Cobra Champion 3000kv 2205 Drone Motors

Discussion in 'Miscellaneous' started by Combatevolved, May 4, 2018.

  1. Combatevolved

    Combatevolved Ace Pilot

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    I bought a few 3000kv drone motors to go in super light builds with the ambition of hitting 3:1 T:W on 2s. It will be interesting to see if it is possible. IMG_3298.JPG
     
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  2. e3_Scott

    e3_Scott Top Gun

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    Interesting. What prop/ESC/battery setup do you plan on using for your experiment?

    Cheers,

    Scott
     
  3. Hey combat, you have a thrust stand and watt/amp meter so you can actually test these motors and props to see what they are coming up with? I guess the other part is how "super light" are these new planes going to be.?

    I have a hard time building light, always seem to need more reinforcements because I don't think it will be strong enough even though they end up in the same trash can when I crash them. :D
     
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  4. Combatevolved

    Combatevolved Ace Pilot

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    I have a power meter and test all motors on scales in situ in the airframe, great indicator of performance in flight. All my planes from 2s up to 4s have unlimited vertical. (Including my Su37 Twin edf)





    Hows the 4s going @e3_Scott? It's a drill I bet. My 350g Mig 29 took a beating on 4s 1550g of ST with a TW of over 4:1!!!

    Regarding the 2s project Let me try a few things out 1st Scott before I make my recommendations. But the best thrust I've seen in situ is 660g on 2s drawing 20a. To make 3:1 I'm looking at a auw of 220g or less and I've got some very light parts coming. It's definitely achievable. (Still using 9g servos)

    Happy flying chaps.
     
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  5. e3_Scott

    e3_Scott Top Gun

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    Interesting stuff. The 4S testing is going well thus far, some video I shot a couple days ago. If you watch on YouTube, links to all the power components are in the video description.

    The plane in the video weighs 575 gr with the 4S battery, so with thrust from the bench testing being 1630 gr with this setup, T/W is about 2.8:1.

    Now that I have had a few flights to experience the power, I have put this same setup in my "Mini Mig-35B" which has a 24" wingspan, so much less drag and weighs 534 gr with the 4S battery, so theoretically a T/W of 3.1:1. It is pretty fast already on 3S, so on 4S it should be pretty crazy!

    I am hoping to get a bit more speed out of the EMAX 2306 2750 setup I'm running once I get a chance to try some 5" props with more pitch, although very fast at the field, I fear that the RPM are getting so high that the 6x3 EMP prop may not be delivering the full bench tested thrust past a certain throttle setting. But that is why we bench and field test these things I suppose:).

    I'm also currently building a modified, downsized RC Powers Su-30 V4 which will have about a 24.5" wingspan, I think it might be an even sleeker airframe than the "mini Mig" I have been doing a video log on my YouTube channel at this playlist

    Best of luck with your testing, interested to hear how those Cobra motors perform :)

    Cheers,

    Scott
     
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  6. Combatevolved

    Combatevolved Ace Pilot

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    Awesome stuff.

    I got pretty brutal performance using a 6x4 tgs on 4s Turnergy Graphenes.

    The secret is to use bursts of 5-6s so you dont saturate the esc and motor with too much heat.

    I'll check out your YouTube footage later.

    4s feels much more exciting and dangerous. I start off my flying outings with a rather mild 2s then 3s then finished on 4s and it's brilliant. Such a buzz and crescendo.

    Theres an idea I'm toying with in my mind of using 5s spinning a 5x3 or 5x4 prop using the emax 2306.
    The 2306 emax is proven to hit 2000g of ST so if you have achieved 1600g then with a perfectly matched setup you may get closer to that figure. Something else to sink our teeth into.
    Rock on.
     
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  7. e3_Scott

    e3_Scott Top Gun

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    Interesting. So this 2000 gr of thrust from the EMAX 2306 2750, do you have any more details? Prop/battery/ESC/amp draw to get that?

    Cheers,

    Scott
     
  8. Combatevolved

    Combatevolved Ace Pilot

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    Hello Scott,
    Engineer x states he has no doubt this will produce 2kg of ST based upon his testing. Forward to 7:50 of the you tube link below.



    Engineer X also tested a 5050x3 drawing 55a so what we know regarding the performance of the emax on a 6x3emp (1650g) so we can make the jump that he is probably quite correct in his statement which should come true if we use a 6x4 king Kong/6x4 tgs or even a HQ 6x4.5x3 as used by miniquadtestbench review for some of his tests.
    Ultimately what is very compelling to me is that miniquadtestbench produces 1700g of thrust at 42a which is circa 25%-30% below what we can use with this motor on 4s.

    I'm more than happy to push my 2306s units and find out. I'd also like to try the new 2206 LS to see if that lives up to all the hype.
    Play time all round.

    Screenshot_20180510-185606_YouTube.jpg Screenshot_20180510-185246_Samsung Internet.jpg 20180510_190914.jpg Screenshot_20180510-185606_YouTube.jpg Screenshot_20180510-185246_Samsung Internet.jpg 20180510_190914.jpg
     
    Last edited: May 10, 2018
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  9. Combatevolved

    Combatevolved Ace Pilot

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    Those little CM2204/2300 produce 1200g of ST at 24g in weight with the wires. Crazy.
     
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  10. e3_Scott

    e3_Scott Top Gun

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    Thanks very much for taking the time to post all this info, I'll have to have a better look through it later on.:) With that much thrust (close to 2 kg) it would be even more critical to select the right airframe, build it light, sleek but also strong to take full advantage of that thrust. In my experience, as the thrust increases in foam park jet, I have got to a point where it feels like I have hit a "drag wall" where no matter how much thrust the motor is producing, it no longer has the torque and power to overcome the drag forces. The challenge becomes greater and greater as the edge of the envelope gets pushed further and further :)

    Cheers,

    Scott
     
  11. Combatevolved

    Combatevolved Ace Pilot

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    I love researching, discussing and testing this stuff probably inspired the guys on this forum.
    Very true about drag.

    I've been battling with nose flare (positive pitch) that occurs when I gun the throttle on 4s. The nose wants to tend upwards which is frustrating when you are trying to fly straight at high speed. Have you manage to eliminate this phenomenon Scott?
     
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  12. e3_Scott

    e3_Scott Top Gun

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    You might try angling the motor down just slightly, you can either use thin spacer washers on the top two screws between the metal "X" mount attached to the motor and the wooden motor mount or use toothpicks to shim it just a couple degrees down so that perhaps the motor shaft is pointing more towards the bottom part of the trailing edge of the prop slot rather than the centre. That way as the plane accelerates, it will push the nose down to help counteract the "zooming" which is normally worse on profile type planes that are going really fast in my experience. Just try a very small amount of down tilt first, see how that goes and then increase it in small increments until you have your plane going fairly level. On high speed runs into the wind, a plane might naturally tend to "zoom" a bit easier because of the extra airflow/lift, so try to evaluate it going downwind if you can.

    Hopefully I have explained so that it is understandable, like I said, small increments at a time, if you go too far too fast with the down tilt, you can end up driving your plane into the ground very quickly :/

    Cheers,

    Scott
     
    Last edited: May 10, 2018
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  13. Combatevolved

    Combatevolved Ace Pilot

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    Superb that makes perfect sense and thanks for explaining all that. I'll give that a try to eliminate the zooming effect. Thanks again.
     
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  14. e3_Scott

    e3_Scott Top Gun

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    Sure thing, it is also a good idea to ensure after you have been flying a plane for awhile to take any trim you might have in back to zero and check that the control surfaces are neutral dead center with no trim. Often with these park jets after a few flights as the hinges break in and the servos and linkages get seated properly under stress, you can end up with control surfaces that are no longer dead center at zero trim and that could also contribute to either having to trim that out or having the plane do things it shouldn't because a control surface isn't quite centered any longer at zero trim. Lots of little things to keep an eye on as you push the speed envelope and as the speed increases, any little thing that isn't dialed in just right can be exaggerated considerably :) Just lessons I have learned over the years, mostly the hard way :(.

    Do you have KF airfoils on the plane or planes in question?

    Cheers,

    Scott
     
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