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Old Feb 07, 2005, 09:04 PM
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Rogerdoger's Avatar
United States, CA, Clovis
Joined Apr 2002
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Micro Brushless Motor

Uttam1,

I am also interested in getting some of these! Nice going!

Can you name a Major Dealer? Or some of them? I'm on the west Coast and we seem to not have local dealers who even know what we are asking about.

Thanks,

Roger
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Old Feb 08, 2005, 12:43 AM
high-speed freak
opualuan's Avatar
San Jose, CA
Joined Sep 2001
3,863 Posts
one of my biggest gripes with the 3oz and under category is the brushed powerplants available... either go n20/m20 for 1-2.5oz, or wes for larger stuff... and they all require messing with the gear lash every time you nose it in (it happens to you too, admit it), and contending with that grinding sound... yeach.. i think this gives people a lot of new options to power planes that would be fiddy to set up otherwise. as long as performance is decent, I'd rather go for something quiet and more rugged.

what's the durability like with these motors, graham? what about pitch speed, are these intended for slow flight or are 2oz 40mph deltas an option?

Also, what servos would you recommend with the different motor sizes? falcons/wes are sort of large for the 3.5g motor, good for the 5.9-7g, but maybe a bit small for the 11-14g motor... any actuator brushless solutions on the horizon?

now if we only had some more prop options for the 3.5g motor...
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Old Feb 08, 2005, 05:16 AM
Micro Brushless crazy
Uttam1's Avatar
India, Bangalore
Joined Jul 2002
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Roger:

BSD micro RC and DWE will be amongst the larger dealers.

Opualuan:

Durability is just fine. I have dropped one of these ( dont ask ) from about 4' without causing and damage, and in a plane, it should handle most normal cases without any problem.

The falcon servos are pefect for the motors, what makes you think they arent? They are only 1.7gms each, and the entire electronics+Motor+Esc+battery will weigh between 15-20gms ( 2 servos, and 2S Kokam 145's/170's, or single cell 145-170 ). The rest of the weight depends on your creativity

What sort of prop options are you looking for? The single cell unit is good for the 4*2.5 and 5*3 props, the 2 cell motor is good for the 3*2 and 4*2.5 props, and the single cell delta version is good for the 3*2 and 4*2.5 props.

-Uttam
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Old Feb 08, 2005, 06:28 PM
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nolasco's Avatar
New York, NY
Joined Dec 2000
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Opualuan,

How about using the Astroflight Firefly motor with the 4:1 gearbox? It does weigh 14g with the gearbox though. But, it provides very good power, especially on 3 cells at 1A current (max).


Jun Nolasco
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Old Feb 08, 2005, 08:12 PM
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So, I have an old MiniDisk (or is it 'Disc'?) player that hasn't been used in years and is (not that I've read this forum) just begging to be -- "repurposed". If I rip the motor from that sucker and use the tech I find at GoBrushless.com , is it possible to wind up with something that works well? Do you think the NE50s stand a chance of fitting in the housing that's on the motor now? Any idea how much modding needs to be done to these little motors to turn them into something useful? Or am I just deluding myself, thinking that my minidisk/c player could turn into a useful powerplant?

[Edit: Rather than hijacking Gordon's excellent thread with my ramblings, I decided to make my own.


-j
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Old Feb 08, 2005, 08:17 PM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
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Jun,
The answer is you have to compare the total system weight. So, although amp draw with the micro BL is higher than a Firefly when a larger battery to go with that higher amp draw is factored in, the BL dominates in terms of thrust to weight. I anticipate that the same will hold true on three cells. And, the Firefly performs virtually identically to the DC5-2.4, except it is slighty heavier (I omitted the Firefly from the table for space reasons). If these are geared to take a larger prop there might be some differences. But, with a 5x3 size prop the BL wins.

Gordon
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Old Feb 09, 2005, 02:22 AM
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New York, NY
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Gordon,

Actually, I was (only) responding to Opualuan's complaint about messing with the gear lash everytime a plane is nosed in. With the firefly, you do not have to worry about such things (as long as you do not destroy the gearbox itself in a really bad nose in).

As for using brushless on the 3-4oz category, I am still somewhat undecided though. I am a bit disappointed with the Feigao 1208430S (10g) motor. I still seem to get better performance from a dual-N20 drive.

Is there a 14g or less brushless motor out there that will put out over 4oz of thrust at 1.5A using 3 cells? The RS-LRK 195.03 looks close. Unfortunately, it looks like the prop would be too small.

As for the Mighty Midget, how much current can it tolerate on 3 cells?

Jun Nolasco
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Old Feb 09, 2005, 07:37 AM
Micro Brushless crazy
Uttam1's Avatar
India, Bangalore
Joined Jul 2002
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Jun,

The Mighty Midget is optimized for 2 cell and one cell operation. 3 cells on the 2 cell version is too much for the current winding. Why would you want to run it on 3 cells?

-Uttam
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Old Feb 09, 2005, 08:07 AM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
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Jun,
The RS-LRK can swing a 7x4 prop. You think this is too small? In general I've not been impressed with the two motor systems I've tested, but maybe that's just me.

Gordon
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Old Feb 09, 2005, 03:21 PM
is it flying time?
Jerry Combs's Avatar
Wyandotte Oklahoma
Joined Oct 2004
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Gordon,

Why is the battery weight listed at 7.4 for all of the motors except the Mini Disk BL? I beleive that the battery weight would be the same?

Jerry Combs
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Old Feb 09, 2005, 09:22 PM
Micro Brushless crazy
Uttam1's Avatar
India, Bangalore
Joined Jul 2002
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Jerry:

I know you asked Gordon this, but it's probably because the recommended 2S 170mahr Worley cells accounts for 7.8gms ( 3.9 gms each cell ), compaired to to 2S Kokam 145's that weigh 7.4gms. Generally though, I think the Worley 170's can be used on the Mighty Midget too.

-Uttam
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Old Feb 09, 2005, 09:55 PM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,439 Posts
Jerry,
Uttam's right. But, for the full explantion of that table, including the fact that the battery weight is for the 170's for a motor that requires higher amp draw, you will have to wait for the March issue of RCMF. There are lots of other details and assumptions in this table that are laid out in the article. Also, I have to check my weights, I think I need to add 0.2g to the weight of the 170mAh pack.

Gordon
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Old Feb 09, 2005, 11:49 PM
is it flying time?
Jerry Combs's Avatar
Wyandotte Oklahoma
Joined Oct 2004
2,777 Posts
Thank you Uttam and Gordon, I was forgetting that the BL used the 170's instead of the 145's. Say Uttam, are you still building any FF models?

Jerry Combs
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Old Feb 09, 2005, 11:59 PM
Micro Brushless crazy
Uttam1's Avatar
India, Bangalore
Joined Jul 2002
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Hi Jerry,

Sure, I'm still building Free flight models, but it's really slow, generally due to lack of enough space for Free flight I still enjoy Free flight.

This is OT, so Gordon will probably get rid of it soon.

-Uttam
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Old Feb 10, 2005, 12:02 AM
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New York, NY
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Uttam,

I have a nice stash of 3-cell 250mah LiPolys. As such, I would like to use them.


*****


Gordon,

Same reason as above.

Also, I am looking for a lightweight outrunner or geared brushless motor that can handle a GWS 8x4.3 prop using 3 cells at 2A max. I am running out of my supply (and suppliers) of the Wattage B2 motors which I use on my dual motor drives. I thought the 10g Feigao could do better. By my tests so far show that it is worse. I also have to try out the GWS N20-sized motors though.


Jun Nolasco
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