- about RC servo motors
Author's note; reading this white paper takes about 30 minutes. And as such, I’m leaving out a lot because any discussion of motor design and manufacturing technology that runs to less
than 300 pages of 6-point type automatically means we're leaving out a lot. In fact, entire careers can be dedicated to just this one subject!
If you haven't got 30-minutes, 1-minute of eyeballing the 1st three photos will get you to 90% understanding. Spend 5 minutes on all 33 photos gets you to 95% of the content from just the show-and-tell.
Another 1% comes from reading Part 1 while reading through Part II gets you to 97%. Go through Part III gets you to 98% understanding. Of course, as every experienced modeler knows . . . that last 2% means you only have 90% to go!
This information is dense because it's a difficult subject. Might couldn't adequately cover it in a semester-long college course! What
this 30-minute read 'will' give you is a solid technical understanding of the factors involved in making good decisions regarding what's best for you before investing in your next set of servos - even if you favor a competitor!
Part 1 - 5-min read - on manufacturing and the impact regarding motors costs
no surprise a motor inside your servos is what converts the electricity
from the battery into the force that powers your servo's control horn,
right? The real question is; what kind of motor is inside. Is it; DC,
coreless, or brushless? What follows holds true for any RC model
servo you buy - from anybody! Yes, regardless of whether it's from
Futaba, Savox, Hitec, or ProModeler it has one of these 3 types of
motors inside! The point being, this article is good reading no matter
what brand of servos you favor! Anyway, let's delve into the subject and
find out more!
- Sorting them from DC, to coreless, then brushless orders them by price.
Note; DC motors have been around the longest and cost the least. And
technically, DC-motor is a misnomer. DC is really more a type because it
includes coreless, so it's more accurate to say iron-core instead of DC
when referring to a 3-pole motors except DC is the accepted industry
nomenclature for ferrite-magnet iron-core motors. Is what it is so
please allow me the leeway to use DC-motors to represent the ubiquitous
iron-core motors available in the market, e.g. an ordinary 3-pole. And
while we're at it, brushless motors are actually AC motors, but more
regarding this, later!
DC-motor servos: What's most important to know about DC-motors
is that they are - by far - the easiest to make and thus, they're the cheapest.
Basically consisting of a bit of copper wire coiled around iron cores
for the electro-magnet, a can lined with a ferrite permanent magnet,
plus a commutator ring and brushes (to switch the fields). Along with a
way of holding the shaft at each end, you've got a DC motor that's very cheap and easy to make - and durable, too.
Coreless motors: these are significantly more expensive than
DC-motors because of how they're made and because of the materials
themselves. Their principal advantage over a DC-motor is they
accelerate/decelerate more quickly. This is because of how the windings
are made. They're formed on a mandrel (a more expensive process) and
rotate without an iron core. As a consequence of the ultralight rotating
mass they are very quick to accelerate/decelerate, which is 'the'
performance benefit. Commutation (field switching the windings) is
mechanical - similar to how it's done with iron-core motors. However,
making the delicate basket-like coils (winding) is a separate process
that's more expensive (by a lot). Add to it, the permanent magnet is
usually an exotic alloy of neodymium and while coreless motors make for
faster servos, they are also more expensive to make. Thus, are you
surprised you'll pay more for servos with coreless motors? Not if you
follow the manufacturing-Benjamins regarding this technology!
Brushless motors: are also called electronic motors and are
quite accurately described as pricey! This is because they're
manufactured similarly to a coreless motor with respect to the delicate
windings and the superior magnets. But beyond mandrel-formed coils and
more costly magnets than found in DC-motors, the relatively inexpensive
mechanical commutation is replaced by electronic commutation. This
brings benefits regarding longevity, and regardless of the direction you
approach it, time is always money! Bottom line? Brushless motors are
the most costly to make - their use is part of why you pay the most for
servos with brushless motors!
So which one's best? For this we need to know; best for who? Best for
you? Best for me? And best for what model? In short, when it comes to
best . . . the answer is, it depends!
Part II - a 10-min read about what makes DC, coreless, or brushless right for you
If you stopped reading after 5-minutes, you know the basics of what
goes into DC, coreless, and brushless motors, and a little bit about why
they cost what they cost. That's fine as far as that goes (meaning
you'll be fine if you read no further because you now grok it's entirely
due to differences in how they're made plus the material differences,
which contribute to their price vs. performance).
But there's more to know. A lot more and this requires we delve a
fair bit deeper when divining the details regarding the makeup of servo
motors. As before, we'll progress from DC, to coreless, and through to
brushless - but now in considerably more depth.
Once you've fully digested this section you'll be prepared to make
good decision regarding which type of motor is best for you as
determined by the technology and your circumstances, e.g. for whichever
type of model, how it's flown, and the available budget considerations.
Moreover, you'll never again be dependent on someone else to help you
because you'll probably be more informed than others about the
composition of servo-motors and know how to judge for yourself which is
best for you!
If you want cheapest, then get DC-motor servos - shop around because
as a class, servos with DC motors cost the least. Doesn't make them bad,
or junky. In fact, they're perfect for maybe 90% of modelers. This is
true whether you're a beginner, sport pilot, or seriously into flying
enormous giant scale models.
- It doesn't take big money for servos, even for very large scale models!
All these sorts of models; trainers, sport, and scale, are easily
controlled by DC-motor servos because the maneuvers they're called on to
perform are within the wheelhouse of durable DC-motor servos - of any
brand! Bottom line? DC-motor servos are nearly perfect for this type of
flying because their characteristics serve the majority of models. Note;
DC-motor servos - by their massive nature of construction - offer very
high levels of torque. Power is good!
Note: please allow a brief bit of advertising . . . ProModeler offer a 360oz-in DC-motor servo for less than 50 bucks. It's a great servo for a great price. Best thing about it is there are no shortcuts in manufacturing. For example, it's assembled
with 10 Allen head machine bolts, has all metal gears, bronze inserts
reinforcing the polymer components where steel gear shafts contend with
the greatest stresses, has a CNC-machined aircraft aluminum center case
with cooling fins for long motor life, and is assembled with 13 o-rings
for protecting the assemblies from foreign intrusion - and it even meets
This last is a big part of what makes the ProModeler different.
Basically, unlike the usual hobby-grade servos, it's built to meet
military standards (and subjected to these tests).
- Shock - Test Method 516.6
- Vibration - Test Method 514.6
- Rain - Test Method 514.5
- A fantastic value, this smooth and powerful servo is a great choice
Meeting these standards is principally due to the requirements of our
primary customer. However, because we're modelers just like you - and -
because we are as clumsy as the next guy and occasionally knock a servo
off a workbench, or have experienced crashes, plus we know a thing or
two about engine vibration (and how a summer afternoon pop-up rain
shower may drench a model before landing), it means these tests
are important for civilian users as well.
So if you're looking at another servo, one which offers similar
performance and pricing, but hasn't been tested to military standards,
then the question is; which would you rather have? The facts are servos
expressly designed to survive the abuse encountered in the non-civilian
world are an important ownership considerations for
most modelers. While ProModeler may be new to you, we offer this one
piece of advice; don't let habit or someone else decide what's best for
you . . . acting in your own best interests (and this is always a good rule
whether buying servos, or anything else).
Also note; the DS360DLHV is neither unusually expensive, nor cheap (middle of the pack is accurate price-wise). One thing is certain,
virtually every model known to man can be controlled with a this
360oz-in servo (regardless of brand, and this servo is built better
than most). The real point being; if you consider Chip Hyde won the
$50,000 tournament of Champion in Las Vegas with a 44-pound model
powered by a 200cc gasoline engine equipped with 195oz-in servos, it's
that, yes, you can spend $1200 on servos for a model, but darned few
of us can tell the difference versus opting to pony up just $50 each! End of self-serving message.
- With a bellowing roar, and roiling smoke, Chip Hyde wins the TOC
What if you want the fastest servos? Then it's coreless motor servos
for the win by a country mile! Once you
get into a given level of transit speed, sub-0.14sec/60°, then the
servos tend to use coreless motors. When the race isn't just one of high
torque, but includes an emphasis on speed also, then coreless motors
become the choice.
Speaking of speed in servos, speed is costly for the same reason
going fastest at Indy takes cubic money! As for why coreless motors cost
more, in part it's because of how their coils are made, which allows
coreless motors to be so fast when accelerating/decelerating. Added to
which, they use superior magnet technology (more costly). So with servos
as with anything else . . . more speed means more money!
- Typical coreless motor parts consisting of just a few parts
One thing is certain, pilots flying higher performance models need
both power 'and' speed because, for example, that Harrier maneuver
everybody oohs and aaahs over (especially when performed down low to the
deck) requires extreme speed to time the deployment of the control
surface quickly, precisely, 'and' the muscle to shove said extremely
large surface against a gale force wind (due to model's forward
acceleration). This takes ooomph and speed.
- Note the amount of elevator being deployed . . . astounding!
What if durability enters the equation? Electronic motors cost more
to make than mechanicals. Basically, you can't replace cheap little bits
of metal used for commutation with Hall effect sensors and a logic
circuit for the same price. Electronics simply cost more. Added to it,
now you need more electronics (the logic) to control the motor in the
ways that were once achieved by a metal ring and brushes. Is this worth the added
expense? Basically, yes, to many pilots (this is even considered indispensable to some).
Usually adding parts is bad, right? Thing is, electronic motors
(brushless motors in other words because Hall effect sensors and a
circuit board replace the mechanical commutation) offer a whole new
level of flexibility and control to offset this. Added to which,
brushless run cooler because the heat of arcing at the contacts is gone.
After all, the dust created as the metal of the brushes vaporizes has
to go somewhere, and the somewhere is coating the inside of the motor -
this is bad for many reasons, heat and fine particles of grit chief
When it comes to electronics, heat is never a good thing. Add grit
plus small parts and it equals a bad mix. Anyway, this means on average a
brushless motor simply lasts longer because they don't have brushes to
wear. 5X longer according to MTBF (specifications which can be taken as a
Painted with this brush; fast, longer lasting, and cooler running,
can the numbers for spending $100 vs. $80 be defended? For many guys the answer is yes. Especially if you're
an 'in for a penny, in for a pound' kind of guy, or the guy who
buys good stuff, tools, etc. secure in the knowledge the good stuff pays off in the long run
(e.g. well after you've forgotten the slight differences due to cost).
Put another way, price isn't everything.
But honestly, things are easy when you're a single issue buyer.
Cheaper faster, more durable - pick one! Things get more complicated when
you want cheapest 'and' most durable. Let's see the inside of these
types of motor to better understand why the costs factor as they do. For
this, let's destroy some. How? By cutting into a few motors with a
- The lathe makes short work of slicing a motor open to examine
Part III - the 15-min that gets into the nitty-gritty of motor construction
This is a DC-motor once again. This time you're seeing the guts of
how they're made. There's a ferrite permanent magnet within the can, and
by winding copper wire around an iron core to generate an
electromagnetic field, the windings may be sequentially energized to
spin the motor.
Sequentially turning the windings on, thus making an electromagnet to
react against the permanent magnet mounted within the can, is what
moves the rotor around and around. Commutation (switching the fields on
and off in a sequence) is what times the force that keeps the rotor
The iron core of a DC motor is the heaviest of any type of motor. The
rotor core is made of thin sections or laminations stacked together.
The thinner the laminations, the lower the iron loses and the more
powerful the motor.
Remember, DC-motors are basically the cheapest to build. In the world
of manufacturing, cost trumps pretty much everything. Especially with
price sensitive consumers. Fortunately, DC motors are reliable,
powerful, and fast enough for nearly any modeling need. This means savvy
buyers, even when you can afford brushless, may opt for DC, regardless.
Why? It's because it may make better sense for the application. E.g. a
scale model where the speed at which an aileron deploys is of little
consequence doesn't require a pricier motor within it's servo - fact.
Moreover, DC motors are durable too; witness the huge brushes ensuring a
long life. Often, the trick to savvy buying is matching the best made
servo mechanics along with an DC-motor to get the best deal. But beware
of internet experts who can spend your money like water!
These are the guts of a coreless motor. Note the wire has been wound
on a mandrel and once it's retracted it leave a wire basket that doesn't
weigh squat - meaning - it's super easy to both accelerate and
decelerate . . . this is how you make servos react quickly!
The key takeaway is that these windings without a core simply weigh
less. In fact, their mass amounts to a small fraction of what the
iron-core within a DC-motor masses, which means it's easier to start and
stop moving. Understanding coreless motors' advantage lies in the fact
their rotor doesn't weigh jack by comparison. This is why they can be
accelerated so much faster than an iron-core DC-motor. But winding these
coreless coils costs more. Also more costly is the type of magnet,
neodymium, which is part of the lanthanoide series. These are the
strongest permanent magnets available commercially and between this and
the mandrel formed windings, higher costs versus the ordinary iron-core
motors can't be avoided.
Bottom line? If speed matters, coreless beats DC every time because
the mass being started and stopped is 'greatly' reduced. Commutation is
still mechanical, e.g. with a commutator ring and brushes. This means
they wear out eventually. FYI, a good friend, a savvy guy who can really
make a dollar squeak tells me the wear issue is why he is happy to buy
used brushless motors, but less so coreless servos (because you can't
tell how much longer they'll last). Anyway, the brushes on coreless
motors are typically a lot smaller.
Coreless motors, due to their reduced mass, require less amperage to
start and stop. Thus, their brushes are more compact, e.g. smaller
brushes are used. Also, eyeball how they're bent into whiskers so as
they wear they maintain good contact with the commutator.
The third and final motor we'll cut open is a brushless or electronic
motor. The electronics for commutation versus mechanical bits are why
brushless motors are significantly more expensive to make than coreless
because otherwise, brushless motors also make use of permanent magnets
made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B
tetragonal crystalline structure that results in the incredible
development in recent years of super servos.
However, while the neodymium type magnets are shared in common with
coreless motors, once the relatively cheap to make mechanical parts that
make up the commutator ring and brushes are replaced by electronics,
costs take another leap higher. And it's a never ending cycle because,
for example, the motors are more complex in other kinds of ways, even in
terms of the number of wires going into them. For example, instead of
two wires connecting this motor, now there are eight!
Next, note brushless motors are also wound using a mandrel. The point
being, just like coreless motors, brushless motors are also used for
high performance servos because they'll accelerate/decelerate more
quickly than iron-core motors (referred to by some manufacturers as
ferrite-motors because of their inexpensive ferrite magnets).
Thus, due to their similarly reduced mass, it means a brushless motor
also generally eclipses a DC-motor in the speed department (but at a
higher cost than coreless because of the added electronics). In this
motor, the rotor is magnetic and and the coils are part of the stator -
in effect, it's been built inside out! The very low weight rotor plays a
role in high performance.
However, it's when we cut this motor apart that reveals something new
and different. There are 3 wires connecting to a round circuit board
section. Hmmm, what's with this?
So what replaces the brushes? The answer to that is simple; what
replaces brushes are Hall effect sensors. Their output voltage is
directly proportional to the magnetic field strength through it. These
are usually combined with threshold detection so that it acts as a
switch. This is the type of technology also employed within the motors
in pricey CNC machines.
Brushless motors are also known as electronic motors. The Hall
sensors measure magnetic fields so that the position of the rotor can be
computed and the driving voltages to the coils (windings) can be
adjusted. Thus, the Hall sensor literally measures the position of the
rotor based on magnetic fields . . . meaning all it has to know is which
sensor produces the highest reading!
Principal advantage of brushless motors vs. coreless motors is the
mere fact there are no brushes to wear out - or what's in a name - duh!
This means the motor lasts longer. Much longer. So much longer the folks
comfortable with basic math often judge they're worth spending extra
for. You? Dunno, your call.
The downside? There's added complexity for electronics, but they're
reliable in the grand scheme of things so the real downside is just one .
. . cost.
Compare and contrast:
Often, the guy who want the cheapest servos considers $20 a lot of
money (and we've heard guys brag about buying a bunch of used servos for
$5-10 each). Or brag about a deal they got for new oriental no-name
imports for just $12 each - brand new! This guy's not shopping quality,
just whether they work! For how long is an open question (and for guys
who don't fly a lot, it may not really matter).
ProModeler's least expensive servo sets you back $30, or 50% more
than cheapskates are generally willing to pay. Thoughtful consumers
weigh the benefits of all-metal gears, Allen-head bolts, o-rings,
cooling fins, and make an altogether different calculus in terms of
value compared to bottom-feeders. Only 'you' know where your desires for
quality fit within the value-spectrum . . . we're not here to judge,
just to inform.
- Honestly, dropping $1200 on servos is easy, the trick is in knowing when not to!
Also, and no offense to anybody because we've worked McWages in our
past and can squeeze a buck with the best, but the reason we're not
going to get into the 'cheapest' possible servo game is because we hold
our models too dearly. Thus, whether it's a $150 ARF or a $15,000
turbine doesn't matter. True if for no other reason than because we're
modelers exactly like you (meaning we're using these same servos in what
we fly or drive). The bottom line reason we don't do cheapo servos is
because we have the same skin as you do in the game when we advance the
throttle. Put another way, we eat our own dog food! This brings up the
questions, should you always opt for coreless or brushless if you're
flying 3D maneuvers? No, not really. Well know central-Florida pilot Doc
Austin shares these thoughts regarding the teeny-tiny DS100DLHV . . .
micro-servos equipped with DL-motors.
- There's such a thing as stupid spending - real pros only pay for what they can feel.
Who should use use brushless servos? Helicopter pilots are often
candidates because the servos are constantly moving, e.g. cyclic servos
are moving continuously as the rotor spins at speeds over 2000rpm -
non-stop! Tail rotor servos even more so because the gyro is constantly
fighting main rotor torque and thus stopping and starting the servo in
incessant and minute increments.
- For helicopters, wise pilots opt for coreless or brushless servos for their speed!
Who else should pony up for the pricey brushless servos? Principally
competitor who practice and generally fly or drive a lot - e.g. if you
attend fun flies and competition events. Ditto serious drivers who
participate in crawling events because brushless can be a no-brainer
when driving events that last 6 hours, or more! This is because for
these dedicated users, lifespan/brush-wear enters the picture. Brushless
servos can deliver decades of solid use, which lowers the cost/year
significantly below servos that are less expensive up front. Basically,
it comes down to math. If it lasts 5X longer, is it then worth an extra
20%? Everybody makes this decision differently. Don't loose sleep over
it but don't lose sight of the big picture either!
- Some machines fool you into thinking they're works of art - yet are driven and abused!
Anyway, for many folks, brushless servos are viewed as an investment
But spending money is personal. This is why we offer all three types of
servos, DC, coreless, and brushless (as do our competitors from Japan,
China, Europe, and the Philippines).
Us? We're a small shop in Florida hogging aluminum. Yes, we buy
Japanese motors and pots because they make the best and there are no
outfits in America who offer us these types of motors. Ditto
potentiometers where Nobel (Japan) are the best. Period. As for gears,
we opt to go to Taiwan. But our niche is that we try to do things better
instead of cheaper. Basically, we justify our spot at the feeding
trough through quality and attention to detail. Put another way, while
there's always room for one more, winning requires two things. First,
that you bring a fresh perspective (our quality versus cheaper argument)
and second, that people give a damn. Everybody doesn't. Fact. However,
for those of you who do, then we offer a compelling product. Also fact.
Anyway, what follows can be viewed as more propaganda because they
are examples of how ProModeler brings fresh perspective and adds value.
Viewed through jaundiced eyes it's just advertising so skip to the end
if you like. However, you should know this; If you see a servo with an
aluminum center section, there's not much doubt it's better than one
with all-plastic case, agreed? Thing is; all aluminum-center servos
aren't the same.
For example, when you eyeball a ProModeler servo - all of them, even
our least expensive - you're getting a servo where the center is
CNC-machined from a solid billet of 6061-T6 aircraft aluminum. El
cheapos are extruded through a die, have screws that pass trhrough the
aluminum and thread into plastic. Meanwhile, CNC means a more precise
fit of the motor to the case for better cooling, and the screw holes are
tapped for machine thread bolts. Just a detail? Sure, but details
Obviously one place the fit of the motor to the case matters is
because a tighter fit means better heat transfer (sheds heat better for
cooler running). However, another equally obvious place it matters is
due to our milling the cooling fins into the case. Extruded case
manufacturers are rarely concerned with engineering so 'if' they'll
extrude. 'then' they also usually won't bother to trouble themselves
will milling fins into the extrusions, capice? 'The lack of cooling fins is a screaming argument (without even going inside to look) that says this is a cheaply made servo!
Anyway, our center cases are made from a solid billet of 6061-T6
aircraft aluminum. We harp on the value of cooling fins because these
help the single hardest working component within the servo shed heat -
the motor - which is important to you if you're reading this article! So
with a ProModeler servo you benefit from our thinking, e.g. where
better is the focus vs. cheaper. Of course, you pay your money and make
your choice (but you really do get what you pay for).
Similarly, when you look at ProModeler polymer case components,
especially pockets, which accept steel gear shafts and handle heavy
loads, you'll see bronze inserts.
Why the bit of bronze for the insert? Simple, it's to reinforce these
high failure wear points. Granted, we may be rednecks living near the
swamps of the deep south but we know a thing or two about value. The
hard points make ProModeler servos more durable. Even if your money
grows on trees, surely you recognize this type of construction is
better, agreed? That ProModeler servos deliver more value begins to
become compelling versus servos when the goal is always cheaper.
Essentially, we don't make el cheapo servos because we don't want to put our reputation on the line!
Robust and durable are two other considerations, which can be
generalized as good. An excellent example is when we have competitors
using a plastic gear within an otherwise metal gear train. ProModeler
servos have all-metal gears.
Moreover, especially in our high performance coreless and brushless
products, they're made entirely of steel (like is found in a Ferrari on
the track because steel is unmatched by anything for gears). Guess what?
Even our least costly servo comes with durable and long lasting
all-metal gear trains - no plastic whatsoever!
MIL-STDS are nice to have. E.g. against shock and vibration it's
better than no certifications, right? This is why ProModeler servos, for
example, get a conformal coating (like electronics launched into space)
versus maybe a little square of foam padding! Anyway, we call the stuff
monkey snot because it's a smelly sticky mess to use but the results?
Worth it - totally!
What about trying to be proof against water intrusion? This effort is
better than a sharp stick in the eye, right? The point being ProModeler
servos are often equipped with 13 o-rings. This is normal so if your
choice is between two otherwise similar servos, surely the one with a
butt load of o-rings for sealing is better than the one with a few, or
none, right? We don't want to say no brainer again because after awhile
it gets to be overused - but for your money - we think ProModeler servos
are built better and many experienced modelers agree.
DC motor equipped servos are least expensive and good enough for 90%
of models. These are the technology as old as Ben Franklin - we kid you
not! And yet, despite being the most cost effective, sometimes it seems
only über savvy modelers know when to opt for them, e.g. when they're
the right choice instead of forking over big dough on servos.
- Into jets? Visit www.rosewoodrc.com - home of the EDF Jet Jam - where this guy's CD
The point we're trying to make is - only - buy fast servos if you
need speed. Otherwise, buy the best DC-motor servos you can find because
the mere fact the motors are inexpensive doesn't mean they're junk, or
poor quality. It is principally an issue of ease of manufacturing that
results in DC-motors costing less. So for scale models, even a lot of 3D
airplanes - but flown by sport pilots performing gentlemen aerobatics
(loops, rolls, stall turns, Immelmann turns, and the occasional Lomcovák
- versus some Jason-wannabees trying his hand at terminators, rifle
rolls, and parachute who needs the fastest and most powerful (read this
as expensive) servos on the market.
High performance models are the product for which coreless motor
servos exist. When you're racing an 1/8th scale buggy or truck and it's
important to hit the apex of a corner timed perfectly, there's no
substitute for speed. Similarly, when performing a low altitude Harrier
with rudder, aileron, and elevator servos in a synchronized dance, speed
and power are everything! Bottom line? When it comes to speed, coreless
and brushless motor servos are a popular answer.
- When only the the best will do, brushless is really the way to go!
What happens when longevity factors in along with speed? Then it's
brushless - clearly because the benefits outweigh the drawbacks. The
same holds true when 'the best' is part of the equation, e.g. where
brushless motors are again the choice. Note; knowing the motors are
pricey, we tend to go for the whole enchilada when making these servos,
e.g. an all-alloy case, steel gears, etc. because when the choice of
folks who are uncompromising in their pursuit of the best in every
regard want the best motor, they also want the best gears, and the best
case components. The best sums it up.
In the end, whether you're facing a budget, or the requirements of
the model are guided by a single factor, perhaps torque, the DC-motor
servo is probably all that's needed. Many national championships and
world events have been won with DC-motor servos. They are a great choice
for almost any model. The point is, most modelers can select a DC-motor
servo based on torque requirements and few modelers need to spend more
than the $50/servo for one of our 360oz-in DS360DLHV servos. For those
who do, it's because servo requirements include the speed parameter.
Competitors will fall into this category when performing difficult
maneuvers often making a coreless servo the best choice. As for those of
you for whom a brushless-motor servo is de rigueur, your needs
dictate servos for which basically, money is no object. You want the
best and are willing to pony up for it! Brushless motor servos are the
best money can buy.
If you've made it through this entire article then you're fully
equipped to decide what motor is best for you based on what you've
learned. We've offered this knowledge nearly for free (we showed you
some of our products). This, in hopes you opt for our servos next time -
but - also in service of all modelers, e.g. educating you regarding the
differences in all servos for the common good - useful info for any and
all brands. Anyway, we offer you a solid selections using all three
motor types without compromising quality.
- With the experience to pick and choose, brushless for rudder, DL-series for throttle and mixture.
Last thoughts; the motor you select for your servos is serious
business, choosing wisely now that you know a bit about the three types:
DC, coreless, and brushless is easier after learning about how they're
made, and why this affects performance, agreed? Ultimately, knowing what
goes into them, how this factors into cost and performance means you're
equipped to make better decisions - like a pro does - which is
important because as the old saw goes . . . knowledge is power!