User Manual

Now that you have a component for your power system,
there are several different ways to select the rest of the
components of your power system. In time, experience will
help you to determine what works best for you, but an easy
way to determine what you need now is the following.
PROCEDURE #1: If you know the size of the propeller you
want to turn and the rpm, then look at the chart included in
the packaging and:
❏ 1. Find the combination in the motor/prop chart that
delivers the closest performance to what you want.
❏ 2. Note the recommended battery voltage.
❏ 3. Determine if you want to use LiPo or NiMH batteries
based on the desired ready-to-fly airplane weight.
Select the number of cells based on the recommended
voltage shown on the chart.
❏ 4. Determine the battery capacity needed based on the
current draw of your system and your desired flight time.
❏ 5. Determine the ESC you need based on the system
current draw shown on the motor/prop chart. See the
ESC section.
PROCEDURE #2: If you know the approximate weight of
your airplane, including the motor and battery, and the
performance you want from it, answer the questions below
to determine the correct power system for your plane. You
may need to make more than one calculation using different
motors and battery combinations. See the battery section for
some of the battery weights for the suggested batteries.
❏ 1. Perform the following calculation to determine the
wattage required:
• If you expect trainer-like performance then multiply
75 x Airplane Weight (lbs)
• If you expect aerobatic or high speed-like performance
then multiply 100 x Airplane Weight (lbs)
• If you expect 3D or extreme performance multiply
150 x Airplane Weight (lbs)
❏ 2. The number you get is the minimum wattage you will
need for your plane to perform as you wish. Look at the
chart and determine what combination gives you the
performance you want based on wattage and
maximum propeller size that will fit on the plane.
❏ 3. Note the recommended battery voltage.
❏ 4. Determine if you want to use LiPo or NiMH batteries
based on the desired ready to fly airplane weight. Select
the number of cells based on the recommended voltage
shown in the chart.
DETERMINE WHAT YOU NEED TO
BUILD YOUR POWER SYSTEM
❏ 5. Determine the battery capacity needed based on the
current draw of your system and your desired flight time.
❏ 6. Determine the ESC you need based on the system
current draw.
In addition to these two procedures, you can also visit the
Great Planes ElectriFly web site for descriptions of the power
systems recommended for our line of electric and glow
airplanes as well as more detailed explanation on the subject.
UNDERSTANDING MOTORS
kV (rpm/volt): This is a number that gets thrown around
quite a bit when talking electrics and it is important to know
what it is. kV is the number of rpm a motor will spin per
each volt applied (rpm/volt) under no load.
This means that basically a motor that has a kV of 1000
when connected to a 12V battery will try to spin at
12,000rpm (1000x12) under no load. Likewise a 3500kV
motor will try to spin at 42,000rpm (3500x12) under no load.
When a propeller is attached to the motor, the motor will try
to spin the prop at the rated kV. Depending on the diameter
and pitch of the propeller (the larger the diameter or higher
the pitch, the harder it is to spin), the motor’s current draw
can be increased or decreased.There are meters available
from your hobby dealer that measure current and voltage.
Because every motor has a maximum current it can take
based on its design and cooling ability, the maximum size of
propeller that can be used with each motor can be
determined.Too large of a propeller and the motor will spin at
a much lower rpm than its rated kV, causing it to draw a lot of
current and overheat. If the propeller/fan is too small, it will
require little effort (current) to turn the prop at the rated kV.
Ideally the motor should be matched with a propeller that
causes the motor to draw 80-100% of its rated maximum
constant current. Once a power system is set up, it can be
fine-tuned by adjusting the propeller size and measuring
the amount of current the motor is drawing.
Please note that the kV of a motor does not change with
voltage, but if a higher voltage is applied to the motor, it will
try to spin the same propeller at a higher rpm. This will
cause the motor to draw more current and possibly exceed
the maximum rated current of the motor. So, if a battery with
lower voltage is replaced with one with a higher voltage, it
is recommended that a smaller propeller be used to keep
the current in check. If a higher voltage battery is replaced
by a lower voltage battery, the size of the propeller can be
increased to keep the motor at its rated current.
Another possibility to fine tune the power system’s
performance is to use another motor with higher kV to
increase the current or a lower kV to lower the current.
Once the required RimFire motor has been determined, it
needs to be installed on the plane. To determine the best
mounting system, the distance from the firewall to the front
of the prop adapter first needs to be determined.
It can be mounted directly to the firewall using the RimFire
aluminum mounting plate (included with the motor). or an
ElectriFly Medium Motor Mount (GPMG1255). Both
mounting systems are direct replacements for the Great
Planes .40-.70 nylon engine mount.
ASSEMBLE YOUR POWER SYSTEM
Check the airplane instruction manual for the correct
distance. These pictures show the distances from the
firewall to the front of the prop adapter using the different
mounting systems.
On the header card, you will find the mounting hole pattern
template for the Brushless Medium Motor Mount and RimFire
mounting plate. If you are replacing a glow engine with an
electric motor system, remove the nylon engine mount and
replace it with the Medium Motor Mount or RimFire mounting
plate, using the same bolts to attach it to the firewall. If the
firewall has not been drilled for an engine mount and blind
nuts, use the mounting template on the header card to locate
the mounting holes. Drill the four mounting holes and install
6-32 blind nuts from the back of the firewall.
If attaching the motor to the firewall using the adjustable motor
mount, skip to the
Adjustable Motor Mount Installation.
Attach the RimFire aluminum mounting plate to the motor
using four 3x8mm flat head machine screws. Apply a drop
of Great Planes Threadlocker (GPMR6060) to the screws
before installing them.
MOUNTING PLATE INSTALLATION
Attach the RimFire mounting plate to the firewall using four
6-32 machine screws and four #6 flat washers. Apply a
drop of Great Planes Threadlocker to the screws before
installing them. Mount the aluminum prop adapter to the
motor case using four 3x7mm SHC screws. Use a drop of
Threadlocker to the threads of each bolt.
Attach the Backplate of the motor mount to the firewall
using four 6-32 machine screws and four #6 flat washers.
Mount the RimFire motor to the motor mount front plate
(front or back) using four 3mm machine screws.
ADJUSTABLE MOTOR MOUNT
INSTALLATION
Install the collet or set screw prop adapter on the motor
shaft or the aluminum prop adapter on the motor case.The
RimFire 42mm motors use the 5mm prop adapter
(GPMQ4966 Collet Type or GPMQ4939 Set Screw Type).
ALUMINUM PROP ADAPTER INCLUDED
WITH MOTOR
Mount the aluminum prop adapter to the motor case using
four 3x7mm SHC screws. Use a drop of Threadlocker
(GPMR6060) to the treads of each bolt to prevent them
from coming loose.
COLLET TYPE PROP ADAPTER INSTALLATION
Slide the prop shaft over the output shaft of the gear drive or
motor. Next slide the prop shaft retainer over the prop shaft.
Note that the hole through the retainer is tapered. Make sure
that the side with the larger diameter hole is installed first.
Install the spinner backplate (if used, not included), the
prop, prop washer and then the prop nut.Tighten the prop nut
against the prop.This will cause the tapered hole in the prop
shaft retainer to squeeze the prop shaft around the output
shaft. Carefully pull on the prop to make sure it is securely
attached to the output shaft of the gear drive.
SET SCREW TYPE PROP
ADAPTER INSTALLATION
Slide the prop adapter over the output shaft of the gear
drive or motor. Apply a drop of Great Planes Threadlocker
(GPMR6060) to the set screws and install them in the prop
adapter, tightening them against the motor shaft.
Position the motor/front plate assembly between the
backplate. Measure the distance from the firewall to the
front of the prop adapter. Attach the front plate of the motor
mount to the back plate using the eight 4-40x1/4" SHC
screws and eight #4 flat washers, spaced out as far as
possible. A drop of Threadlocker on the threads of the
screws will prevent the screws from coming loose.
Note: Once the motor is mounted in position, the prop
adapter can be removed to allow the cowl to be mounted.
This adapter is easily installed with the cowl already installed.
• Once the battery is connected to the ESC, stay clear of
the motor and prop.
• DO NOT apply an input voltage that exceeds the
maximum specification of each motor.
• DO NOT apply currents to the motor that exceed the
maximum specifications of each motor.
• DO NOT allow the input connectors to accidentally touch
each other while power is applied to the motor. Make sure
all input connections are insulated electrically.
• DO NOT allow water or moisture to enter the motor, as it
can cause permanent damage to the motor and possibly
short out the attached ESC.
• DO NOT cut the coated wires from the motor. If you must
remove the bullet connectors, unsolder them.
• Allow the motor to cool after each flight.
• The motor shaft of the motor will rotate at very high rpm.
DO NOT attempt to touch the shaft while it is rotating. If
setting up the motor/ESC on the workbench, make sure
the motor is securely attached and that nothing is
attached to the motor shaft BEFORE applying power.
• Never attempt to use a damaged motor (having
mechanical or electrical defects).
• ElectriFly carries a complete line of Ammo (in-runner
style) and RimFire (out-runner style) brushless motors,
gear drives, motor mounts, prop adapters and speed
controls. For a complete list of these products, check out
our web site at:
www.greatplanes.com
www.electrifly.com
or visit your nearest hobby shop that carries the full line of
Great Planes and ElectriFly products.
IMPORTANT PRECAUTIONS
Because these motors have a wide range of current draws,
a variety of ElectriFly Silver Series Brushless ESCs are
recommended.
• SS-45 (GPMM1840) 45 amp continuous current for
motors drawing 45 amps or less.
• SS-60 (GPMM1850) 60 amps continuous current for
motors drawing 60 amps or less.
• SS-80 (GPMM1860) 80 amps continuous current for
motors drawing 80 amps or less.
See the chart on the header card for the current draw of
some of the motor/prop combinations that have been
tested. Always make sure that the ESC is positioned so
that it gets some cooling air flowing over it.
Use the instructions included with the ESC to correctly
connect the ESC.
RimFire brushless motors require virtually no maintenance.
There are no brushes to wear out and replace. The
precision bearings have a very long service life and should
last a very long time.The internal parts of the motor should
not require any cleaning. The only thing that needs to be
checked is to make sure all the screws and set screws
remain tight.
RIMFIRE MOTOR MAINTENANCE
INSTALL THE BRUSHLESS ESC
GPMZ0029 for Rimefire 42mm SystemsEntire Contents Copyright © 2006
Rimfire 42mm 4fold.qxd 6/15/2006 3:57 PM Page 2