG]
    Figure 3. T-Motor U13 (100kV) box design, very neat.

    [​IMG]
    Figure 4. T-Motor U13 with all the goodies that come in the box.

    You should not judge a book by its cover so I definitely had to take the motor apart to see what’s inside. Items found inside – a thick (17mm) shaft and some blue material that is used to balance the motor. It is good to know that the factory has paid attention to balancing the motor. I found three different spots that had the blue balancing material. On Figure 6 and 7 You can see that the shaft is bolted tight with three bolts. When I say tight, I really mean tight – it took two grown man to disassemble the motor. The three bolts that hold the shaft are locked in place with thread locker. Due to the magnetic field it is also quite a hussle to separate the top and bottom part of the motor. The details of the motor are up to the T-Motor standard. On Figure 7 it is shown that the three wires that come out of the motor are fixed with heat-shrink and hot glue so You cannot break them too easily. I would also like to point out that this is the first brushless motor that I have come across that has motor wires pre-wrapped in mesh-guard. It’s also important to note that motor wires are 150 mm long and very stiff. There are two different prop adapters included (with bolts). The center diameter of one adapter is 8 mm and the other is 10 mm (Figure 9).

    [​IMG]
    Figure 5. The motor has been pre-balanced by the factory.

    [​IMG]
    Figure 6. The shaft of U13 (diameter 17mm)

    [​IMG]
    Figure 7. Bottom side of the motor.

    [​IMG]
    Figure 8. Stator of U13.

    [​IMG]
    Figure 9. Prop adapters that are included on the U13 package.

    Some additional photos to show the size of U13 and CF 29x9.5 props.

    [​IMG]

    [​IMG]

    [​IMG]


    T-Motor CF 29x9.5 Three blade propeller

    When it comes to propellers, then one of the most important things about it is the quality. The propeller should be well-balanced out of the box, it should be rigid, lightweight and if there is any room left – it should also look nice. I had never before used three-bladed props so assembling a propeller is a new thing to me. At first I was definitely a bit skeptical about the quality and balance – in theory it’s easier to produce a two bladed prop that is well-balanced than a three-bladed one that needs to be assembled with bolts. Note – there is also a manual with assembly instructions included in the package. Oh, about the package and its contents.

    [​IMG]
    Figure 10. CF 29”-3 blade propeller package.

    Included:
    *Three CW spinning prop blades
    *Three CCW spinning prop blades
    *CW spinning quick-mount
    *CCW spinning quick-mount
    *Pile of bolts


    The prop blades are packed in two separate soft pouches (CW and CCW). It is really nice to see that there has been some thought put in the packaging – all the blades in pouches are separated with a thin layer of foam so they don’t scratch each other.


    [​IMG]
    Figure 11. Three CW spinning blades, their pouch on the background and two thin foam layers in front.

    One should also notice that the blades are marked differently – there is blade A, blade B and blade C. These markings are for assembling the blade. The same markings are on the quick-mount propeller adapter (A, B, C) and the blades should be placed according to the letters starting from the letter “A”. This is also noted in the propeller manual.

    [​IMG]
    Figure 12. Three blades with markings A, B and C.

    [​IMG]
    Figure 13. Quick-mount propeller adapter with marking “A” and blade with marking “A”.

    The quick-mount propeller adapters are marked differently – the one with white circle on top is CCW and the black one is CW. It takes total of 9 special bolts to assemble on propeller mount and the process is divided in two parts. At first You have to fix every blade with one bolt and centering piece, then add the top plate and fix that one with 6 additional bolts. It takes four and a half full revolutions to unscrew the propeller from motor.

    [​IMG]
    Figure 14. Propeller quick-mount adapters.


    Practical tests


    1. Weight of each blade

    So, now that the quick overview of the package is done we should get to the practical part. I paid a visit to a goldsmith to use his scale to measure the weight of each blade. The mean weight of blades is 49,9g per blade. The maximum weight was 50,0g and the minimum 49,8g which means that blades are maximum of 0,2g apart. I would also point out that the 0,2g is the maximum deviation when I compare both CW and CCW blades. When only three blades of CW or three blades of CCW are compared then the maximum weight difference between blades is 0,1g. This means that the maximum weight difference between blades is 0,2%, which is pretty much next to nothing.

    2. Balancing on prop-balancer

    Next step – balancing the propeller on prop-balancer. I also could just skip this step since there was nothing to balance – both of the propellers stayed in any position that I moved them to. Kudos. It is great to see that the $585 price tag for a CW/CCW set can be justified with great quality. Note: DuBro prop-balancer was used.


    3. 3D scanning of the blades

    Since I am a partner in a 3D scanning service company I also have access to a high-end 3D scanner. I was curious to see how much shape difference there is between the blades. I 3D scanned all six blades with resolution of 0,2mm. Note: Do not mix up resolution with accuracy. CreaForm Metrascan 210 + C-Track that were used offer accuracy of 85 microns. Accuracy shows how accurately each of the 3D scanning points are taken. Resolution shows how far apart they are taken – for example, 0,2mm resolution means the points are 0,2mm apart from each other. To be honest, I was expecting a bit more difference between blade profiles. The deviation was mostly <0,05mm and the maximum was under 0,29mm. All of this means that the blades are really well done and are almost identical to each other. Software used – VXElements and Geomagic Design X. On Figure 15 You can see CCW blades “A” and “C” placed inside each-other with the “best fit” method. Green means nearly identical points. There is also some section cuts of the profile where You can see difference between the blades (Figure 16, 17 and 18).

    [​IMG]
    Figure 15. Deviation between CCW blade “A” and “C”.

    [​IMG]
    Figure 16. Section 1 view of blade “A” and “C” comparison.

    [​IMG]
    Figure 17. Section 2 view of blade “A” and “C” comparison.

    [​IMG]
    Figure 18. Section 3 view of blade “A” and “C” comparison.


    [​IMG]

    Figure 19. Deviation between CCW blade “A” and “B”.

    [​IMG]
    Figure 20. Section 1 view of blade “A” and “B” comparison.

    [​IMG]
    Figure 21. Section 2 view of blade “A” and “B” comparison.

    [​IMG]
    Figure 22. Section 3 view of blade “A” and “B” comparison.

    I have also made the 3D scanned files available for everyone. You can get them here:

    http://www.upload.ee/files/5793553/CW_A.stl.html
    http://www.upload.ee/files/5793554/CW_B.stl.html
    http://www.upload.ee/files/5793555/CW_C.stl.html


    THRUST TEST

    Can You trust manufacturer’s data about motor thrust? Sadly the answer is more often “No” than “Yes”. I blew dust off of my trustworthy thrust test bench, mounted U13 along with 29x9.5 prop and Flame 80A ESC, recharged some batteries and got on to testing.

    Worth mentioning:

    Item(s): T-Motor U13 (100kV) + T-Motor CF 29-3 prop + T-Motor Flame 80A 6S-12S ESC.
    Batteries: 4pcs Gens Ace 16 000 mAh 6S connected as 32 000 mAh 12S (2S2P)
    Weather: Tested outside, nearly minimal wind, temperature +21C.

    [​IMG]
    Figure 23. T-Motor official U13 (100kV) test data


    [​IMG]
    Figure 24. Thrust test data.

    [​IMG]

    If tables are too boring for You, check the video of the thrust test in action:




    Comparison of factory test data and my test data:


    I was really surprised that the motor was able to perform slightly over factory test data. I have tested various motors before and all of them have been ~5% worse than factory data claims them to be. The motor itself run smoothly and produced less noise than I would assume from 18,6 kg of thrust. I ran the motor at 50% throttle for a while after thrust testing and the motor was slightly warm after that. Since Flame 80A ESC was placed in the airflow it was near outside temperature after testing.


    Conclusion

    In conclusion, both T-Motor U13 motor and CF 29x9.5 propeller seem to be up to the T-Motor quality standards that we have seen on their previous products. U13 is definitely not appropriate motor for Your everyday fun flyer, but it has some other (larger) shoes to fill – it can be used in agricultural & mapping applications and perhaps even on serious-heavy-lift aerial video multirotors that need to lift ARRI with all the necessary bells and whistles. The build quality is great, motor is pre-balanced, many different propeller mounting options and what’s even more important – lots of thrust! Be aware – U13 has a lot of torque so make sure Your multirotor frame is up to the standard!

    T-Motor CF 29x9.5 three-bladed propellers look like a decent choice for U13 if You prefer to use 12S instead of 10S. They may perform a bit worse than two-bladed CF 32” props efficiency-wise but You gain more stability due higher RPM, the motor runs cooler and You are able to build multirotor with a bit smaller diameter when compared to CF 32”, 34” or 36”.

    T-Motor U13 (100kV)
    + Excellent quality
    + Thrust capabilities
    + Pre-balanced
    + Motor cables are covered with mesh-guard
    + Shaft is fixed with three bolts instead of one bolt or clip
    + You can use long screws to mount the motor without having to worry about hitting coil wires with bolt ends

    +- Price

    -There seems to be a bit too much thread locker on shaft bolts (three in the bottom). I nearly ruined the bolt heads when trying to unscrew them.

    T-Motor CF 29x9.5 three-bladed propeller
    + Well balanced out of the box
    + Very tight tolerances on blade profile
    + Quick-mount adapters included
    + Assembly manual included

    +- Price

    -Three-bladed propellers take a lot of space and are more difficult to travel with than two-bladed propellers.

    T-Motor Quick-detach propeller mount
    + Markings (A, B, C) for each propeller blade
    + CW an CCW adapter marked differently (white circle on CCW)
    + They seem to lock in place very well
    + Lock/unlock direction markings


    +- U13 mount not included in the CF 29x9.5 package.
    +- Since the U13 quick-detach prop mount was a prototype it did not have white circle on top of the mount to mark CCW direction but most likely the final version will have the marking like other T-Motor quick-detach mounts.


    -An extra lock would be great for additional safety. Some people may be worried with the prop unscrewing itself with active braking ESCs.

    NOTE: At this moment U13 adapter is not included in T-Motor CF 29x9.5 propeller package. At this point I would like to thank T-Motor rep for sending me a U13 prop adapter early production set to carry out my tests.


    So....who is the first brave one to build a X8 with these monsters?
     
    Last edited by a moderator: May 9, 2016
    Vitali, sabeer and Av8Chuck like this.
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  2. STEVE5

    STEVE5 Member

    31
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    Sep 30, 2011
    CZECH
    Posted by STEVE5, May 22, 2016 #2
    You can make X8 for flying with Alexa and cameraman on board. :)
     
    sabeer likes this.
  3. Av8Chuck

    Av8Chuck Member

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    May 28, 2011
    Posted by Av8Chuck, May 24, 2016 #3
    I really don't have a great deal of interest in that motor/prop, but your review was so well done I went through the the entire thing.

    Nicely done.
     
  4. Skewp

    Skewp Member

    47
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    1
    Mar 31, 2013
    Estonia
    Posted by Skewp, Jul 18, 2016 #4
    Thanks, Av8Chuck!

    I was curious of how well will the U13 handle full throttle for a long period of time. I was not disappointed.

    I ran the U13 + CF 29x9.5 three-blade prop combo @ 12S @ full throttle for over 12 mintues straight and the outside temperature of the motor was only ~60° C (140° F) and the inside temperature was 78° C (172.4° F).

     
  5. Skewp

    Skewp Member

    47
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    1
    Mar 31, 2013
    Estonia
    Posted by Skewp, Aug 22, 2016 #5
  6. _sOnGoKu_

    _sOnGoKu_ Member

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    Jul 9, 2016
    europe
    Posted by _sOnGoKu_, Aug 23, 2016 #6
    beautiful! great job, thanks for sharing
     
    Skewp likes this.
  7. sabeer

    sabeer New Member

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    Feb 4, 2017
    india
    Posted by sabeer, Feb 4, 2017 #7
    can i know how to calculate thrust from motor and propeller ?
     
  8. Skewp

    Skewp Member

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    Mar 31, 2013
    Estonia
    Posted by Skewp, Feb 4, 2017 #8
    You should always do a real life thrust measuring test since calculations are never exact.
     
    sabeer likes this.
  9. sabeer

    sabeer New Member

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    Feb 4, 2017
    india
    Posted by sabeer, Feb 5, 2017 #9
    thanks for your advice bro
     
  10. Chudik

    Chudik New Member

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    Mar 5, 2017
    USA
    Posted by Chudik, Mar 5, 2017 #10
    Unfortunately they are not available any more. Could you upload them again?
     
    Last edited: Mar 5, 2017
  11. Vitali

    Vitali New Member

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    Dec 29, 2017
    BY
    Posted by Vitali, Dec 29, 2017 #11
  12. Skewp

    Skewp Member

    47
    12
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    Mar 31, 2013
    Estonia
    Posted by Skewp, Dec 30, 2017 #12
  13. Vitali

    Vitali New Member

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    Posted by Vitali, Jan 3, 2018 #13
    Many thanks for the files!
    Happy New Year!
     
  14. gurra2

    gurra2 New Member

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    Sep 12, 2018
    sweden
    Posted by gurra2, Sep 12, 2018 #14
    Sorry to bother, but the links are dead again. I would really like do do some CFD analysis with these!
    If u can re-upload them, maybe i can help hosting them somewehere more permanent.
     
  15. Skewp

    Skewp Member

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    Mar 31, 2013
    Estonia
    Posted by Skewp, Sep 16, 2018 #15
    gurra2 likes this.
  16. Trias

    Trias New Member

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    Sep 19, 2018
    Greece
    Posted by Trias, Sep 19, 2018 #16
    Hi,

    I have a combo set with U8 135Kv + 29"x9.5" props for sale here: https://www.ebay.co.uk/itm/332812115688

    We set this up for a customer but they quad was above 7 kg and we had to downgrade the quadcopter. As such we used the kit only for 4 demonstration flights

    Thanks
     

    Attached Files:

  17. Trias

    Trias New Member

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    Sep 19, 2018
    Greece
    Posted by Trias, Nov 15, 2018 #17
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