RE: ** WALKERA DRAGONFLY 36 *  
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    • All Forums >> RC Helicopters >> Electric RC Helis >> Walkera Helis - Dragonfly, etc.. >> RE: ** WALKERA DRAGONFLY 36 *
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    [Poll]

    ** WALKERA DRAGONFLY 36 *
    THE WORST HELI IN THE UNIVERSE
      7% (22)
    VERY VERY VERY BAD
      4% (13)
    DOING MY HEAD IN
      7% (20)
    ACCEPTABLE
      12% (35)
    OK
      10% (28)
    OK
      5% (15)
    GOOD COULD BE BETTER
      23% (65)
    GREAT HELI
      17% (50)
    ABSOLUTLEY LOVE THIS HELI
      8% (24)
    THE BEST HELI IN THE UNIVERSE
      2% (7)


    Total Votes : 279
    (last vote on : 7/7/2008 4:30:31 PM)
    (Poll will run till: -- )
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    RE: ** WALKERA DRAGONFLY 36 * - 11/5/2005 10:22:04 PM   
    borisboy


     

    Posts: 84
    Joined: 10/5/2005
    From: minehead, UNITED KINGDOM
    Status: offline     		HI guys i am secound posting again.sorry

    Just tried gtx soloution to esc and it works.But as he said at the bottom of his post it still gerks up at mid throttle so have we set it to soft start or not,whats going on as it still seems the same to me.

    (in reply to borisboy)
           Post #: 276

    RE: ** WALKERA DRAGONFLY 36 * - 11/6/2005 6:23:23 PM   
    GTX SlotCar



    Posts: 2067
    Joined: 10/7/2005
    From: Gorham, ME, USA
    Status: offline     		I'm still having power problems.
    When I got my 36 it had the stock motor and battery and wouldn't lift off. Gear mesh was good but I took a little tension off the tail belt. It didn't help. I bought one of the blue $29.95 2200Mah LiPo battery/charger combos. With that, I could hop quite high, but the battery didn't last long and I couldn't really hover, just hop several times. Now I've got the Align 420LF and 25A ESC. It will fly, but only for a couple minutes (and that's being generous).
    At full throttle, the rotors actually seem to slow down even if I take the pitch out of the blades.
    After my initial 2 minutes I can hover a bit in ground effects (a foot or so off the ground), but the heli goes up and down. I can actually hear the motor going fast then slow then fast then slow (you know BBRRRbbrrrrBBRRRbbrrr). It also seems to squeak while it's doing this. After that, it goes back to the hopping I had before. I can hop it high or low, but it doen't have power to hover. After a hop, I turn my throttle down to zero for a couple seconds and I can hop again. I can do this several times until I eventually get bored.
    At first I thought the up and down motion might be caused the the up/down play in the main gear, but now I don't think so. It seems more like the battery is just loosing power. I charge it until the green LED comes on and the voltage is up there.
    Others have this battery and it works for them. Could it be a thing of chance, though? Has anyone else had one that didn't work well?
    Maybe I should set the ESC battery discharge protection to 60% (high discharge rate) and see what happens. Maybe I should just get a good 16C battery, but I'm not even sure what that means.
    I'd appreciate any help or comments.

    _____________________________

    Gary
    SuperSkids® www.super-skids.com

    (in reply to borisboy)
           Post #: 277

    RE: ** WALKERA DRAGONFLY 36 * - 11/6/2005 7:13:03 PM   
    Mikey-Flies


     

    Posts: 81
    Joined: 9/30/2005
    From: Fort Saskatchewan, AB, CANADA
    Status: offline     		My "blue" battery was useless. The cells were also configured in a "not so good" way that I don't feel is safe. The NiMH cells flew the heli a lot better than the provided 2200 Lipo did but not long enough.

    The 16C refers to draing the pack at the C rating of the cell which is generally it's stated capacity/1hr (Cell size is 2200 mah so the "C" rating would be 2200 ma). You can then use the C rating to determine the amps that the cell can provide. Generally the higher C you draw from the cell the less usefull capacity you get and the shorter the flighttimes. a 14C continuous 2000 mah battery can provide ~ 28 amps of current (14 * 2.0 amps) but likely won't do this for 1/14 or 4.28 minutes at such a high drain. Likely it will be in the 80% range or 3:50 or so. Luckily we don't use 100% throttle so the average current draw is usually less than the maximum rating of the cells (it really should be!!) so we get nice long flights. You can use this to calculate the battery size for the flighttime you want. If you hover at 8 amps and you want to fly for 20 minutes (hovering) then 60/20 = 3C. 8 / 3 ~= 2.7 so a 2.7 AH battery should give around 20 minutes of flight. Keep in mind that the higher the current compared to capacity (C rating) the lower the % of usable capacity (generally).

    How freely does your rotor spin and have you checked the pitch of the main blades? What is your pitch range? Perhaps you are trying to fly on too much pitch rather than head-speed although it likely is the batteries. If you still have the NiMH cells give them a try. They should be good for 3-5 minutes at least after a couple of cycles.

    (in reply to GTX SlotCar)
           Post #: 278

    RE: ** WALKERA DRAGONFLY 36 * - 11/6/2005 7:41:00 PM   
    GTX SlotCar



    Posts: 2067
    Joined: 10/7/2005
    From: Gorham, ME, USA
    Status: offline     		My rotors spin pretty freely, Mikey. I get nowhere with my NiMh battery pack.
    Here's what was throwing me off about the C rating. Look at the 2nd & 3rd batteries on this page:
    http://www.helikraft.com/advanced_search_result.php?keywords=li-po

    The cheaper one is 2100Ma 16C and the more expensive one is 2000ma 18C. Yet, they appear to be the same brand.
    So, any battery with a 10C rating should do it then, right?


    _____________________________

    Gary
    SuperSkids® www.super-skids.com

    (in reply to Mikey-Flies)
           Post #: 279

    RE: ** WALKERA DRAGONFLY 36 * - 11/6/2005 9:32:20 PM   
    Mikey-Flies


     

    Posts: 81
    Joined: 9/30/2005
    From: Fort Saskatchewan, AB, CANADA
    Status: offline     		10 C and the right capacity should work fine. The advantage of the Higher C cells is usually less voltage drop and lower internal resistance (the two generally go hand in hand).

    All of our electric "things' get power from watts (volts * amps) and our job is to adjust things to get the mix that we (and the electronics) want and can handle. For the same watts, if you can increase the voltage you will decrease the amps needed which allows things to run cooler and more efficiently (voltage regulator in the BEC may not, as they typically convert >5V into heat) as well as allowing longer run times.

    A non real-world fictional example;

    Heli A needs 100 watts to hover.

    Lets pick round numbers to make this easy.

    Battery A can sustain 10V under load at the amps required to hit 100W (10A) and has a capacity of 2000 mah. This would be a drain of 10A/2000ma = 5C and should give a flight of ~ 12 minutes (It will actually be less but...)

    Battery B can sustain 11V under load at the amps required to hit 100W (9.09A) and has a capacity of 1900 mah. This would be a drain of 9.09A / 1900 ma = 4.78C and should give a flight of 12.5 minutes (It will actually be less but ...) The second system should keep resistive heat generation down as well.

    In general, the higher C rated packs will hold better voltage under load BUT how to determine the C rating also seems to vary from manufacturer to manufacturer and even sometimes by distributor! Best is to try to obtain some discharge graphs at various current levels and compare the different brands of Lipo's to see what works best or find out what battery brands/capacities etc others are using successfully for the same setup.

    (in reply to GTX SlotCar)
           Post #: 280

    RE: ** WALKERA DRAGONFLY 36 * - 11/6/2005 10:48:07 PM   
    GTX SlotCar



    Posts: 2067
    Joined: 10/7/2005
    From: Gorham, ME, USA
    Status: offline
    quote:

    ORIGINAL: Mikey-Flies

    ... The advantage of the Higher C cells is usually less voltage drop and lower internal resistance ...In general, the higher C rated packs will hold better voltage under load...

    Ok, so go for the higher C rating when possible, right? I went to school for electronics about 100 years ago so I have a pretty good understanding of how things work, but the C rating on batteries is something I haven't seen until I got into helis, and LiPo's in particular.

    I tried different programming in my Align ESC, lowered and raised motor timing and battery discharge in several combinations. Nothing really helped except I noticed that high timing for the 420LF makes it scream even more.

    Oh, and a bit of good news, while I was reprogramming the ESC, the Soft-Start really started working great. The rotor now starts slow and then kicks up. Kind of like shifting gears.


    _____________________________

    Gary
    SuperSkids® www.super-skids.com

    (in reply to Mikey-Flies)
           Post #: 281

    RE: ** WALKERA DRAGONFLY 36 * - 11/6/2005 11:50:40 PM   
    pmfmod


     

    Posts: 33
    Joined: 10/29/2005
    From: , MA, USA
    Status: offline     		but when you go for higher C, it costs more and most of the time, heavier.

    (in reply to GTX SlotCar)
           Post #: 282

    RE: ** WALKERA DRAGONFLY 36 * - 11/7/2005 2:07:13 AM   
    floatyboy


     

    Posts: 108
    Joined: 3/6/2005
    From: auckland, NEW ZEALAND
    Status: offline     		Hello GTX, chuck the battery, its ****. I got the same deal as you at $29.95. Believe it or not but the charger actually does an ok job of charging those blue batterys. After i bought the battery i noticed no "c" rating. Thats because the chinese don't know what the C rating is!!
    I found this out from my suppliers. My heli was doing exactly what yours is doing. Except i have a walkera brushless, not an align one like you which is probably more powerful than mine. In the end i bout an 1800 mah lipo, 10C. And then came the power! I can fly higher now than i'm comfortable with. at least 30ft plus. I know the charger worked with mine as i re charged the battery on an expensive Robbe charger and it indicated a full charge. The charge was there but the discharge rate is not! In the end i bought a swallow charger and 2 Eflight batterys, now i'm sorted. The Gyro has to go next! Get any good quality 11.1 volt lipo,10c and up and you should be away! good luck

    (in reply to pmfmod)
           Post #: 283

    RE: ** WALKERA DRAGONFLY 36 * - 11/7/2005 2:07:35 AM   
    Mikey-Flies


     

    Posts: 81
    Joined: 9/30/2005
    From: Fort Saskatchewan, AB, CANADA
    Status: offline     		Yes. It pays to shop around and mostly stick with the "accepted" cells rather than unknowns. Even within the accepted cells there is quite a variability for the same C rating (weight, actual capacity, temperature rise etc).

    Some of these are Apogee, Polyquest, Thunderpower, and Tanics (I'm not sure where the kokam line falls now, but their 340's are still top dog in the small cell sizes from what I have seen). Look around at what others are using with the same power setup you have and why. If you're more curious, look for discharge graphs in the amp capacity you are interested in comparing various cells.

    (in reply to pmfmod)
           Post #: 284

    RE: ** WALKERA DRAGONFLY 36 * - 11/7/2005 2:11:17 AM   
    inline2542


     

    Posts: 5
    Joined: 10/15/2005
    From: , NC, USA
    Status: offline     		GTX,
    Mine does the exact same thing. I think it is the battery too. Hope someone can tell us for sure.

    (in reply to GTX SlotCar)
           Post #: 285

    RE: ** WALKERA DRAGONFLY 36 * - 11/7/2005 5:17:08 AM   
    edzinator


     

    Posts: 82
    Joined: 8/19/2005
    From: san marcos, CA, USA
    Status: offline     		GTX,

    What pinion are you using on your 420L? I started with a 10t on my 36 I may move up to an 11t but I really enjoy the fly time, I'm not sure how long my flights are yet. I will time them soon. I'm running the align 420L 3550kv with align esc and 1800mha 15C pack. My head speed at near liftoff is 2100 rpm. I do hope to get a new gyro soon as well, O my!, I flew my brothers 450XL pro yesterday.... O how the dreams start hehe I may just sell this 36 and go Trex asap. the 36 has way too heavy of a flybar and paddles, as Edzinator eyes the Trex rotor parts at the store. My brother said, those come with a Trex...

    I do enjoy the 36 it did give me the heli bug, and I thank it for that. For now it's just a holding test bed for Trex equipment.

    See ya all at the park!

    (in reply to GTX SlotCar)
           Post #: 286

    RE: ** WALKERA DRAGONFLY 36 * - 11/7/2005 7:51:52 AM