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Old Oct 20, 2012, 04:51 AM
starting at RC
Zagreb,Croatia
Joined Aug 2004
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What about this motor:
http://www.bidproduct.com/more/cartview.php?id=5633
20 pcs for 8$
Is this too big?
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Old Oct 20, 2012, 08:40 AM
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vinnieg's Avatar
United States, NJ, Edgewater
Joined Feb 2012
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Quote:
Originally Posted by KoekieMonster View Post
If commercial ESC's were less then $5, I would just buy those, but with a feeling I can build for about $3 ~ $4 ea. and commercial starting at around $8 (for as far as I know)
would using the ESC from a servo work for this purpose or is it not able to carry the AMP draw needed by the motor ?
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Old Oct 20, 2012, 08:44 AM
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Originally Posted by vinnieg View Post
would using the ESC from a servo work for this purpose or is it not able to carry the AMP draw needed by the motor ?
He was talking about brushless ESC. So this doesn't work
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Old Oct 22, 2012, 09:35 AM
RC beginner
New York
Joined Oct 2008
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yes, mystman is right. that shows how to convert servo guts to drive brush motors. the v939 board already drives brush motors directly so no such converter is necessary. and if you want to use brushless motors a pwm converter is needed which in not related to that project.

note that captk (of kk fame) posted an excellent diy to mod a brushless esc to drive brush motors, including open source code, in the electronics forum here. it was a great thread and worked perfectly for me but has nothing to do with converting brush to brushless either but actually the opposite.
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Old Oct 23, 2012, 10:38 AM
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New York
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Quote:
Originally Posted by zoohr View Post
What about this motor:
http://www.bidproduct.com/more/cartview.php?id=5633
20 pcs for 8$
Is this too big?
those are k20 type motors very common for use in servos. you will notice by coincidence similar ones in the servo mod thread i just mentioned. doubtful they can use a prop as big as the ones in those bidproduct photos but i think our smaller walkera. wlt, udi props might work. they do have 1mm shaft. only way to tell is try it. $8 (40 cents ea) is very cheap but you have to be careful of his shipping charges. sometimes only a dollar or two and other times 5-10 bucks. if shipping is not too much i might try those on my next order.
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Old Oct 24, 2012, 03:43 AM
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The Netherlands, GE, Doetinchem
Joined Apr 2012
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Does anyone know how to toggle the led connections on this board: http://www.banggood.com/Wholesale-Wl...6-p-47484.html ?
I am nog using the stock TX but the turnigy 9x (ER9X), have tried toggling the ch5 and 6, but nothing happened.
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Old Oct 24, 2012, 04:54 AM
starting at RC
Zagreb,Croatia
Joined Aug 2004
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Thank you!
Shipping cost from Bidproduct and arrival times is mystery!
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Old Oct 24, 2012, 05:41 PM
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Joined Feb 2003
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Quote:
Originally Posted by zoohr View Post
What about this motor:
http://www.bidproduct.com/more/cartview.php?id=5633
20 pcs for 8$
Is this too big?
I ordered this motor:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=290666938196

which I think it is the same motor as above.
I will report how it works after I receive them.
Just took a chance in order to help the project along.

Lloyd
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Old Oct 25, 2012, 10:29 AM
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Israel
Joined Jan 2011
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How about these motors:
http://www.ebay.com/itm/Mini-K30-Mot...90639246248%26
Seems to be a little bigger and stronger - but relatively slower.

Does anyone know the rotation speed (KV or RPM) of the V939 and V929 props on full throttle?
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Old Oct 25, 2012, 10:36 AM
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United States, VA
Joined Dec 2006
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Originally Posted by asanado View Post
Does anyone know the rotation speed (KV or RPM) of the V939 and V929 props on full throttle?
I don't know about he V929 but jesolins tested the V939 motors:
http://www.rcgroups.com/forums/showp...&postcount=514
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Old Oct 25, 2012, 10:59 AM
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Israel
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Originally Posted by LittleMo View Post
I don't know about he V929 but jesolins tested the V939 motors:
http://www.rcgroups.com/forums/showp...&postcount=514
Thanks, I guess I missed it...

From jesolins's numbers - Calculating KV and RPM for 3V (this is usually the voltage used for testing these kind of motors):
18,500 RPM for Full Throttle ==> 18,500 RPM for 4.2V (I assume jesolins was testing it with fully charged battery - Voltage range should be 3.4V-4.2V)
==> 4400 KV ==> ~13,000 RPM for 3V

It seems that the motors I linked in my previous post are slower (10,000 RPM), but maybe they are stronger and can be loaded with V929 Props.

It will be great, if anyone has this kind of motor and can test it... RPM with V939 Props or V929 Props and current consumption for each.
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Old Oct 25, 2012, 04:03 PM
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United States, VA
Joined Dec 2006
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I just got some of the Ailexpress Mike Guo 716 motors and they have 1mm shafts with thin black and white wires. Are these the "good" versions? I guess I'll find out.

Still waiting for my V939 boards though...
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Old Oct 25, 2012, 04:04 PM
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Originally Posted by LittleMo View Post
I just got some of the Ailexpress Mike Guo 716 motors and they have 1mm shafts with thin black and white wires. Are these the "good" versions?
As Dave mentioned: Yes. I got the blue/red with "no" power :-(
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Old Oct 26, 2012, 10:07 AM
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New York
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the blk/wht motors i got from mike had .8mm not 1mm shaft and were quite powerful compared to the 2nd batch of blu/red with 1mm shaft. so we really dont know how good the blk/wht with 1mm are. it would be very interesting to see mos results.

of the half dozen different 7mm pagers i tried they all worked for the dquad except for those blu/red 1mm ali ones. so chances are good that any 7mm motors you get your hands on will be ok. 6mm it was 50:50 but thats to be expected with such a small case. im very anxious to see how those k20 and k30 servo motors lquick and asanado found work out.

if you really want top of the line performance and dont mind spending a buck more then these long case walkera lb replacements are a good deal:

http://www.banggood.com/Wholesale-7m...r-p-51897.html

from preliminary thrust tests and real world flying impressions id say:

1. blu/red 1mm shaft from ali and most of the 6mm i tried are not useable.

2. some selected 6mm pagers (solar grasshopper, aero ace, etc) about 50% more power.

3. 7mm motors with .8mm shaft like the s107 from focal (post #1 partlist) and blk/wht ali more than 2x the power.

4. v939 and lb replacements, about 50% more power than those.
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Last edited by dave1993; Oct 26, 2012 at 12:38 PM. Reason: motors not mortos
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Old Oct 27, 2012, 05:37 AM
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Israel
Joined Mar 2012
470 Posts
I ordered the 7mm motors from banggood and received the blue/red motors.
So I decided to splurge and go for the 7mm LB replacements.
Banggood are listing black/white and red/blue wires - I assume one is clockwise and one is counter-clockwise, right?


Quote:
Originally Posted by dave1993 View Post
the blk/wht motors i got from mike had .8mm not 1mm shaft and were quite powerful compared to the 2nd batch of blu/red with 1mm shaft. so we really dont know how good the blk/wht with 1mm are. it would be very interesting to see mos results.

of the half dozen different 7mm pagers i tried they all worked for the dquad except for those blu/red 1mm ali ones. so chances are good that any 7mm motors you get your hands on will be ok. 6mm it was 50:50 but thats to be expected with such a small case. im very anxious to see how those k20 and k30 servo motors lquick and asanado found work out.

if you really want top of the line performance and dont mind spending a buck more then these long case walkera lb replacements are a good deal:

http://www.banggood.com/Wholesale-7m...r-p-51897.html

from preliminary thrust tests and real world flying impressions id say:

1. blu/red 1mm shaft from ali and most of the 6mm i tried are not useable.

2. some selected 6mm pagers (solar grasshopper, aero ace, etc) about 50% more power.

3. 7mm motors with .8mm shaft like the s107 from focal (post #1 partlist) and blk/wht ali more than 2x the power.

4. v939 and lb replacements, about 50% more power than those.
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