Rewinding Emax CF2805 & CF2822 - Page 2

MiseryQ · Mar 11, 2009, 12:33 AM

Quote:

Originally Posted by renns

BTW, are you the same MiseryQ from the old days on the MegaSquirt forum? Small world! :-)

How many MiseryQs can there be? (:
I go more by the also unique name of fr4nklyn now o:

Looks like your getting some good help over there.
What I did, and what I'll be doing to the FC2822, is run it up in a low speed drill.
Measured the AC output to caluclate the KV and ran it through MotoCalc to get a rough estimate on wire size and turns. I also had to convert with 1.73 since I didn't see how to convert in MotoCalc from delta to Wye.

But in the end I just aimed for TimoCharis's 12turn of 24 wind which he said was the best he could get from the motor.
I could only get 11t.

If you want I have some odd wire pulled from a Chrysler transmission solenoid pack. IIRC it's metric in between 23 and 24gauge.
Here's the link I followed (: http://www.rcgroups.com/forums/showt...highlight=2805

Bare · Mar 12, 2009, 03:58 PM

Optimal and more efficient reside in the land of 'theory' On these V inexpensive with ..Nothing.. optimal about them, motors the advantages are v small and mostly invisible in use. Although to be fair a dlrk does give smoother throttle control IF used in a performance Heli by a skilled operator.

grumman5277 · Mar 15, 2009, 02:11 AM

I myself like the 2805 DLRK. I wind mine for higher KV due to their use.
I have found that 11t delta works very well on props smaller than 6in.
I have just started to get into testing kv loaded and unloaded.

The only test this far has been as follows.
17960 rpm Apc 4.1x4.1 - 6.97v (amps-watts still need measured)
I have guessed that this motor is near 3500kv. The loaded KV measured
shows 2576. that's a lose of 923 kv or minus 26.4 percent of estimated no load kv.

Being just shy of 18k loaded and determined kv of 3500 I need at least
24500 rpm no load rpm at the same voltage.

We have tested this motor on a wing spinning both a 5x5 and 4.7x4.7. The wing weights about 17oz .This setup isn't for speed but spirited performance and
duration. On a 2100 2 cell it gives about 9 min. WOT. plenty for combat use.

Ohio Combat RC Wing Guillotine 32" (7 min 10 sec)

The link provided is not a product plug and there is a misstatement made about the number of turns. It is an 11T motor and will give you an idea of what it will do.
Jeremy

timocharis · Mar 15, 2009, 06:21 PM

The 12T I did was Wye, and 23 awg. And _still_ I didn't care for the results with an 8040 prop:

12T 23awg Y Kv 1907 ( 22350/11.72 ) 1.31 i0
8040 GWS *D TP 730 2S:
8924 rpm @ 6.46v/9.87a 442 grams 15.6 oz 73.1% Efficient

Poor effiency. But I did try it 3S with a 5030 and got a reasonable result, which started me thinking maybe this motor is better at higher RPMs. So I got a stock 15T Delta and tested it:

Stock 15T Delta using GWS 5043 and a Hex 620 2S
Kv 22321/7.97 = 2800 Io: 2.08
15381 rpm @ 7.29v/10.58a 307 grams 10.8 oz 58.2% Efficient

Then rewound it with 23awg, same setup:
15T 23g spk Delta Kv = 2830 ( 20578/7.90 ) Io = 1.71
16763 rpm @ 7.18v/11.11a 365 grams 12.9 oz 72.4% Efficient

That's about as good as I was able to manage with this motor. The bearings tend to be bad, and especially pay attention to the clip -- most of the later motors had the shaft too tight for the clip placement, and the drag from the oversnug setup really messes with performance. You may have to loosen the set screws and back the shaft out a shade. In practice, this usually means backing the shaft out a lot, then easing it back to the proper position.

Dave

MiseryQ · Mar 15, 2009, 06:34 PM

My first rewind, IIRC, was 7t or 22awg.
I was going for 2s performance since the stock motor performed well on 2s with a 6x4.
The motor would up being so hot I had to drop the prop down to a 4.5x4.1, again IIRC.

My current favorite wind it 11t of 24awg which I use a Graupner 5,5x4,3.
8t seems much more reasonable with that KV.

grumman5277 · Mar 17, 2009, 12:02 AM

OK ,now I'm starting to see why people get so frustrated with this. I work for
SEW Eurodrive. When we test gear drives we use a rpm meter that rotates
off of the output shaft. It's hand held and tip spins when contact is made.

Here's what I did this morning.

4.1x4.1 APC (5gr weight)
17860 rpm 6.97v about 8A 55.7W (2562 kv)

Disk load (15gr weight)
21870 rpm 7.54V 2.9A 21.8W (2900 kv)

Carbon flat stock (2gr weight)
21999 rpm 7.61v 3A 22.8W (2890 kv)

Actual no load
7.77V 1.5A 11.6W (rpm not determined)

I believe (which may be incorrect) that the disk provided better information than the others even though the weight was 3 times that of the prop.
It was far more rigid than the carbon.

I think the Kv of 2900 is accurate based off of this information.
the difference between the disk and no load is almost half the wattages as well as half the amperage. The difference between the KV measurments
using the disk and carbon was less than 1%.

annihil8ted · Mar 18, 2009, 02:15 AM

hey guys, what's the static thrust you are getting out of you rewound motor?

MiseryQ · Mar 20, 2009, 08:40 PM

Quote:

Originally Posted by annihil8ted

hey guys, what's the static thrust you are getting out of you rewound motor?

As I posted earlier I got 17 ounces out of mine with a 6x4.
With a 5,5x4,3 it'll send the approx 10oz plane straight up.

Now to start the thread on the FC-2822 o:

MiseryQ · Mar 20, 2009, 08:47 PM

Just got my HobbyCity FC28-22 in and I'm ready to start winding.

I'm going to head out and measure each leg in my 1200rpm drill and figure the KV.
Not sure what I did with my MotoCalc install file, I thin kit's on my downed server ):

The goal is to turn a "small" prop fast.
I haven't seen anyone rewind this for a parkjet.

I have a busy night building a test plane rewinding AND I have a 1700kv Blue Wonder to test and rewind too o:

Here's the quick results:
All three legs measured .83 @ 1200rpm = 1446kv
A long way from the advertised 1200kv.
Good news is ea tooth had 14 turns. Winds were also much neater than the FC28-05s I got a couple years ago.

I'm getting the feeling this is not going to be a fast motor.
So far I'm thinking of 2 strands of 23 with 6turns. That might be within my skill level.

grumman5277 · Mar 21, 2009, 11:27 PM

consolidated

MiseryQ · Mar 21, 2009, 11:49 PM

I've been going over my old threads and my fc28-05s have been flying for about 2years and I've had no broblems with the bearings on 3s.

As for my fc28-22 I've been playing with it for the better part of the day.
Some of the winds are beyond my skill level.
I settled on 5 turns of 2x24awg.
Spun in the drill the kv came out to approx 2400.
I wanted about 2800 so I'm thinking of 4turns of 2x"23.5" if I can pull it off.
I'm hoping to turn the 5,5x4,3 Graupner faster than the 28-05.

Not sure if it's worth it over the '05

grumman5277 · Mar 22, 2009, 12:34 AM

I am kind of curious about the kv change by number of turns. Is there a general rule of thumb or doe's it vary to much.

Ron van Sommeren · Mar 22, 2009, 12:16 PM

Kv * #winds = constant
therefore
Kv_new = (winds_old/ winds_new) *Kv_old

e.g. double #winds to get half the Kv, halve #winds to get double Kv.

www.gobrushless.com/kb
-> basic overview 1-5

Vriendelijke groeten

Ron

MiseryQ · Mar 23, 2009, 12:48 AM

Thanks.

That confirms I need 4 turns to get into the 2800kv area I want.

2900kv = (15t/7.5)*1446kv.
Since I'll be going Wye the 7.5 turns will be 4.

Another question. On a high kv motor what does the larger stator do?
I'm assuming it will give more torque allowing the motor to "hold" rpm better than a smaller stator(?).
This motor as every one might know already is like a double stator fc28-05.

MiseryQ · Mar 29, 2009, 07:03 PM

Finally got some motivation since it's too windy to fly today.
Here's the results of the first speed rewind(?) of the FC28-22 I've seen (:

Four turns, two strands, of my "Mystery" wire (24BWG).
In the drill test all three legs measured .44vAC. 1200/.44=2724kv
Tested with a SuperSimple 40amp ESC, Even though it passed all the tests I didn't want to risk a Thunderbird.
No Load current measured 3.89amps with my automotive scope inline.
I'll try for current and voltage when I get to a clamp-on DC ammeter.

I'm light on props right now so I went straight to the APE6x4e..

Wait for it...

...

Thrust was 1lb 12oz on my scale! 28 Ounces of thrust!
Reversing the numbers with ThrustXL indicated approx 20k RPM.
Which works out to approx 75mph pitch speed.

Needless to say I'm thrilled. I need to order a 6x5.5 APE to try.

Mar 15, 2009, 06:34 PM	#20
MiseryQ Registered User Join Date: May 2006 Location: Norfolk, Va Posts: 1,777	I thought I responded to this this morning o: My first rewind, IIRC, was 7t or 22awg. I was going for 2s performance since the stock motor performed well on 2s with a 6x4. The motor would up being so hot I had to drop the prop down to a 4.5x4.1, again IIRC. My current favorite wind it 11t of 24awg which I use a Graupner 5,5x4,3. 8t seems much more reasonable with that KV.

Mar 17, 2009, 12:02 AM	#21
grumman5277 Registered User Join Date: Jan 2004 Location: Troy ,OH Posts: 1,439	OK ,now I'm starting to see why people get so frustrated with this. I work for SEW Eurodrive. When we test gear drives we use a rpm meter that rotates off of the output shaft. It's hand held and tip spins when contact is made. Here's what I did this morning. 4.1x4.1 APC (5gr weight) 17860 rpm 6.97v about 8A 55.7W (2562 kv) Disk load (15gr weight) 21870 rpm 7.54V 2.9A 21.8W (2900 kv) Carbon flat stock (2gr weight) 21999 rpm 7.61v 3A 22.8W (2890 kv) Actual no load 7.77V 1.5A 11.6W (rpm not determined) I believe (which may be incorrect) that the disk provided better information than the others even though the weight was 3 times that of the prop. It was far more rigid than the carbon. I think the Kv of 2900 is accurate based off of this information. the difference between the disk and no load is almost half the wattages as well as half the amperage. The difference between the KV measurments using the disk and carbon was less than 1%. Last edited by grumman5277; Mar 22, 2009 at 12:38 PM.

Mar 20, 2009, 08:47 PM	#24
MiseryQ Registered User Join Date: May 2006 Location: Norfolk, Va Posts: 1,777	Rewinding Emax CF2822 Just got my HobbyCity FC28-22 in and I'm ready to start winding. I'm going to head out and measure each leg in my 1200rpm drill and figure the KV. Not sure what I did with my MotoCalc install file, I thin kit's on my downed server ): The goal is to turn a "small" prop fast. I haven't seen anyone rewind this for a parkjet. I have a busy night building a test plane rewinding AND I have a 1700kv Blue Wonder to test and rewind too o: Here's the quick results: All three legs measured .83 @ 1200rpm = 1446kv A long way from the advertised 1200kv. Good news is ea tooth had 14 turns. Winds were also much neater than the FC28-05s I got a couple years ago. I'm getting the feeling this is not going to be a fast motor. So far I'm thinking of 2 strands of 23 with 6turns. That might be within my skill level. Last edited by MiseryQ; Mar 21, 2009 at 11:51 PM. Reason: oops: bad math.

Mar 21, 2009, 11:27 PM	#25
grumman5277 Registered User Join Date: Jan 2004 Location: Troy ,OH Posts: 1,439	consolidated Last edited by grumman5277; Mar 22, 2009 at 12:14 PM.

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Mar 12, 2009, 03:58 PM	#17
Bare Registered User Join Date: Nov 2000 Location: Canada Posts: 2,275	Optimal and more efficient reside in the land of 'theory' On these V inexpensive with ..Nothing.. optimal about them, motors the advantages are v small and mostly invisible in use. Although to be fair a dlrk does give smoother throttle control IF used in a performance Heli by a skilled operator.

Mar 15, 2009, 06:21 PM	#19
timocharis Dave North Join Date: Apr 2004 Location: San Jose, California Posts: 4,627	The 12T I did was Wye, and 23 awg. And _still_ I didn't care for the results with an 8040 prop: 12T 23awg Y Kv 1907 ( 22350/11.72 ) 1.31 i0 8040 GWS *D TP 730 2S: 8924 rpm @ 6.46v/9.87a 442 grams 15.6 oz 73.1% Efficient Poor effiency. But I did try it 3S with a 5030 and got a reasonable result, which started me thinking maybe this motor is better at higher RPMs. So I got a stock 15T Delta and tested it: Stock 15T Delta using GWS 5043 and a Hex 620 2S Kv 22321/7.97 = 2800 Io: 2.08 15381 rpm @ 7.29v/10.58a 307 grams 10.8 oz 58.2% Efficient Then rewound it with 23awg, same setup: 15T 23g spk Delta Kv = 2830 ( 20578/7.90 ) Io = 1.71 16763 rpm @ 7.18v/11.11a 365 grams 12.9 oz 72.4% Efficient That's about as good as I was able to manage with this motor. The bearings tend to be bad, and especially pay attention to the clip -- most of the later motors had the shaft too tight for the clip placement, and the drag from the oversnug setup really messes with performance. You may have to loosen the set screws and back the shaft out a shade. In practice, this usually means backing the shaft out a lot, then easing it back to the proper position. Dave

Mar 18, 2009, 02:15 AM	#22
annihil8ted Registered User Join Date: May 2008 Location: San Diego Posts: 424	hey guys, what's the static thrust you are getting out of you rewound motor?

Mar 21, 2009, 11:49 PM	#26
MiseryQ Registered User Join Date: May 2006 Location: Norfolk, Va Posts: 1,777	I've been going over my old threads and my fc28-05s have been flying for about 2years and I've had no broblems with the bearings on 3s. As for my fc28-22 I've been playing with it for the better part of the day. Some of the winds are beyond my skill level. I settled on 5 turns of 2x24awg. Spun in the drill the kv came out to approx 2400. I wanted about 2800 so I'm thinking of 4turns of 2x"23.5" if I can pull it off. I'm hoping to turn the 5,5x4,3 Graupner faster than the 28-05. Not sure if it's worth it over the '05

Mar 22, 2009, 12:34 AM	#27
grumman5277 Registered User Join Date: Jan 2004 Location: Troy ,OH Posts: 1,439	I am kind of curious about the kv change by number of turns. Is there a general rule of thumb or doe's it vary to much.

Mar 22, 2009, 12:16 PM	#28
Ron van Sommeren homo ludens modellisticus Join Date: Feb 2001 Location: near Nijmegen, Netherlands Posts: 8,674	Kv * #winds = constant therefore Kv_new = (winds_old/ winds_new) *Kv_old e.g. double #winds to get half the Kv, halve #winds to get double Kv. www.gobrushless.com/kb -> basic overview 1-5 Vriendelijke groeten Ron

Mar 23, 2009, 12:48 AM	#29
MiseryQ Registered User Join Date: May 2006 Location: Norfolk, Va Posts: 1,777	Thanks. That confirms I need 4 turns to get into the 2800kv area I want. 2900kv = (15t/7.5)*1446kv. Since I'll be going Wye the 7.5 turns will be 4. Another question. On a high kv motor what does the larger stator do? I'm assuming it will give more torque allowing the motor to "hold" rpm better than a smaller stator(?). This motor as every one might know already is like a double stator fc28-05.

Mar 29, 2009, 07:03 PM	#30
MiseryQ Registered User Join Date: May 2006 Location: Norfolk, Va Posts: 1,777	Finally got some motivation since it's too windy to fly today. Here's the results of the first speed rewind(?) of the FC28-22 I've seen (: Four turns, two strands, of my "Mystery" wire (24BWG). In the drill test all three legs measured .44vAC. 1200/.44=2724kv Tested with a SuperSimple 40amp ESC, Even though it passed all the tests I didn't want to risk a Thunderbird. No Load current measured 3.89amps with my automotive scope inline. I'll try for current and voltage when I get to a clamp-on DC ammeter. I'm light on props right now so I went straight to the APE6x4e.. Wait for it... ... Thrust was 1lb 12oz on my scale! 28 Ounces of thrust! Reversing the numbers with ThrustXL indicated approx 20k RPM. Which works out to approx 75mph pitch speed. Needless to say I'm thrilled. I need to order a 6x5.5 APE to try.