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Old Dec 05, 2011, 05:16 PM
Facts, Logic, 3D
Tom K.'s Avatar
Florida
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Originally Posted by dead View Post
Thanks Tom. Just trying to keep my facts straight.
No problem.

--Tom K.
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Old Dec 05, 2011, 06:15 PM
3D Hack
JC Spohr's Avatar
United States, IL, Glen Carbon
Joined Jul 2010
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Originally Posted by leespaddock View Post
Most Excellent work.

I was surprised at the siginificant amp draw on the APC, but that is why multiple independent tests are a necessity and can be so revealing. I can't help but wonder how a electric Xoar 16x7 would perform in this power system test and if it would yield the best prop performance. However how these puppies fly is the really important the question.

I can't wait to see the flight test results as that is where the proof really is in the puddin. Thank you again Tom, Frank and Jim for all your effort and for seeing this interesting test thru completion. I only wish I lived a bit closer so I could play right along side you.

To complement your stellar results, attached is my compiled test comparisons results for the APC vs Xoar (14x7 / 15x8 / 16x8) show down. Slightly different data but the end result is the same Xoar is the top prop at least on the bench.
Lee
Hey Lee,

Which motor was used for these numbers?

Thanks again for your time and effort,

JC
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Old Dec 05, 2011, 06:47 PM
Not as Good as The Kid
Aeroplayin's Avatar
South Pasadena, FL
Joined Sep 2009
6,200 Posts
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Originally Posted by dead View Post
Thanks Tom. Just trying to keep my facts straight.
And to further clarify, we maintained the restriction on the motor throughout the entire testing sequence in order to keep things relative. Running the motor without restrictions with the Vox 16x6 is certainly an option now since some extrapolated results show the following:

We already know the Xoar, unrestricted, will reach 8490 RPMs and 83.63 Amps with 13.36 pounds of thrust. When I extrapolated all results, the Xoar 16x8 results fell right in line at 8500 RPMs. With this accuracy in mind, I’m predicting that the Vox 16x6 will top out, with no restrictions, at 74.00 Amps, 22.09 volts, and 12.72 pounds of thrust.

Since this is still above the Amp level I would consider for this power setup, my calculations would predict that the system would peak about 65 to 68 Amps at around 8900 RPMs, 22.44 volts, and 12.02 pounds. The unrestricted 12.02 pounds at 68 Amps at WOT may be better than the restricted 61.4 Amps and 11.13 pounds now registering on the Xoar 16x8, but the Vox 16x6 data does not perform better than the 16x8 Xoar at any current data ranges. Better performance just at WOT is not what we’re looking for. Additionally, comparing the two in the midrange settings, the Xoar was pulling almost 2 pounds more thrust at virtually the same RPMs at only 8 more Amps. Here is what I’m considering:

Xoar 16x8:
7.80 lbs at 6800 RPMs and 34A
11.13 lbs at 8100 RPMs and 61A
13.36 lbs at 8500 RPMs and 84A (in an earlier unrestricted test)

Vox 16x6:
5.94 lbs at 6900 RPMs and 26A
10.60 lbs at 8550 RPMs and 54A
12.72 lbs at 9050 RPMs and 74A (extrapolated from the current data)

Can the Vox 16x6 go another pound at 84 Amps? I’m not sure I care, since we’re already 10 Amps higher than I want to go with the setup.

The data evidence suggests that dialing the restrictions up to 80 Amps may be where the 16x6 Vox and the 16x8 Xoar reach some par on the thrust and Amps level, but this is certainly not the range were we are trying to find efficiency.
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Old Dec 05, 2011, 07:00 PM
They Call him Dead!
YellowJacketsRC's Avatar
United States, SC, Pawleys Island
Joined Jul 2003
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This sounds reasonable to me AP. Couple questions: If the esc is an 80 amp or better, why is it important to keep the amps below 70? I here you say it is due to a lose in efficiency above 70 amps... but how do you know this? Is there a spec on the motor ratings or is it based on your measurements?

Also, I am still hoping to find a system that operates this motor at full throttle and at good efficiency. If I can not find that balance with this motor with a 16" prop, then I may want to switch to the lower KV??

AP. don't you have this motor with one more turn on it? Have you tested that motor with the xoar 16 x 8?
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Old Dec 05, 2011, 07:15 PM
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USA, WA, Redmond
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Originally Posted by JC Spohr View Post
Hey Lee,

Which motor was used for these numbers?

Thanks again for your time and effort,

JC
System Constants
Motor Torque 4016T-500 (Turns 16/ KV 500)
Battery Turnigy nano-tech 3300mah 6S 45~90C Lipo
ESC Airboss 80 Elite (80A)

I updated the thread post to avoid confusion with others as well. Thanks for the heads up. Lee
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Old Dec 05, 2011, 07:33 PM
They Call him Dead!
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United States, SC, Pawleys Island
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Oh, Wait a minute, I thought Tom was flying the motrofly? So all this was tested with the Torque 500? Well that changes some things for me at least.

PS I know we are talking about the relative usefulness of different brands of props. However, I am also looking for the best prop/ motor combo for the 60" edge on a personal level. I plan On using the Motrofly motor with either 480 KV or 430 KV. I am trying to discern which motor would be better suited.

At this point the Xoar has it hands down for ME, but I still need to figure which KV motrofly and which pitch 16" Xoar to get.

I wonder what the difference in the 500 KV torque on a 16 x 8 and a 480 KV motrofly would be?
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Old Dec 05, 2011, 07:52 PM
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vienquach's Avatar
Chicago, IL
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Originally Posted by dead View Post
Oh, Wait a minute, I thought Tom was flying the motrofly? So all this was tested with the Torque 500? Well that changes some things for me at least.

PS I know we are talking about the relative usefulness of different brands of props. However, I am also looking for the best prop/ motor combo for the 60" edge on a personal level. I plan On using the Motrofly motor with either 480 KV or 430 KV. I am trying to discern which motor would be better suited.

At this point the Xoar has it hands down for ME, but I still need to figure which KV motrofly and which pitch 16" Xoar to get.

I wonder what the difference in the 500 KV torque on a 16 x 8 and a 480 KV motrofly would be?
Motrolfly 4315-480kv is sweet on Xoar 16x8 on 6s.

I ran my 4315-500kv with Xoar 16x8 on 6s without problem. Still very efficient.

--> My vote for the 4315-480 ...

430kv is too low.

Vien
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Old Dec 05, 2011, 07:57 PM
They Call him Dead!
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United States, SC, Pawleys Island
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Originally Posted by vienquach View Post
Motrolfly 4315-480kv is sweet on Xoar 16x8 on 6s.

I ran my 4315-500kv with Xoar 16x8 on 6s without problem. Still very efficient.

--> My vote for the 4315-480 ...

430kv is too low.

Vien
Thanks Vien
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Old Dec 05, 2011, 08:08 PM
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Chicago, IL
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Originally Posted by dead View Post
Thanks Vien
You will love it. 4315-480kv. About 40g lighter than the Torque 4016-500. Runs MUCH cooler on 6s (Xoar 15x8 and 16x8 prop)

Vien
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Old Dec 05, 2011, 08:13 PM
They Call him Dead!
YellowJacketsRC's Avatar
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How can it be 40 grams lighter AND run cooler?
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Old Dec 05, 2011, 08:17 PM
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Chicago, IL
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Originally Posted by dead View Post
How can it be 40 grams lighter AND run cooler?
_ Lighter due to the fiber glass/carbon X mount + no motor back end (open end) --> less metal, more high strength composite material.

_ Running cooler due to no motor back end + larger rotor diameter --> better heat transfer (convection).

Vien
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Old Dec 05, 2011, 08:23 PM
VOLTS > AMPS
stgdz's Avatar
United States, MN, Buffalo
Joined Jul 2011
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So with these results could we step up to a 13x6 or 7 Xoar on 4s with torque 2814-820?
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Old Dec 05, 2011, 08:24 PM
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vienquach's Avatar
Chicago, IL
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Originally Posted by stgdz View Post
So with these results could we step up to a 13x6 or 7 Xoar on 4s with torque 2814-820?
Maybe Xoar 13x6. Will get hot with the Xoar 13x7.

Vien
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Old Dec 05, 2011, 08:47 PM
KING of PING!
JDMCARPETS's Avatar
United States, PA, Lancaster
Joined Nov 2008
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I`m fly`n a xoar 13x5 with no problem.It really needs a 13x6 though
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Old Dec 05, 2011, 08:54 PM
It's gone...
_OZ_'s Avatar
Germany, NRW, Heinsberg
Joined Aug 2004
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Lets see a pic of your plane.
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