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Old Oct 13, 2008, 02:10 PM
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GryphonRCU's Avatar
United States, CA, SF
Joined Mar 2008
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War Machine,

The Medusa 28-40-X series (small 480 size) are way superior to E-flight six series (400 sized).

The price difference is $4.

At low Amp settings you will not see a difference...but as AMPs get higher, the difference becomes bigger and bigger....keep pushing even higher and the six series will get burned out.


Compare the six series 2700KV to 28-40-2500 V2

For less of a lump sided test compare the six series 2700 to medusa 2200KV....LOL...(let's not even mention the higher voltage handling of this one)


Note: Lower resistance is better because generally speaking; motors will run cooler/more efficient and handle higher AMPs.


Gryphon
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Old Oct 13, 2008, 02:47 PM
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Dr Kiwi's Avatar
Chattanooga, Tennessee, United States
Joined May 2003
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Quote:
Originally Posted by War Machine
Good point.

In case anyone is interested Im using a Six Series 2700kv motor with a 2200mah 3S pack.
With a 6 X 5.5 APC prop Im drawing 42A (on the motors limit) at WOT.
Johannesburg is 5750 feet above sea level. A 6 X 4 prop draws the same current at sea level.
Im concerned that I will burn the motor out - can anyone tell me what the surface temperature limit of the motor will be ?
If it gets above 50-60C it is getting too hot.
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Old Oct 13, 2008, 03:49 PM
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Lostlad's Avatar
SoCal
Joined Feb 2008
279 Posts
Quote:
Originally Posted by War Machine
Good point.

In case anyone is interested Im using a Six Series 2700kv motor with a 2200mah 3S pack.
With a 6 X 5.5 APC prop Im drawing 42A (on the motors limit) at WOT.
Johannesburg is 5750 feet above sea level. A 6 X 4 prop draws the same current at sea level.
Im concerned that I will burn the motor out - can anyone tell me what the surface temperature limit of the motor will be ?
That motor can take up to 104C or 220F. But as you may guess once a motor get's to 104C it's really hot to the touch.

"* Maximum Operating Temperature: 220 degrees Fahrenheit
* Adequate cooling is required for all motor operation at maximum current levels.
* Maximum Burst Current duration is 15 seconds. Adequate time between maximum burst intervals is required for proper cooling and to avoid overheating the motor.
* Maximum Burst Current rating is for 3D and limited motor run flights. Lack of proper throttle management may result in damage to the motor since excessive use of burst current may overheat the motor."

That is from the EFlite site.

Lostlad
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Old Oct 13, 2008, 06:28 PM
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GryphonRCU's Avatar
United States, CA, SF
Joined Mar 2008
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Lostlad,

I've read that too, 210-220 degree range. But that is generally for an inefficient motor like Himaxx or something when pushed hard so it can make big power with their relatively high resistance.
My best friend smoked 3 Himaxx 480 motors all 3 were different KVs.


I have to agree with Dr Kiwi regarding the temp range up to 140 degrees....o.k. even 150 if you are pushing HARD.
But we better not aim for those higher 200 degree temps if we want the motor to have a decent life span.
At those higher temps a lot of the energy being put in gets wasted.
I'm not one after max efficiency and really do want max power...but there are reasonable limits.

Some people can see the motors in their planes run very hot and claim that it has high efficiency. I'm happy that there is not too many of those folks.
Loosely put: itís the inefficiency that is generating the heat....that is power inputted to the motor that did not go out to the prop....that is reduced flight duration, a pack that runs hotter and lasts fewer charges, etc....

Gryphon
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Old Oct 13, 2008, 09:14 PM
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gwong's Avatar
Vancouver, B.C., Canada
Joined Sep 2003
935 Posts
This is probably old hat to you Funjet veterans but I upgrade from running 3S 2100mah packs to 4S 2100 Zippy packs from Hobbycity. Here is my setup and static test.

Mega 16/15/4
CC35
CC BEC
APC 6x4e
4S 2100mah Zippy Lipos
2 Hitech HS65
Spektrum 6100e

Static test results at WOT, pulling 40Amps and 600Watts

Should be fun :-)

Cheers,

Gord.
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Old Oct 13, 2008, 10:30 PM
What smoke?
Lostlad's Avatar
SoCal
Joined Feb 2008
279 Posts
Quote:
Originally Posted by GryphonRCU
Lostlad,

I've read that too, 210-220 degree range. But that is generally for an inefficient motor like Himaxx or something when pushed hard so it can make big power with their relatively high resistance.
My best friend smoked 3 Himaxx 480 motors all 3 were different KVs.


I have to agree with Dr Kiwi regarding the temp range up to 140 degrees....o.k. even 150 if you are pushing HARD.
But we better not aim for those higher 200 degree temps if we want the motor to have a decent life span.
At those higher temps a lot of the energy being put in gets wasted.
I'm not one after max efficiency and really do want max power...but there are reasonable limits.

Some people can see the motors in their planes run very hot and claim that it has high efficiency. I'm happy that there is not too many of those folks.
Loosely put: itís the inefficiency that is generating the heat....that is power inputted to the motor that did not go out to the prop....that is reduced flight duration, a pack that runs hotter and lasts fewer charges, etc....

Gryphon
Maximum Operating Temperature: 220 degrees Fahrenheit - Key word "Maximum" I almost never run my motor that hot but it has come down near that at times when I've pushed it the whole flight.

I know nothing about the inefficient motor like Himaxx so I can't say anything about them but this is from the E-Flite site about their motor and not about the Himaxx, so the statment stands about what there 2700kv motor can take. But I make no clames has to how long it can go at those temps.

Most of the time mine is just fine at around 37C even with pushing it for a min or two on high speed passes. I do fly around with a 2200mah 3cell and get around 9mins flight time but when I place a 3300 4cell it does get hotter as I run much faster and push it most of the flight.

Lostlad
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Old Oct 14, 2008, 02:39 AM
Registered User
Joined Oct 2008
490 Posts
Ive recently aquired a I/R temp. gauge. I plan on testing temps of motor and battery after 30 sec of WOT.
Testing to check effectiveness of :
1.) enlarged motor vent - vent will be taped up for comparison.
2.) heat sink.
3.) aluminium motor mount (T-shape)

If anyone has any suggestions I'd like to hear them - is 30 sec WOT enough ?
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Old Oct 14, 2008, 09:46 AM
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Zimm98's Avatar
USA, SD, Rapid City
Joined Jan 2008
683 Posts
I would try these tests in the air. I dont see the motorvents doing much with out air flow.
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Old Oct 14, 2008, 09:59 AM
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Joined Oct 2008
490 Posts
Unfortunately I don't have any in-flight logging equipment to do it with - Im going to have to land and take readings.
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Old Oct 15, 2008, 11:19 PM
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USA, CA, Santa Clarita
Joined Feb 2008
3,575 Posts
Ya know I have flown a few aileron planes in my day but nothing like this thing. I swear this plane is almost impossible to fly right. I give it full throttle & it torque rolls in that direction, then just gliding around it rolls the other way. I trim it out, then I'm back to the torque roll when I've got any throttle. I crash this thing every day, thankfully not bad, but today was the worst. I'm about to give up on funjets!
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Old Oct 15, 2008, 11:37 PM
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Vantasstic's Avatar
Las Vegas, NV
Joined Sep 2003
18,468 Posts
What size prop are you using EyeFlyPlanes? The larger the diameter the more torque you'll contend with I fly mine with a 5.5x4 APC (cut down from a 6x4) and I do have a little torque tendencies with different throttle settings, but not enough to be problematic.
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Old Oct 15, 2008, 11:56 PM
To drive or to fly......BOTH!!
FresnoJay's Avatar
USA, CA, Clovis
Joined Apr 2007
6,202 Posts
I have played with many props and the worst was with the 6" props. But again it was nothing that couldn't be compinsated for. For a good range of performance and minimal torque issues I recommend the 5" prop sizes. The 4" range is a little on the small size unless you run huge power.

Jason
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Old Oct 16, 2008, 12:29 AM
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EyeFlyPlanes's Avatar
USA, CA, Santa Clarita
Joined Feb 2008
3,575 Posts
Currently I'm running a 5.1x 4.5 apc e prop. I perfer more thrust because without it i'll have to throw it with all my might at full throttle and it drops like a tank. Thats really been my experience with the 5x5 prop. I just can seem to find a happy medium.
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Old Oct 16, 2008, 12:53 AM
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gotboostedvr6's Avatar
USA, NJ, Mt Laurel
Joined Oct 2007
3,691 Posts
eyefly
try a 6 x 4 cut down to 5.4 x 4.. you will be impressed
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Old Oct 16, 2008, 05:44 AM
I buy, I fly, I buy....
Wingwrecker's Avatar
United States, OH, Toledo
Joined Feb 2008
1,969 Posts
My FJ was the straightest flying plane I've ever owned. Did you check your lateral balance?
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