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Old May 12, 2011, 04:47 PM
Jack
USA, ME, Ellsworth
Joined May 2008
16,956 Posts
With the same turn count, the Delta termination will give 1.73 times more RPM than the Star termination. It also draws 1.73 time more current but it has a little less torque. So all things considered, the Delta would have had more performance.

But I don't think you can't pull 13A especially 1.7 times 13A from a 25 gram motor for very long. If that wind is on that BW-winds spreadsheet you should be able to see the Kv for both Delta and Star and estimate your propeller RPM and pitch speed.

Jack
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Old May 13, 2011, 11:47 AM
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Truglodite's Avatar
Carmichael, CA
Joined Feb 2007
3,520 Posts
2s with a 10T-delta and 4.75 should work good if you're interested in a more modest increase in power. That should go about as fast as 3s-Y/4.75. I have seen 3s-10T-delta/4.75 work on 3s, but 25awg isn't much for the kind of power you'll get with a 4.75. These motors can only take around 70W heat with proper cooling (fast planes only, no cowling).

A note on emp/tgs vs apc. I've tested several varieties in the 4-5" range and hace found a few differences that may explain why they behave so different. EMP has a much wider chord and less pitch than apc. Take the analogy of a plane with high aspect ratio vs low aspect. The low aspect wing gives more lift at high alpha, but less lift at optimal operating conditions. In the same manner, the emp will give more static thrust, but the apc gets more efficient as flight speed increases (& aoa decreases), eventually giving more thrust than the emp. I've seen my theory play out in flight: my buddies sunracer felt way more flyable with the emp, and so it felt faster to the pilot. I reality the actual top speed dropped from 125mph with apc, to 110mph with emp. So the apc is 5th gear, emp is 4th gear.

Another tidbit... The apc 5x5e is really slightly more than 5 pitch. Compare it to a 6x5.5e, and you'll notice the pitch profile is closer than a 4.75 pitched apc prop (should be the other way around). This is why everyone hates 5x5's... they see numbers that go with a 5x5.3ish prop, and that's too much amps for a 5x5. Just my $.02 on the stinky 5x5e.

Moral of the story... static thrust isn't the only metric to worry about, apc is a "taller gear" than emp/tgs, and that apc "5x5.3" is mismarked "5x5".

Kev
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Last edited by Truglodite; May 13, 2011 at 11:58 AM.
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Old May 13, 2011, 12:13 PM
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Dr Kiwi's Avatar
Chattanooga, Tennessee, United States
Joined May 2003
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Just my $.02 on the stinky 5x5e.


Very useful analysis, Kev! Explains a lot of things, which my static tests cannot hope to answer.
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Old May 13, 2011, 03:40 PM
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gazza2003au's Avatar
Sydney, Australia
Joined Jul 2003
4,481 Posts
i tested the rewound motor on a 17" flying wing yesterday it was pretty much useless i might have to save it for another model with a larger prop
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Old May 15, 2011, 07:13 PM
Winging it >
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Joined May 2006
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Blue Wonder powered F-35 VTOL. This will be worthy of a couple of rewound motors.

F-35 VTOL Doing it all! (3 min 31 sec)
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Old Jun 13, 2011, 05:03 AM
Will work for foam
wingnutt's Avatar
United States, WI, Muskego
Joined Apr 2005
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last week i rewound a 16 mag version to a 14 turn, 24ga (Wye) motor. it was previously a 13 turn, but I wanted a little longer flight time. It is perfect now. on a 900mAh, 3S pack and 7x4 prop (cut down GWS 8x4), it will push my mini SuperFly delta clone (9 oz. AUW) vertical for over 15 min. it was well worth the 2 hrs spent on the rewind.

i have to say that it was the most challenging wind i have done yet. should have taken a picture as the wire-spoke look of a 12 tooth ABC wind is rather beautiful.
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Old Jun 14, 2011, 10:29 AM
Dave North
timocharis's Avatar
USA, CA, San Jose
Joined Apr 2004
5,254 Posts
Quote:
Originally Posted by wingnutt View Post
... the wire-spoke look of a 12 tooth ABC wind is rather beautiful.
Definitely! One of the neatest looking winds. Sometimes it seems a shame to plow 'em in, but heck, that's what they're for.

Dave
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Old Jun 14, 2011, 05:57 PM
tree scavenger
USA, OH, Cincinnati
Joined Sep 2006
585 Posts
umm...looks kinda plain from where im sitting !?

man, remember when ya could find a nice handsomely-wound, + 5-8% efficient 25g mtr on the sale forums here !??

...guess thats why everyones growin-their-own huh!?
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Old Jun 15, 2011, 10:46 AM
Dave North
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USA, CA, San Jose
Joined Apr 2004
5,254 Posts
The blanks really sucked for a while. Sure messed with me; I'm not sure what the status is now!

Dave
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Old Jun 16, 2011, 08:53 AM
Winging it >
leadfeather's Avatar
Joined May 2006
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Quote:
Originally Posted by wingnutt View Post
last week i rewound a 16 mag version to a 14 turn, 24ga (Wye) motor. it was previously a 13 turn, but I wanted a little longer flight time. It is perfect now. on a 900mAh, 3S pack and 7x4 prop (cut down GWS 8x4), it will push my mini SuperFly delta clone (9 oz. AUW) vertical for over 15 min. it was well worth the 2 hrs spent on the rewind.

i have to say that it was the most challenging wind i have done yet. should have taken a picture as the wire-spoke look of a 12 tooth ABC wind is rather beautiful.
After 15 min of vertical it must have been getting hard to see the plane.
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Old Jun 17, 2011, 05:31 AM
Will work for foam
wingnutt's Avatar
United States, WI, Muskego
Joined Apr 2005
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I'm not gonna lie, it was a struggle. The real problem came when the FAA showed up!
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Old Jun 18, 2011, 12:08 PM
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Quote:
Originally Posted by wingnutt View Post
I'm not gonna lie, it was a struggle. The real problem came when the FAA showed up!
LOL, I think NASA might have been watching too.
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Old Jun 20, 2011, 05:37 AM
Will work for foam
wingnutt's Avatar
United States, WI, Muskego
Joined Apr 2005
1,502 Posts
Oh yeah! You're right. Sorry, I don't remember much once Homeland Security was done w/ me.
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Old Jul 16, 2011, 03:42 PM
Sorry, but they're all toys.
Eric Odle's Avatar
United States, WA, Bellingham
Joined Jun 2009
292 Posts
Here's a dLRK question with this motor, I've noticed a slight difference in cogging between different dLRK-wound motors. Does more or less cogging suggest a quality difference between them? My thinking is that a dLRK motor with less cogging is probably better, but I'm not so sure...
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Old Jul 16, 2011, 05:40 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
Joined Feb 2001
10,721 Posts
Cogging is not affected by winding diagram, number of winds. It's a strictly magnetical phenomenon, not electrical. Maybe you shorted the wires, in that case the motor acts as a generator and you will feel more resistance. Or you hooked up the motor in delta, whilst you miscounted some winds. That will give an unbalance and current will flow in the (closed) delta circuit.

Vriendelijke groeten Ron
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