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Old Oct 21, 2012, 08:06 AM
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Hilton (Rochester), NY
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Good to hear you're up and running. Glad to hear you have favorable flying conditions.
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Old Oct 23, 2012, 09:12 PM
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United States, TX, Huntsville
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How afton do the little motor smoke? I did get a good hour of flying in (no I never found the motors hot not at all like the c10) before I striped a main gear with a moving pinion. when i tryed to test before final assy. one of the blue 3800kv motors started smoking dead short in the windings
I did like the control of the Olliw's mini pro coax mixer and stock ga250 gyro can't wait to get the new motor and Olliw's ga250 coax mixer. I got a unit to work on the computer now I need to see it work in the heli.
fly on
nathan
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Old Oct 24, 2012, 09:35 AM
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3800Kva?!!!!!!!! The C-10's and the others we use are around 2900. Hey, whatever floats your boat - Opps, wrong forum!
When guys were doing brushless HBFP's, they were using one 3800 motor to lift a 300 size heli. You're using 2 to lift a 180 size heli.
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Old Oct 24, 2012, 11:57 AM
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Originally Posted by kodak_jack View Post
3800Kva?!!!!!!!! The C-10's and the others we use are around 2900. Hey, whatever floats your boat - Opps, wrong forum!
When guys were doing brushless HBFP's, they were using one 3800 motor to lift a 300 size heli. You're using 2 to lift a 180 size heli.
Power out the butt, it hovers with about 50% throttle. My thanking is the should last longer it they don't need 50-80% I maybe wrong about that
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Old Oct 24, 2012, 12:15 PM
OlliW
Joined Sep 2009
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two comments please

i) the KV value is NOT a measure of the power of a motor or anything like that

ii) if at all then it actually goes vice versa - at least trendwise/phenomenologically: the "bigger" the motor the smaller the KV (but the "bigger" the battery packs)

BTW: somewhere in the various coax threads it has recently be discussed that 3800 KV can be appropriate for a cx2 type heli

Quote:
it hovers with about 50% throttle
if the motors don't get hot then this too me sounds like a good setup (if you aim at power)
Quote:
My thanking is the should last longer it they don't need 50-80% I maybe wrong about that
this is IMHO not correlated, build quality and overload (heat) should determine longevity more...
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Old Oct 24, 2012, 09:43 PM
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Originally Posted by OlliW View Post
i) the KV value is NOT a measure of the power of a motor or anything like that
longevity more...


you can estimate rpm from kv kv*v=rpm 3800a*12.4v=47120 rpm's and that full motor shaft speed.
I'll try and get some amp readings
kodak_jack
[QUOTE=3800Kva?!!!!!!!! The C-10's and the others we use are around 2900. Hey, whatever floats your boat - Opps, wrong forum!
When guys were doing brushless HBFP's, they were using one 3800 motor to lift a 300 size heli. You're using 2 to lift a 180 size heli..[/QUOTE]

my heli weight is 329g with 11.4v 1600amh battery not sure how to take weight and blade pitch and calqlate power to lift heli
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Last edited by sonnier00; Oct 24, 2012 at 09:48 PM. Reason: apologys
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Old Oct 25, 2012, 02:56 AM
OlliW
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Quote:
you can estimate rpm from kv kv*v=rpm 3800a*12.4v=47120 rpm's and that full motor shaft speed.
no... well, yes and no... ok, yes, but the key point is missed here

this rpm is obtained only WITHOUT load... the real rpm will be lower because of the load, and how much lower it is depends on the load... and the power of the motor (that's there the motor power comes in)

does anyone believe that one of these very small 6mm motors with KVs of e.g. 48000 (see e.g. here) will make your CX2 rotor head spin at 48000 x 3.7V = 177600 devided by the gear ratio = 20500 rpm (I assumed a gear ratio of 70/8)? I hope not. This would be possible though if the motor would be "big" enough and provide that much power, but this little cute tiny motor obviously won't do that and just would stall...

so, any rpm calculation based on KV has to assumes that you have a properly powered motor, and this is achieved if the real rpm is about 80-90% of the KV rpm, hence rpm calculators always ask you to set also an "efficiency"...

so, with a properly matched motor of let's say an "efficiency" of 85% the rpm would be estimated to 3800 * 11.3 * 0.85 = 36500 rpm
but this holds ONLY and ONYL if the motor is powerwise properly matched!

In short, the KV doesn't tell anything! You first have to get your power matched, and then choose the KV (and the gear) such that it matches your rpm wishes.

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I'll try and get some amp readings
this would be interesting... but be carefull how to measure that... with PWM units it is easy to measure nonsense.
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Old Oct 25, 2012, 01:13 PM
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this would be interesting... but be carefull how to measure that... with PWM units it is easy to measure nonsense.

I can measure amps at the battery wont tell much about balance just total consumed amps
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Old Oct 27, 2012, 03:30 PM
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Ryan, welcome to RCGroups. Please tell us more so we can try to help you. Do your motors themselves turn at all?
Lee
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Old Nov 04, 2012, 07:37 AM
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Sonnier, what is happening with your heli? I wish guys would do a little more research before buying the WOW brushless conversion. I also think a drop-in coaxmixer would be a big seller. Then again, the Aero-Nutz are back and a safe alternative to stock brushed motors.
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Old Nov 04, 2012, 12:52 PM
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United States, MA, Malden
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Quote:
Originally Posted by kodak_jack View Post
Sonnier, what is happening with your heli? I wish guys would do a little more research before buying the WOW brushless conversion. I also think a drop-in coaxmixer would be a big seller. Then again, the Aero-Nutz are back and a safe alternative to stock brushed motors.
Even if the Aero~Nuts were not available, I could never see the reasoning on spending a bunch of money on a $90.00 heli (V4/CX2) doing a BL conversion. Oh yeah, I have about $60.00 in upgrades and mods. Before I'd go for BL in a coax, I'd go for a BL in a FP first. But, that is me.

Mike.
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Old Nov 04, 2012, 04:09 PM
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Quote:
Originally Posted by kodak_jack View Post
Sonnier, what is happening with your heli? I wish guys would do a little more research before buying the WOW brushless conversion. I also think a drop-in coaxmixer would be a big seller. Then again, the Aero-Nutz are back and a safe alternative to stock brushed motors.
Well that was a big wast it did nothing they said it would. Very disappointed with it. Only If we would do more research. I did get Olliw's coax mixer working and love the control it gave me I think it had a lot to do with the GA250 gyro too. DO NOT USE C10 motors I keep braking the leads.
I have finished my Olliw's GA250 coax mixer and will be trying it next.
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Old Nov 04, 2012, 09:42 PM
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United States, WA, Spokane
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Quote:
Originally Posted by sonnier00 View Post
Well that was a big wast it did nothing they said it would. Very disappointed with it. Only If we would do more research. I did get Olliw's coax mixer working and love the control it gave me I think it had a lot to do with the GA250 gyro too. DO NOT USE C10 motors I keep braking the leads.
I have finished my Olliw's GA250 coax mixer and will be trying it next.
That's because the wire is so nasty in the C10 motors. Brittle. Poor conductivity to boot. Should be interesting to get your view now as to the difference in performance using Ollis gyromixer. I keep telling you guys. Once I added some weight, went 3s with enough mods to keep things controlled. And used the OlliW gyromixer. I have an entirely new heli. And it flies much much better than any FP heli I have played with. I just got back in from flying it just an hour ago after seating in a new pinion. This little thing is fast. Wind? What wind!
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Old Nov 05, 2012, 07:24 AM
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I've said this before in another thread, but worth repeating here, if that combo is the cat's behind, then that's the way to go. If the same motors and ESC's and gyro are used on either a CX-2/3 or Lama 3/4 or 5#10, they're all the same basic heli and should require the exact same coaxmixer. Why can't that coaxmixer be sold already programmed so you don't have to jump through hoops to put a heli together? Again, the average Joe or Mike is not going to go through all that is required to get 'er done if it includes having to program the Arduino! Heck, when I wanted to put together a parts list, I couldn't even get the right information on which Arduino chip set to buy, let alone try to follow all the programming steps. As much as guys complain about Walkera heli's, at least after the first introduction on most of their heli's, at least they offer you a brushless version later on. Why doesn't Eflite and what's left of Esky follow suit? I think the work done for the coaxmixer and gyromixer are brilliant, but putting one together without a decent how-to is beyond what the average heli pilot is willing to dive into. There is nothing left of the original heli anyway, why not sell a complete brushless heli or a kit that has easy to understand instructions? Then again, like Mike says, it's a simple $100 heli. How much money do you put into it before you move on to something else anyway?
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Old Nov 05, 2012, 01:04 PM
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KJ it's so much fun but your so right, The only stock part I use now is the radio.
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