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
"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
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).
DuceNova's Profile: http://www.rcgroups.com/forums/member.php?u 859
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