Introduction to Electric Power

AT THIS POINT this series will begin to split off into the specialty
areas of model aviation. Radio Control (RC), as noted in the past few
months, takes up the major portion of interest. However, equally
important to so many modelers are the non-RC aircraft, such as Free
Flight, Control Line, Hand-Launched Gliders, rubber-powered models,
and more! As the months go by, this series will “spin off” into all of
these fascinating areas.
From a primary power standpoint, the most popular for model
aviation today involves the use of glow-fueled engines. To a lesser
degree, but just as important, are the gasoline-fueled engines as
employed in the larger models (quarter scale and the like). The third
power category is electric, and this has become increasingly popular in
recent years because of the many technological improvements in
motors and batteries.
Guest-author experts will soon be writing about glow- and
gasoline-fueled models. Electric has been
my specialty for some years; it is the
only power source I use today. Read
on in the next few months as I
explain electric power and take you
through the process of assembling,
installing power in, and flying an
electric-powered model.
What is electric? Electric power uses the energy supplied from
batteries to operate motors without the need for “wet” fuels. At the
beginning of this series I pointed out that when you are referring to
fuel, the power plant is an “engine.” When you are referring to electric
power, it is a “motor.”
Why would someone, especially a beginner, want to try electric
power? The two primary advantages of electric power are that it is
clean and quiet. It’s clean in the sense that you will not end up with
fuel residue on your model after each flight. It’s also clean because
there is no fuel to accidentally spill on the ground and get into the
water table. There is a remote chance of that happening, but it is still a
big concern in certain areas of our country.
Introduction
toE ectric Power


The three basic components of model-aircraft electric power system: (L) Speed 400 6-
volt winding ferrite motor, (center) Jeti Models JES-110 ESC, (R) eight-cell 1100 mAh
NiMH battery pack. New Creations R/C has custom-preinstalled all necessary APP
connectors. No soldering is necessary. A plus for beginners! Inset: Speed 400 6-volt
winding direct-drive motor. Wires, APP connectors were preinstalled.
Direct-drive propeller is mounted on propeller adapter that
mounts on motor shaft. New Creations R/C supplies this adapter
already mounted to motor shaft. The propeller is a white plastic
Gunther 5 x 4.
■ Bob Aberle
Red dot on rear of motor
casing denotes positive (+)
terminal. Red APP connector
is placed on positive motor
lead wire; black APP
connector is on negative lead.
Both wires are connected to
“motor” lead wires on ESC.
56 MODEL AVIATION
Electric power is quiet, as in no noise!
Probably the loudest sound you will get from
an electric motor is the propeller or air noise,
and that isn’t much. Quiet operation means
that you have the ability to fly in urban areas
without disturbing the public. Electric power
is so quiet that you can fly at sunrise, in dead
air or calm wind conditions, without the fear
of waking up neighbors.
There are more subtle advantages
associated with electric power. Without a
piston and connecting rod pounding away,
there is little vibration. This makes it much
easier on the radio-system components, which
need little isolation or padding to survive.
Electric motors are basically turned on by
a switch or controller. You don’t have to
prime and flip a propeller, use a starter motor,
or light a glow plug to get your model in
flight. This easy starting feature is particularly
nice when flying in colder weather. You can
sit in your warm car while the battery
recharges, then venture outside for the flight.
There is never any waiting.
When you are finished, you just put the
aircraft in your vehicle; no cleaning is
necessary. With the absence of fuel, you don’t
have to be concerned about the finish applied
to your models. Anything will work!
After hearing these advantages, could
there be any disadvantages? Yes! When you
apply electricity from the battery to the motor,
it will start instantly. If you fail to realize this,
you might accidentally connect a battery, have
the motor start, and it might hit you or take off
across your shop, wrecking everything in its
path. Most modern speed controllers have
safety features to help with this that I will
discuss in a moment.
Is electric power better than glow-fuel
power? I’ve used both in the last 50 years (30
for electrics!). I think there will always be a
place in our hobby for fueled engines.
Modelers love the sound, and they like
fueling, starting, and adjusting an engine.
On the other hand, a beginner in modeling
has much to learn in a short time. Sometimes
the problems with starting and operating a
fueled engine can consume most of the
available time while attempting to learn to fly.
And if not adjusted properly, the engine may
stop in flight.
With electric power, the motor always
starts and will keep running as long as you
have a charge in the battery. Yes, a wire could
break or a fuse could blow, but that motor is
usually going to keep running in a reliable
fashion. As the charge wears down during a
flight, the electric-powered aircraft will fly
noticeably slower. This is your warning to set
up for a landing. For these reasons, electric
power is the perfect choice for the beginner in
our hobby.
There are many things you have to learn to
use electric power. Since this is a beginners’
series, my intention is to gradually bring you
up to speed. Battery charging is important.
Hooking up all of the necessary wiring could
prove a problem for some.
My first choice for an electric-powered
ARF (Almost Ready-to-Fly) model will not
require any soldering. Each power-system
component will be what we call “plug and
play”; that is, the radio and electric-powersystem
installations are totally handled with
preassembled connectors. An entire electricpower-
component package (which I will
describe) will be available from Kirk Massey
of New Creations R/C.
What does an electric power system consist
of? The basic components are the motor, the
propeller and any adapter that might be
required to attach the propeller to the motor
shaft, an Electronic Speed Control (ESC) to
control the motor throttling, the battery pack
to supply the energy, and the charger to
charge that battery.
For an electric-powered model you must
install the motor, ESC, and battery inside the
aircraft and integrate it into your onboard RC
system. The radio essentially operates the
ESC, which operates the motor’s speed in
flight.
Your biggest concern at the start with
electric power is understanding and correctly
charging the battery. A battery that is not fully
charged is much like a fueled model with only
a partial tank of fuel.
Motors: The electric motor itself is of
primary importance. There are different types,
such as simple ferrite magnet motors; the
more sophisticated cobalt (samarium cobalt)
magnet motors; and the highly efficient, longlasting,
expensive brushless motors.
After selecting the type of motor, your
next concern is to size it so that it is capable of
flying a model aircraft of a particular weight.
In this case the choice has been made for you.
July 2003 57
Right: Jeti Model 110 ESC with BEC circuit (explained in text).
Left pair of wires go to motor; right pair goes to battery pack.
Cable with servo-style connector plugs into throttle port on RC
receiver. On/off switch at end of remaining cable is mounted on
exterior of aircraft’s fuselage. Above: Close-up of Jeti Model JES
110 ESC. Note polarity symbols (+ and –) printed on ESC case.
Above is an eight-cell 1100 mAh NiMH battery pack with preinstalled APP connectors.
On the right is a close-up of the battery label.
Photos courtesy the author Graphic Design by Lydia Whitehead
Another consideration is running the motor
direct drive (with the propeller attached
directly to the motor shaft) or through a gearreduction
drive that can add an advantage to
the power output.
Since this is a beginners’ article I’ve
selected a basic ferrite motor known in the
generic sense as a Speed 400. These come in
three different windings designated by
voltage. This project will use the 6-volt
winding. The motor can be obtained from
many sources.
This size motor is capable of flying a
model with a total flying weight of roughly
10-18 ounces. It can accomplish this using a
direct-drive propeller, so for this first try we will not use a gear-drive
assembly. Be advised for the future that a gear drive will allow you to
fly heavier-weight models and/or it can extend the flying time of a
model flown on direct drive.
My choice of direct drive was to keep it simple and inexpensive. A
Speed 400 motor costs approximately $15. It is a sealed can. When
you eventually burn out the brushes, you throw out the motor and buy
another!
The motor will have two terminals, and they are polarized (positive
and negative). Most have a red dot or mark indicating the positive
terminal. For our beginner’s package, a wire has already been attached
to each terminal. The connectors applied to the wire ends are the
popular Anderson Power Pole (APP) variety. There are many popular
connectors available, but I felt that the APP were best for this
application. These connectors have already been attached for you.
Almost any brushed electric motor will generate some form of
electrical noise which could conceivably feed back into the RC system.
To supress this brush noise, one or more bypass capacitors are added.
Generally, one capacitor goes from each terminal to the case, which is
like a ground connection. In this case, the motor selected has the
capacitors installed inside the motor can, so nothing else is necessary.
When you start your motor the first time, the wind created by the
propeller should blow toward the rear of the model. If it blows
forward, it means that the motor polarity has been reversed and the
propeller is turning in the wrong direction. That shouldn’t happen in
this instance since the work has been done for you. Be advised for the
future that if the propwash blows forward, reverse or swap the motor
terminal connections.
The motor shaft protrudes from the front of the motor. Some directdrive
propellers are simply pressed onto the motor shaft. I’m not in
favor of that approach, so I specified the use of a propeller adapter. The
adapter is slipped onto the motor shaft. A collet-type device essentially
clamps to the motor shaft as you tighten the adapter. I found the
adapter already installed on my motor shaft; you might find the same.
Once the adapter is in place, put the propeller on, followed by a
propeller washer then the nut. Tighten the nut, and you are set. The
propeller of choice for this project is a Gunther 5 x 4 white plastic. You
will likely have to drill the center shaft hole somewhat to fit on the
58 MODEL AVIATION
The battery pack is attached to the charger.
Placard on PF-12. Press start button to initiate charge, at which
time red charge light will glow steady. When peak is reached,
battery is fully charged and will stop automatically, at which time
red light will flash.
Left: Global Hobby Distributors’ WattAge
PF-12 Park Flyer AC/DC Peak Charger. At
left is 115VAC power input cable. At right
is 12VDC power input cable. In front is
pair of output wires with preinstalled APP
connectors which attach to battery pack
when it is being charged. Below: PF-12 is
set at its maximum charge current of 2000
mA (2.0 amps) as noted by pointer. This
will fully charge eight-cell 1100 mAh NiMH
battery in roughly 30 minutes. You must
select battery type—NiMH in this case.
adapter shaft. Next month I’ll write about how
to install this motor on your aircraft.
The ESC is probably the heart of the electric
power system. The ESC in electric-powered
flight takes the place of the throttle (or engine)
servo used on a fueled model.
The ESC in this instance weighs roughly
3⁄4 ounce and has two pairs of wires: a servotype
cable and a cable with a switch on the
end, all exiting the case. Two wires, with APP
connectors already attached, will plug into the
motor wire connectors. Polarity is important,
so it is red to red and black to black.
Two more wires will have APP connectors
attached, and they will plug into the battery
pack. The third cable has a servo cable
connector on the end. That cable is plugged
into the throttle port (usually the number-three
position) on your RC receiver. The switch will
be mounted on the side of the fuselage and
must be manually turned on to activate the
entire electric power system.
There are all kinds and sizes of ESCs on
the hobby market. The one chosen for this
project is the Jeti 110. The ESC will be rated
for current; in this case it is 11 amps
July 2003 59
All electric-power-system components are plugged together as
they would be inside model’s fuselage. ESC cable with servo
connector is plugged into RC receiver. Add two more servos for
rudder and elevator control, and you have complete power and
control system for your model.
Cable from ESC plugs into throttle port on RC receiver. It doesn’t
look it, but connector is plugged into CH3 on this Hitec Electron
6 receiver.
Never charge a hot battery pack. Use a “cooling device” such as this, consisting of a 3-
inch-diameter PVC pipe approximately 12 inches long. Attach RadioShack 12-volt fan on
one end. Battery pack is inserted in other end so that air from fan passes over battery,
thereby cooling it. In this case the battery is being cooled while it is on charge (battery
plugged into charger).
A 12-volt RadioShack fan is simply epoxied in place at end of PVC tube with the help of
a few pieces of scrap wood. Fan draws little power from car battery.
Rear of PF-12 showing 115VAC and
12VDC power input cables. This charger
allows you to recharge battery packs
indoors or at flying field from 12-volt car
battery
July 2003 61
continuous operation. For our application we
need 8-9 amps, so there is a margin of safety.
If the rating wasn’t high enough, you could
overheat and possibly burn out the ESC. The
rating must also take into account the number
of cells in the battery pack. The Jeti 110 can
handle six to 10 cells. We will be using an
eight-cell battery.
Many small ESCs (such as the Jeti 110)
will contain what is called a “Battery
Eliminator Circuit” (BEC). It will permit the
main motor battery pack to also power the
onboard RC system (receiver and servos) on a
shared basis. This saves the weight of an extra
airborne battery pack. It is also a convenience
because this one battery is recharged for every
flight.
In actual practice, the BEC has a special
circuit that provides a regulated 5 volts to the
RC system via that cable that is plugged into
the receiver throttle port. When the battery
gets down near 5 volts the circuit cuts off the
motor, but it still provides the necessary
power to operate the RC system so that you
can safely land the model.
Most ESCs with this BEC feature (the Jeti
110 included) will allow you to briefly restart
the motor after the first shutdown. You do this
by moving the throttle stick on the transmitter
all the way to idle, then back up. That resets
the ESC and will allow a few more seconds of
power so that you can line up on the runway
for a safe landing.
Most modern ESCs (including the Jeti
110) employ “smart” circuitry via a
microchip, which can add considerably to the
safety of electric motor operation. Remember
what I wrote earlier: when the battery is
attached to the motor, it could start instantly.
If you have the throttle stick at full or partial
with the entire system plugged in, the motor
and propeller could start turning.
The microchip in the ESC will sense
anything other than a dead idle position and
prevent the motor from starting. To start the
motor you must physically move the
62 MODEL AVIATION
transmitter throttle stick down to idle then go
back up. The motor will then start, and its
speed will be proportional to the controlstick
position.
The Battery: This is also an important part of
the electric power system. Batteries come in
all types, sizes, weights, and capacities. The
choices are critical to the model’s
performance. For this project the choice of
battery has been made for you; it is a Nickel
Metal Hydride type (NiMH) consisting of
eight cells made up as a pack. Each cell has a
capacity rating of 1100 milliampere-hours
(mAh). The nature of these ratings will be
explained in later articles.
APP connectors have thoughtfully been
attached to the two wire cables. As in the case
of the motor connections, the polarity is
critical to the system’s correct operation. It is
always positive to positive and negative to
negative. If the color-code convention is
followed, it is usually the usual red to red and
black to black. However, not everyone uses
that color convention.
Do not mix up connections between the
motor and battery. The connectors going from
the ESC to the motor are generally connected
once at the time of initial installation and not
touched thereafter. Placing a piece of masking
tape on each connector can remind you not to
touch them until such a time as you transfer
the equipment to another aircraft.
Estimating that this direct-drive Speed 400
motor will have a current of 8-9 amps, this
particular battery pack should be capable of
providing six to seven minutes of electric
power at full throttle. In reality you will have
much more power than you need; therefore,
you will be able to throttle back during a
normal training flight.
Throttling back reduces the motor current,
and, as a result, increases the flight time. With
average throttling back it will be possible to
extend your flying times to 10 minutes or so.
Owning more than one battery pack will allow
you to fly on one while the other is on charge.
That will provide you with more flying time
and less waiting time.
Charging: The last item in the electric
power package is the essential battery
charger. There are many choices, simple
and complex, available at varied prices.
Kirk Massey’s favorite for a beginner is the
Global (WattAge brand) PF-12 Park Flyer
AC/DC peak-detect charger. The key words
are “peak detect”!
Some of the simplest battery chargers
come with just a rotary-crank type timer.
You rotate the timer switch to 15-20
minutes and wait for the timer to run down.
The trouble with this is that the charger
can’t sense the amount of charge already in
the battery. This can easily result in
overcharging, which can cause excessive
heat buildup in the battery. An overheated
battery can quickly be ruined.
A peak-detect charger is essentially an
automatic charger. All Nickel Cadmium
(Ni-Cd) and NiMH batteries have a
characteristic where the voltage applied
July 2003 63
during charging increases until the point of
full charge (full capacity) is reached, at
which point the voltage peaks then begins
to drop off. At the peak, or slightly
thereafter, the charge cuts off
automatically.
Since this is a sensing cutoff and not a
timed cutoff, only what is necessary to
reach full charge is put into the battery. If
your battery had residual charge in it, the
charge period would be reduced
accordingly.
The one thing you must do manually is
tell the charger the amount of charge
current required. For NiMH batteries it is
suggested that you apply a charge current
equal to two times the rated capacity of the
battery. We refer to this as “2C.”
In this case the battery is rated at 1100
mAh (which is the same as saying 1.1 amp
per hour). Mulitiply 2.0 by 1.1 amps,
which equals 2.2 amps. This particular
Global charger has a maximum charge
current of 2.0 amps, so you would set the
charger to that maximum current. At that
approximate 2C charge rate, a fully
depleted NiMH battery pack would take
roughly 30 minutes to reach full charge.
Each battery will vary according to the
number of cells, the type of the cells, and
the capacity rating. You will pick up on
this concept as you progress with electric
power. For this first choice I’ve selected a
charger that can’t overcharge the battery
pack because its maximum current of 2.0
amps is close to what this battery requires.
When you purchase this or any charger,
it is generally your responsibility to
prepare a cable that will allow the charger
to connect to your battery pack. Kirk
Massey has prepared a cable with APP
connectors to attach between the Global
charger and our battery pack. Note the
output connectors on the front of the
Global charger. Press down on each
connector, insert the wire, then release. Do
that for the positive (red) and negative
(black) connectors.
Later you might want to purchase a
more sophisticated charger that has a
higher current rating or can handle battery
packs with more cells. (The Global is
capable of handling four to 12 cells.)
There are several fully automatic
chargers on the market. When you attach a
battery to one for charging, it will sense all
of the necessary parameters and set the
charger accordingly. The concept involves a
computer sensing system and has a menu
that must be accessed for regular operation.
These chargers work well, but they are
more complicated to use than this basic
Global unit and they cost much more.
It is typically a good idea to remove the
battery pack from the model when charging.
Immediately after a flight the battery may
be quite warm—even hot. A basic rule is to
never charge a hot battery. You should cool
it off before attempting to recharge. Putting
a hot battery in your soda cooler isn’t the
right method. It will result in uneven
temperatures throughout the pack.
The better approach is to buy a
RadioShack 12-volt electric fan (part
number 273-243). You can mount it at one
end of a length of 3-inch-diameter PVC
(polyvinyl chloride) plumbing pipe. Power
the fan from your 12-volt car battery. Put
your hot battery pack at the other end of
the PVC tube. This will allow the air the
fan blades generate to pass over the battery
pack and cool it. Approximately five
minutes in this tube will reduce the
temperature to a safe level for charging.
This Global charger can be powered by
115VAC for indoor (shop) use or from 12
volts DC from your car battery. At the
field, most of us just raise our car hoods
and attach the charger input cables
(alligator clips) to the battery terminals.
The polarity is important. Make sure that
the red alligator clip goes to the car-battery
positive (+) terminal and the black goes to
the ground or negative (–) terminal. The
Global charger has a built-in timer circuit
that cuts off the charger after a 90-minute
period. If you left the charger unattended
and something went wrong, the charger
would safely cut off after 11⁄2 hours.
That’s the full electric power system.
Remember that this article has been
prepared as a starting point for a rank
beginner who is entering electric flight.
There is a shopping list in the
accompanying table that you can use to
purchase all of the necessary equipment.
You can purchase all of the items from
Kirk Massey at New Creations R/C, Box
497, Willis TX 77378; Tel.: (936) 856-
4630. (Kirk prefers telephone calls to Email
correspondence.)
You can buy the components on the list
from other sources; for simplicity’s sake I
specified one source and the exact
equipment necessary. The addition of the
connectors made this a custom order. If
you are lucky to live near experienced
electric modelers, by all means solicit their
help; it can save you a great deal of time.
However, the theme of this series is to get
you going on your own—with little or no
help!
Next month I will start with a basic
electric-powered ARF trainer: the
AeroCraft Pogo. It was specifically
selected to use the electric power
equipment I have described and the Hitec
Neon three-channel RC system, which I
discussed in part two of this series (in the
April 2003 Model Aviation, starting on
page 54).
I expect to take the Pogo from the kit
box to the flying field, which includes final
assembly of the model and installation of
the electric power and RC system. MA
Bob Aberle
Sources:
Balsa Products
122 Jansen Ave.
Iselin NJ 08830
(732) 634-6131
www.balsapr.com
Dymond Modelsports USA Ltd.
683 N. Main St.
Oshkosh WI 54901
(920) 203-1100
[email protected]
www.rc-dymond.com
Hobby Lobby International
5614 Franklin Pike Cir.
Brentwood TN 37027
(615) 373-1444
[email protected]
www.hobby-lobby.com
Maxx Products International
815 Oakwood Rd., Unit D
Lake Zurich IL 60047
(847) 438-2233
[email protected]
www.maxxprod.com
New Creations R/C
Box 496
Willis TX 77378
(936) 856-4630
[email protected]
www.newcreations-rc.com
Northeast Sailplane Products
948 Hercules Dr., Suite 12
Colchester VT 05446
(802) 655-7700
www.nesail.com
Radical R/C
7046 Harshmanville Rd.
Huber Heights OH 45424
(937) 237-7889
[email protected]
www.radicalrc.com
64 MODEL AVIATION
Quantity Item Number Description Prices as of
March 2003
1 GR3321PWA Speed 400 6-volt motor with APP connectors $15
1 MATPA104 2.3mm propeller adapter for Speed 400 motor $5.50
1 ZAG1400P Gunther 5 x 4 white plastic propeller with 5mm $2
hole (Order several propellers; expect breakage!)
1 HLJE110A Jeti 110 ESC with APP connectors installed $46.90
1 1288554A Eight-cell 1100 NiMH battery pack with APP $32.95
connectors
1 130108 Global PF-12 Park Flyer charger $49.95
1 NCAPCL PF-12 Anderson charge lead $3
Your First Electric Power System
Our Full-Size
Plans List
has hundreds
of models
to choose from.
See page 183
for details.

AT THIS POINT this series will begin to split off into the specialty
areas of model aviation. Radio Control (RC), as noted in the past few
months, takes up the major portion of interest. However, equally
important to so many modelers are the non-RC aircraft, such as Free
Flight, Control Line, Hand-Launched Gliders, rubber-powered models,
and more! As the months go by, this series will “spin off” into all of
these fascinating areas.
From a primary power standpoint, the most popular for model
aviation today involves the use of glow-fueled engines. To a lesser
degree, but just as important, are the gasoline-fueled engines as
employed in the larger models (quarter scale and the like). The third
power category is electric, and this has become increasingly popular in
recent years because of the many technological improvements in
motors and batteries.
Guest-author experts will soon be writing about glow- and
gasoline-fueled models. Electric has been
my specialty for some years; it is the
only power source I use today. Read
on in the next few months as I
explain electric power and take you
through the process of assembling,
installing power in, and flying an
electric-powered model.
What is electric? Electric power uses the energy supplied from
batteries to operate motors without the need for “wet” fuels. At the
beginning of this series I pointed out that when you are referring to
fuel, the power plant is an “engine.” When you are referring to electric
power, it is a “motor.”
Why would someone, especially a beginner, want to try electric
power? The two primary advantages of electric power are that it is
clean and quiet. It’s clean in the sense that you will not end up with
fuel residue on your model after each flight. It’s also clean because
there is no fuel to accidentally spill on the ground and get into the
water table. There is a remote chance of that happening, but it is still a
big concern in certain areas of our country.
Introduction
toE ectric Power


The three basic components of model-aircraft electric power system: (L) Speed 400 6-
volt winding ferrite motor, (center) Jeti Models JES-110 ESC, (R) eight-cell 1100 mAh
NiMH battery pack. New Creations R/C has custom-preinstalled all necessary APP
connectors. No soldering is necessary. A plus for beginners! Inset: Speed 400 6-volt
winding direct-drive motor. Wires, APP connectors were preinstalled.
Direct-drive propeller is mounted on propeller adapter that
mounts on motor shaft. New Creations R/C supplies this adapter
already mounted to motor shaft. The propeller is a white plastic
Gunther 5 x 4.
■ Bob Aberle
Red dot on rear of motor
casing denotes positive (+)
terminal. Red APP connector
is placed on positive motor
lead wire; black APP
connector is on negative lead.
Both wires are connected to
“motor” lead wires on ESC.
56 MODEL AVIATION
Electric power is quiet, as in no noise!
Probably the loudest sound you will get from
an electric motor is the propeller or air noise,
and that isn’t much. Quiet operation means
that you have the ability to fly in urban areas
without disturbing the public. Electric power
is so quiet that you can fly at sunrise, in dead
air or calm wind conditions, without the fear
of waking up neighbors.
There are more subtle advantages
associated with electric power. Without a
piston and connecting rod pounding away,
there is little vibration. This makes it much
easier on the radio-system components, which
need little isolation or padding to survive.
Electric motors are basically turned on by
a switch or controller. You don’t have to
prime and flip a propeller, use a starter motor,
or light a glow plug to get your model in
flight. This easy starting feature is particularly
nice when flying in colder weather. You can
sit in your warm car while the battery
recharges, then venture outside for the flight.
There is never any waiting.
When you are finished, you just put the
aircraft in your vehicle; no cleaning is
necessary. With the absence of fuel, you don’t
have to be concerned about the finish applied
to your models. Anything will work!
After hearing these advantages, could
there be any disadvantages? Yes! When you
apply electricity from the battery to the motor,
it will start instantly. If you fail to realize this,
you might accidentally connect a battery, have
the motor start, and it might hit you or take off
across your shop, wrecking everything in its
path. Most modern speed controllers have
safety features to help with this that I will
discuss in a moment.
Is electric power better than glow-fuel
power? I’ve used both in the last 50 years (30
for electrics!). I think there will always be a
place in our hobby for fueled engines.
Modelers love the sound, and they like
fueling, starting, and adjusting an engine.
On the other hand, a beginner in modeling
has much to learn in a short time. Sometimes
the problems with starting and operating a
fueled engine can consume most of the
available time while attempting to learn to fly.
And if not adjusted properly, the engine may
stop in flight.
With electric power, the motor always
starts and will keep running as long as you
have a charge in the battery. Yes, a wire could
break or a fuse could blow, but that motor is
usually going to keep running in a reliable
fashion. As the charge wears down during a
flight, the electric-powered aircraft will fly
noticeably slower. This is your warning to set
up for a landing. For these reasons, electric
power is the perfect choice for the beginner in
our hobby.
There are many things you have to learn to
use electric power. Since this is a beginners’
series, my intention is to gradually bring you
up to speed. Battery charging is important.
Hooking up all of the necessary wiring could
prove a problem for some.
My first choice for an electric-powered
ARF (Almost Ready-to-Fly) model will not
require any soldering. Each power-system
component will be what we call “plug and
play”; that is, the radio and electric-powersystem
installations are totally handled with
preassembled connectors. An entire electricpower-
component package (which I will
describe) will be available from Kirk Massey
of New Creations R/C.
What does an electric power system consist
of? The basic components are the motor, the
propeller and any adapter that might be
required to attach the propeller to the motor
shaft, an Electronic Speed Control (ESC) to
control the motor throttling, the battery pack
to supply the energy, and the charger to
charge that battery.
For an electric-powered model you must
install the motor, ESC, and battery inside the
aircraft and integrate it into your onboard RC
system. The radio essentially operates the
ESC, which operates the motor’s speed in
flight.
Your biggest concern at the start with
electric power is understanding and correctly
charging the battery. A battery that is not fully
charged is much like a fueled model with only
a partial tank of fuel.
Motors: The electric motor itself is of
primary importance. There are different types,
such as simple ferrite magnet motors; the
more sophisticated cobalt (samarium cobalt)
magnet motors; and the highly efficient, longlasting,
expensive brushless motors.
After selecting the type of motor, your
next concern is to size it so that it is capable of
flying a model aircraft of a particular weight.
In this case the choice has been made for you.
July 2003 57
Right: Jeti Model 110 ESC with BEC circuit (explained in text).
Left pair of wires go to motor; right pair goes to battery pack.
Cable with servo-style connector plugs into throttle port on RC
receiver. On/off switch at end of remaining cable is mounted on
exterior of aircraft’s fuselage. Above: Close-up of Jeti Model JES
110 ESC. Note polarity symbols (+ and –) printed on ESC case.
Above is an eight-cell 1100 mAh NiMH battery pack with preinstalled APP connectors.
On the right is a close-up of the battery label.
Photos courtesy the author Graphic Design by Lydia Whitehead
Another consideration is running the motor
direct drive (with the propeller attached
directly to the motor shaft) or through a gearreduction
drive that can add an advantage to
the power output.
Since this is a beginners’ article I’ve
selected a basic ferrite motor known in the
generic sense as a Speed 400. These come in
three different windings designated by
voltage. This project will use the 6-volt
winding. The motor can be obtained from
many sources.
This size motor is capable of flying a
model with a total flying weight of roughly
10-18 ounces. It can accomplish this using a
direct-drive propeller, so for this first try we will not use a gear-drive
assembly. Be advised for the future that a gear drive will allow you to
fly heavier-weight models and/or it can extend the flying time of a
model flown on direct drive.
My choice of direct drive was to keep it simple and inexpensive. A
Speed 400 motor costs approximately $15. It is a sealed can. When
you eventually burn out the brushes, you throw out the motor and buy
another!
The motor will have two terminals, and they are polarized (positive
and negative). Most have a red dot or mark indicating the positive
terminal. For our beginner’s package, a wire has already been attached
to each terminal. The connectors applied to the wire ends are the
popular Anderson Power Pole (APP) variety. There are many popular
connectors available, but I felt that the APP were best for this
application. These connectors have already been attached for you.
Almost any brushed electric motor will generate some form of
electrical noise which could conceivably feed back into the RC system.
To supress this brush noise, one or more bypass capacitors are added.
Generally, one capacitor goes from each terminal to the case, which is
like a ground connection. In this case, the motor selected has the
capacitors installed inside the motor can, so nothing else is necessary.
When you start your motor the first time, the wind created by the
propeller should blow toward the rear of the model. If it blows
forward, it means that the motor polarity has been reversed and the
propeller is turning in the wrong direction. That shouldn’t happen in
this instance since the work has been done for you. Be advised for the
future that if the propwash blows forward, reverse or swap the motor
terminal connections.
The motor shaft protrudes from the front of the motor. Some directdrive
propellers are simply pressed onto the motor shaft. I’m not in
favor of that approach, so I specified the use of a propeller adapter. The
adapter is slipped onto the motor shaft. A collet-type device essentially
clamps to the motor shaft as you tighten the adapter. I found the
adapter already installed on my motor shaft; you might find the same.
Once the adapter is in place, put the propeller on, followed by a
propeller washer then the nut. Tighten the nut, and you are set. The
propeller of choice for this project is a Gunther 5 x 4 white plastic. You
will likely have to drill the center shaft hole somewhat to fit on the
58 MODEL AVIATION
The battery pack is attached to the charger.
Placard on PF-12. Press start button to initiate charge, at which
time red charge light will glow steady. When peak is reached,
battery is fully charged and will stop automatically, at which time
red light will flash.
Left: Global Hobby Distributors’ WattAge
PF-12 Park Flyer AC/DC Peak Charger. At
left is 115VAC power input cable. At right
is 12VDC power input cable. In front is
pair of output wires with preinstalled APP
connectors which attach to battery pack
when it is being charged. Below: PF-12 is
set at its maximum charge current of 2000
mA (2.0 amps) as noted by pointer. This
will fully charge eight-cell 1100 mAh NiMH
battery in roughly 30 minutes. You must
select battery type—NiMH in this case.
adapter shaft. Next month I’ll write about how
to install this motor on your aircraft.
The ESC is probably the heart of the electric
power system. The ESC in electric-powered
flight takes the place of the throttle (or engine)
servo used on a fueled model.
The ESC in this instance weighs roughly
3⁄4 ounce and has two pairs of wires: a servotype
cable and a cable with a switch on the
end, all exiting the case. Two wires, with APP
connectors already attached, will plug into the
motor wire connectors. Polarity is important,
so it is red to red and black to black.
Two more wires will have APP connectors
attached, and they will plug into the battery
pack. The third cable has a servo cable
connector on the end. That cable is plugged
into the throttle port (usually the number-three
position) on your RC receiver. The switch will
be mounted on the side of the fuselage and
must be manually turned on to activate the
entire electric power system.
There are all kinds and sizes of ESCs on
the hobby market. The one chosen for this
project is the Jeti 110. The ESC will be rated
for current; in this case it is 11 amps
July 2003 59
All electric-power-system components are plugged together as
they would be inside model’s fuselage. ESC cable with servo
connector is plugged into RC receiver. Add two more servos for
rudder and elevator control, and you have complete power and
control system for your model.
Cable from ESC plugs into throttle port on RC receiver. It doesn’t
look it, but connector is plugged into CH3 on this Hitec Electron
6 receiver.
Never charge a hot battery pack. Use a “cooling device” such as this, consisting of a 3-
inch-diameter PVC pipe approximately 12 inches long. Attach RadioShack 12-volt fan on
one end. Battery pack is inserted in other end so that air from fan passes over battery,
thereby cooling it. In this case the battery is being cooled while it is on charge (battery
plugged into charger).
A 12-volt RadioShack fan is simply epoxied in place at end of PVC tube with the help of
a few pieces of scrap wood. Fan draws little power from car battery.
Rear of PF-12 showing 115VAC and
12VDC power input cables. This charger
allows you to recharge battery packs
indoors or at flying field from 12-volt car
battery
July 2003 61
continuous operation. For our application we
need 8-9 amps, so there is a margin of safety.
If the rating wasn’t high enough, you could
overheat and possibly burn out the ESC. The
rating must also take into account the number
of cells in the battery pack. The Jeti 110 can
handle six to 10 cells. We will be using an
eight-cell battery.
Many small ESCs (such as the Jeti 110)
will contain what is called a “Battery
Eliminator Circuit” (BEC). It will permit the
main motor battery pack to also power the
onboard RC system (receiver and servos) on a
shared basis. This saves the weight of an extra
airborne battery pack. It is also a convenience
because this one battery is recharged for every
flight.
In actual practice, the BEC has a special
circuit that provides a regulated 5 volts to the
RC system via that cable that is plugged into
the receiver throttle port. When the battery
gets down near 5 volts the circuit cuts off the
motor, but it still provides the necessary
power to operate the RC system so that you
can safely land the model.
Most ESCs with this BEC feature (the Jeti
110 included) will allow you to briefly restart
the motor after the first shutdown. You do this
by moving the throttle stick on the transmitter
all the way to idle, then back up. That resets
the ESC and will allow a few more seconds of
power so that you can line up on the runway
for a safe landing.
Most modern ESCs (including the Jeti
110) employ “smart” circuitry via a
microchip, which can add considerably to the
safety of electric motor operation. Remember
what I wrote earlier: when the battery is
attached to the motor, it could start instantly.
If you have the throttle stick at full or partial
with the entire system plugged in, the motor
and propeller could start turning.
The microchip in the ESC will sense
anything other than a dead idle position and
prevent the motor from starting. To start the
motor you must physically move the
62 MODEL AVIATION
transmitter throttle stick down to idle then go
back up. The motor will then start, and its
speed will be proportional to the controlstick
position.
The Battery: This is also an important part of
the electric power system. Batteries come in
all types, sizes, weights, and capacities. The
choices are critical to the model’s
performance. For this project the choice of
battery has been made for you; it is a Nickel
Metal Hydride type (NiMH) consisting of
eight cells made up as a pack. Each cell has a
capacity rating of 1100 milliampere-hours
(mAh). The nature of these ratings will be
explained in later articles.
APP connectors have thoughtfully been
attached to the two wire cables. As in the case
of the motor connections, the polarity is
critical to the system’s correct operation. It is
always positive to positive and negative to
negative. If the color-code convention is
followed, it is usually the usual red to red and
black to black. However, not everyone uses
that color convention.
Do not mix up connections between the
motor and battery. The connectors going from
the ESC to the motor are generally connected
once at the time of initial installation and not
touched thereafter. Placing a piece of masking
tape on each connector can remind you not to
touch them until such a time as you transfer
the equipment to another aircraft.
Estimating that this direct-drive Speed 400
motor will have a current of 8-9 amps, this
particular battery pack should be capable of
providing six to seven minutes of electric
power at full throttle. In reality you will have
much more power than you need; therefore,
you will be able to throttle back during a
normal training flight.
Throttling back reduces the motor current,
and, as a result, increases the flight time. With
average throttling back it will be possible to
extend your flying times to 10 minutes or so.
Owning more than one battery pack will allow
you to fly on one while the other is on charge.
That will provide you with more flying time
and less waiting time.
Charging: The last item in the electric
power package is the essential battery
charger. There are many choices, simple
and complex, available at varied prices.
Kirk Massey’s favorite for a beginner is the
Global (WattAge brand) PF-12 Park Flyer
AC/DC peak-detect charger. The key words
are “peak detect”!
Some of the simplest battery chargers
come with just a rotary-crank type timer.
You rotate the timer switch to 15-20
minutes and wait for the timer to run down.
The trouble with this is that the charger
can’t sense the amount of charge already in
the battery. This can easily result in
overcharging, which can cause excessive
heat buildup in the battery. An overheated
battery can quickly be ruined.
A peak-detect charger is essentially an
automatic charger. All Nickel Cadmium
(Ni-Cd) and NiMH batteries have a
characteristic where the voltage applied
July 2003 63
during charging increases until the point of
full charge (full capacity) is reached, at
which point the voltage peaks then begins
to drop off. At the peak, or slightly
thereafter, the charge cuts off
automatically.
Since this is a sensing cutoff and not a
timed cutoff, only what is necessary to
reach full charge is put into the battery. If
your battery had residual charge in it, the
charge period would be reduced
accordingly.
The one thing you must do manually is
tell the charger the amount of charge
current required. For NiMH batteries it is
suggested that you apply a charge current
equal to two times the rated capacity of the
battery. We refer to this as “2C.”
In this case the battery is rated at 1100
mAh (which is the same as saying 1.1 amp
per hour). Mulitiply 2.0 by 1.1 amps,
which equals 2.2 amps. This particular
Global charger has a maximum charge
current of 2.0 amps, so you would set the
charger to that maximum current. At that
approximate 2C charge rate, a fully
depleted NiMH battery pack would take
roughly 30 minutes to reach full charge.
Each battery will vary according to the
number of cells, the type of the cells, and
the capacity rating. You will pick up on
this concept as you progress with electric
power. For this first choice I’ve selected a
charger that can’t overcharge the battery
pack because its maximum current of 2.0
amps is close to what this battery requires.
When you purchase this or any charger,
it is generally your responsibility to
prepare a cable that will allow the charger
to connect to your battery pack. Kirk
Massey has prepared a cable with APP
connectors to attach between the Global
charger and our battery pack. Note the
output connectors on the front of the
Global charger. Press down on each
connector, insert the wire, then release. Do
that for the positive (red) and negative
(black) connectors.
Later you might want to purchase a
more sophisticated charger that has a
higher current rating or can handle battery
packs with more cells. (The Global is
capable of handling four to 12 cells.)
There are several fully automatic
chargers on the market. When you attach a
battery to one for charging, it will sense all
of the necessary parameters and set the
charger accordingly. The concept involves a
computer sensing system and has a menu
that must be accessed for regular operation.
These chargers work well, but they are
more complicated to use than this basic
Global unit and they cost much more.
It is typically a good idea to remove the
battery pack from the model when charging.
Immediately after a flight the battery may
be quite warm—even hot. A basic rule is to
never charge a hot battery. You should cool
it off before attempting to recharge. Putting
a hot battery in your soda cooler isn’t the
right method. It will result in uneven
temperatures throughout the pack.
The better approach is to buy a
RadioShack 12-volt electric fan (part
number 273-243). You can mount it at one
end of a length of 3-inch-diameter PVC
(polyvinyl chloride) plumbing pipe. Power
the fan from your 12-volt car battery. Put
your hot battery pack at the other end of
the PVC tube. This will allow the air the
fan blades generate to pass over the battery
pack and cool it. Approximately five
minutes in this tube will reduce the
temperature to a safe level for charging.
This Global charger can be powered by
115VAC for indoor (shop) use or from 12
volts DC from your car battery. At the
field, most of us just raise our car hoods
and attach the charger input cables
(alligator clips) to the battery terminals.
The polarity is important. Make sure that
the red alligator clip goes to the car-battery
positive (+) terminal and the black goes to
the ground or negative (–) terminal. The
Global charger has a built-in timer circuit
that cuts off the charger after a 90-minute
period. If you left the charger unattended
and something went wrong, the charger
would safely cut off after 11⁄2 hours.
That’s the full electric power system.
Remember that this article has been
prepared as a starting point for a rank
beginner who is entering electric flight.
There is a shopping list in the
accompanying table that you can use to
purchase all of the necessary equipment.
You can purchase all of the items from
Kirk Massey at New Creations R/C, Box
497, Willis TX 77378; Tel.: (936) 856-
4630. (Kirk prefers telephone calls to Email
correspondence.)
You can buy the components on the list
from other sources; for simplicity’s sake I
specified one source and the exact
equipment necessary. The addition of the
connectors made this a custom order. If
you are lucky to live near experienced
electric modelers, by all means solicit their
help; it can save you a great deal of time.
However, the theme of this series is to get
you going on your own—with little or no
help!
Next month I will start with a basic
electric-powered ARF trainer: the
AeroCraft Pogo. It was specifically
selected to use the electric power
equipment I have described and the Hitec
Neon three-channel RC system, which I
discussed in part two of this series (in the
April 2003 Model Aviation, starting on
page 54).
I expect to take the Pogo from the kit
box to the flying field, which includes final
assembly of the model and installation of
the electric power and RC system. MA
Bob Aberle
Sources:
Balsa Products
122 Jansen Ave.
Iselin NJ 08830
(732) 634-6131
www.balsapr.com
Dymond Modelsports USA Ltd.
683 N. Main St.
Oshkosh WI 54901
(920) 203-1100
[email protected]
www.rc-dymond.com
Hobby Lobby International
5614 Franklin Pike Cir.
Brentwood TN 37027
(615) 373-1444
[email protected]
www.hobby-lobby.com
Maxx Products International
815 Oakwood Rd., Unit D
Lake Zurich IL 60047
(847) 438-2233
[email protected]
www.maxxprod.com
New Creations R/C
Box 496
Willis TX 77378
(936) 856-4630
[email protected]
www.newcreations-rc.com
Northeast Sailplane Products
948 Hercules Dr., Suite 12
Colchester VT 05446
(802) 655-7700
www.nesail.com
Radical R/C
7046 Harshmanville Rd.
Huber Heights OH 45424
(937) 237-7889
[email protected]
www.radicalrc.com
64 MODEL AVIATION
Quantity Item Number Description Prices as of
March 2003
1 GR3321PWA Speed 400 6-volt motor with APP connectors $15
1 MATPA104 2.3mm propeller adapter for Speed 400 motor $5.50
1 ZAG1400P Gunther 5 x 4 white plastic propeller with 5mm $2
hole (Order several propellers; expect breakage!)
1 HLJE110A Jeti 110 ESC with APP connectors installed $46.90
1 1288554A Eight-cell 1100 NiMH battery pack with APP $32.95
connectors
1 130108 Global PF-12 Park Flyer charger $49.95
1 NCAPCL PF-12 Anderson charge lead $3
Your First Electric Power System
Our Full-Size
Plans List
has hundreds
of models
to choose from.
See page 183
for details.

AT THIS POINT this series will begin to split off into the specialty
areas of model aviation. Radio Control (RC), as noted in the past few
months, takes up the major portion of interest. However, equally
important to so many modelers are the non-RC aircraft, such as Free
Flight, Control Line, Hand-Launched Gliders, rubber-powered models,
and more! As the months go by, this series will “spin off” into all of
these fascinating areas.
From a primary power standpoint, the most popular for model
aviation today involves the use of glow-fueled engines. To a lesser
degree, but just as important, are the gasoline-fueled engines as
employed in the larger models (quarter scale and the like). The third
power category is electric, and this has become increasingly popular in
recent years because of the many technological improvements in
motors and batteries.
Guest-author experts will soon be writing about glow- and
gasoline-fueled models. Electric has been
my specialty for some years; it is the
only power source I use today. Read
on in the next few months as I
explain electric power and take you
through the process of assembling,
installing power in, and flying an
electric-powered model.
What is electric? Electric power uses the energy supplied from
batteries to operate motors without the need for “wet” fuels. At the
beginning of this series I pointed out that when you are referring to
fuel, the power plant is an “engine.” When you are referring to electric
power, it is a “motor.”
Why would someone, especially a beginner, want to try electric
power? The two primary advantages of electric power are that it is
clean and quiet. It’s clean in the sense that you will not end up with
fuel residue on your model after each flight. It’s also clean because
there is no fuel to accidentally spill on the ground and get into the
water table. There is a remote chance of that happening, but it is still a
big concern in certain areas of our country.
Introduction
toE ectric Power


The three basic components of model-aircraft electric power system: (L) Speed 400 6-
volt winding ferrite motor, (center) Jeti Models JES-110 ESC, (R) eight-cell 1100 mAh
NiMH battery pack. New Creations R/C has custom-preinstalled all necessary APP
connectors. No soldering is necessary. A plus for beginners! Inset: Speed 400 6-volt
winding direct-drive motor. Wires, APP connectors were preinstalled.
Direct-drive propeller is mounted on propeller adapter that
mounts on motor shaft. New Creations R/C supplies this adapter
already mounted to motor shaft. The propeller is a white plastic
Gunther 5 x 4.
■ Bob Aberle
Red dot on rear of motor
casing denotes positive (+)
terminal. Red APP connector
is placed on positive motor
lead wire; black APP
connector is on negative lead.
Both wires are connected to
“motor” lead wires on ESC.
56 MODEL AVIATION
Electric power is quiet, as in no noise!
Probably the loudest sound you will get from
an electric motor is the propeller or air noise,
and that isn’t much. Quiet operation means
that you have the ability to fly in urban areas
without disturbing the public. Electric power
is so quiet that you can fly at sunrise, in dead
air or calm wind conditions, without the fear
of waking up neighbors.
There are more subtle advantages
associated with electric power. Without a
piston and connecting rod pounding away,
there is little vibration. This makes it much
easier on the radio-system components, which
need little isolation or padding to survive.
Electric motors are basically turned on by
a switch or controller. You don’t have to
prime and flip a propeller, use a starter motor,
or light a glow plug to get your model in
flight. This easy starting feature is particularly
nice when flying in colder weather. You can
sit in your warm car while the battery
recharges, then venture outside for the flight.
There is never any waiting.
When you are finished, you just put the
aircraft in your vehicle; no cleaning is
necessary. With the absence of fuel, you don’t
have to be concerned about the finish applied
to your models. Anything will work!
After hearing these advantages, could
there be any disadvantages? Yes! When you
apply electricity from the battery to the motor,
it will start instantly. If you fail to realize this,
you might accidentally connect a battery, have
the motor start, and it might hit you or take off
across your shop, wrecking everything in its
path. Most modern speed controllers have
safety features to help with this that I will
discuss in a moment.
Is electric power better than glow-fuel
power? I’ve used both in the last 50 years (30
for electrics!). I think there will always be a
place in our hobby for fueled engines.
Modelers love the sound, and they like
fueling, starting, and adjusting an engine.
On the other hand, a beginner in modeling
has much to learn in a short time. Sometimes
the problems with starting and operating a
fueled engine can consume most of the
available time while attempting to learn to fly.
And if not adjusted properly, the engine may
stop in flight.
With electric power, the motor always
starts and will keep running as long as you
have a charge in the battery. Yes, a wire could
break or a fuse could blow, but that motor is
usually going to keep running in a reliable
fashion. As the charge wears down during a
flight, the electric-powered aircraft will fly
noticeably slower. This is your warning to set
up for a landing. For these reasons, electric
power is the perfect choice for the beginner in
our hobby.
There are many things you have to learn to
use electric power. Since this is a beginners’
series, my intention is to gradually bring you
up to speed. Battery charging is important.
Hooking up all of the necessary wiring could
prove a problem for some.
My first choice for an electric-powered
ARF (Almost Ready-to-Fly) model will not
require any soldering. Each power-system
component will be what we call “plug and
play”; that is, the radio and electric-powersystem
installations are totally handled with
preassembled connectors. An entire electricpower-
component package (which I will
describe) will be available from Kirk Massey
of New Creations R/C.
What does an electric power system consist
of? The basic components are the motor, the
propeller and any adapter that might be
required to attach the propeller to the motor
shaft, an Electronic Speed Control (ESC) to
control the motor throttling, the battery pack
to supply the energy, and the charger to
charge that battery.
For an electric-powered model you must
install the motor, ESC, and battery inside the
aircraft and integrate it into your onboard RC
system. The radio essentially operates the
ESC, which operates the motor’s speed in
flight.
Your biggest concern at the start with
electric power is understanding and correctly
charging the battery. A battery that is not fully
charged is much like a fueled model with only
a partial tank of fuel.
Motors: The electric motor itself is of
primary importance. There are different types,
such as simple ferrite magnet motors; the
more sophisticated cobalt (samarium cobalt)
magnet motors; and the highly efficient, longlasting,
expensive brushless motors.
After selecting the type of motor, your
next concern is to size it so that it is capable of
flying a model aircraft of a particular weight.
In this case the choice has been made for you.
July 2003 57
Right: Jeti Model 110 ESC with BEC circuit (explained in text).
Left pair of wires go to motor; right pair goes to battery pack.
Cable with servo-style connector plugs into throttle port on RC
receiver. On/off switch at end of remaining cable is mounted on
exterior of aircraft’s fuselage. Above: Close-up of Jeti Model JES
110 ESC. Note polarity symbols (+ and –) printed on ESC case.
Above is an eight-cell 1100 mAh NiMH battery pack with preinstalled APP connectors.
On the right is a close-up of the battery label.
Photos courtesy the author Graphic Design by Lydia Whitehead
Another consideration is running the motor
direct drive (with the propeller attached
directly to the motor shaft) or through a gearreduction
drive that can add an advantage to
the power output.
Since this is a beginners’ article I’ve
selected a basic ferrite motor known in the
generic sense as a Speed 400. These come in
three different windings designated by
voltage. This project will use the 6-volt
winding. The motor can be obtained from
many sources.
This size motor is capable of flying a
model with a total flying weight of roughly
10-18 ounces. It can accomplish this using a
direct-drive propeller, so for this first try we will not use a gear-drive
assembly. Be advised for the future that a gear drive will allow you to
fly heavier-weight models and/or it can extend the flying time of a
model flown on direct drive.
My choice of direct drive was to keep it simple and inexpensive. A
Speed 400 motor costs approximately $15. It is a sealed can. When
you eventually burn out the brushes, you throw out the motor and buy
another!
The motor will have two terminals, and they are polarized (positive
and negative). Most have a red dot or mark indicating the positive
terminal. For our beginner’s package, a wire has already been attached
to each terminal. The connectors applied to the wire ends are the
popular Anderson Power Pole (APP) variety. There are many popular
connectors available, but I felt that the APP were best for this
application. These connectors have already been attached for you.
Almost any brushed electric motor will generate some form of
electrical noise which could conceivably feed back into the RC system.
To supress this brush noise, one or more bypass capacitors are added.
Generally, one capacitor goes from each terminal to the case, which is
like a ground connection. In this case, the motor selected has the
capacitors installed inside the motor can, so nothing else is necessary.
When you start your motor the first time, the wind created by the
propeller should blow toward the rear of the model. If it blows
forward, it means that the motor polarity has been reversed and the
propeller is turning in the wrong direction. That shouldn’t happen in
this instance since the work has been done for you. Be advised for the
future that if the propwash blows forward, reverse or swap the motor
terminal connections.
The motor shaft protrudes from the front of the motor. Some directdrive
propellers are simply pressed onto the motor shaft. I’m not in
favor of that approach, so I specified the use of a propeller adapter. The
adapter is slipped onto the motor shaft. A collet-type device essentially
clamps to the motor shaft as you tighten the adapter. I found the
adapter already installed on my motor shaft; you might find the same.
Once the adapter is in place, put the propeller on, followed by a
propeller washer then the nut. Tighten the nut, and you are set. The
propeller of choice for this project is a Gunther 5 x 4 white plastic. You
will likely have to drill the center shaft hole somewhat to fit on the
58 MODEL AVIATION
The battery pack is attached to the charger.
Placard on PF-12. Press start button to initiate charge, at which
time red charge light will glow steady. When peak is reached,
battery is fully charged and will stop automatically, at which time
red light will flash.
Left: Global Hobby Distributors’ WattAge
PF-12 Park Flyer AC/DC Peak Charger. At
left is 115VAC power input cable. At right
is 12VDC power input cable. In front is
pair of output wires with preinstalled APP
connectors which attach to battery pack
when it is being charged. Below: PF-12 is
set at its maximum charge current of 2000
mA (2.0 amps) as noted by pointer. This
will fully charge eight-cell 1100 mAh NiMH
battery in roughly 30 minutes. You must
select battery type—NiMH in this case.
adapter shaft. Next month I’ll write about how
to install this motor on your aircraft.
The ESC is probably the heart of the electric
power system. The ESC in electric-powered
flight takes the place of the throttle (or engine)
servo used on a fueled model.
The ESC in this instance weighs roughly
3⁄4 ounce and has two pairs of wires: a servotype
cable and a cable with a switch on the
end, all exiting the case. Two wires, with APP
connectors already attached, will plug into the
motor wire connectors. Polarity is important,
so it is red to red and black to black.
Two more wires will have APP connectors
attached, and they will plug into the battery
pack. The third cable has a servo cable
connector on the end. That cable is plugged
into the throttle port (usually the number-three
position) on your RC receiver. The switch will
be mounted on the side of the fuselage and
must be manually turned on to activate the
entire electric power system.
There are all kinds and sizes of ESCs on
the hobby market. The one chosen for this
project is the Jeti 110. The ESC will be rated
for current; in this case it is 11 amps
July 2003 59
All electric-power-system components are plugged together as
they would be inside model’s fuselage. ESC cable with servo
connector is plugged into RC receiver. Add two more servos for
rudder and elevator control, and you have complete power and
control system for your model.
Cable from ESC plugs into throttle port on RC receiver. It doesn’t
look it, but connector is plugged into CH3 on this Hitec Electron
6 receiver.
Never charge a hot battery pack. Use a “cooling device” such as this, consisting of a 3-
inch-diameter PVC pipe approximately 12 inches long. Attach RadioShack 12-volt fan on
one end. Battery pack is inserted in other end so that air from fan passes over battery,
thereby cooling it. In this case the battery is being cooled while it is on charge (battery
plugged into charger).
A 12-volt RadioShack fan is simply epoxied in place at end of PVC tube with the help of
a few pieces of scrap wood. Fan draws little power from car battery.
Rear of PF-12 showing 115VAC and
12VDC power input cables. This charger
allows you to recharge battery packs
indoors or at flying field from 12-volt car
battery
July 2003 61
continuous operation. For our application we
need 8-9 amps, so there is a margin of safety.
If the rating wasn’t high enough, you could
overheat and possibly burn out the ESC. The
rating must also take into account the number
of cells in the battery pack. The Jeti 110 can
handle six to 10 cells. We will be using an
eight-cell battery.
Many small ESCs (such as the Jeti 110)
will contain what is called a “Battery
Eliminator Circuit” (BEC). It will permit the
main motor battery pack to also power the
onboard RC system (receiver and servos) on a
shared basis. This saves the weight of an extra
airborne battery pack. It is also a convenience
because this one battery is recharged for every
flight.
In actual practice, the BEC has a special
circuit that provides a regulated 5 volts to the
RC system via that cable that is plugged into
the receiver throttle port. When the battery
gets down near 5 volts the circuit cuts off the
motor, but it still provides the necessary
power to operate the RC system so that you
can safely land the model.
Most ESCs with this BEC feature (the Jeti
110 included) will allow you to briefly restart
the motor after the first shutdown. You do this
by moving the throttle stick on the transmitter
all the way to idle, then back up. That resets
the ESC and will allow a few more seconds of
power so that you can line up on the runway
for a safe landing.
Most modern ESCs (including the Jeti
110) employ “smart” circuitry via a
microchip, which can add considerably to the
safety of electric motor operation. Remember
what I wrote earlier: when the battery is
attached to the motor, it could start instantly.
If you have the throttle stick at full or partial
with the entire system plugged in, the motor
and propeller could start turning.
The microchip in the ESC will sense
anything other than a dead idle position and
prevent the motor from starting. To start the
motor you must physically move the
62 MODEL AVIATION
transmitter throttle stick down to idle then go
back up. The motor will then start, and its
speed will be proportional to the controlstick
position.
The Battery: This is also an important part of
the electric power system. Batteries come in
all types, sizes, weights, and capacities. The
choices are critical to the model’s
performance. For this project the choice of
battery has been made for you; it is a Nickel
Metal Hydride type (NiMH) consisting of
eight cells made up as a pack. Each cell has a
capacity rating of 1100 milliampere-hours
(mAh). The nature of these ratings will be
explained in later articles.
APP connectors have thoughtfully been
attached to the two wire cables. As in the case
of the motor connections, the polarity is
critical to the system’s correct operation. It is
always positive to positive and negative to
negative. If the color-code convention is
followed, it is usually the usual red to red and
black to black. However, not everyone uses
that color convention.
Do not mix up connections between the
motor and battery. The connectors going from
the ESC to the motor are generally connected
once at the time of initial installation and not
touched thereafter. Placing a piece of masking
tape on each connector can remind you not to
touch them until such a time as you transfer
the equipment to another aircraft.
Estimating that this direct-drive Speed 400
motor will have a current of 8-9 amps, this
particular battery pack should be capable of
providing six to seven minutes of electric
power at full throttle. In reality you will have
much more power than you need; therefore,
you will be able to throttle back during a
normal training flight.
Throttling back reduces the motor current,
and, as a result, increases the flight time. With
average throttling back it will be possible to
extend your flying times to 10 minutes or so.
Owning more than one battery pack will allow
you to fly on one while the other is on charge.
That will provide you with more flying time
and less waiting time.
Charging: The last item in the electric
power package is the essential battery
charger. There are many choices, simple
and complex, available at varied prices.
Kirk Massey’s favorite for a beginner is the
Global (WattAge brand) PF-12 Park Flyer
AC/DC peak-detect charger. The key words
are “peak detect”!
Some of the simplest battery chargers
come with just a rotary-crank type timer.
You rotate the timer switch to 15-20
minutes and wait for the timer to run down.
The trouble with this is that the charger
can’t sense the amount of charge already in
the battery. This can easily result in
overcharging, which can cause excessive
heat buildup in the battery. An overheated
battery can quickly be ruined.
A peak-detect charger is essentially an
automatic charger. All Nickel Cadmium
(Ni-Cd) and NiMH batteries have a
characteristic where the voltage applied
July 2003 63
during charging increases until the point of
full charge (full capacity) is reached, at
which point the voltage peaks then begins
to drop off. At the peak, or slightly
thereafter, the charge cuts off
automatically.
Since this is a sensing cutoff and not a
timed cutoff, only what is necessary to
reach full charge is put into the battery. If
your battery had residual charge in it, the
charge period would be reduced
accordingly.
The one thing you must do manually is
tell the charger the amount of charge
current required. For NiMH batteries it is
suggested that you apply a charge current
equal to two times the rated capacity of the
battery. We refer to this as “2C.”
In this case the battery is rated at 1100
mAh (which is the same as saying 1.1 amp
per hour). Mulitiply 2.0 by 1.1 amps,
which equals 2.2 amps. This particular
Global charger has a maximum charge
current of 2.0 amps, so you would set the
charger to that maximum current. At that
approximate 2C charge rate, a fully
depleted NiMH battery pack would take
roughly 30 minutes to reach full charge.
Each battery will vary according to the
number of cells, the type of the cells, and
the capacity rating. You will pick up on
this concept as you progress with electric
power. For this first choice I’ve selected a
charger that can’t overcharge the battery
pack because its maximum current of 2.0
amps is close to what this battery requires.
When you purchase this or any charger,
it is generally your responsibility to
prepare a cable that will allow the charger
to connect to your battery pack. Kirk
Massey has prepared a cable with APP
connectors to attach between the Global
charger and our battery pack. Note the
output connectors on the front of the
Global charger. Press down on each
connector, insert the wire, then release. Do
that for the positive (red) and negative
(black) connectors.
Later you might want to purchase a
more sophisticated charger that has a
higher current rating or can handle battery
packs with more cells. (The Global is
capable of handling four to 12 cells.)
There are several fully automatic
chargers on the market. When you attach a
battery to one for charging, it will sense all
of the necessary parameters and set the
charger accordingly. The concept involves a
computer sensing system and has a menu
that must be accessed for regular operation.
These chargers work well, but they are
more complicated to use than this basic
Global unit and they cost much more.
It is typically a good idea to remove the
battery pack from the model when charging.
Immediately after a flight the battery may
be quite warm—even hot. A basic rule is to
never charge a hot battery. You should cool
it off before attempting to recharge. Putting
a hot battery in your soda cooler isn’t the
right method. It will result in uneven
temperatures throughout the pack.
The better approach is to buy a
RadioShack 12-volt electric fan (part
number 273-243). You can mount it at one
end of a length of 3-inch-diameter PVC
(polyvinyl chloride) plumbing pipe. Power
the fan from your 12-volt car battery. Put
your hot battery pack at the other end of
the PVC tube. This will allow the air the
fan blades generate to pass over the battery
pack and cool it. Approximately five
minutes in this tube will reduce the
temperature to a safe level for charging.
This Global charger can be powered by
115VAC for indoor (shop) use or from 12
volts DC from your car battery. At the
field, most of us just raise our car hoods
and attach the charger input cables
(alligator clips) to the battery terminals.
The polarity is important. Make sure that
the red alligator clip goes to the car-battery
positive (+) terminal and the black goes to
the ground or negative (–) terminal. The
Global charger has a built-in timer circuit
that cuts off the charger after a 90-minute
period. If you left the charger unattended
and something went wrong, the charger
would safely cut off after 11⁄2 hours.
That’s the full electric power system.
Remember that this article has been
prepared as a starting point for a rank
beginner who is entering electric flight.
There is a shopping list in the
accompanying table that you can use to
purchase all of the necessary equipment.
You can purchase all of the items from
Kirk Massey at New Creations R/C, Box
497, Willis TX 77378; Tel.: (936) 856-
4630. (Kirk prefers telephone calls to Email
correspondence.)
You can buy the components on the list
from other sources; for simplicity’s sake I
specified one source and the exact
equipment necessary. The addition of the
connectors made this a custom order. If
you are lucky to live near experienced
electric modelers, by all means solicit their
help; it can save you a great deal of time.
However, the theme of this series is to get
you going on your own—with little or no
help!
Next month I will start with a basic
electric-powered ARF trainer: the
AeroCraft Pogo. It was specifically
selected to use the electric power
equipment I have described and the Hitec
Neon three-channel RC system, which I
discussed in part two of this series (in the
April 2003 Model Aviation, starting on
page 54).
I expect to take the Pogo from the kit
box to the flying field, which includes final
assembly of the model and installation of
the electric power and RC system. MA
Bob Aberle
Sources:
Balsa Products
122 Jansen Ave.
Iselin NJ 08830
(732) 634-6131
www.balsapr.com
Dymond Modelsports USA Ltd.
683 N. Main St.
Oshkosh WI 54901
(920) 203-1100
[email protected]
www.rc-dymond.com
Hobby Lobby International
5614 Franklin Pike Cir.
Brentwood TN 37027
(615) 373-1444
[email protected]
www.hobby-lobby.com
Maxx Products International
815 Oakwood Rd., Unit D
Lake Zurich IL 60047
(847) 438-2233
[email protected]
www.maxxprod.com
New Creations R/C
Box 496
Willis TX 77378
(936) 856-4630
[email protected]
www.newcreations-rc.com
Northeast Sailplane Products
948 Hercules Dr., Suite 12
Colchester VT 05446
(802) 655-7700
www.nesail.com
Radical R/C
7046 Harshmanville Rd.
Huber Heights OH 45424
(937) 237-7889
[email protected]
www.radicalrc.com
64 MODEL AVIATION
Quantity Item Number Description Prices as of
March 2003
1 GR3321PWA Speed 400 6-volt motor with APP connectors $15
1 MATPA104 2.3mm propeller adapter for Speed 400 motor $5.50
1 ZAG1400P Gunther 5 x 4 white plastic propeller with 5mm $2
hole (Order several propellers; expect breakage!)
1 HLJE110A Jeti 110 ESC with APP connectors installed $46.90
1 1288554A Eight-cell 1100 NiMH battery pack with APP $32.95
connectors
1 130108 Global PF-12 Park Flyer charger $49.95
1 NCAPCL PF-12 Anderson charge lead $3
Your First Electric Power System
Our Full-Size
Plans List
has hundreds
of models
to choose from.
See page 183
for details.