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        Micro Brushless Motor Test Results

#1 Gordon Johnson Feb 04, 2005 10:05 PM

Micro Brushless Motor Test Results
3 Attachment(s)
The past several weeks or more I've been testing the almost available commercial micro BL motors. These are the Gary Jones MiniDisc BL sold by BSDmicroRC.com, which weighs 7.7g complete with wires and plugs and the integrated motor mount. The Mighty Midget family of outrunners by Uttam and his father, which weigh 3.5g, and 5.9g for an upcoming longer version of the motor. And, the RS-Motoren 11g LRK (14g for the prop saver version I tested.

I have not had time to put these up on my web site yet. But, here they are. The complete article will be in the March RCMF.


#2 watersharer Feb 04, 2005 11:24 PM


These are going to open up a whole new ballgame.

I have on my desk a beautiful Matchbox collectable P-51, 6" ws. Everytime I look at it I want it to fly. Within 2 years I bet it can.


#3 NitroCharged Feb 05, 2005 06:39 PM

You lucky guy, Gordon - oh the joy of being able to play with these before they are on the market :D

Uttam has really teased us for a while now on the release of his Mighty Midget. I can't wait! :):)

#4 66tbird Feb 05, 2005 07:53 PM

Thanks, I know I've had a spot open on my workbench for months now while waiting on the MiniDisk BL. Just have to the chin up and wait for any bugs to be worked out I guess.

#5 Gordon Johnson Feb 05, 2005 08:24 PM

Well, with these results you can begin planning planes to use these. I'll post more details in the next few days when I get a chance.


#6 WarpdSpazm Feb 05, 2005 09:50 PM

Sorry for being late to the party on this, but from reading around; none of these are market ready yet? Is there an ETA? These would solve my weight/thrust problem on my pitts.

#7 del Feb 05, 2005 10:26 PM

Fun for the future? Most likely.
Thrust to weight ratio? Looks good...
But efficiency?

Compared to other motors in Gordon's reports, no so good.
What's with that?

#8 Gordon Johnson Feb 06, 2005 02:30 PM


If it is efficiency you are after in motors this small then outrunners are probably not the answer. I don't know if this is due to outrunners this small having lower efficiencies, or that motors developed by individuals don't have the resources of, say, Mabuchi. Probably it is due to being more concerned with obtaining power than efficiency.

However, the theoretical max efficiency when the motor is running at max power rpm is 50%. When looking at this figure rather than the max efficiency figure these motors don't look too bad. It's different for duration planes. But, I told Bob Wilder micro outrunners were not the direction I would suggest going for duration planes. These motors are best for taking more amps or more volts than comparably sized micro brushed motors can. And, there is the alure of quiet no-gearbox flight.


#9 WarpdSpazm Feb 06, 2005 08:37 PM


As Im new to micro flight... well E-flight in general, I've never really taken eff. into consideration. I'm assuming by duration flying you mean contest level? At our gym, we only get 2-5 minute openings at a time to fly RC (got to give way for the rubber guys). Is it safe to say that these motors on an average battery (say the 145mah lipos) will last 4 or so minutes??

I'm not quite sure whats an acceptable flight time in the general E-world.


#10 Gordon Johnson Feb 06, 2005 09:40 PM

I was referring to the indoor RC duration competition category, which I know Del is interested in. Yes, no problem with obtaining the flight times you are talking about. The amp draw of the Micro Midget is not much different from many M20 setups. Look at the static tests on my site and compare those amp draws to the ones for the micro BL motors.


#11 Uttam1 Feb 06, 2005 10:01 PM

Depending on your plane setup, and weight, you'll definitely get more than
4mins! For example, for a single cell motor powering a plane with an AUW of
lets say 28gms, you'll probably be cruising at the 500ma range. For the 2
cell wind, lets say you have a plane that weighs 40gms, you'll probably be
doing most of the flying in the 500-600ma range, and using higher bursts
occasionally to get higher quicker, or to get out of trouble. IMHO, you
should be getting around 12-15mins with some throttle mgnt with the 145's,
more with the 170's.


#12 WarpdSpazm Feb 06, 2005 10:04 PM

That's wonderful Uttam... It means I can fly three rounds on 1 charge.... Now when you gonna start shipping those babies? :D

#13 Uttam1 Feb 06, 2005 10:10 PM

WarpdSpazm, you should be looking at about a month or so, they will be available thru major dealers:)


#14 NitroCharged Feb 07, 2005 02:00 AM

yippee!!! :D

#15 del Feb 07, 2005 02:50 PM

Thanks for the info Gordon,

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