AXI 4120/14 w 3S or 10 Ni-xx? - RC Groups
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Nov 10, 2005, 07:53 AM
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Ken Myers's Avatar

AXI 4120/14 w 3S or 10 Ni-xx?


I'm looking for real test data for the AXI 4120/14 using either a 3S Li-Poly or 10 nickel-based cells. I don't need simulated data, but real motor runs. ESC settings for the tests would be very helpful as well. Please be specific about the prop(s) used. Include RPM, amps in, volts in

Thanks,
Ken Myers
Croswell, MI, USA
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Nov 13, 2005, 05:36 AM
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Ken Myers's Avatar
Okay, I realize this is 4-cell plus motor, but has no one ever really tried it on 3-cell Li-Po or 10-cell Ni-xx?
Nov 13, 2005, 10:39 AM
Baptised Heathen
batman's Avatar
To get the power from this motor on 3S or 10 cells you would have to prop it up to get enough amps. You will have to draw 50+ amps to give you the power and a larger prop. Doesn't make sense to push your batteries that hard and then ground clearance becomes an issue also.
Nov 13, 2005, 05:23 PM
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Ken Myers's Avatar
I do thank you for a reply batman, but it does not answer my question. Please, please, I am not trying to be rude of ungrateful, but I asked a specific question. I do appreciate your taking time to reply, but it really wasn't helpful.
I have a lot of data on this motor, and read most of the threads where it appears, I just would like to see some real world data when it is run with an APC 13x10E or the like on 3 cells or 10 Ni-xx. Any 13 or 14 inch diameter prop data will give me what I need.
Nov 13, 2005, 05:39 PM
High Roller designer
Impact's Avatar
P-calc says about 27 amps with a 13x10 and about 53 amps with a 18x10... Best thing to do is run these test yourself, other people's results may be quite different than what you get because of battery's, prop brand and altitude......Impact
Nov 13, 2005, 06:11 PM
Registered User
Hello Ken,

I think the question will put many off replying, for example, last season we were displaying a 4120/14 in a Crazy Impulse on 10 and 11 cells, and it is a hugely successful system on a 14x10 APC-E, with Watts in the 300s, but unfortunately I don't have the specific info that you seek.

I hope someone else will be more helpful.

BTW, I haven't forgotten you!

Best regards,

John
Nov 13, 2005, 10:18 PM
Registered User
Ken, have a look at this link. It might help you

http://www.bnhof.de/~BKoenig/d_bl_axi.pdf

Fred
Nov 14, 2005, 06:26 AM
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Ken Myers's Avatar
Quote:
...last season we were displaying a 4120/14 in a Crazy Impulse on 10 and 11 cells, and it is a hugely successful system on a 14x10 APC-E, with Watts in the 300s, but unfortunately I don't have the specific info that you seek.
Thanks John. This is a lot closer to the kind of information I'm seeking. I am trying to verify whether this motor will produce the power and efficiency I believe it will on a 3S pack. Yes, I do realize it is a 4+ cell motor.
Nov 14, 2005, 06:30 AM
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Ken Myers's Avatar
Quote:
Originally Posted by navkan
Ken, have a look at this link. It might help you

http://www.bnhof.de/~BKoenig/d_bl_axi.pdf

Fred
Thanks, I do have the Koenig calculated values. I also know about the Calc programs, and I do appreciate those who are trying to help with pointing me in the "right" direction.

If I had the motor, I would run it to find out the answer to the question that I'm asking.

Thanks to those who've responded.
Nov 17, 2005, 11:31 PM
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Ken Myers's Avatar
I've continued to try and find info on using 3 cells with this motor and ran across this, for those interested:

https://www.rcgroups.com/links/index.php?id=4651

Found this for 3S:
"12x8 3s 22 amps (this is not enough power for this plane)
14x10 3s 40 amps"

This helped me a lot! Using Drive Calculator I'd come up with the following values if a Kokam 3200 20C 3S1P pack was used:
APC 12x8E, 11.11v, 24.6 amps, 273.1 watts in, 6773 RPM, 51.3 mph, 224.6 watts out, 82.2% eff.
APC 14x10E, 10.69v, 42 amps, 448.5 watts in, 6083 RPM, 57.6 mph, 361.2 watts out, 80.6% eff.

I'm still looking for more real world data on using a 3S with this motor.
Nov 18, 2005, 07:49 AM
Time for me to Fly...
Mr. Wiz's Avatar
Ken,

A couple seasons ago I flew a ModelTech Magic with a 4120/14. I used 10 cells (Sanyo 2600) and a 14x10 APC. I can't give you any numbers because I don't recall them, but it worked well.

Wiz
Nov 18, 2005, 11:04 AM
Registered User
Ken Myers's Avatar
Thanks Wiz!

It looks to me like this is a decent .40 setup for a lower power .40 glow conversion using only a 3S pack, better than the AXI 2826/12 on 3S as advertised by HL. It weighs about 4 oz. more than the 2826/12, but HL is "suggesting" the use of an 1800mAh NiMH Rx battery with their setups. Using a UBEC brings the weight in about equal, and the 4120/14 puts more "weight" in the front, where it is needed on a lot of planes. It also can produce more power more efficiently than the 2826/12 on 3S packs.
Nov 18, 2005, 11:17 AM
Time for me to Fly...
Mr. Wiz's Avatar
I also used a UBEC and a Phoenix 60. As I recall, nothing in the system got very hot. Well, the Nimh batteries got fairly warm when I pushed it hard, but that was the norm back then.

Wiz
Nov 26, 2005, 09:28 AM
Registered User
Cosmic's Avatar
OK, it cost me a LiPo pack and an esc, but here are the 'real world' results:

AXI 4120/14, Hacker Master 77-0-Flight esc (30Deg advance, 8Hz), 3S2P Thunder Power 4200 (rated 63A cont, 84A burst).

14x7 APC 'E', 31.5A, 325W

15x8 APC 'E', 40A, 420W

No RPM figures I'm afraid as my workshop is flo' tube lit. Also limited on props, though could test 17x8 if needs arise. Motor is now mounted on front of Pilot Seduction Wildstyle and awaits flight testing, initially with the 14x7, then 15x8. Will be nice to see if it's any better than the geared 2820/10 that was in it.

Alan.
Nov 26, 2005, 09:53 AM
FLL
FLL
Registered User
FWIW, I'm using the same motor with a 4s PQ 3700 and 12x8 prop. Motocalc projected 500 watts and my actual full throttle static results were nearly identical. Run the simulations and trust the power predictions. They're more than close enough for goverment work.

Frank


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