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Old Feb 26, 2004, 12:51 PM
luc
I plant balsa sticks too
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France
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16/15/2-3 and MF480

I want to remotorize my hawker, presently on hp 200-25-4 and 3S lipo. I want max 35A (static) on my 3S pack and am wondering wether a 16/15/2 mega will not be too hot.
I'd like hands on experience (i have motocalc) on MF480 and 10 cells with mega 2 and 3 turns
thx
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Last edited by luc; Feb 26, 2004 at 12:54 PM.
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Old Feb 26, 2004, 01:30 PM
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Ed Waldrep's Avatar
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From the data posted on the Zone I've been recording in an Excel file (occasionally), the 16/15/2 in the MF480 on 8 cells pulls 36-39 amps (two different readings from two different people). Since 3series lipo is about equal to 10 cells, you'd be in the low to mid 40s amp wise, so the 2 turn mega is too hot unless you use a lot of throttle management, which may be too much for some controllers at part throttle operation.

The 16/15/3 on 10 cells in MF480 pulls about 20 amps. 12 cells makes for 26 or so.

Recording this data from posts I've been starting to see that there's sort of a dead spot between the 2 and 3 turn Megas. The 3 turn's KV is 3000, and the KV of the 2 turn is 4600. That's a huge jump. If you want to use 3S lipo then you either have to much amp draw or not enough. 220watts or over 400, whcih is above the 35 amp limit for the 2 turn motor. What we need is a 2.5 turn motor. With the higher prices of the Megas lately (at least here in the US), these motors are less attractive for use with lipos, at least in the 3 series config. Some have uses the 5 turn Mega with something like 6 series lipo packs but then you run into haveing to have a seperate BEC or receiver battery in a small airplane.

If I were to run a MF480 on 3S I'd look at the Kontronic Fun 400-36 with a KV of 3600, that pulls somewhere in the mid to high 30s on 10 cells/3S lipo.
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Old Feb 26, 2004, 01:44 PM
luc
I plant balsa sticks too
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France
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interesting, that's what I feared: the dead spot. We would really need a mega with 3700 KV... I have checked on the 400/36 but it is quite heavier (120g) and much more expensive....
Thx for your input, valuable, anyway...
any other possibility (cheap BL)?
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Old Feb 26, 2004, 01:55 PM
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The new Himaxx motors might have something in the range you need but be sure to check on the shaft sizes...the smaller 2020 motors have 2mm shafts. The larger motors probably have 3.2mm shafts I would guess....
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Old Feb 26, 2004, 02:12 PM
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Fallon, NV
Joined Oct 2003
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Mega 16/15/2 Minifan 8 cells

Luc,
I run a Mega 16/15/2 with a Minifan in an EAM F-18 with 8-cell and 9-cell 1950 FAUP packs. The 8-cell pack will pull 35A max (static) right off the charger, but then goes below 35A rather quickly and seems to hold at around 33A. With the 9-cell pakc it initially pulls 36A and then goes down to 33A in about 10 sec. These are actual measured numbers using my craftsman clamp ammeter.

Big Ben
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Old Feb 26, 2004, 02:17 PM
luc
I plant balsa sticks too
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France
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interesting. 3S is equivalent to 9 cells, slightly more. it then might be ok...
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Old Feb 26, 2004, 02:37 PM
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San Bernardino, CA
Joined Aug 2003
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The Himaxx 2025 series has a 2mm shaft, same as the smaller 2015 series, but it has a longer can. I don't think they can take the watts he's looking to run, and I've "heard" the 2mm shafts are kinda soft when compares to standard 2.3mm shafts of other manufacturers.

I'm not sure if Dave Morris has anthing to add here as his Micro Bandit is in this range. He just smoked a quality motor so I considered him over qualified He might just be in the same boat as you until a company comes to fill this "gap" in our present day BL motor lineup.

Justin
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Old Feb 26, 2004, 05:38 PM
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I was just pointing out that the 2025 series shaftsize was a bit unusual....those motors are too small for the MF480 clearly. Hacker B40 series, Kontronic Fun 400-480, Mega 16/15 or maybe 25 series is what you need.
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Old Feb 26, 2004, 07:53 PM
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Calgary, Alberta, Canada
Joined Sep 2002
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Meteor has posted tests to the effect that the more you load a high kv motor, the lower the effective kv. Try a search - you can't miss it.

Anyway, I have tested - but not flown - a 3S2P iRate pack (1100 mah x 2) on my MF480 and 16/15/2. At 15C these little cells are maxed out at a little over 3V each , and are deliverying between 30 and 35 amps. Punishment for sure, but I don't intend to run the plane at WOT for more than a few seconds at a time.

Oh - and a P45, so (hopefully) I have some headroom for running part throttle much of the time.
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