Park View: Stevens AeroModel RingRat - 2011/01

January 2011 47
Park View: Stevens AeroModel RingRat
BOB ABERLE
The completed Stevens AeroModel Ring Rat kit spans 18 inches and weighs a total of only 6 ounces.
An electricpowered
CL model
for everybody
Photos by the author
The author (L) has programmed the
timer for a 1-minute-duration flight. To
the right—35 feet away—is Tom Hunt
coaching young Mark Salvator, who will
fly for the first time.
ELECTRIC POWER HAS been with
us for many years and continues to grow
as various technologies (motors,
batteries, ESCs, etc.) continue to
improve. Until approximately six years
ago, electric power was primarily
associated with radio-controlled model
aircraft. Today we are seeing it used in
more applications, such as FF and CL.
The lead photo in the article I wrote
titled “Advantages of Electric Power”
(published in the July MA) shows me
01sig2.QXD_00MSTRPG.QXD 11/22/10 1:32 PM Page 47
48 MODEL AVIATION
Specifications
Pluses and Minuses
+•
Accurate laser-cut parts.
• No plans required and builds quickly.
.
• Economic power system for flight
training, with higher-power options
available.
• Easy to fly for beginners.
• Flies smoothly and is durable. -•
Maximum flight time is three minutes
with recommended battery.
Test-Model Details
Power system: Stevens AeroModel
SA Sport BL-300 brushless outrunner
1,400 Kv motor; SA Sport 10-amp ESC;
Thunder Power two-cell, 325 mAh Li-
Poly battery; GWS 7 x 3.5 propeller; Eflite
Control Line Motor Timer
Motor current: 4.8 amps
Voltage: 7.20
Power input: 34 watts
Battery loading: 14.8C
Power loading: 90.6 watts/pound
Flight time: Four minutes all at full
throttle
Type: Electric CL
Skill level: Beginner builder,
beginner pilot
Wingspan: 18 inches
Wing area: 100 square inches
Length: 17.5 inches
Weight: 6.0 ounces
Wing loading: 8.7 ounces/square foot
Power required: 50-watt system
Construction: Laser-cut balsa
Price: $37.99
Right: The laser-cut
balsa parts supplied
with the RingRat
kit are extremely
accurate. Accessory
items needed to
complete the model
are available for a
reasonable price.
Below: The RingRat
can be f lown for
one to three minutes
at a pref l ightdetermined
speed.
Its lap times as a
trainer on 35-foot
lines are comfortable.
It has no problem
taking off from grass
with the available
power.
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:49 PM Page 48
January 2011 49
The author cut black stripes from MonoKote trim
material. He made the decals using adhesive-backed
decal paper from Desktop Publishing Supplies and his
ink-jet printer.
Bob points to the two holes he had to drill at the inboard wingtip for
passage of the leadout wires. These wires are installed permanently
after covering is applied.
The underside includes an access opening to allow inspection of the
bellcrank and lead wires. Velcro holds the battery and accessories
in place.
The fully assembled RingRat
was completed without the
need for full-size plans. The
wing will be covered with
film, and the fuselage and
tail will be painted.
Any output from zero to full can be obtained by
adjusting the motor speed using a small screwdriver.
This must be set while the airplane is on the ground.
The motor run-time period is set by pressing this switch. It has no
memory, so the timer must be set at the start of each flight, but
it takes no effort to do.
The vertical fin is attached to the
upper rear of the fuselage. The rudder
is set for some right turn, to keep the
control lines tight in flight.
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:51 PM Page 49
hand-launching a 300-square-inch FF model.
As a US CL Aerobatics team member in
2006, Bob Hunt (MA’s editor emeritus) flew
the first electric-powered model entered in a
World Championships.
So the message is clear; the use of electric
power is expanding. The question modelers
might have is how they can get involved with
an electric-powered CL model. I’ll answer
that question in detail.
Flying electric CL has a couple of
advantages, one of which is that flight is limited
to line length. Therefore, parking lots,
schoolyards, and even some large indoor
facilities can be used for flying. This eliminates
traveling long distances to flying sites.
Another benefit is that electric power is
quiet. So you can fly almost any time of the
day without upsetting the neighbors.
With these advantages in mind, Bill
Stevens of Stevens AeroModel introduced a
series of three small electric CL designs. He
has produced a variety of excellent kits
throughout the years, including trainers, sport
fliers, aerobatic 3-D models, scale racers,
micro airplanes, and FF aircraft.
Bill’s specialty is laser-cut parts kits that
require assembling, painting, and/or
covering. He also sells all of the support
equipment for these designs, including
motors, batteries, ESCs, cements, covering
materials, etc.
The electric CL aircraft that Bill added to
his product line are a basic trainer named the
RingRat (item CL-100), a larger RingRat
(item CL-250) that is intended for use as an
introduction into CL Aerobatics, and the
SCRAM!: an electric Combat model.
The basic RingRat is a good starting point
for CL. The concept is that there are two
kinds of fliers who would be interested in
this kind of airplane.
The first is an experienced aeromodeler
who wants to get a child interested in model
aviation. The second type of flier is an oldtime
modeler who flew CL years ago but has
been an RC pilot for many years. At this
point in life this person might want to get
back to his or her roots.
In either situation, the little RingRat
offers a quick and inexpensive way to
participate in CL—and now with electric
power.
The Kit: The RingRat kit is total simplicity.
It consists of eight sheets of laser-cut balsa
and plywood parts. Everything fits perfectly
and easily.
It also includes essentially all necessary
hardware, including the bellcrank, control
horn, control rod, wheels, landing gear, tail
skid, and more. The 26-page assembly
manual contains many photos with detailed
captions. Full-size plans are neither supplied
nor required.
Assembly involves a built-up wing with
laser-cut ribs and spars. The fuselage is a
profile type made from 3/16 balsa. The tail
surfaces are all sheet balsa. I built the entire
aircraft frame using medium CA glue and
accelerator.
The wing was covered with yellow Solite
(Solarfilm). I sprayed the fuselage and tail
surfaces with a coat of Rust-Oleum Painter’s
Touch sandable primer, followed by a spray
coat of Krylon-brand Short-Cuts. Sun Yellow
(item SCS036) matched the Solite perfectly.
I estimate that the total assembly and
finishing time on my RingRat was less than
two days. The only slight problem I had was
not providing clearance holes for the two
leadout wires. Those holes are needed on the
inboard wingtip. I simply corrected the
problem by drilling the two 1/16-inchdiameter
holes and then inserting the supplied
tubing.
I rate the assembly process as easy.
Having a reasonably experienced modeler as
a coach would be helpful, but it is not
essential.
All of the necessary power-system
components must be purchased separately.
You can buy the equipment you want to use
or purchase all of it from Stevens
AeroModel.
My model is powered by an SA Sport
BL-300 1400 Kv brushless outrunner motor
($17.95) that runs at approximately 34 watts
of input power. It also has an SA Sport 10-
amp brushless ESC ($16.99); a Thunder
Power two-cell, 325 mAh 45C Li-Poly
battery (item THP3252SP45, for $16.99); a
GWS 7 x 3.5 propeller; and, most important,
an E-flite Control Line Motor Timer (item
EFLA172, for $10.99), which Bob Wilder, a
noted indoor modeler, designed.
The combination of the kit and these extra
items totaled nearly $115. That price does
50 MODEL AVIATION
Ever Soaring Models (ESM) has 28 Scale models to choose
from, ranging in size from 71” to 103”. Prices start at $279!!!
Please see our website for complete listing details!
ARF Pros are Now the
Exclusive US
Impor ter for
ARFPROMODELPLANES.COM
CALL 941-488-9088 TO ORDER
or email [email protected]
We are the ARF Professionals
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:51 PM Page 50
January 2011 51
AMA WEB SITE TAKES
FLIGHT
As does building a model from
scratch, the process of creating a Web
site takes months of planning and
design. Our objective was to make the
AMA site—www.modelaircraft.org—
more user-friendly, highly interactive,
and feature-driven.
The six-month process began with
you, the AMA member. We compiled
surveys, shared ideas, and conducted
a lot of research. A few dozen designs
and hundreds of pots of coffee later, we
landed on a layout that encompasses
our objectives.
AMA members and clubs have
access to all of the fi les and resources
found on the previous site, plus so
much more. Visit the newly
updated AMA Web
site and share
your thoughts
on our forum or at
www.facebook.com/
modelaviation.
Search
Easily fi nd features
and resources with our
improved search tool.
Learn
You are always just one
click away from your
favorite AMA publications
and online resources.
Engage
Interact with other
AMA members and staff
through social networks.
Receive
Stay in the know with a
news ticker that rotates
with breaking stories,
features, and regulations.
Read
Discover dozens
of stories, features,
and AMA efforts to
preserve the hobby
throughout the site.
Gather
Tab over the different
departments and
services in this more
user-friendly layout.
www.modelaircraft.org www.masportaviator.com
not include covering, adhesive, or paint.
Installing the electric power equipment is
easy. All of the components have connectors,
so no soldering is necessary. Four wood
screws attach the motor to the plywood
firewall. The ESC, battery, and motor timer
are affixed to the profile fuselage with hookand-
loop fastener.
To start and stop the motor, you need that
all-important motor timer. It will let you
adjust the motor speed from idle to full power
by rotating one knob with a screwdriver. A
push-button switch on the timer will allow
you to set the motor-run duration in oneminute
increments. Instructions supplied with
my motor timer spell out everything.
The power system I selected worked
flawlessly during the many test flights that
were made for this article.
The are other items to consider. You will
need a control handle and a pair of 35-foot
Dacron lines. Stevens AeroModel sells a Sig
1/2A handle and lines (item SIGSH544) for
$7.99.
Another required piece of equipment is a
battery charger that can handle two Li-Poly
cells. Make sure that whatever charger you
employ mates with the balanced node
connector on your battery. (In my case it was
a Thunder Power connector.)
Final Touches: I set elevator control travel at
a minimum since the RingRat is a trainer.
This particular model is not meant to do
loops. I measured the elevator control throw
on my model as 1/2 inch up and 3/8 inch down,
with respect to the neutral (level) position.
The total weight of the RingRat with the
specified battery pack was 6.0 ounces. I
measured the balance point at 11/2 inches back
from the wing LE.
Flying:My friends and I have flown this
RingRat several dozen times. We have made
every flight off of a low-cut grass field.
On several occasions the model went
straight into the ground, and the only damage
in each case was a broken propeller. The
message was to take plenty of propellers to
the field and plenty of O-rings to hold the
propeller to the prop-saver adapter.
We basically use full power, which is
close to 34 watts of input at a 6-ounce total
weight. That works out to a power loading of
90 watts per pound, so the airplane takes off
in a hurry. Several experienced modelers, who
learned to fly years ago with CL models, had
no problem flying the Ring Rat.
At first we set one-minute motor runs on
the timer. Then we worked up to two and
three minutes. That’s nearing the time limit
for this size of battery. Three minutes with a
fast model such as this on 35-foot lines is
enough.
I let several 10- to 12-year-olds fly the
RingRat. One thing we learned for sure is that
it does not like a lot of wind. Approximately 5
mph is comfortable. At 10 mph we had our
hands full—especially the younger fliers.
We employed several battery packs. One
was always on charge while we flew with
another, which permitted almost continuous
flying. No one got bored with this activity.
All of the test pilots eventually performed
wingovers (in low winds). As I mentioned,
loops cannot be done with this model unless
elevator control throw is increased and the
CG (balance point) is shifted aft somewhat.
Moving on to the next-size RingRat would
be a better way to advance.
This is one rugged airplane. The grass
field helped, but we did not hold back in the
learning process and it held together
perfectly (except for the propellers).
The RingRat is a perfect electric CL trainer.
It’s easy to build, is inexpensive, and flies
exceptionally well.
Keep in mind that this series of models
was made small intentionally, so that short
control lines could be used. This keeps the
necessary field size to a minimum and even
allows you to fly it indoors in facilities with
the proper ceiling clearance.
If you catch on with this size of model, be
aware that many larger electric CL ARFs are
being advertised these days. This is getting
serious. MA
Bob Aberle
[email protected]
Manufacturer:
Stevens AeroModel
Box 15347
Colorado Springs CO 80935
(719) 387-4187
www.stevensaero.com
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:52 PM Page 51

January 2011 47
Park View: Stevens AeroModel RingRat
BOB ABERLE
The completed Stevens AeroModel Ring Rat kit spans 18 inches and weighs a total of only 6 ounces.
An electricpowered
CL model
for everybody
Photos by the author
The author (L) has programmed the
timer for a 1-minute-duration flight. To
the right—35 feet away—is Tom Hunt
coaching young Mark Salvator, who will
fly for the first time.
ELECTRIC POWER HAS been with
us for many years and continues to grow
as various technologies (motors,
batteries, ESCs, etc.) continue to
improve. Until approximately six years
ago, electric power was primarily
associated with radio-controlled model
aircraft. Today we are seeing it used in
more applications, such as FF and CL.
The lead photo in the article I wrote
titled “Advantages of Electric Power”
(published in the July MA) shows me
01sig2.QXD_00MSTRPG.QXD 11/22/10 1:32 PM Page 47
48 MODEL AVIATION
Specifications
Pluses and Minuses
+•
Accurate laser-cut parts.
• No plans required and builds quickly.
.
• Economic power system for flight
training, with higher-power options
available.
• Easy to fly for beginners.
• Flies smoothly and is durable. -•
Maximum flight time is three minutes
with recommended battery.
Test-Model Details
Power system: Stevens AeroModel
SA Sport BL-300 brushless outrunner
1,400 Kv motor; SA Sport 10-amp ESC;
Thunder Power two-cell, 325 mAh Li-
Poly battery; GWS 7 x 3.5 propeller; Eflite
Control Line Motor Timer
Motor current: 4.8 amps
Voltage: 7.20
Power input: 34 watts
Battery loading: 14.8C
Power loading: 90.6 watts/pound
Flight time: Four minutes all at full
throttle
Type: Electric CL
Skill level: Beginner builder,
beginner pilot
Wingspan: 18 inches
Wing area: 100 square inches
Length: 17.5 inches
Weight: 6.0 ounces
Wing loading: 8.7 ounces/square foot
Power required: 50-watt system
Construction: Laser-cut balsa
Price: $37.99
Right: The laser-cut
balsa parts supplied
with the RingRat
kit are extremely
accurate. Accessory
items needed to
complete the model
are available for a
reasonable price.
Below: The RingRat
can be f lown for
one to three minutes
at a pref l ightdetermined
speed.
Its lap times as a
trainer on 35-foot
lines are comfortable.
It has no problem
taking off from grass
with the available
power.
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:49 PM Page 48
January 2011 49
The author cut black stripes from MonoKote trim
material. He made the decals using adhesive-backed
decal paper from Desktop Publishing Supplies and his
ink-jet printer.
Bob points to the two holes he had to drill at the inboard wingtip for
passage of the leadout wires. These wires are installed permanently
after covering is applied.
The underside includes an access opening to allow inspection of the
bellcrank and lead wires. Velcro holds the battery and accessories
in place.
The fully assembled RingRat
was completed without the
need for full-size plans. The
wing will be covered with
film, and the fuselage and
tail will be painted.
Any output from zero to full can be obtained by
adjusting the motor speed using a small screwdriver.
This must be set while the airplane is on the ground.
The motor run-time period is set by pressing this switch. It has no
memory, so the timer must be set at the start of each flight, but
it takes no effort to do.
The vertical fin is attached to the
upper rear of the fuselage. The rudder
is set for some right turn, to keep the
control lines tight in flight.
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:51 PM Page 49
hand-launching a 300-square-inch FF model.
As a US CL Aerobatics team member in
2006, Bob Hunt (MA’s editor emeritus) flew
the first electric-powered model entered in a
World Championships.
So the message is clear; the use of electric
power is expanding. The question modelers
might have is how they can get involved with
an electric-powered CL model. I’ll answer
that question in detail.
Flying electric CL has a couple of
advantages, one of which is that flight is limited
to line length. Therefore, parking lots,
schoolyards, and even some large indoor
facilities can be used for flying. This eliminates
traveling long distances to flying sites.
Another benefit is that electric power is
quiet. So you can fly almost any time of the
day without upsetting the neighbors.
With these advantages in mind, Bill
Stevens of Stevens AeroModel introduced a
series of three small electric CL designs. He
has produced a variety of excellent kits
throughout the years, including trainers, sport
fliers, aerobatic 3-D models, scale racers,
micro airplanes, and FF aircraft.
Bill’s specialty is laser-cut parts kits that
require assembling, painting, and/or
covering. He also sells all of the support
equipment for these designs, including
motors, batteries, ESCs, cements, covering
materials, etc.
The electric CL aircraft that Bill added to
his product line are a basic trainer named the
RingRat (item CL-100), a larger RingRat
(item CL-250) that is intended for use as an
introduction into CL Aerobatics, and the
SCRAM!: an electric Combat model.
The basic RingRat is a good starting point
for CL. The concept is that there are two
kinds of fliers who would be interested in
this kind of airplane.
The first is an experienced aeromodeler
who wants to get a child interested in model
aviation. The second type of flier is an oldtime
modeler who flew CL years ago but has
been an RC pilot for many years. At this
point in life this person might want to get
back to his or her roots.
In either situation, the little RingRat
offers a quick and inexpensive way to
participate in CL—and now with electric
power.
The Kit: The RingRat kit is total simplicity.
It consists of eight sheets of laser-cut balsa
and plywood parts. Everything fits perfectly
and easily.
It also includes essentially all necessary
hardware, including the bellcrank, control
horn, control rod, wheels, landing gear, tail
skid, and more. The 26-page assembly
manual contains many photos with detailed
captions. Full-size plans are neither supplied
nor required.
Assembly involves a built-up wing with
laser-cut ribs and spars. The fuselage is a
profile type made from 3/16 balsa. The tail
surfaces are all sheet balsa. I built the entire
aircraft frame using medium CA glue and
accelerator.
The wing was covered with yellow Solite
(Solarfilm). I sprayed the fuselage and tail
surfaces with a coat of Rust-Oleum Painter’s
Touch sandable primer, followed by a spray
coat of Krylon-brand Short-Cuts. Sun Yellow
(item SCS036) matched the Solite perfectly.
I estimate that the total assembly and
finishing time on my RingRat was less than
two days. The only slight problem I had was
not providing clearance holes for the two
leadout wires. Those holes are needed on the
inboard wingtip. I simply corrected the
problem by drilling the two 1/16-inchdiameter
holes and then inserting the supplied
tubing.
I rate the assembly process as easy.
Having a reasonably experienced modeler as
a coach would be helpful, but it is not
essential.
All of the necessary power-system
components must be purchased separately.
You can buy the equipment you want to use
or purchase all of it from Stevens
AeroModel.
My model is powered by an SA Sport
BL-300 1400 Kv brushless outrunner motor
($17.95) that runs at approximately 34 watts
of input power. It also has an SA Sport 10-
amp brushless ESC ($16.99); a Thunder
Power two-cell, 325 mAh 45C Li-Poly
battery (item THP3252SP45, for $16.99); a
GWS 7 x 3.5 propeller; and, most important,
an E-flite Control Line Motor Timer (item
EFLA172, for $10.99), which Bob Wilder, a
noted indoor modeler, designed.
The combination of the kit and these extra
items totaled nearly $115. That price does
50 MODEL AVIATION
Ever Soaring Models (ESM) has 28 Scale models to choose
from, ranging in size from 71” to 103”. Prices start at $279!!!
Please see our website for complete listing details!
ARF Pros are Now the
Exclusive US
Impor ter for
ARFPROMODELPLANES.COM
CALL 941-488-9088 TO ORDER
or email [email protected]
We are the ARF Professionals
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:51 PM Page 50
January 2011 51
AMA WEB SITE TAKES
FLIGHT
As does building a model from
scratch, the process of creating a Web
site takes months of planning and
design. Our objective was to make the
AMA site—www.modelaircraft.org—
more user-friendly, highly interactive,
and feature-driven.
The six-month process began with
you, the AMA member. We compiled
surveys, shared ideas, and conducted
a lot of research. A few dozen designs
and hundreds of pots of coffee later, we
landed on a layout that encompasses
our objectives.
AMA members and clubs have
access to all of the fi les and resources
found on the previous site, plus so
much more. Visit the newly
updated AMA Web
site and share
your thoughts
on our forum or at
www.facebook.com/
modelaviation.
Search
Easily fi nd features
and resources with our
improved search tool.
Learn
You are always just one
click away from your
favorite AMA publications
and online resources.
Engage
Interact with other
AMA members and staff
through social networks.
Receive
Stay in the know with a
news ticker that rotates
with breaking stories,
features, and regulations.
Read
Discover dozens
of stories, features,
and AMA efforts to
preserve the hobby
throughout the site.
Gather
Tab over the different
departments and
services in this more
user-friendly layout.
www.modelaircraft.org www.masportaviator.com
not include covering, adhesive, or paint.
Installing the electric power equipment is
easy. All of the components have connectors,
so no soldering is necessary. Four wood
screws attach the motor to the plywood
firewall. The ESC, battery, and motor timer
are affixed to the profile fuselage with hookand-
loop fastener.
To start and stop the motor, you need that
all-important motor timer. It will let you
adjust the motor speed from idle to full power
by rotating one knob with a screwdriver. A
push-button switch on the timer will allow
you to set the motor-run duration in oneminute
increments. Instructions supplied with
my motor timer spell out everything.
The power system I selected worked
flawlessly during the many test flights that
were made for this article.
The are other items to consider. You will
need a control handle and a pair of 35-foot
Dacron lines. Stevens AeroModel sells a Sig
1/2A handle and lines (item SIGSH544) for
$7.99.
Another required piece of equipment is a
battery charger that can handle two Li-Poly
cells. Make sure that whatever charger you
employ mates with the balanced node
connector on your battery. (In my case it was
a Thunder Power connector.)
Final Touches: I set elevator control travel at
a minimum since the RingRat is a trainer.
This particular model is not meant to do
loops. I measured the elevator control throw
on my model as 1/2 inch up and 3/8 inch down,
with respect to the neutral (level) position.
The total weight of the RingRat with the
specified battery pack was 6.0 ounces. I
measured the balance point at 11/2 inches back
from the wing LE.
Flying:My friends and I have flown this
RingRat several dozen times. We have made
every flight off of a low-cut grass field.
On several occasions the model went
straight into the ground, and the only damage
in each case was a broken propeller. The
message was to take plenty of propellers to
the field and plenty of O-rings to hold the
propeller to the prop-saver adapter.
We basically use full power, which is
close to 34 watts of input at a 6-ounce total
weight. That works out to a power loading of
90 watts per pound, so the airplane takes off
in a hurry. Several experienced modelers, who
learned to fly years ago with CL models, had
no problem flying the Ring Rat.
At first we set one-minute motor runs on
the timer. Then we worked up to two and
three minutes. That’s nearing the time limit
for this size of battery. Three minutes with a
fast model such as this on 35-foot lines is
enough.
I let several 10- to 12-year-olds fly the
RingRat. One thing we learned for sure is that
it does not like a lot of wind. Approximately 5
mph is comfortable. At 10 mph we had our
hands full—especially the younger fliers.
We employed several battery packs. One
was always on charge while we flew with
another, which permitted almost continuous
flying. No one got bored with this activity.
All of the test pilots eventually performed
wingovers (in low winds). As I mentioned,
loops cannot be done with this model unless
elevator control throw is increased and the
CG (balance point) is shifted aft somewhat.
Moving on to the next-size RingRat would
be a better way to advance.
This is one rugged airplane. The grass
field helped, but we did not hold back in the
learning process and it held together
perfectly (except for the propellers).
The RingRat is a perfect electric CL trainer.
It’s easy to build, is inexpensive, and flies
exceptionally well.
Keep in mind that this series of models
was made small intentionally, so that short
control lines could be used. This keeps the
necessary field size to a minimum and even
allows you to fly it indoors in facilities with
the proper ceiling clearance.
If you catch on with this size of model, be
aware that many larger electric CL ARFs are
being advertised these days. This is getting
serious. MA
Bob Aberle
[email protected]
Manufacturer:
Stevens AeroModel
Box 15347
Colorado Springs CO 80935
(719) 387-4187
www.stevensaero.com
01sig2.QXD_00MSTRPG.QXD 11/19/10 4:52 PM Page 51