BP21 brushless & GWS 1047 prop

ExtremeSkyes · Jan 19, 2005, 11:34 PM

Hi folks,

anyone recommend against this combination or got specs on it? I just have a spare GWS 1047 prop hanging around to play with. Otherwise I'll have to head down to the LHS to get one of the direct drive props.

FYI...I'll be using this motor to drive a 3Dfoamy F18 when I finish building it.

Ex.

dtm360 · Jan 20, 2005, 04:06 AM

How many cells are you running?

ExtremeSkyes · Jan 20, 2005, 04:34 AM

I've got a 2s and 3s lipo between this one I'm building and two others. I'll probably use the 3s in the F18.

It's a GWS 3s 1050mah Lipo battery.

Ex.

dtm360 · Jan 20, 2005, 11:19 PM

I measured a 1047 with 3s on this motor. I stop pushing the throttle when it hit 17A....almost at WOT. You would be frying your batteries pretty quickly. The GWS cells are only 6C so 6A is a good max target to aim for.

I believe with the original specs, a 8043 on 3s is still pushing 10+A. You could try a 7035 prop to bring it down further and not use WOT too much.

This is the reason why I rewound the motor to 19T WYE. Now pulls around 9A with 3s 1400 at WOT. Still has plenty of kick for a 400g 3D plane.

Gene Bond · Jan 21, 2005, 12:14 AM

Are you running the 8040HD prop?

dtm360 · Jan 21, 2005, 12:46 AM

Oops...didn't mention the prop! the rewound 19T WYE is pulling a 1047sf with 3s and 9A draw.

Trikky · Jan 22, 2005, 09:10 PM

what size wire did you rewind it with?
as I am looking at rewinding mine as well

boomerace · Jan 22, 2005, 11:35 PM

I get a kick out of the people that think the 8 X 4 prop is wimpy on the BP 21. Check out the vid on my website what it does in a 24.1oz Slow Stick with 3S1P Lipos! Most of the flying was at 55% throttle.
boomer
www.boomerseflight.com

ExtremeSkyes · Jan 23, 2005, 12:57 AM

Thanks dtm...much appreciated. Looks like another battery investment so my F18 might not fly for a while yet.

Ex.

dtm360 · Jan 23, 2005, 01:50 AM

8x4 is not wimpy.....there is no mention of "wimpy" in any of the posts neither....the point of re-winding the motor was to keep the amps down (my cells could not handle the draw)..... However, if you read my post you would have probably figured that out yourself!

Trikky- I used the 26 awg stuff than comes with the Gobrushless CDR motors.

Correction...the plane I'm using the motor on is 375g AUW...not 400g. I'm getting confused!

boomerace · Jan 23, 2005, 02:02 AM

Quote:

Originally Posted by dtm360

8x4 is not wimpy.....there is no mention of "wimpy" in any of the posts neither....the point of re-winding the motor was to keep the amps down (my cells could not handle the draw)..... However, if you read my post you would have probably figured that out yourself!

Trikky- I used the 26 awg stuff than comes with the Gobrushless CDR motors.

Correction...the plane I'm using the motor on is 375g AUW...not 400g. I'm getting confused!

Several posters have remarked that the 8 X 4 wouldn't fly a Slow Stick is what I was referring to. Any motor that puts out the watts the BP 21 and 12 do will fly a plane like the Slow Stick just fine! Wimpy was my words in reference to the no-sayers.

boomer
www.boomerseflight.com

dtm360 · Jan 23, 2005, 02:33 AM

Yes, there is a lot of "mis-information" on the internet, that's why is better to do some filtering. There are a lot of people who will always knock cheap stuff and made in China stuff. If they wish to remain in their life of ignorance then I'm certainly not going to be the one to bring them out of it. Providing me (or you) aren't in that same "ignorant" state!!

Anyway...getting off my soapbox now. Has anyone dissected a B12 motor to find out the turns of the thing?

ExtremeSkyes · Jan 23, 2005, 06:16 PM

Besides rewinding, can you reduce AMPs by installing a gearbox? I think I read in another thread about installing this motor in a gearbox...??

Ex.

Jan 19, 2005, 11:34 PM	#1
ExtremeSkyes Registered User Join Date: Nov 2004 Posts: 480	BP21 brushless & GWS 1047 prop Hi folks, anyone recommend against this combination or got specs on it? I just have a spare GWS 1047 prop hanging around to play with. Otherwise I'll have to head down to the LHS to get one of the direct drive props. FYI...I'll be using this motor to drive a 3Dfoamy F18 when I finish building it. Ex.

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Jan 20, 2005, 04:06 AM	#2
dtm360 Registered User Join Date: Sep 2004 Posts: 102	How many cells are you running?

Jan 20, 2005, 04:34 AM	#3
ExtremeSkyes Registered User Join Date: Nov 2004 Posts: 480	I've got a 2s and 3s lipo between this one I'm building and two others. I'll probably use the 3s in the F18. It's a GWS 3s 1050mah Lipo battery. Ex.

Jan 20, 2005, 11:19 PM	#4
dtm360 Registered User Join Date: Sep 2004 Posts: 102	I measured a 1047 with 3s on this motor. I stop pushing the throttle when it hit 17A....almost at WOT. You would be frying your batteries pretty quickly. The GWS cells are only 6C so 6A is a good max target to aim for. I believe with the original specs, a 8043 on 3s is still pushing 10+A. You could try a 7035 prop to bring it down further and not use WOT too much. This is the reason why I rewound the motor to 19T WYE. Now pulls around 9A with 3s 1400 at WOT. Still has plenty of kick for a 400g 3D plane.

Jan 21, 2005, 12:14 AM	#5
Gene Bond Crash Master Join Date: Sep 2001 Location: Indianapolis, IN Posts: 16,207	Are you running the 8040HD prop?

Jan 21, 2005, 12:46 AM	#6
dtm360 Registered User Join Date: Sep 2004 Posts: 102	Oops...didn't mention the prop! the rewound 19T WYE is pulling a 1047sf with 3s and 9A draw.

Jan 22, 2005, 09:10 PM	#7
Trikky Balsa Abuser Join Date: Jul 2003 Location: Wyong, Australia Posts: 343	what size wire did you rewind it with? as I am looking at rewinding mine as well

Jan 22, 2005, 11:35 PM	#8
boomerace Been There! Done That! Join Date: Sep 2001 Location: Eugene, Oregon, United States Posts: 19,172	I get a kick out of the people that think the 8 X 4 prop is wimpy on the BP 21. Check out the vid on my website what it does in a 24.1oz Slow Stick with 3S1P Lipos! Most of the flying was at 55% throttle. boomer www.boomerseflight.com

Jan 23, 2005, 12:57 AM	#9
ExtremeSkyes Registered User Join Date: Nov 2004 Posts: 480	Thanks dtm...much appreciated. Looks like another battery investment so my F18 might not fly for a while yet. Ex.

Jan 23, 2005, 01:50 AM	#10
dtm360 Registered User Join Date: Sep 2004 Posts: 102	8x4 is not wimpy.....there is no mention of "wimpy" in any of the posts neither....the point of re-winding the motor was to keep the amps down (my cells could not handle the draw)..... However, if you read my post you would have probably figured that out yourself! Trikky- I used the 26 awg stuff than comes with the Gobrushless CDR motors. Correction...the plane I'm using the motor on is 375g AUW...not 400g. I'm getting confused!

Jan 23, 2005, 02:33 AM	#12
dtm360 Registered User Join Date: Sep 2004 Posts: 102	Yes, there is a lot of "mis-information" on the internet, that's why is better to do some filtering. There are a lot of people who will always knock cheap stuff and made in China stuff. If they wish to remain in their life of ignorance then I'm certainly not going to be the one to bring them out of it. Providing me (or you) aren't in that same "ignorant" state!! Anyway...getting off my soapbox now. Has anyone dissected a B12 motor to find out the turns of the thing?

Jan 23, 2005, 06:16 PM	#13
ExtremeSkyes Registered User Join Date: Nov 2004 Posts: 480	Besides rewinding, can you reduce AMPs by installing a gearbox? I think I read in another thread about installing this motor in a gearbox...?? Ex.