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Old May 09, 2013, 04:06 PM
Sometimes I break things
Oslo, Norway
Joined May 2004
328 Posts
6x4 sounds big on small motors with 3S; but that would explain the vertical

I will try the three-blades; and maybe replace the motors with some lower KV ones; maybe even four-blade would be possible. That would be cool.
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Old May 11, 2013, 07:06 AM
We want... Information!
Bruce Abbott's Avatar
Hastings, New Zealand
Joined Jan 2001
5,179 Posts
Quote:
Originally Posted by Steffeo View Post
With two 5030 motors on 3S on full whack...

Do you know the KV of the stock 300h motors?
3860Kv, which on 3S with 5030 props would be doing about 21,000rpm! You really should only be running them on 2S, with 4.5x3 props.
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Old May 11, 2013, 08:53 AM
Dance the skies...
Tom Frank's Avatar
United States, MA, Walpole
Joined Dec 2003
17,442 Posts
Quote:
Originally Posted by Steffeo View Post
6x4 sounds big on small motors with 3S; but that would explain the vertical

I will try the three-blades; and maybe replace the motors with some lower KV ones; maybe even four-blade would be possible. That would be cool.
For clarification, my motors are 1710 kV outrunners of the "2208" stator size class. They have been tested with 6x4 props on 3S and are very capable of handling the load for the very brief time I fly at WOT (5 sec. max.) If you look at the vendor prop charts for your stock motors, you'll see what Bruce just mentioned. They don't list the motor kV, but they do show prop size recommendations for various battery voltages.
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Old May 12, 2013, 07:59 PM
Registered User
Taiwan, 北市
Joined Dec 2010
1,215 Posts
The KV of EM300H motor is 22950 at 7.2V without any load, and with 0.75A Amp drawn.
This was find out from their web site home page written in Mandarin. http://www.gws.com.tw/chinese/product/MOTOR/motor.htm

Be reminded that my PC gave me an warning that the English version of GWS web site home page might come with virus when I was trying to make further search, so I signed off their English page and entered the Mandarin one instead. Hope they could correct this problem earlier, also hope yours could be safer when trying to do the same at your sites.

It's OK to run 2S with prop 5030 on the brushed 300H motor, I used to run th same on brushed 150 motor that comes with higher KV on my motor glider years ago. It worked great.

Chen
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Old Jun 09, 2013, 12:32 PM
Sometimes I break things
Oslo, Norway
Joined May 2004
328 Posts
So, I've had a few flights now. When I got the CG corrected, she was a different animal all together. I could do a proper flare at landing and everything.

Did a amp draw check, and it was doing around 15 amp static at full throttle. It should unload a little in the air, so I'm guessing I'm at around 13? The motors I think were rated at 7 amp each.

So, not really much room for different props. I bought some 5x5 ones (using 5x3 now) from APC; they could work. I guess my real issue is that I'm getting a too high rpm, and thats why I'm not happy. I have not left any space for a 6 prop, so I'm guessing I need to move the motors if I want something that spins slower (and going with different motors).

I am using these motors : http://www.radicalrc.com/search/RRCCDROM2500

Or am I going about this all wrong? Could I use a three blade, and expect the rpm to fall without increasing the amps ?
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Old Jun 09, 2013, 11:34 PM
Registered User
Taiwan, 北市
Joined Dec 2010
1,215 Posts
I'm afraid that a 3 blade could not reduce the Amp unless it's well balanced, and with less diameter and pitch.
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Old Jun 10, 2013, 02:49 AM
Sometimes I break things
Oslo, Norway
Joined May 2004
328 Posts
Not looking to reduce, just not increase... Really looking to reduce rpm without increasing amps too much.
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