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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Dennis Toth on March 06, 2009, 12:48:11 PM
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Guys,
With the thread by Robert on the problems with the rear firewall mount of the Out-runners it seem we have an option. Mike P has used the NEU in-runner motor in his "60" size P51 with great success. NEU makes several motors in the 19XX series and I was wondering what would be the choice for replacing the AXI 2826/10 (IC "46") and also a smaller one for say a "35 or 25" IC?
Best, Dennis
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Hi Dennis,
Okay, there are two Neus I would consider as swaps for a 2826/10.
For a baseline, the AXI weighs 6.4 oz, has a Kv of 920 (I think) a winding resistance of 0.04 Ohms and a no-load current of 1.7 A.
The 1905/2Y weighs the same 6.4 oz. has a Kv of 1025, a winding resistance of 0.025 Ohms and a no-load current of 0.9A. It will be more efficient at both light load and heavy load, thought the slightly higher Kv means that the resistive losses will be only 20% less than the AXI rather than the 40% based on just the relative resistance values. The 2Y can also possibly be used on 3S X 4000 mAh batteries with a 12-6 if you are flying a ship just at or under 50 oz. on 65 feet or less.
The 1905/2.5Y weighs the same 6.4 oz, has a Kv of 865, a resistance of 0.035 Ohms, and a no-load current of 0.7A. This is slightly more efficient than the AXI all around, and would probably allow the use of slightly smaller 4S batteries like a 3200 mAh if you can find them at less weight than the Pro-Lite 400's.
If and only if you are talking about a sub 50 ouncer, then the slightly smaller Neu 1706/1.5Y will produce a 3S 4000 mAh setup that will weigh under 16 oz.
The motor is 5.6 oz, with a Kv of 1225, Resistance of 0.022 Ohms, and no-load current of 1.5A. Expect to actually use 3000 ~ 3300 mAh to fly a schedule with a 50+ ouncer. Don't try this with a 60 ounce ship.
TMI?
Dean P.
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Dean,
This is not TMI. It's exactly what Dennis and I were talking about this morning. Thanks for the info.
Robert Compton
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Just one small note here - Axi 2826/10 has internal resistance 28mohm (measured) H^^
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Hi Igor and thanks!
Now that is interesting. Maybe it is even a first ... the actual item is better than the advertised specifications?
It almost looks like AXI's 40 milli-Ohm spec is for a single winding in a Delta configuration. That would work out to about 27 or 28 milli-Ohms across any two terminals.
Okay, that suggests that the 1905/2Y will only be a "better" choice efficiency-wise (the mechanics should still be better) and that the 2.5Y will be more appropriate for systems running at slightly lower current like light 4S ships and maybe 5S A123s.
later,.
Dean
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yes AXIs are deta a home page state single winding :-)
and I will tell you another secret ... AXI 2826/12 (760/42) which is good for 6sA123 has F2B brother which has one extra turn of the same wire on stator VD~
means lower KV and almost the same Ri as the "standard" brother (680/45) ... S?P
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Dean and Igor,
Thanks for the details it is exactly what is needed, we need more of this. It is sometimes difficult to judge from the published motor spec's if it will work for us. I think this gives us choices in motor style that will work for the planes in the range that many are flying. The In-runner should eliminate the bending moment problem should allow simpler cooling arrangements and motor mounting. The downside of these motors is cost but that is a personnel choice. The bearing support approach you presented is another way to solve the problem I hope it can be published and offered as an add-on kit.
Best, Dennis
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Hi Gang,
So Igor, you wouldn't have had something to do with the AXI factory creating this new "/11" variant, no?
That sounds like an excellent solution for 6S A123 and 5S LiPo. The added bearing mount will be a good idea. How is your bearing life at present?
Regards,
Dean
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/11 ??? :-) ... I do not think so ... I think it is really better to try 5s lipo and that new /13
regarding bearing - I did not find anything ill after whole seasone. I do not see any free play or different sound or something like that. I think I will rather mount the motor on front wall and use back fan to cool it insted of back bearing.
I still do not know why Keith R. has troubles with MVVS 4,6. It has very well made bearing and dynamically ballanced rotor. Bacause such a construction could be good solution for us.
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OK, What is the "35" sized in-runner going to be?? What Li-po?? (3S, 4S??)
John Cralley
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Hi John,
I don't believe that Neu make anything that I would describe as ideal for a 35 sized ship, yet. The closest they have is the 1902/37 motor with a Kv of 1350, a winding resistance of 48 milli-Ohms and a no-load current of 0.7 A. The Kv says it is best suited for a 3s application, but the winding resistance is a little bit high. It weighs 4.4 ounces.
It might work in a 4S-2500 mAh application, with a 4" to 5" pitch prop. Neu are expanding their motor line with the 1700 series, so i'd hang tight for a while.
take care,
Dean
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Hi John,
It might work in a 4S-2500 mAh application, with a 4" to 5" pitch prop. Neu are expanding their motor line with the 1700 series, so i'd hang tight for a while.
take care,
Dean
Dean,
Roger that "hang tight"!! LOL I'll await further developments.
Thanks,
John