PARKJET MOTOR BENCH TESTING

Discussion in 'Electronics' started by e3_Scott, Jul 6, 2013.

  1. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    The field test session of the GepRC 2306 2750 kv motor on 4S in my RC Powers Su30 V4 "speed build" did not go exactly as planned, however, something positive did come out of it:)

    Here is a bit of post incident video taken at the field.


    As mentioned in the video, the bullet style prop nut I was using came loose, combination of me probably not tightening it enough and the torque of this beast of a motor helping to loosen it after about 6 good speed runs. In future, I will use the proper prop lock nut that comes with the motor for running on 4S.

    Fortunately, the motor and ESC seemed to be OK, I was a bit worried about the very high (60A) amp draw I saw on bench testing, but I think the motor and ESC can handle it. I will put this motor and ESC in another plane and continue testing to see how it works after a few more flights on 4S.

    I have new plans already back from the print shop, I will build it at the same size, it was very stable at this size and as mentioned, I did see a bit of torque roll with this more powerful motor, so I think if I downsized it even a little bit, torque roll will be an issue and rob me of some precious speed. 98.8 mph before the prop came loose, so I'm hoping the elusive 100 mph is achievable with this plane and power system if I build the same size and weight. :)

    Cheers,

    Scott
     
  2. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Was out putting some serious 4S action into the GepRC GR2306 2750 kv motor setup today:)

    Obviously this larger Mig-35B is not as fast as the smaller, sleeker Su-30 V4 which will be built again in the near future, but this motor continues to prove that it is quite the beast on 3 and 4S. I ran it hard through about 4 flights on 4S with multiple high speed runs and full throttle climb outs, no problem whatsoever, no hesitation, just down to business :) As mentioned in the video, without a doubt this is the most powerful quad motor I have tested in my park jets and it seems to be able to handle some seriously high amps without too much trouble. Since I only have two 4S batteries, I was only able to do two flights back to back at a time, I might have been able to do a third if I had the batteries, other than that and I think it would be best to let the motor cool a bit or fly it on 3S for a flight or two.

    I noticed today that Banggood has the 2750 kv motor under restocking (it also comes in 2450 kv), but with no expected date of restocking. I did find it available at Gear Best also, a little cheaper, but Gear Best would charge me a bit of shipping, so it works out about the same in the end. Here is the link to this motor on the Gear Best site. https://www.gearbest.com/motor/pp_1496940.html?wid=1433363

    Cheers,

    Scott
     
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  3. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Second motor test of the day, this time with the EMAX LS2206 2700 kv motor, 6x4 APC gas prop on 3S. All the test data from the bench is available here on the motor test spreadsheet. https://docs.google.com/spreadsheets/d/1KLR_wdkJ1OdGcf5f9jxxxU8qqmz_kXjMQH8NOLjW3NQ/edit?usp=sharing


    Respectable performance with this motor with today's setup, about the middle of the pack compared with several other motors I have tested over the past year.

    As mentioned in the video, although the bench numbers were significantly better with the Gemfan 6045 Carbon nylon prop without a huge increase in amp draw over the 6x4 APC gas, the motor at times struggled to keep spinning the 6045 prop. I could hear the motor "laboring" somewhat at full throttle, especially on vertical climb outs when the motor was under heaviest load. The difference in top end thrust between the two props is about 250 gr/8.8 oz, but I certainly didn't think it was that much of a difference in the air. Maybe about a 10% increase in top end speed, certainly not about a 20% increase as shown on the bench. However, the 6045 prop caused the motor to run much hotter and as mentioned it struggled quite a bit to keep spinning the prop effectively under heavy load.

    Cheers,

    Scott
     
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  4. XDmToter

    XDmToter Ace Pilot

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    Thanks for the flight video and all the testing you do, Scott. I think that motor will be a perfect fit when I get around to building another SR-71.
    I just can't get over the fact that you are getting more thrust from that motor than the NTM Propdrive 3000KV when it weighs 60% less... mindblown.
     
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  5. XDmToter

    XDmToter Ace Pilot

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    Have you ever put any of your quad racing motors to the test using an APC 4.75x4.75 prop? That has been my go to prop for speed planes lately. I have counter rotating 4.75's on my Flitetest SuperBee, and it is a screamer.
     
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  6. e3_Scott

    e3_Scott Top Gun

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    Sure thing :) For a plane like your SR-71 which has a very low drag profile, hopefully this GepRC motor setup on 4S will work well. I could certainly feel the drag difference flying this bigger 27" wingspan plane over the sleeker, smaller Su-30 V4.

    The one drawback with some of the quad racing motors is although they crank out a lot of power, they do struggle producing enough torque to "muscle" through the drag caused by bigger planes compared to the NTM size and kv motors because they are physically so much smaller. But with a low drag plane, if you can save about 3 oz in weight over the heavier motor and ESC, it should really scream:) I have not tried the 4.75 by 4.75 prop yet, I might eventually get around to that, I have lots of other testing to get done over the summer as well as a plane or two to build to make up for some recent carnage :(

    Cheers,

    Scott
     
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  7. e3_Scott

    e3_Scott Top Gun

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    Hi Everyone -

    Did a bit more testing today:)


    Now that I am almost finished up with the largest amount of testing of quad racing motors after experimenting for almost a year, I started another thread where I hope to consolidate more of the quad motor specific info like build considerations, motor choices, some of the best motors I have tested (if price isn't a big issue;)), the "middle of the pack" bunch which all tend to have pretty good performance and price and a more "budget oriented" selection. I will be doing more in depth reviews and summarizing my lessons learned in that thread regarding quad racing motors more often in the future so that finding the info is not as hard as reading through this more lengthy thread :)

    You can find the new thread here https://rcpowers.com/community/thre...in-single-motor-prop-in-slot-park-jets.22460/

    Cheers,

    Scott
     
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