RCU Forums

RCU Forums (http://www.rcuniverse.com/forum/)
-   Brushed/Brushless motors, speed controls, gear drives (http://www.rcuniverse.com/forum/brushed-brushless-motors-speed-controls-gear-drives-123/)
-   -   Axi 4120/18 (http://www.rcuniverse.com/forum/brushed-brushless-motors-speed-controls-gear-drives-123/11237317-axi-4120-18-a.html)

squeaky penguin 09-22-2012 05:07 PM

Axi 4120/18
 
Hi all,

I got an Axi 4120/18 in a trade that is mounted on a .46 size Cap 232 that is suppose to weigh 5.5-6lbs. First off will this motor be a good fit for the plane? It appears to be a .60 size replacement, but I do live at 7,000'asl and wouldn't mind the extra power.

That in mind what battery ESC combo should I go with. I was thinking about a 5s would give me the right power, or do I need 6s? I guess that would then equate to a 4000-5000mah battery and about an 80amp ESC?

I've done a lot with electrics, but never anything this big. I just don't know where to start,

Thanks,

Brett

Dr Kiwi 09-23-2012 06:35 AM

RE: Axi 4120/18
 
http://www.modelmotors.cz/index.php?...e=18&line=GOLD


It seems to be rated very sensibly for around 3W/g = 960W max.. which gives you about 150W/lb....so on 6s that's about 40A....5s will let you use a slightly larger prop which might be advantageous given your altitude.... the Axi site indicates around 12x8 on 6s... 13" on 5s.

squeaky penguin 09-24-2012 04:38 PM

RE: Axi 4120/18
 
So the idea behind that is on 5s, you would have less rpm, allowing you to use a larger prop? Giving you similar current draw? I went ahead and orderd an Ice 75. So I'm good there, just trying to figure out the battery. Is 5000mah overkill for a 46 size electric? Looks like it will physically fit, of course a small battery will be less weight and could provide better performace.

Thanks

Dr Kiwi 09-24-2012 06:54 PM

RE: Axi 4120/18
 
Assuming equal C-rating, a larger mAh battery will cope with current draw better (less voltage drop under load)... and will give you better motor performance and longer flight time... conversely a lighter battery may give you better flight performance!

ray foley 10-03-2012 05:55 PM

RE: Axi 4120/18
 
hi there from Toledo

With my axi 412018 I typically use 4000 mah lipos, a 2s and a 3s connected in series and prop for about 750 watts. I works great. At 7000 asl i can't recommend a prop or pitch but a watt meter will help you get it right.

ciao -rjf

squeaky penguin 10-04-2012 07:25 AM

RE: Axi 4120/18
 
Already picked up some 5000mah 5s 20c batteries. I don't have the patience for charging two batteries for one flight. I've got a bunch of props to try and will run it though the watt meter before I madien it.

squeaky penguin 10-08-2012 04:00 PM

RE: Axi 4120/18
 
Had it out at the field yesterday, and ran it though the wattmeter. The biggest prop I had out there was a 15x6, and it only pulled 32 amps for about 600 watts. 30 amps with a 14x7. On the postive note it flew well even with that setup. Hovering at 3/4 throttle.

So, time to order some more props. I might be able to fit a 16" with some bigger wheels. So maybe a 15x12, or 16x10, or 16x8. I think 40-45 amps would be best.


All times are GMT -8. The time now is 12:58 AM.