Mar 03, 2011, 10:27 PM
Registered User

more data

sorry about this. for some reason I could not get excel to attach to post. willing to email it to the keeper of the data. anyway this is data i got. form is same as excel. how do you calc efficiency? any good links to how to bench test motors? I am just looking at peaks.

16 11 1464 star GWS9050 6.7 7.4 11.4 frantz5000msl 26awg? 2c460 47.4 4.2 6.82 stock 1500
16 11 1464 star apc 9x4.7 6.6 7.6 11 frantz5000msl 26awg 2c460 50.2 4.6 6.22
16 11 1464 APC9x4.7 10.1 12 16.8 frantz5000msl 26awg 3c460 114 6.8 4.18
16 13 1295 star apc9x4.7 9.7 8.2 14.6 frantz5000msl 26awg? 3c460 79 5.4 5.24 stock 1300
16 13 1295 star apc9x4.7 7.1 5 10 frantz5000msl 26awg 2c460 40 4.0 7.09
16 13 1295 star gws9050 6.9 5 9.6 frantz5000msl 26awg 2c460 37.6 3.9 7.24
16 13 1295 star gws9050 9.7 7.6 14.6 frantz5000msl 26awg 3c460 76 5.2 5.45

16 10 1608 star GWS9050 9.86 11.9 16.7 frantz5000msl 24awg 3c460 111 6.6 4.27 rewound 1300
APC9X4.7 9.25 12.1 18.6 frantz5000msl 24awg 3c460 115 6.2 4.59
APC9x4.7 6.7 8.2 12.4 frantz5000msl 24awg 2c460 55.6 4.5 6.33
GWS9050 6.6 7.6 12.2 frantz5000msl 24awg 2c460 50.6 4.1 6.84
16 11 1464 apc9x4.7 9.76 13.7 19.2 frantz5000msl 24awg 3c460 126 6.6 4.32 rewound 1300
16 11 1464 apc9x4.7 6.63 9.4 11.8 frantz5000msl 24awg 2c460 61.8 5.2 5.42
16 11 1464 gws9050 6.62 9 12.2 frantz5000msl 24awg 2c460 60.6 5.0 5.71
16 11 1464 gws9050 10.04 12.6 18 frantz5000msl 24awg 3c460 121.2 6.7 4.21
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Mar 03, 2011, 10:31 PM
Registered User

12 turns 24awg

I tried 12 turns 24 awg abc, wouldnt fit. (wire rubbed on magnets) had to settle for 11. I know guys are getting 24awg 12-14 turns. any tips to get it to fit? motor is black and red.

my 11 turn is less efficient than the factory 1300kv. wonder if i miscounted a turn. makes 4 oz more pwr though.

To figure efficiency, I was comparing how many watt it takes to make 8 oz of thrust, takes about 4% more watts to make same thrust on my rewind compared to factory 1300 (same motor before rewind vs after rewind)

real happy with 10 turn abc wye with 9050 here at 5000msl on 2 cell for 3 d! for some reason it is just as efficient as 1300 kv factory,

efficiency from worst to best, watts req to make 8 oz thrust on 3 cell gws 9050

factory 1500 36.9 watts
custom 11 turn 36.1 watts
factory 1300 32.6 watts
custom 10 turn 32.2 watts

all abc wye customs are 24 awg

dont understand why 10 turn would be more efficient than 11 turn, could this make sence or did i miscouunt wraps?
Last edited by brokeneck; Mar 04, 2011 at 08:37 AM.
Mar 06, 2011, 09:47 AM
Winging it >
leadfeather's Avatar

low kV

Is there any way to modify the Bw motor for low kV other than delta/Y and # turns?

I'd like to go for really low kV motor but without all the winding. The high turn winds are a little bit tedious and the wires size gets smaller and the smaller wires break easier.

For instance can changing the number of magnets change the kV? What is the change to kV of 13, 14, 15 or16 magnets?
Mar 06, 2011, 09:52 AM
Registered User
Dr Kiwi's Avatar
You must have the correct ratio of magnets to stator arms. The BW is 12-arm, 14-magnet pole. And if you can't fit any more magnets in you cannot lower the Kv (you can take out magnets and raise the Kv - I believe 8-magnet poles would work on a 12-arm stator motor). Well, maybe you could add magnets if they were half the width of the originals, but I have no idea how many you'd need to suit a 12-arm stator.

Gee, I researched some other variants......I wonder what happens to Kv if you leave all 14-magnets, but only wind half the 12-stator arms (LRK)?
Last edited by Dr Kiwi; Mar 06, 2011 at 10:29 AM.
Mar 06, 2011, 10:13 AM
jackerbes's Avatar
If you look at Trug's spreadsheet for the RBW motors the lowest Kv's are a little under 1,000, in the high 900's.

You have to look at the magnet counts, wind methods, and terminations used there to get the same result. But you can also see the prop testing results to get a feel for the power expectations.

Mar 06, 2011, 10:46 AM
Registered Aircraft Offender
Truglodite's Avatar
From my understanding, with a 12n stator, the only options are 10p, 14p, and 16p. There is a 16magnet pole version available (1300, 1500, & 1700 are 16p), but oddly enough my tests have shown a very slight increase in Kv going from 14p dLRK to 16p ABCx4 with the same # turns and termination.

Mar 06, 2011, 10:59 AM
Registered User
Dr Kiwi's Avatar
I found this (one of Brian Mulder's excellent articles):
Mar 06, 2011, 11:42 AM
Registered Aircraft Offender
Truglodite's Avatar
Thanks Phil, I saved that image to my motor folder.

Mar 06, 2011, 02:43 PM
Registered User
Dr Kiwi's Avatar
Originally Posted by Truglodite View Post
Thanks Phil, I saved that image to my motor folder.

There is actually a slightly better version of it on the gobrushless site.
Mar 07, 2011, 12:24 PM
W5BSA's Avatar

Question for Manuel

Good morning Manuel,

Could you please detail the wind info in this post of yours from 2009. I believe it is exactly what I am looking for based on everything you mentioned. I have included a picture of my 2EZ delta foamy that I am currently using the stock Turnigy 2730 Red Black 1700KV version. The battery I use is the 450 25C 3s Gens Ace. I run the Mystery 20 amp ESC

For props I run either the Master Airscrew 5.5 x 4.5 or EMP 6 x 4.

What's your winding scheme wire guage in the example mentioned and how many magnets are in the bell of your motor?

We use them in Saturday morning combat so speed is more important than extended run times.

Thank you very much for your suggestions and have a very blessed day,

Joe Ross ARS W5BSA

Registered User

Join Date: Aug 2004
Location: Mexico, BC, Mexicali
Posts: 3,842
Distance from you: 1689 km
What kind of plane you have.
My 12 turn Delta has a 2500KV. and it is good for 3s with a 19,000 rpm, 17.7A at 10.4V. with APC 5x5.
I have it mounted on a Fun Jet and is just for speed.

A motor 12 turns a BW has to be mounted in a position where you get a lot of air with speed and should be maintained to ensure the flow of air but only in short periods.
since everything accelerated is produced much warming.

For a quieter flight. I put a 17T, Delta, 1730Kv,APC 6x4, 15,700 rpm to 11.67V, 11.2A. and 14,000 to 10V.

Manuel V.
Last edited by manuel v; May 09, 2009 at 03:01 PM
Mar 08, 2011, 12:57 AM
W5BSA's Avatar

Is this one wound DLRK?

Hi Kev, is this one wound DLRK. It's from your spread sheet? I like the EMP props.

Motor ID Mags Turns Wire Gage Parallel Effective Turns Termi- nation Wire [in] Kv [RPM/V] Io [A] Rm [Ohm] Prop. Temp [C] Alt [m] RPM V A Thrust [oz] Note Battery Thrust* [oz] Ptch Spd [mph] Effy* *gm/W *"Heat" [W] Pin [W] Kv*T Kv*T "D" Kv*T "Y" Convert to Delta Kv*T "D" Kv*T "Y" Convert to Delta Index Test Density
36 14 12 24awg 1 12 Delta 38 2583 0.93 0.051 4.5x4.5 EMP 24.6 29 24046 11.85 17.76 22 Truglodite Rhino 3s1250 22.6 102.5 105.0% 3.0 -11 210 30996 30996 30996 350 1.181420909
Mar 08, 2011, 02:05 AM
Registered User
manuel v's Avatar

The wind is DLRK. 12t delta 25AWG. but is best 24AWG. (even easy wind)
44 in wire longitude.

Manuel V.
Mar 08, 2011, 08:06 AM
W5BSA's Avatar
Good Morning Manuel,

Good deal, Thanks for confirming the Info,

Mar 09, 2011, 06:00 PM
W5BSA's Avatar

Colorized DLRK Road Map

Hi Everyone, thanks to all who have helped me with my DLRK wind. I colorized the pictograph by Morris M and it helped me stay on the right path and crossovers while winding my 2730 Red Black. I cannibalized an older 2730 Red Black 3000 KV so it already had the bell with the needed 14 mags. I am doing 12 T Delta with Manuel's recommended 24 AWG with Micro Dan's newbie wire. Hope to fly it in combat this weekend with my 6 X 4 EMP prop. Will let you know the results. I also came up with a neat tool for keeping the winds where i wanted them. It's the little yellow corn on the cob handle with the little stainless 2 inch long needle. I just cut one of the prongs off. The little handle helps you get the leverage you need without sore thumbs.

73, W5BSA
Apr 13, 2011, 01:18 AM
Registered Aircraft Offender
Truglodite's Avatar
Quick correction, that wind was indeed 24awg. W5BSA, usually when you don't hear back it means things went good... how did it run?

Speaking of 12turn motors, my T2730-14p-6x2t-24awg-Y gem is back in action again. Here's the motor powering my own pylon 300 design during maiden:

'Un-Named' Pylon 300 Scratchbuild - Brian's Perspective (6 min 47 sec)

111mph?! The maiden video contained several upwind passes that doppler between 109-111mph; factor in wind that day and it travels 120mph. This should make it clear that pitch speed on the bench is not a speed limit. Based on a hunch that this thing is slippery enough, I chopped down few 6x5.5e props to around 4". FYI, a 6x5.5 cut to 4.0" EXACTLY matches the 4.75e in both static amps and thrust (verified by my thrust stand). I'm hoping the extra 15mph pitch speed with the 4x5.5 equates to roughly that much more airspeed this Sunday. If not, there's always a 10T-23awg-D.


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