EFLM108 E-Flight brushed motor w/4:1 gearbox

Greetings,
I just acquired an E-flight EFLM108 brushed motor with 4:1 planetary
gearbox that has a reccomendation of a 11x8 prop. It's speced for 7-8
cells of nicad. I'm wanting to run 3-cell lipoly (11.1v). I'm not
too concerned about the voltage but I can't find any spec that says
max current or input watts. I don't want to grossly overpower it but
I don't mind pushing it a little. I haven't used brushed type motors
or nicad/NIMH cell in a long time. All my brushless motors are
400-2000 watts and won't do for the plane I have in mind. Any
suggestions as to max current/watts this thing will stand without
smoking? I'll be sure it gets adequate air flow. Just don't want to
burn up the brushes.
Thanks,
Art
Reply to
Art Horne
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I'm not familar with the EFLM108 but I did ruin a Zagi 400X motor with a 3 cell LiPo. mk
Reply to
MJKolodziej
You can ruin anything if you load it too hard. You could ruin it with a 2 cell lipo too if you swing too big a prop. That's why I'm asking what is a good power range for a 480 can motor?
Reply to
Art Horne
I see this has been answered in RCgroups already..
Reply to
The Natural Philosopher
Art:
I too just bought a EFLM108 brush motor with gear box and folding prop I too was mistified by the lack of data about it on Horizon Hobby's we site. Usually, E-flite products have TONS of information about them bu for some reason this type of setup is the "red headed child".
The back of the package that it came in has some data but not as muc as you usually find on an E-flite data sheet. Anyway, on there it say that the operating voltabe should be 8.4 to 9.6 V. operating ams shoul be 5 to 6.5 amps. What it doesn't tell you (and the LHS owner said an I believe him) is that there aren't any LiPo batteries that come near t that voltage ( 7.4 VDC = 2S would be too low and 11.1 VDC = 3S would b too high).
"So what'st he answer?" I querried him. He didn't know the exac answer so we pulled just about every battery out of the case and off th wall to see what could/might/should work. The only ones we found wer NiMh batteries that are usually found in park fliers. His concern wa that there wasn't enough mAH built into one of these batteries to give long enough flight.
So, last night I couldn't sleep and decided to find out just what kin of power requirements it actually needed. I connected my MRC Supe Brain 969 to it, put it SB in power supply mode and bumped the voltag up and down to see what was happening. It ran well and cool on al setting from 7.4 VDC to 11.1 VDC and ran cool enough to hold my hand o it.
Having proved that it would run on about anything, I decided to hook i up to the NiMh 7.2 VDC 900 mAH battery that came with my Aerobir Challanger and put my E-flite power meter in series with it to monito voltage, wattage, and aperage. At startup it ran at about 8.4 VDC an 3+ amps WOT. After 15 (yes fifteen) minutes at WOT, it was stil running very cool at 6.5 VDC and close to 3 amps!
Assumption: if it'l run at those specs and not be hot to the touch, think that one could safely assume that it will run OK with one of thes batteris and might run a little better with two of them in parallel. BUT are two necessary on a glider where at the most it MIGHT b necessary to run the motor for five to eight minutes to get to altitud or back safely to our arms? Probably not but it couldn't hurt to pu two in the aircraft as they only weigh 4.5 oz each.
BTW, the card on the back has the limited data on it. It's on the ver bottom line with all the other motor combination data sets. I allread emailed Horizon Hobby about getting a better data set on their web sit (like 99% of all the rest of the E-flite equipment).
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DuceNova
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From your scan the motor appears to be a 4:1 geared long can 480
10x7 or 11x7 on 3s LIPO, draws 12A or so.
Reply to
The Natural Philosopher

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