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Old Jul 25, 2014, 08:52 PM
Jack
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USA, ME, Ellsworth
Joined May 2008
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Quote:
Originally Posted by sr175 View Post
Your comment on the flat on the shaft reminded me of something. I have tried making a flat or a groove in a motor shaft before and the metal was so hard that nothing worked. What kind of dremel attachment do you use to do that? I think i have the wrong attachment to work this hard of metal.
What KC Flyer said!

Has to be an abrasive process for shafts in the typical motor. You can see the process in these threads:

Making and Replacing a Brushless Motor Shaft - http://www.rcgroups.com/forums/showthread.php?t=1240725

HexTronik DAT-750/DT750 Replacing a Shaft - http://www.rcgroups.com/forums/showp...postcount=1080

Prop Savers - Fitting, Using, Testing, & Making Thera-Band Bands - http://www.rcgroups.com/forums/showthread.php?t=1419378

I could not live without my Dremel tool. The abrasive cutting discs come in a variety of types and thicknesses. The one I use for adding flats, cutting shafts, and cutting snap ring grooves is the Dremel #409 abrasive disc and it is held in a #102 arbor. That will cut a groove that is about 0.025" wide and, of course, with continued cutting will cut all the way through a shaft.

Use them with light pressure and wear eye protection. They can and will shatter in use occasionally. The fragments are not heavy or particularly dangerous but you definitely do not want to get them in your eyes. A light caress with the disc at full RPM and at a right angle to the shaft will produce a stream of sparks and a nice little flat. And that stream of sparks is the perfect load on them for cutting.

I recently got some diamond coated rotary cutting discs at Harbor Freight and they are simply wonderful:

http://www.harborfreight.com/diamond...-pc-69657.html

There are five discs in the set and I am still on the first one of them after a number of cuts.

As you use the Dremel and abrasive cutters, keep in mind that the stream of abrasive debris coming off of the cut is not without health dangers (eyes, lungs, etc.) and can be damaging it if gets into the wrong place. Direct it away from yourself and put delicate things like motors in a plastic bag if you cut a shaft with a running motor (the perfect way to do it for the perfect cut).

I have a tuna fish can with about 1/4" of water in it on the bench. I most often hold the item (shaft, screw, whatever) over the can and let the water catch the spark stream.

I think I have worn out two Dremel tools so far but it has taken over 50 years to do it...

Jack
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Old Jul 25, 2014, 11:17 PM
Planes in flames,,,
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I appreciate what you guys see and your comments are definitely appreciated.
In fact, on of the winds was taking a shortcut over the top of the tooth.
Fortunately I could feel it when I assembled the motor and packed it back down over the tooth with a credit card (number one motor winding tool!)
Thanks for your eyes!


Quote:
Originally Posted by KC Flyer View Post
It's hard to tell from the pic, but your last winds look to be pretty close to the magnets.

I had a rewind where a wire was a bit loose, crept up between the teeth and got buggered up by the spinning magnets. Now I try to thread the last turn(s) of each tooth through the middle or bottom of the bundle to lock it in so that everything is tight. I've also used a drop of CA to secure loose wires as well.

Your winds look very neat otherwise - just don't want you to lose a motor/ESC to something easy to prevent.

Where did you get the upgraded bearings? Are they sealed?

FWIW, I recently rewound one of these motors for a CTH Widowmaker where both bearings were the big size (8mm OD x 3mm ID x 4mm thick). It is now 8T/23g with a 7x6 APC clone prop cut down to 6".
Yes, the bearings are sealed. I got them from this place.
http://www.advantageracingproducts.c...ts/default.asp

I popped for the sealed ceramic for a couple of my favorite planes.
The rest will get the sealed 99 cent bearings.

Great. This is one of the gotchas with this little motor.
I have seen three different combinations of bearing sizes.
And now four different combos with the big bearing in the front and in the back

I'm running the Assassin on an 8 turn with the regular 7x6 prop... I may need to prop down and see if I get better flight times. 32 apms and 412 watts!
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Old Jul 26, 2014, 07:35 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
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Iron dust, magnets in motor: put motor in plastic bag before you start grinding.

Vriendelijke groeten Ron
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Old Jul 27, 2014, 01:26 AM
Planes in flames,,,
jetpackninja's Avatar
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Quote:
Originally Posted by Ron van Sommeren View Post
Iron dust, magnets in motor: put motor in plastic bag before you start grinding.

Vriendelijke groeten Ron
+1 and put the shaft through a tiny hole in the baggie exposing it so you can cut it
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Old Jul 27, 2014, 09:25 AM
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Lee's Summit, MO USA
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Quote:
Originally Posted by jetpackninja View Post
I'm running the Assassin on an 8 turn with the regular 7x6 prop... I may need to prop down and see if I get better flight times. 32 apms and 412 watts!
Using 9T motors, I had previously cut down some of the 7x6 props to 6x6 for my Widowmaker and Assassin and couldn't tell much performance difference.

But after flying the Scythe for awhile with 7T and then flying the bigger planes immediately afterwards, I was saying - what happened to the performance?

So that's why I rewound a motor for my WM to 8T using a 6x6 prop.
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Old Dec 10, 2014, 08:26 AM
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Anyone, can you post Io and resistance of your rewound motor, along with other parameters?
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Old Feb 06, 2015, 05:42 AM
Defies Logic & Common Sense
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Philippines, NCR, Makati City
Joined Jun 2012
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guys question what about the star Wye wind is it recomended .Ive notice the Bluewonder 1300kv seems to use them . just dont know the turns recomended.
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Old Feb 06, 2015, 03:28 PM
Jack
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USA, ME, Ellsworth
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Quote:
Originally Posted by speedactyl View Post
guys question what about the star Wye wind is it recomended .Ive notice the Bluewonder 1300kv seems to use them . just dont know the turns recomended.
Read about the differences here:

http://www.bavaria-direct.co.za/info/

If they wind that motor with a given number of turns and terminate it Wye for the 1300 Kv motor, they can change to the Delta termination and use the same winding to get a 2249 Kv motor.

So it they sell 1300 and 2200 versions, that would explain the different terminations. The Kv used in model names are not precise and accurate measurements, they can be easily off by 50 to 100 RPM/V or even more.

Jack
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Old Feb 06, 2015, 06:59 PM
Defies Logic & Common Sense
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cause i cant get a guage 26 in emax CF motor on the recomended windings of 15 turns.
The blue wonder seems to get away with such guage wire
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Old Feb 09, 2015, 06:02 PM
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I was able to wind 15T with 25g MicroDan wire so 26g should be easier. You may need to use a hotel key card to flatten the windings and a T-pin to carefully poke a space thru the bundle for the last turn.
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Old Feb 13, 2015, 01:52 AM
Defies Logic & Common Sense
speedactyl's Avatar
Philippines, NCR, Makati City
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Boy my last wind was crazy.
stuff a 24g wire 14 turns on the first 4 poles then the rest is 26g at 14 turns I did use a Card to force em in . when powerd up its like it has more torque than the Stock motor but feeling I manage only 1300KV something only but that should be enough for a 8x45 or a 9x45 prop right? when I put the 10x45 in it went vertical on something weighs 650g ??
I think I better get a bigger ESC before I burn something..

----------------------------
the funny question is having two different gauges wire just to cheat the windings does it alter the KV results like you can have more speed and torque at the same time or would the motor jackrabbit between poles between speed and torque stressing the ESC's timing.

has anyone experiment on this like alternating poles 12T on a 24g and 14T on a 26g
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Last edited by speedactyl; Feb 13, 2015 at 01:57 AM.
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Old Feb 13, 2015, 07:38 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
The Netherlands, GE, Nijmegen
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Copper cross-sectional area has no effect on Kv and speed.
The lower the overall copper resistance, the lower RPM drop under load.
Max. current, and therefore toque, depends on thinnest wire.

Prettig weekend Ron
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Old Feb 13, 2015, 08:10 AM
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so it explains why I dont have the torque when I use the 28guage wire on my first attempts.
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