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Old May 04, 2009, 12:37 AM
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What you wrote is obvious to me, Ron. Well, a master's degree in technical sciences does mean something after all I just did not expect that much difference in cogging of 14 and 16 magnet motors.

Well, now it looks that I have 2 motors to rewind. This Saturday a 1700 kv Blue Wonder stopped working on one of my planes in mid-flight. Luckily I was able to land the plane safely. The ESC works with another outrunner, so I guess that the problem is in motor. Maybe one phase broke off or there is a short somewhere? Well, I do not care. I will rewind the motor. this will improve my skill and I will end up with a somewhat more efficient motor in the end.
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Old May 08, 2009, 04:34 AM
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Yesterday rewound my "broken" 1700 kv Blue Wonder. The motor originally had 10 turns of wire (that looked slightly thinner than my 0.5 mm wire which is almost exactly 24 awg), ABC wind, WYE termination. So I guess the the motor was wound with 0.45 mm (25 awg) wire. I wound it with 11 turns of the above-mentioned 0.5 mm wire, ABC wind, WYE termination. But the funny part is that it still does not work (or, better to say, does not work correctly) . Just as before rewinding it either fails to start or spins too slowly. I thoroughly controlled the motor for shorts, so I am pretty sure that the winding was done correctly. So I am afraid that the problem is still in the ESC . Will probably try another ESC today. But anyway, rewinding should noticeably increase the efficiency as I managed to wind with more turns of thicker wire.

Today rewound the (originally 3000 kv) Blue'n'red Wonder. Original had 9 or 10 turns (can it be 9.5 turns?) of 4 strands of some thin wire (DLRK wind, Delta termination). I wound it with 12 turns of my 0.5 mm wire (DLRK wind, Delta termination). Have not tested it yet, hope I did not make any mistakes, it is my first DLRK wind . Well, hope to find out today. It should spin something like 6030 or 5040 prop. I expect to get about 15-16 A at WOT, though plan to fly most of the time at about 7A. I wonder what the efficiency will be at WOT and at the "normal" throttle. I definately need to build myself a thrust measuring stand...
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Old May 08, 2009, 04:49 AM
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Hi

The air gap looks good from what I can see in the picy but the flux ring looks thin , does the shaft rock ? Magnets are thick looking
Glad to hear its an improved stator , its a popular motor , just let me have my Motro though, its the tops
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Old May 08, 2009, 09:13 AM
homo ludens modellisticus
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near Nijmegen, Netherlands
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Alex, maybe you mixed up the beginnings and endings of a phase when hooking up in start/delta?

Vriendelijke groeten Ron
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Old May 08, 2009, 01:44 PM
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Thanks for suggestion, Ron, but (un)fortunately I have not mixed up anything. Just tried with another ESC, both rewound motors work flawlessly (well, I have not tested the DLRK one with prop yet). Old ESC either cannot deliver more then about 4.5 A current or "considers" WOT to be only about 40% throttle. In any case it is now a hardly usable garbage.
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Old May 08, 2009, 08:50 PM
Dave North
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Alex: the 3000Kv Blue-n-red wonder is supposed to be 10T quad strand 32swg (the gauge is, maybe, questionable). Your 12T when terminated delta will be excellent for a 5043 on 2S, and hot as a pistol 3S (but still probably okay if your ESC can handle it). It is in fact one of my favorite 2S winds for the 5043 and a Phoenix 10.

Too bad about the ESC, but that's the way it goes sometimes.


Dave
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Old May 08, 2009, 10:07 PM
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Noise

Its 12 tooth so it should be quiet , is it as quiet as a Motrol on 8x4's?

Im pleased with the motrol on 8x4 its not noisy at 7am in the mornings
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Old May 08, 2009, 10:50 PM
Dave North
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Not much diff in sound at all, NX. Just a little less power and efficiency (and nowhere near the cool looks!)


Dave
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Old May 09, 2009, 03:57 AM
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That's just what I need. The AUW of the plane on which I plan to use this motor will be about 450 grams (16 oz), so I want at least 17 oz of thrust at WOT. The more - the better. But I usually fly at a pretty small field so I use WOT very seldom. I guess I will find myself flying at 60-70% throttle most of the time. Maybe even 50%. I am planning to use a 20A ESC so I think it will be fine. The biggest problem will be to find a suitable prop. GWS ones that I have will simply disintegrate on 3S. So I am about to order a whole bunch of diffenent props from HobbyCity. They are cheap and will allow me to thoose the best prop for each motor.

Quote:
Originally Posted by timocharis
Alex: the 3000Kv Blue-n-red wonder is supposed to be 10T quad strand 32swg (the gauge is, maybe, questionable). Your 12T when terminated delta will be excellent for a 5043 on 2S, and hot as a pistol 3S (but still probably okay if your ESC can handle it). It is in fact one of my favorite 2S winds for the 5043 and a Phoenix 10.

Too bad about the ESC, but that's the way it goes sometimes.


Dave
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Old May 09, 2009, 08:49 AM
Usual suspect.
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Alex, for clarity, are you using 3s lipos on a 16oz plane to be flown slowly in a small'ish area?

If all of that is correct, you may want to reconsider the Delta termination, and may even want to rewind it with 14T Wye.
Using this information, we can quickly see that Dave got 17oz of thrust at 7a on 3s and the 8x4DD gws prop.
That wind/prop is much better suited to slow/small area flying than a high rpm motor spinning a small prop.
The high Kv wind on the little 5" prop will be less efficient, less responsive and give less run-time.

With nearly a 1:1 power to weight ratio, you'll like the "grunt" of the 8x4 vs the small 5" prop.

If you were flying something fast in a bigger sky you'd be right on track with the 9T motor.
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Old May 09, 2009, 02:17 PM
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So, how many watts per lb is a 1:1 power to weight ratio?

Just curious..
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Old May 09, 2009, 02:51 PM
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Alex.
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.
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Old May 09, 2009, 05:20 PM
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I am currently building an F4D Skyray jet, 24 inches wing span. Well, I could use a 8 inch prop, maybe even 9 inch. But the plane I am building now is intended to be a "trainer" for EDF version of same plane, so I decided to use a small prop. I originally wanted about 2000 kv motor, but since I already had that 0.5 mm wire... If I made it with WYE termination it would be about 1500 kv I guess. So here I am, with a 2500 kv motor instead. A good experiment. Should allow me to fly rather slowly (with lower efficiency though), but will also allow the plane to go really fast once I get to the bigger field. Well, I am afraid that I will never make myself go to that big field unless I get an airplane that requires more space to fly then my usual field provides . If I will not be satisfied, I will simply rewind the motor. After all, I am just learning. And for me this learning is half of the fun

P.S. My old ESC is really fried, I found the component that failed. The reason is simple: I fixed it to my current foamie with that side down where main heating components are (on bigger ESCs this side has a heat sink). This side is almost flat so it was easier to glue velcro there that on another side. Well, foam is a good thermal insulator you know... The ESC was in the air flow, but this air cooled the anyway "cold" side of the ESC. Do not repeat my mistake. Look how you mount your ESCs on your planes.
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Old May 09, 2009, 07:35 PM
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Alex.

For your plane, I do not think it is practical to use a propeller 8x4, let alone a 9x4.
at least for the blue wonder. is ok. for 3s and 12 tuens star.

I like for a model of that size and the type of plane and an APC 6x4 a 5x5 minimum.

I am sending you the table of bw. to choose the combination that best provide for your needs.

Manuel V.
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Old May 10, 2009, 04:22 AM
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Thanks Manuel. I already have that file. 6x4 was the prop I was aiming for (that is why I wanted about 2000 kv motor). But as I did not want to buy new wire I ended up with a 2500 kv motor. That table has only one motor with such wind that was tested on 3S and it was tested with 5x5 prop. As I ordered a whole bunch of different props I think I will probably test mine with 6x3 as well as some weird props like 4.75x4.75, 4.5x4.5 and 5.5x4. However I guess I will end up using 6x3.
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