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Old Mar 07, 2014, 06:47 PM
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Wallingford, Ct
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You are not going to twist anything on an Astro. New Creations RC might still have some Pasquito motor mounts left. Give Kirk a call. He is more of a phone person than an internet person and is very helpful and an expert on Astro's.
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Old Mar 08, 2014, 06:48 AM
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Commerce Township, MI
Joined Aug 2001
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Here is a link on mounting brushed motors in Keith Shaw's talk to the EMFSO.

http://www.theampeer.org/shaw/SHAW4.PDF

Scroll to the second page. Lots of information.
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Old Mar 08, 2014, 02:59 PM
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Quote:
Originally Posted by Dr Kiwi View Post
Not saying I know anything about these motors , but whoa, that is a hellishly high Io isn't it? I'm also surprised by the efficiency curve.. if you look at efficiency curves in DriveCalc most motors peak at perhaps 20% of max amps... this one is >50%.
Usually what I notice in Drive Calc is efficiency maxes at about 80% of the no-load rpm, which looks nominally what this motor is doing. The efficiency at this point is just below 80% (~75% I think). I guess the high Io is due to the iron core of the motor, I have no idea how thin those stampings were. There may be more drag due to the brushes or even the gearbox, so I'm not sure how Io was measured/calculated and if it includes that drag or not.

I think max power depends on a lot of design issues. This Astro uses Samarium-Cobalt magnets that can take a lot of heat compared to the current Neodymium magnets. And in addition, the armature, with the wiring is spinning here, and so the copper may be benefiting from some indirect cooling. In other words, these old motors could likely withstand more heat than out current ones.

These are just guesses of course.
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Old Mar 08, 2014, 03:10 PM
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Central Lake, Michigan
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ken would probably shake his head if I mentioned I've run Astro 25G past 700watts.
But then I won't ever mention it.
Now let's see if I can get that much out of my FAI 15G...
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Old Mar 09, 2014, 01:27 PM
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United States, CA, Garden Grove
Joined Oct 2000
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I think that these motors were intended for quick climb and shutdown for a certain FAI powered glider competition. Not sure how good they are with a 2-cell lipo pack to keep temperature/amp draw down. I am using an old Astro 25 brushed geared motor in my Sig 1/6 Scale Cub on two 3S 2200mah lipos in series. Speed control is old "dumb"Astro 211 with help from a Li-Saver and a UBEC. APC 11x5.5 prop works well. Mount is Pasquito tubular aluminum mount bought long ago from Kurt at New Creations RC.

Also have an FAI brushed 15 that I've never used, designed for powered glider competition as above. might be OK on 2 cells with large prop for slow flying scale models.
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Old Mar 09, 2014, 02:33 PM
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USA, NC, Southern Pines
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I may put this geared 05 into a 72" Buzzard Bombshell old timer on 2S with a 14x5 or something like that. Needs lots of cooling, so it will be in open air.
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Old Mar 10, 2014, 05:09 PM
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Central Lake, Michigan
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The motors are a lot tougher than advertised. Astro Bob is always conservative with his motor ratings. Like I mentioned before about running the 25G way past 700 watts in an LT-40. Didn't hurt the motor one bit. I don't remember how many round cells I used...either 12 or 16.
An 05 in the Bombshell sounds like a great combination. Those old FF planes makes great conversions anyway. I'd like to do a 100" Dallaire Sportster with the 25G and 4S.
There's something about those old timers, ..... graceful flyers.
cheers.
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Old Mar 10, 2014, 05:55 PM
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Jolly - the old timers are wonderful floaters and will thermal on a good day! I have a 108" Dallaire, a 84" Comet Interceptor, a Boehle Giant (16ft span), all with Hacker motors. The bigger planes run on 6S. A 84" Quaker awaits a new motor and the Buzzard may be the right size for the Astro. I see that I can get a 2S6000 pack for a modest cost. I like doing these electric conversions of old timers.
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Last edited by Louierc; Mar 11, 2014 at 09:45 PM.
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Old Mar 11, 2014, 09:02 PM
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Canada
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Quote:
Originally Posted by Alan Hahn View Post
This Astro uses Samarium-Cobalt magnets that can take a lot of heat compared to the current Neodymium magnets. And in addition, the armature, with the wiring is spinning here, and so the copper may be benefiting from some indirect cooling. In other words, these old motors could likely withstand more heat than out current ones.
.
Cobalt magnets are tested safe to 600 C !! (currie point) conservatively rated too. I've seen claims of 800 C
But that seems scary high.
Assuming that Astrobob used Decent wire with hi temp insulation /coatings.. Very likely.
(Unlike the congealed Duck Soup used as varnish on Chinese wire)
Venerable Astros would likely melt before they stopped being motors.
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Old Mar 12, 2014, 06:13 AM
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Nashville, NC, USA
Joined Mar 1999
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I overheated (operator error) an Astro 25 SF geared, and a magnet or two came loose. The motor got sizzling hot You could smell the cooked odor. The motor still worked after that.
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Old Mar 12, 2014, 11:39 AM
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Moab, Utah, USA
Joined Apr 2003
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Quote:
Originally Posted by Bare View Post
Cobalt magnets are tested safe to 600 C !! (currie point) conservatively rated too. I've seen claims of 800 C
But that seems scary high.
Assuming that Astrobob used Decent wire with hi temp insulation /coatings.. Very likely.
(Unlike the congealed Duck Soup used as varnish on Chinese wire)
Venerable Astros would likely melt before they stopped being motors.
That's all fine and well, but even if the motor can withstand the heat, why would you want to use half of your battery energy generating heat?

Larry
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Old Mar 12, 2014, 11:50 AM
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Haha, the answer I usually get is 'because we can ! '

Always happens when I ask - why put a bigger motor, bigger ESC and bigger LiPO in a great flying plane ?
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Old Mar 12, 2014, 09:02 PM
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Canada
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Fair enough.
But AstroBob produced 'quality product' :-)
Compare his products ...with the current cheap crap out of Shengzen
Twenty years on and it's still competitive :-)
Despite the perceived obsolete Brushed technology
Check out the efficiency charts on the venerable Astro Cobalts..
They don't give up much at all.
Competent engineering, components and Mfg care produced lasting result.
Old ...even brushed in the case of Astros..... Does Not mean substandard or inefficient.
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Old Mar 13, 2014, 06:50 AM
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Wallingford, Ct
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His brushless motors do the job also.
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