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Old Jun 10, 2012, 01:55 AM
Just flitting about!!
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I say stay at 750kv and dial it back or modulate a bit in ke spins or blenders.

I have my dm3615-750 dialed back to 80% to save amps from the lipo on my slick and honestly 65A vs 79A I can't really feel it in flight.
Still unlimited vertical and tumbles that make you shake your head in disbelief.
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Old Jun 10, 2012, 01:56 AM
Grumpy old git.. Who me?
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Originally Posted by bryansifsof44 View Post
I was thinking of maybe a 700-710kv on my next 2820... 683 may be plenty but then again I'm used to the power of the 750
It's likely not possible to wind 700-710kv on the DM2820. The minimum step you can make is one turn per stator tooth and that is likely to be the difference between 750 and 683kv.
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Old Jun 10, 2012, 03:00 AM
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I may have done WOT KE spin a couple of times... Didn't like the way sounded, so I backed off and usually modulate throttle. Did you do WOT spins on a regular basis? If so maybe that is what led to your failure. I really believe with what I'm doing with my 750kv it will be structurally fine. Also when I do a high speed down line blender, I take throttle to 0 before I start the maneuver. Probably still putting some stress on the motor, but nothing like keeping throttle going. Just a thought.
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Old Jun 10, 2012, 03:05 AM
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yeah, I did WOT KE spins regularly and, yes, I'm sure that's what did the damage.
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Old Jun 10, 2012, 03:22 AM
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Quote:
Originally Posted by JetPlaneFlyer View Post
It's likely not possible to wind 700-710kv on the DM2820. The minimum step you can make is one turn per stator tooth and that is likely to be the difference between 750 and 683kv.
IDK, I am by no means a motor guru... But I had Ken hit right at 1130kv as requested with a 2810 for a smaller 3s 3D application. BTW very nice work by Ken. The 2810 usually comes in 732, 1056, and 1240 kv. Also, with bigger motors he hits the kv others request. Like I said I'm no pro, so I leave it up the zen master himself.
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Old Jun 10, 2012, 03:22 AM
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I am sure the issue of bigger props in high energy spins will be the root cause of alot of these failures....I am sure some motor designs will handle the bigger props better than others.....does anyone own a high speed camera?? I think a prop when spinning and facing gyroscopic loads...will bend and twist that shaft more than people think...something a high speed camera would capture....
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Old Jun 10, 2012, 03:27 AM
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United States, AK, Anchorage
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Quote:
Originally Posted by bigroger View Post
I say stay at 750kv and dial it back or modulate a bit in ke spins or blenders.

I have my dm3615-750 dialed back to 80% to save amps from the lipo on my slick and honestly 65A vs 79A I can't really feel it in flight.
Still unlimited vertical and tumbles that make you shake your head in disbelief.
What do you do to limit max?
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Old Jun 10, 2012, 03:30 AM
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Originally Posted by Space Bat View Post
I am sure the issue of bigger props in high energy spins will be the root cause of alot of these failures....I am sure some motor designs will handle the bigger props better than others.....does anyone own a high speed camera?? I think a prop when spinning and facing gyroscopic loads...will bend and twist that shaft more than people think...something a high speed camera would capture....
I spend to much on RC to afford one of those
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Old Jun 10, 2012, 03:33 AM
Team Hillbilly (UK)
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Originally Posted by bryansifsof44 View Post
I spend to much on RC to afford one of those
Was a stab in the dark - but someone may have one for work or can get hands on one
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Old Jun 10, 2012, 07:44 AM
Just flitting about!!
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Quote:
Originally Posted by bryansifsof44 View Post
What do you do to limit max?
Brian,
I've only run the 750 motor in this size with Turnigy batts and struggled to get much over 8500rpm on 14x7 props.

On my bigger 3615-750 I am using a 85A ZTW esc and after setting throttle end points as per instructions, I dial the throttle top end point down to 80% or something under 8500rpm at WOT.

I fly this way in the 51" slick and it doesn't suffer one little bit. In fact I think it gives my Gens 25C4s2600 lipos a bit more head space doing this as I'm a bit of a throttle hog when it comes to tumbles etc and will use wot if its available to accelerate the plane.
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Old Jun 10, 2012, 01:09 PM
They Call him Dead!
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United States, SC, Pawleys Island
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FYI

http://www.rcgroups.com/forums/showthread.php?t=1668988
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Old Jun 10, 2012, 02:33 PM
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Quote:
Originally Posted by JetPlaneFlyer View Post
It's likely not possible to wind 700-710kv on the DM2820. The minimum step you can make is one turn per stator tooth and that is likely to be the difference between 750 and 683kv.
I have a custom 700kv 2820
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Old Jun 10, 2012, 04:50 PM
Grumpy old git.. Who me?
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Originally Posted by GetSome! View Post
I have a custom 700kv 2820
Have you checked the actual kv?

There are other winding patterns that could achieve in-between kv's (e.g.star, half parallel) but nobody no matter how good they are can wind to precise kv unless that just happens to correspond with a particular winding pattern. The basic fact is you have a number of turns of wire which go in increments of one turn.
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Old Jun 10, 2012, 05:32 PM
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Ken wrote 700kv on it
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Old Jun 10, 2012, 11:00 PM
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Originally Posted by GetSome! View Post
Ken wrote 700kv on it
want to trade for my 683kv? :-)

I flew my Edge again today, with the 14x8, and that seems to fit my style better! I'm happy with the punch power and the top end speed, so this may be the middle ground I wanted. 53-54a continuous, about 8100rpm, and just over 800w.

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