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New Heavy lifter motor testing results

Discussion in 'Cinestar Misc' started by Dave King, Aug 17, 2014.

  1. Dave King

    Dave King Well-Known Member

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    I have been researching motors to use on my copters for a while now. Basically I have not been pleased with my either of my copters ability to carrying my 11 pound payload that consists of my red scarlet with brushless motor gimbal. This coming week I am upgrading the gimbal I fly with the red and that will make things heavier so I really needed to address the motors. With my flat 8 Tiger U5 motor, Tiger 16 inch props combo I was hovering around 62-65 percent depending upon air conditions, more on the 65% range in the current summer air. The 2nd copter with KDE 4014 motors and Tiger 18" inch props X8 combo hovers between 63-67% depending upon air.

    Issues that I had to consider.
    The MK BL electronics is rated at 40 amps max, probably even a little under that so many of the higher power motors such as U7, newer KDE motors were not even a consideration with the amount of current they draw. Even the U7 420 KV motors were probably borderline of being much.

    Why I can't run KDE motors
    I would have been willing to install the KDE 4014’s and convert to a more efficient flat 8 along with 16 inch props but it appears that that combo would actually hover higher than what I’m seeing now. It appears that the KDE motors really need the KDE ESC’s to be efficient and if you use other electronics the efficiency goes down significantly. Here’s how I am assessing my information.

    My X8 KDE 4014-18 inch prop motor configuration hovered at 64-65% throttle at a flying weight of 26-26.5 pounds. According to the KDE motor specs this combo puts out 2520 grams of thrust at the exact throttle it requires for me to hover. If I remove 15-20% that’s required for the X8 configuration I should “technically” need about 2016-2142 grams of thrust to hover my 26 pound flat 8 copter with everything else being the same but that would not be enough motor, not even close.

    So based on what I am actually seeing with my 2 copters that both use the same electronics, same flying weight, same everything else I’m estimating that I need about 460 grams of thrust to make up for the inefficiency of using the KDE motors through the MK electronics. That’s about a 23% loss in efficiency. So it appears to me based on the information and conclusions I came up with that to use KDE motors with the MK electronics requires a significantly larger, heavier motor that consumes more a lot more current. More power consumed means shorter flight times as well. It’s pretty hard to make up 466 grams of thrust in a similar size motor package. Tigers 4120 KV motor puts out about 1570 grams of thrust at 50 percent throttle which is about exactly where I need to be considering the actual data I am seeing with the U5 motors.

    Tiger 4120 motors.
    So with "many" back and forth discussions with Michael McVay (thanks again Michael) I have decided to try the tiger 4120 400 kv motors. After seeing the specs for the 4120 400 kv motors I tried to research user experiences and feedback. Guess what? I couldn't find anything. Not even one user that used them. Based on my current Tiger results and assuming that the data matches up I thought they would be a perfect fit. I decided to convert my X8 back to a flat 8 and have 2 flat 8 combos.
    Here's some of the negatives I do not like about these motors.
    #1. They are heavier than what I am used to running at about 260 grams each. My new flat 8 weights 1.5 pounds more than my U5 flat 8 that is an exact duplicate besides the motor difference.
    #2. The bearings are not as smooth as the KDE motors or the Tiger U5 motors.
    #3. It uses a goofy bolt pattern that wont bolt up any of the known motor plates out there. I had to modifiy a set of the aliexpress plates I used on my X8 to make them work. About 5 hours of work.
    #4. They use the poor C clip design
    #5 They bearings do not have as long as a running life as the newer motors, they recommend changing them out around 60 flight hours.

    With that said let me get to the nuts and bolts (the results).
    These motors perform exactly as expected and I believe I have a winner here.

    5D payload testing
    The copter just climbs effortless, and with AH off and the stick at center it just climbs. The hover throttle is around 42% and draws about 58 amps of current. Giving it full throttle it just rockets to the moon and drew 157 amps of power. So its hovering about 38% of its total power so tons of headroom.
    Flight time - 18 minutes 7 seconds with 12% reserve left. This is about a 1.5 to 2 minutes less flight time than I was seeing with the U5 flat 8 copter.

    Red Scarlet - Brushless motor gimbal testing
    I switched gimbals and tested the heavier setup. It was like night and day difference with the U5 flat and KDE 4014 X8 combo. The power for hover is exactly where it needs to be. I am hovering around 52% pulling about 77-78 amps. After observating it for a few minutes at hover I started moving around and doing hard yaw's and it was perfect, no motor restarts or errors. I then lowered the copter to about 15 feet off the ground and gunned it. The throttle response was tremendous and went up to 207 amps. One motor went as high as 33 amps, and the rest stayed in the high twenties which is better than I could have hoped for. So the copter hovering at 78 amps is about 38% of the maximum current its drawing which is exactly what I hoped for.
    Flight time - 13 minutes 30 seconds leaving 10% reserve. I probably would have gotten about 14 minutes plus had I not done the full throttle test. On average I was seeing about 15-16 minutes flight time with the U5 copter. So I have lost about a minute or slightly more of flight time. Motor temperatures are very good. In humid 80% weather the motors were barely warm where the U5's would be hot to the touch.

    Conclusions
    I have a really good motor to fly my red Scarlet combo. I have a lot of head room, and the copter isn't working hard at all to maintain hover or even going forward at a pretty fast pace if needed. I will use the Tiger 4120 flat 8 copter with red payloads and the U5 flat 8 copter for 5D payloads. I just wish the KDE motors worked as efficiently with the MK electronics like the Tiger motors do. I prefer the quality of the KDE motors but I just can't enough power.

    Here's the GPX summary of both flights, I can't attach the GPX files because they are over 2meg in size. But I have them for anyone that wants to look.

    Flight date: 8/17/2014 12:29:34 PM
    Flight time: 12:29:34 PM.0 - 12:43:10 PM.8 (816 secs, 00:13:36)
    Batt. time : 810 secs, 00:13:30

    Start Lat./Lon. : 40.397073 / -80.0789573
    Elevation(GPS) : 0.096 10.08 77.516 m (min/avg/max)
    Altitude(Barom.): 2.25 13 81.4 m
    Vertical speed : -3.68 -0.01 13.33 m/s
    Max speed : 17.4 km/h
    Max target dist.: 29.9 m
    Max distance/LOS: 99.4 m / 99.9 m

    Sats : 10 11 12

    Voltage : min. 21.1, max. 24.2 V
    Current : 0.5 80 207.5 A
    Wattage : 11 1796 4399 W
    Capacity: 18003 mAh

    Motor1: 0.0 9.5 25.0 A Temp: 34 37 43 °C
    Motor2: 0.0 10.4 29.0 A Temp: 31 39 46 °C
    Motor3: 0.0 8.5 24.0 A Temp: 32 37 43 °C
    Motor4: 0.0 11.7 30.0 A Temp: 34 41 44 °C
    Motor5: 0.0 9.8 23.0 A Temp: 35 39 44 °C
    Motor6: 0.0 10.0 24.0 A Temp: 35 43 46 °C
    Motor7: 0.0 6.7 19.1 A Temp: 39 41 45 °C
    Motor8: 0.0 11.4 33.0 A Temp: 32 40 47 °C

    Magnet Field: 100 103 107 % (ok)
    Magnet Inclination: 64 68 79 deg

    Errors / warnings:
    FC-Flag "LowBat" (5) occured 496 times!





    Flight date: 8/17/2014 12:06:46 PM
    Flight time: 12:06:46 PM.2 - 12:24:58 PM.8 (1092 secs, 00:18:12)
    Batt. time : 1087 secs, 00:18:07

    Start Lat./Lon. : 40.397099 / -80.0790122
    Elevation(GPS) : 0.001 12.89 26.711 m (min/avg/max)
    Altitude(Barom.): 0.8 15.34 29.05 m
    Vertical speed : -1.59 -0.03 3.77 m/s
    Max speed : 17.2 km/h
    Max target dist.: 24.5 m
    Max distance/LOS: 207.6 m / 208.9 m

    Sats : 11 11 12

    Voltage : min. 21.3, max. 24.2 V
    Current : 0.5 58 69.3 A
    Wattage : 11 1325 1663.2 W
    Capacity: 17711 mAh

    Motor1: 0.0 6.7 9.5 A Temp: 30 33 38 °C
    Motor2: 0.0 7.8 12.2 A Temp: 28 35 41 °C
    Motor3: 0.0 6.1 8.4 A Temp: 30 34 39 °C
    Motor4: 0.0 8.7 12.3 A Temp: 32 36 40 °C
    Motor5: 0.0 6.9 8.9 A Temp: 33 37 42 °C
    Motor6: 0.0 7.4 11.1 A Temp: 32 38 42 °C
    Motor7: 0.0 4.3 6.9 A Temp: 36 38 43 °C
    Motor8: 0.0 8.5 14.5 A Temp: 30 36 42 °C

    Magnet Field: 102 103 106 % (ok)
    Magnet Inclination: 63 68 79 deg

    Errors / warnings:
    FC-Flag "LowBat" (5) occured 458 times!
     

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