| Title: | Welcome To The Radio Control Conference |
| Notice: | dir's in 11, who's who in 4, sales in 6, auctions 19 |
| Moderator: | VMSSG::FRIEDRICHS |
| Created: | Tue Jan 13 1987 |
| Last Modified: | Thu Jun 05 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 1706 |
| Total number of notes: | 27193 |
After seeing numerous ads in the R/C car magazines, I decided to
order an AstroFlight Turbo 05 cobalt motor for my Kyosho Optima
Mid.
I had been using various modified 540 motors from Twister and Cam.
These motors give amazing performance for a few runs; then, the
high temperatures and rotor currents begin to demagnetize the magnets
and chew up the commutator. For $20, you can turn the commutator
and zap the magnets, but it is a pain to say the least.
AstroFlight claims that their cobalt motor is extremely durable. The
commutator is about .50" dia versus .25" dia for the 540 type motors.
That would reduce the current density on the brushes tremendously,
extending commutator and brush life. The cobalt magnets can withstand
much higher temperatures than ceramics without permanent
demagnetization.
So, I ordered one from Doug's Hobbies for $49 (retail=$80) and three
days later it arrived. 15 minutes later it was mounted and wired
into my car.
This motor is obviously of very high quality. It is a three piece
affair, with machined aluminum endbells with a steel flux sleeve.
All the steel is silicon steel, which has higher saturation flux
density than simple cold rolled, hence a smaller thickness is needed
to close the magnetic circuit. The armature laminations are skewed,
which reduces torque ripple. Not a necessity in an R/C buggy with
huge reflected inertia, but a nice design practice anyway. The
motor is totally sealed, so there's no way for dirt to enter.
How does it work? Well, this motor makes lots of torque. I mean
lots. With the stock Optima Mid gearing (20 tooth pinion and 76
tooth main gear) and soft rubber tires, I could burn rubber at all
four wheels with the slightest throttle pressure. In fact, the
car was almost uncontrollable. I installed a 25 tooth pinion (the
largest available) to reduce the torque at the wheels, which helped
some.
However, this motor can't touch a modified 540 for top speed, at
least not with the gearing I'm using. I've ordered some special
64 pitch gears to further increase the top speed, but with the 25
tooth pinion, I think it's about 60-75% as fast as a fresh Twister.
The run times are fairly long, maybe 25-30% longer than a hot 540,
which may be of greater importance in some applications. I'd say
this would be an ideal motor for an off-road race.
Ed.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 686.1 | Astro Turbo-05 | MAGIC1::BEAUDET | Beware...the Junk_Yard_Dog! | Wed Sep 07 1988 09:28 | 24 |
<Revised>
My local hobby shop (and several "pullers") have told me that this
is an ideal motor for monster trucks or truck pulls. When mated
to a low tooth - (8) - pinion, gobs of torque are produced. Until
this note, I hadn't heard about the apparent lack of top speed.
Research I've done looking for high-torque motors keep bringing
me to boat motors. And, although I haven't found a source, the
top of the line as far as the NRCTPA (National Radio Control Truck
Pulling Association) is concerned is something called the "Black
Magic" Modified Motor. This thing is suppose to be in all the winning
truck pulls.
Anyway, Astro apparently also makes a stronger version of the Turbo-05
for planes - something over $130.00! While I haven't seen the motor
except for pictures, it looks like it's the same physical size,
except the shaft may need shortening prior to pinion mounting.
It was good to hear a "road test" of the Astro Turbo-05.
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| 686.2 | LEDS::ACCIARDI | Heisenberg may have slept here | Wed Sep 07 1988 16:48 | 11 | |
Actually, I may have set some pretty high standards for an 'acceptable'
top speed. The Turbo 05 is OK, but I have clocked this Kyosho buggy at
speeds of close to 50 mph with a 540 motor. I don't know what exactly
my error budget was in measuring the distance/time; I just marked off
.10 miles with my auto odometer and made a few top speed runs with a
stopwatch. I may be off by +/- 10%. I hit my best speeds with a Cam
pro motor (540) and a 25 tooth pinion. This is an abnormally tall
pinion for normal use (I usually use a 17 tooth with the Cam motor).
Ed.
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| 686.3 | access to internals | 3D::COMINS | Tue Sep 13 1988 13:57 | 9 | |
Can the Turbo 05 be disassembled for cleaning? Can you adjust spring
tension on the brushes? From the pictures I've seen of it I can't
determine what access there is to the internals.
I have a Big Brute (rugged as hell) and I am considering the Turbo
05.
Todd
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| 686.4 | buy it | LEDS::COHEN | Tue Sep 13 1988 14:32 | 28 | |
> Can the Turbo 05 be disassembled for cleaning? Can you adjust spring
> tension on the brushes? From the pictures I've seen of it I can't
> determine what access there is to the internals.
>
> I have a Big Brute (rugged as hell) and I am considering the Turbo
> 05.
>
Yes, the motor housing comes apart into three sections, a front
bell (with armature bearing), a center flux ring (with magnets
glued to the inside), and a rear end bell (with armature bearing
and brush holders). The armature is easily removed. The entire
assembly is held together by two hex-head screws. The spring
tension can be adjusted by turning the cap screws that hold the
brushes in their holders (the things that look like frankenstien
neck bolts in the picture) either in or out, but I seriously doubt
that you will need to make any adjustments. All the Astro motors
are excellent, and in my opinion are built considerably better
than any other 05 motor. The end bells are turned from aluminum
bar stock, not pressed from a piece of sheet metal. The motor
has a large commutator and even larger brushes, for lower current
density (less loss due to resistance). The motor is wound with
2000 degree wire, and the wire is spot welded to the commutator,
not soldered, so heat is no worry. Cobalt magnets survive high
temperatures much better than ferrite, and much much better than
wet magnets. You really can't go wrong to buy this motor,
specially at the $49.99 price.
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