60 MODEL AVIATION
BOB ABERLE
Static photos by the author
Flight photos by Ray Juschkus This electric-powered racer features
high-end extras and color options
Pluses and Minuses
+
• Shock-absorbing main landing gears
with wheels.
• Steerable, shock-absorbing tail-wheel
assembly.
• Molded-fiberglass wheel pants and
cowl with scale radial engine cylinders.
• Scale wing struts.
• All control surfaces are hinged with
provided control rods and hardware.
• Completely covered model with
certain areas spray-painted.
-• Prototype assembly manual was not
particularly helpful, but this has been
updated making assembly much easier.
The Gee Bee is eye-catching in
the air. Tom Hunt performed all
the flight-testing and gave the
thumbs-up afterward.
GRANVILLE BROTHERS Aircraft’s
series of full-scale racing airplanes dates
back to the early 1930s. The company
built a total of 24 aircraft, and only three
of the originals are known to exist today.
(For more information about the Granville
brothers’ aircraft, see the source list at the
end of this article.)
Through the years, many of the
Granville designs have been featured as
scale RC models in various hobby
publications. The AMA Plans Service has
several pages of model plans for many of
the company’s various aircraft.
The Granville airplanes’ sleek lines
make them popular modeling subjects that
have earned the reputation of being good
fliers. Most of these designs were
characterized by large engine cowls,
streamlined wheel pants, and wing struts
mounted on top of low wings.
Green RC Models (based in China)
designed and constructed the Gee Bee
Model Y Senior Sportster I have reviewed
for this article. The model is distributed in
the US by Maxford USA. (See the source
list for contact information.) On the Web
site you can access an excellent set of
detailed photos by clicking on “View
More Images.” There is also a link to a
flight video.
Be advised that the particular kit I
reviewed was an early prototype model
and has been replaced with an improved
version that is easier to assemble and is
supplemented with the updated instruction
sheet, just mentioned. But understand that
this prototype ARF was still an excellentflying
aircraft.
The electric-powered Model Y is
slightly larger than an average park flyer.
It is constructed from laser-cut balsa and
plywood that is factory covered and spraypainted
in some areas. There is a choice of
three color schemes: red/black, red/white,
and yellow/black.
The Gee Bee ARF includes everything
except the motor, ESC, battery, and RC
system. There is also a combo deal, which
includes the airplane, brushless outrunner
motor, and ESC, for $209.99. Then you
will need to buy only a battery and supply
the RC system (which needs a receiver
and four servos).
The model has a 40-inch wingspan,
306 square inches of wing area, and
weighs 28-34 ounces. The recommended
motor is the Uranus 28309 (from Maxford
USA), running on a three-cell Li-Poly
battery pack at approximately 18-23 amps
and 200-250 watts of input power. This
will provide power loadings in the range
of 100-130 watts per pound, making it an
aggressive aerobatic performer (at full
throttle).
This Gee Bee seems to have been crafted
by people who understand model
building. Thanks to precision lasercutting,
all major parts fit easily. Both the
Park View: Green RC Models Gee Bee Model Y Senior Sportster
Test-Model Details
Specifications
Type: Park Pilot Program-legal
semiscale ARF
Skill level: Intermediate builder and
pilot
Wingspan: 40 inches
Wing area: 306 square inches
Length: 30 inches
Weight: 28-34 ounces
Wing loading: 16 ounces/square
foot
Power (recommended): 275-
watt motor, 11.1-volt Li-Poly
battery, 25-amp ESC
Radio: Four channels (minimum),
four miniservos
Construction: Balsa, light plywood,
fiberglass cowling and wheel spats
Covering/finish: Heat-shrink film,
high-gloss paint
Price: $145.99
Motor: Uranus 28309 brushless
outrunner
Battery: Three-cell, 2200 mAh with
15C load capability
Propeller: APC 9 x 6E
Motor current: 18 amps
Power loading: 92 watts/pound
Motor output: 197 watts input
Radio system: Polk’s Hobby
Tracker III transmitter, Polk’s Hobby
Seeker 6 receiver, four Hitec HS-81
servos, two 6-inch extensions, one Y
harness, one 25-amp ESC
Ready-to-fly weight: 34 ounces
Flight duration: Seven to 10
minutes
Above: The Gee Bee is available in a
choice of three color schemes, as
shown on the side of the box.
Left: The balsa and plywood has
iron-on covering. All hinges are
already in place. The cowl and wheel
pants are spray-painted.
scale engine cowl and the large wheel
pants are made from molded fiberglass
that has been spray-painted to match the
color of the covering material exactly.
Equally impressive are the scalelike
shock-absorbing main landing-gear
assemblies. Even the steerable tail-wheel
assembly has a shock-absorbing spring.
Totally impressive is the best way to
describe the construction.
Your RC system will require a receiver
and four servos (one for the elevator, one
for the rudder, and two for the ailerons). I
selected Hitec HS-81 servos, which were
larger than the openings provided in the
wing. This required some “surgery” to get
them mounted in place. Choosing a
smaller servo, like the HS-65 or even the
HS-55, would provide more than enough
power and eliminate the time-consuming
step I took of enlarging the pockets in the
wing.
Since the wing arrives covered, the
manufacturer thoughtfully provided a
length of string so you can pull the aileron
servo cables through a series of holes in
the wing ribs and then out through the top
center-section. I needed a 6-inch aileron
extension cable on each servo, and then in
the center-section I combined the two
extensions with a Y-harness cable that
allowed both aileron servos to plug into
one port on the receiver.
The rudder is controlled by two cables
for a pull-pull-type installation. The trick
is to get these cables through holes in the
rear of the fuselage and then bring them
forward into the RC compartment.
Clip connectors are preinstalled on one
side of these cables. Put the other end of
the cables (no connector) in the
preinstalled wire tubes that exit at the rear
of the fuselage, on both sides. The cables
then come out inside of the fuselage,
where they can be brought forward to the
rudder-servo output arm. The final step is
to use the little metal tube and clip to
attach the cables to both sides of the servo
arm.
You can mount the motor directly to
the plywood box, without using the
adapter plate. The only problem is that the
four screws are slightly short. So I
countersunk each hole from the rear,
September 2008 61
62 MODEL AVIATION
Left: The power-system air-cooling holes
in the front of the cowl are more than
adequate. The air passes out through the
open cockpit. A neat and practical idea!
Above: The stabilizer
has been cemented in
place; the vertical
fin/rudder goes next.
Notice the tabs and
slots that add strength
and make aligning
these tail surfaces easy.
Right: Be careful when
installing the two main
landing-gear struts. The
shock-absorbing spring
must face the rear of
the aircraft or it won’t
fit into the wheel pant.
Above: The rudder
servo is located aft of
the elevator servo and
in the center of the
RC compartment. A
separate cable goes to
each side of the
rudder; equal tension
on these control wires
is essential.
Above: The first step in the landing-gear
installation is to place the small plywood
insert in the end of the wire strut. No glue
is necessary.
allowing the screws to go a bit deeper, and it worked. Once
mounted to the plywood box, the motor will have a slight amount
of down and right thrust.
A battery box is located directly under the motor mounting
box. The three-cell Li-Poly battery pack I selected weighed 5.7
ounces. This was close to the recommended 2100 mAh battery
pack.
If a lower-capacity and lighter-weight pack were used, the
model could come out tail-heavy. Be sure to consider that when
you select the battery for this application. The current version of
the Gee Bee has a much larger battery-compartment cover,
making it easy to remove the battery for charging purposes
without having to remove the wing.
I did find that the motor rubbed against the forward portion of
the cowl. The opening had to be opened somewhat using a
Dremel tool and a drum-sander attachment. This also provided
more cooling air to enter the front of the motor, which was a
bonus.
The two main landing-gear struts must be installed exactly per
the instructions. The U-shaped wire strut top goes into a slot that
is precut in the wing. You actually remove the wire from the top
of the strut assembly.
After pressing it into the slot, pass the remainder of the
landing gear (with the shock-absorbing spring) up through the
wheel pant and out the top. Then engage the landing-gear
assembly into the protruding wire. Move the pant in place and
screw it to the lower side of the wing in two places.
Take particular note of the tail-wheel bracket. There is a metal
bracket that attaches to the lower rear of the fuselage that is most
important. It acts as a bearing and eliminates any stress placed on
the hinges. Failure to use that bracket could result in the rudder’s
falling off the aircraft.
When I ran up the brushless motor the first time on the
recommended APC 10 x 4.7SF propeller, it drew 23 amps and
258 watts of input power, which is at the upper end of what this
unit can handle. That particular propeller should not be run at that
power level. I decided to switch to an APC 9 x 6E (a high-rpm
propeller) and got the current down to 18 amps and the input
power to just less than 200 watts.
The resulting power loading is still a respectable 92 watts per
pound, which can make for some aggressive flying at full throttle.
With the 2200 mAh battery pack, I was able to obtain flights
exceeding 10 minutes with some throttling.
My Gee Bee’s final weight was at the upper end: 34 ounces.
The CG ended up slightly forward of the recommended 60mm
(23/8 inches, or 28% of the chord) from the wing LE. That
location worked well for me and being that it was so close to the
recommendation, I did not change the location.
Final control throws worked out to 7/8 inch on either side of
the neutral position for the ailerons and elevator and 11/4 inches
on either side for the rudder.
Flying: I finished the Gee Bee’s assembly in late January. Since I
was heading south to Florida during February and March, I
passed the model on to Tom Hunt, fellow Model Aviation Hall of
Famer and NEAT [Northeast Electric Aircraft Technology] Fair
director, who volunteered to do the initial flight tests. Ray
Juschkus, a professional photographer and AMA District II
associate vice president, took all the flight photos shown in this
review.
The Gee Bee certainly isn’t a candidate for hand launching, but
it can take off from rough fields with comparative ease, thanks to
that pair of shock-absorbing landing-gear struts. Make sure there is
enough clearance between the wheels and the fiberglass pants for
movement and a freely rotating wheel.
The Gee Bee flew great. It has plenty of power for all kinds of
aerobatics. Because of the speed at full throttle, consider adding
some exponential rate control (if you have it on your transmitter) to
the ailerons, elevator, and rudder. I used roughly 20% exponential
rate on all three flight controls to smooth things out a little.
This Gee Bee proved to be a wonderful experience. My prototype
ARF took a little longer to assemble. The new version, now being
sold, eliminates some of the “start-up” problems I found. The
assembly job should prove to be easy and fast.
I would have no problem assembling and flying other Green
RC Models aircraft, and the price tag is well worth it. Had I built
this Gee Bee from scratch, I estimate that it would have cost
much more than the current street price and might have taken
several months to construct. With this ARF, an RC pilot can be at
the flying field in less than a week. Best of all was the model’s
great performance in the air. It’s a totally worthwhile project! MA
Bob Aberle
[email protected]
Manufacturer/Distributor:
Green Models/Maxford USA
(866) 706-8288
www.maxfordusa.com/gm-gb-ep-wr.aspx
Sources:
Granville Brothers information
http://en.wikipedia.org/wiki/Granville_Brothers_Aircraft
Landing Products (APC propellers)
(530) 661-0399
www.apcprop.com
Polk’s Hobby
(973) 351-9800
www.polkshobby.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Other Reviews:
Model Airplane News: January 2008
RC Sport Flyer: June 2008
Fly RC: April 2008
Left: The front
portion of the
battery box had to
be trimmed to
provide clearance
for the ring cowl.
The battery box
will suit a 3S 1300-
2100 mAh Li-Poly
pack.
Once the two upper wing
struts are attached, you
are likely not to touch
the wing again. The 40-
inch span makes it easy
to transport with the
wing in place.
Above: The Gee Bee’s
empennage houses a
steerable, spring-loaded
tail-wheel assembly. All
control-surface hinging
is done at the factory.
Above: The molded-fiberglass wheel
pants add so much to the overall scale
appearance. There are two aileron
servos—one in each wing.
September 2008 63
Edition: Model Aviation - 2008/09
Page Numbers: 60,61,62,63
Edition: Model Aviation - 2008/09
Page Numbers: 60,61,62,63
60 MODEL AVIATION
BOB ABERLE
Static photos by the author
Flight photos by Ray Juschkus This electric-powered racer features
high-end extras and color options
Pluses and Minuses
+
• Shock-absorbing main landing gears
with wheels.
• Steerable, shock-absorbing tail-wheel
assembly.
• Molded-fiberglass wheel pants and
cowl with scale radial engine cylinders.
• Scale wing struts.
• All control surfaces are hinged with
provided control rods and hardware.
• Completely covered model with
certain areas spray-painted.
-• Prototype assembly manual was not
particularly helpful, but this has been
updated making assembly much easier.
The Gee Bee is eye-catching in
the air. Tom Hunt performed all
the flight-testing and gave the
thumbs-up afterward.
GRANVILLE BROTHERS Aircraft’s
series of full-scale racing airplanes dates
back to the early 1930s. The company
built a total of 24 aircraft, and only three
of the originals are known to exist today.
(For more information about the Granville
brothers’ aircraft, see the source list at the
end of this article.)
Through the years, many of the
Granville designs have been featured as
scale RC models in various hobby
publications. The AMA Plans Service has
several pages of model plans for many of
the company’s various aircraft.
The Granville airplanes’ sleek lines
make them popular modeling subjects that
have earned the reputation of being good
fliers. Most of these designs were
characterized by large engine cowls,
streamlined wheel pants, and wing struts
mounted on top of low wings.
Green RC Models (based in China)
designed and constructed the Gee Bee
Model Y Senior Sportster I have reviewed
for this article. The model is distributed in
the US by Maxford USA. (See the source
list for contact information.) On the Web
site you can access an excellent set of
detailed photos by clicking on “View
More Images.” There is also a link to a
flight video.
Be advised that the particular kit I
reviewed was an early prototype model
and has been replaced with an improved
version that is easier to assemble and is
supplemented with the updated instruction
sheet, just mentioned. But understand that
this prototype ARF was still an excellentflying
aircraft.
The electric-powered Model Y is
slightly larger than an average park flyer.
It is constructed from laser-cut balsa and
plywood that is factory covered and spraypainted
in some areas. There is a choice of
three color schemes: red/black, red/white,
and yellow/black.
The Gee Bee ARF includes everything
except the motor, ESC, battery, and RC
system. There is also a combo deal, which
includes the airplane, brushless outrunner
motor, and ESC, for $209.99. Then you
will need to buy only a battery and supply
the RC system (which needs a receiver
and four servos).
The model has a 40-inch wingspan,
306 square inches of wing area, and
weighs 28-34 ounces. The recommended
motor is the Uranus 28309 (from Maxford
USA), running on a three-cell Li-Poly
battery pack at approximately 18-23 amps
and 200-250 watts of input power. This
will provide power loadings in the range
of 100-130 watts per pound, making it an
aggressive aerobatic performer (at full
throttle).
This Gee Bee seems to have been crafted
by people who understand model
building. Thanks to precision lasercutting,
all major parts fit easily. Both the
Park View: Green RC Models Gee Bee Model Y Senior Sportster
Test-Model Details
Specifications
Type: Park Pilot Program-legal
semiscale ARF
Skill level: Intermediate builder and
pilot
Wingspan: 40 inches
Wing area: 306 square inches
Length: 30 inches
Weight: 28-34 ounces
Wing loading: 16 ounces/square
foot
Power (recommended): 275-
watt motor, 11.1-volt Li-Poly
battery, 25-amp ESC
Radio: Four channels (minimum),
four miniservos
Construction: Balsa, light plywood,
fiberglass cowling and wheel spats
Covering/finish: Heat-shrink film,
high-gloss paint
Price: $145.99
Motor: Uranus 28309 brushless
outrunner
Battery: Three-cell, 2200 mAh with
15C load capability
Propeller: APC 9 x 6E
Motor current: 18 amps
Power loading: 92 watts/pound
Motor output: 197 watts input
Radio system: Polk’s Hobby
Tracker III transmitter, Polk’s Hobby
Seeker 6 receiver, four Hitec HS-81
servos, two 6-inch extensions, one Y
harness, one 25-amp ESC
Ready-to-fly weight: 34 ounces
Flight duration: Seven to 10
minutes
Above: The Gee Bee is available in a
choice of three color schemes, as
shown on the side of the box.
Left: The balsa and plywood has
iron-on covering. All hinges are
already in place. The cowl and wheel
pants are spray-painted.
scale engine cowl and the large wheel
pants are made from molded fiberglass
that has been spray-painted to match the
color of the covering material exactly.
Equally impressive are the scalelike
shock-absorbing main landing-gear
assemblies. Even the steerable tail-wheel
assembly has a shock-absorbing spring.
Totally impressive is the best way to
describe the construction.
Your RC system will require a receiver
and four servos (one for the elevator, one
for the rudder, and two for the ailerons). I
selected Hitec HS-81 servos, which were
larger than the openings provided in the
wing. This required some “surgery” to get
them mounted in place. Choosing a
smaller servo, like the HS-65 or even the
HS-55, would provide more than enough
power and eliminate the time-consuming
step I took of enlarging the pockets in the
wing.
Since the wing arrives covered, the
manufacturer thoughtfully provided a
length of string so you can pull the aileron
servo cables through a series of holes in
the wing ribs and then out through the top
center-section. I needed a 6-inch aileron
extension cable on each servo, and then in
the center-section I combined the two
extensions with a Y-harness cable that
allowed both aileron servos to plug into
one port on the receiver.
The rudder is controlled by two cables
for a pull-pull-type installation. The trick
is to get these cables through holes in the
rear of the fuselage and then bring them
forward into the RC compartment.
Clip connectors are preinstalled on one
side of these cables. Put the other end of
the cables (no connector) in the
preinstalled wire tubes that exit at the rear
of the fuselage, on both sides. The cables
then come out inside of the fuselage,
where they can be brought forward to the
rudder-servo output arm. The final step is
to use the little metal tube and clip to
attach the cables to both sides of the servo
arm.
You can mount the motor directly to
the plywood box, without using the
adapter plate. The only problem is that the
four screws are slightly short. So I
countersunk each hole from the rear,
September 2008 61
62 MODEL AVIATION
Left: The power-system air-cooling holes
in the front of the cowl are more than
adequate. The air passes out through the
open cockpit. A neat and practical idea!
Above: The stabilizer
has been cemented in
place; the vertical
fin/rudder goes next.
Notice the tabs and
slots that add strength
and make aligning
these tail surfaces easy.
Right: Be careful when
installing the two main
landing-gear struts. The
shock-absorbing spring
must face the rear of
the aircraft or it won’t
fit into the wheel pant.
Above: The rudder
servo is located aft of
the elevator servo and
in the center of the
RC compartment. A
separate cable goes to
each side of the
rudder; equal tension
on these control wires
is essential.
Above: The first step in the landing-gear
installation is to place the small plywood
insert in the end of the wire strut. No glue
is necessary.
allowing the screws to go a bit deeper, and it worked. Once
mounted to the plywood box, the motor will have a slight amount
of down and right thrust.
A battery box is located directly under the motor mounting
box. The three-cell Li-Poly battery pack I selected weighed 5.7
ounces. This was close to the recommended 2100 mAh battery
pack.
If a lower-capacity and lighter-weight pack were used, the
model could come out tail-heavy. Be sure to consider that when
you select the battery for this application. The current version of
the Gee Bee has a much larger battery-compartment cover,
making it easy to remove the battery for charging purposes
without having to remove the wing.
I did find that the motor rubbed against the forward portion of
the cowl. The opening had to be opened somewhat using a
Dremel tool and a drum-sander attachment. This also provided
more cooling air to enter the front of the motor, which was a
bonus.
The two main landing-gear struts must be installed exactly per
the instructions. The U-shaped wire strut top goes into a slot that
is precut in the wing. You actually remove the wire from the top
of the strut assembly.
After pressing it into the slot, pass the remainder of the
landing gear (with the shock-absorbing spring) up through the
wheel pant and out the top. Then engage the landing-gear
assembly into the protruding wire. Move the pant in place and
screw it to the lower side of the wing in two places.
Take particular note of the tail-wheel bracket. There is a metal
bracket that attaches to the lower rear of the fuselage that is most
important. It acts as a bearing and eliminates any stress placed on
the hinges. Failure to use that bracket could result in the rudder’s
falling off the aircraft.
When I ran up the brushless motor the first time on the
recommended APC 10 x 4.7SF propeller, it drew 23 amps and
258 watts of input power, which is at the upper end of what this
unit can handle. That particular propeller should not be run at that
power level. I decided to switch to an APC 9 x 6E (a high-rpm
propeller) and got the current down to 18 amps and the input
power to just less than 200 watts.
The resulting power loading is still a respectable 92 watts per
pound, which can make for some aggressive flying at full throttle.
With the 2200 mAh battery pack, I was able to obtain flights
exceeding 10 minutes with some throttling.
My Gee Bee’s final weight was at the upper end: 34 ounces.
The CG ended up slightly forward of the recommended 60mm
(23/8 inches, or 28% of the chord) from the wing LE. That
location worked well for me and being that it was so close to the
recommendation, I did not change the location.
Final control throws worked out to 7/8 inch on either side of
the neutral position for the ailerons and elevator and 11/4 inches
on either side for the rudder.
Flying: I finished the Gee Bee’s assembly in late January. Since I
was heading south to Florida during February and March, I
passed the model on to Tom Hunt, fellow Model Aviation Hall of
Famer and NEAT [Northeast Electric Aircraft Technology] Fair
director, who volunteered to do the initial flight tests. Ray
Juschkus, a professional photographer and AMA District II
associate vice president, took all the flight photos shown in this
review.
The Gee Bee certainly isn’t a candidate for hand launching, but
it can take off from rough fields with comparative ease, thanks to
that pair of shock-absorbing landing-gear struts. Make sure there is
enough clearance between the wheels and the fiberglass pants for
movement and a freely rotating wheel.
The Gee Bee flew great. It has plenty of power for all kinds of
aerobatics. Because of the speed at full throttle, consider adding
some exponential rate control (if you have it on your transmitter) to
the ailerons, elevator, and rudder. I used roughly 20% exponential
rate on all three flight controls to smooth things out a little.
This Gee Bee proved to be a wonderful experience. My prototype
ARF took a little longer to assemble. The new version, now being
sold, eliminates some of the “start-up” problems I found. The
assembly job should prove to be easy and fast.
I would have no problem assembling and flying other Green
RC Models aircraft, and the price tag is well worth it. Had I built
this Gee Bee from scratch, I estimate that it would have cost
much more than the current street price and might have taken
several months to construct. With this ARF, an RC pilot can be at
the flying field in less than a week. Best of all was the model’s
great performance in the air. It’s a totally worthwhile project! MA
Bob Aberle
[email protected]
Manufacturer/Distributor:
Green Models/Maxford USA
(866) 706-8288
www.maxfordusa.com/gm-gb-ep-wr.aspx
Sources:
Granville Brothers information
http://en.wikipedia.org/wiki/Granville_Brothers_Aircraft
Landing Products (APC propellers)
(530) 661-0399
www.apcprop.com
Polk’s Hobby
(973) 351-9800
www.polkshobby.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Other Reviews:
Model Airplane News: January 2008
RC Sport Flyer: June 2008
Fly RC: April 2008
Left: The front
portion of the
battery box had to
be trimmed to
provide clearance
for the ring cowl.
The battery box
will suit a 3S 1300-
2100 mAh Li-Poly
pack.
Once the two upper wing
struts are attached, you
are likely not to touch
the wing again. The 40-
inch span makes it easy
to transport with the
wing in place.
Above: The Gee Bee’s
empennage houses a
steerable, spring-loaded
tail-wheel assembly. All
control-surface hinging
is done at the factory.
Above: The molded-fiberglass wheel
pants add so much to the overall scale
appearance. There are two aileron
servos—one in each wing.
September 2008 63
Edition: Model Aviation - 2008/09
Page Numbers: 60,61,62,63
60 MODEL AVIATION
BOB ABERLE
Static photos by the author
Flight photos by Ray Juschkus This electric-powered racer features
high-end extras and color options
Pluses and Minuses
+
• Shock-absorbing main landing gears
with wheels.
• Steerable, shock-absorbing tail-wheel
assembly.
• Molded-fiberglass wheel pants and
cowl with scale radial engine cylinders.
• Scale wing struts.
• All control surfaces are hinged with
provided control rods and hardware.
• Completely covered model with
certain areas spray-painted.
-• Prototype assembly manual was not
particularly helpful, but this has been
updated making assembly much easier.
The Gee Bee is eye-catching in
the air. Tom Hunt performed all
the flight-testing and gave the
thumbs-up afterward.
GRANVILLE BROTHERS Aircraft’s
series of full-scale racing airplanes dates
back to the early 1930s. The company
built a total of 24 aircraft, and only three
of the originals are known to exist today.
(For more information about the Granville
brothers’ aircraft, see the source list at the
end of this article.)
Through the years, many of the
Granville designs have been featured as
scale RC models in various hobby
publications. The AMA Plans Service has
several pages of model plans for many of
the company’s various aircraft.
The Granville airplanes’ sleek lines
make them popular modeling subjects that
have earned the reputation of being good
fliers. Most of these designs were
characterized by large engine cowls,
streamlined wheel pants, and wing struts
mounted on top of low wings.
Green RC Models (based in China)
designed and constructed the Gee Bee
Model Y Senior Sportster I have reviewed
for this article. The model is distributed in
the US by Maxford USA. (See the source
list for contact information.) On the Web
site you can access an excellent set of
detailed photos by clicking on “View
More Images.” There is also a link to a
flight video.
Be advised that the particular kit I
reviewed was an early prototype model
and has been replaced with an improved
version that is easier to assemble and is
supplemented with the updated instruction
sheet, just mentioned. But understand that
this prototype ARF was still an excellentflying
aircraft.
The electric-powered Model Y is
slightly larger than an average park flyer.
It is constructed from laser-cut balsa and
plywood that is factory covered and spraypainted
in some areas. There is a choice of
three color schemes: red/black, red/white,
and yellow/black.
The Gee Bee ARF includes everything
except the motor, ESC, battery, and RC
system. There is also a combo deal, which
includes the airplane, brushless outrunner
motor, and ESC, for $209.99. Then you
will need to buy only a battery and supply
the RC system (which needs a receiver
and four servos).
The model has a 40-inch wingspan,
306 square inches of wing area, and
weighs 28-34 ounces. The recommended
motor is the Uranus 28309 (from Maxford
USA), running on a three-cell Li-Poly
battery pack at approximately 18-23 amps
and 200-250 watts of input power. This
will provide power loadings in the range
of 100-130 watts per pound, making it an
aggressive aerobatic performer (at full
throttle).
This Gee Bee seems to have been crafted
by people who understand model
building. Thanks to precision lasercutting,
all major parts fit easily. Both the
Park View: Green RC Models Gee Bee Model Y Senior Sportster
Test-Model Details
Specifications
Type: Park Pilot Program-legal
semiscale ARF
Skill level: Intermediate builder and
pilot
Wingspan: 40 inches
Wing area: 306 square inches
Length: 30 inches
Weight: 28-34 ounces
Wing loading: 16 ounces/square
foot
Power (recommended): 275-
watt motor, 11.1-volt Li-Poly
battery, 25-amp ESC
Radio: Four channels (minimum),
four miniservos
Construction: Balsa, light plywood,
fiberglass cowling and wheel spats
Covering/finish: Heat-shrink film,
high-gloss paint
Price: $145.99
Motor: Uranus 28309 brushless
outrunner
Battery: Three-cell, 2200 mAh with
15C load capability
Propeller: APC 9 x 6E
Motor current: 18 amps
Power loading: 92 watts/pound
Motor output: 197 watts input
Radio system: Polk’s Hobby
Tracker III transmitter, Polk’s Hobby
Seeker 6 receiver, four Hitec HS-81
servos, two 6-inch extensions, one Y
harness, one 25-amp ESC
Ready-to-fly weight: 34 ounces
Flight duration: Seven to 10
minutes
Above: The Gee Bee is available in a
choice of three color schemes, as
shown on the side of the box.
Left: The balsa and plywood has
iron-on covering. All hinges are
already in place. The cowl and wheel
pants are spray-painted.
scale engine cowl and the large wheel
pants are made from molded fiberglass
that has been spray-painted to match the
color of the covering material exactly.
Equally impressive are the scalelike
shock-absorbing main landing-gear
assemblies. Even the steerable tail-wheel
assembly has a shock-absorbing spring.
Totally impressive is the best way to
describe the construction.
Your RC system will require a receiver
and four servos (one for the elevator, one
for the rudder, and two for the ailerons). I
selected Hitec HS-81 servos, which were
larger than the openings provided in the
wing. This required some “surgery” to get
them mounted in place. Choosing a
smaller servo, like the HS-65 or even the
HS-55, would provide more than enough
power and eliminate the time-consuming
step I took of enlarging the pockets in the
wing.
Since the wing arrives covered, the
manufacturer thoughtfully provided a
length of string so you can pull the aileron
servo cables through a series of holes in
the wing ribs and then out through the top
center-section. I needed a 6-inch aileron
extension cable on each servo, and then in
the center-section I combined the two
extensions with a Y-harness cable that
allowed both aileron servos to plug into
one port on the receiver.
The rudder is controlled by two cables
for a pull-pull-type installation. The trick
is to get these cables through holes in the
rear of the fuselage and then bring them
forward into the RC compartment.
Clip connectors are preinstalled on one
side of these cables. Put the other end of
the cables (no connector) in the
preinstalled wire tubes that exit at the rear
of the fuselage, on both sides. The cables
then come out inside of the fuselage,
where they can be brought forward to the
rudder-servo output arm. The final step is
to use the little metal tube and clip to
attach the cables to both sides of the servo
arm.
You can mount the motor directly to
the plywood box, without using the
adapter plate. The only problem is that the
four screws are slightly short. So I
countersunk each hole from the rear,
September 2008 61
62 MODEL AVIATION
Left: The power-system air-cooling holes
in the front of the cowl are more than
adequate. The air passes out through the
open cockpit. A neat and practical idea!
Above: The stabilizer
has been cemented in
place; the vertical
fin/rudder goes next.
Notice the tabs and
slots that add strength
and make aligning
these tail surfaces easy.
Right: Be careful when
installing the two main
landing-gear struts. The
shock-absorbing spring
must face the rear of
the aircraft or it won’t
fit into the wheel pant.
Above: The rudder
servo is located aft of
the elevator servo and
in the center of the
RC compartment. A
separate cable goes to
each side of the
rudder; equal tension
on these control wires
is essential.
Above: The first step in the landing-gear
installation is to place the small plywood
insert in the end of the wire strut. No glue
is necessary.
allowing the screws to go a bit deeper, and it worked. Once
mounted to the plywood box, the motor will have a slight amount
of down and right thrust.
A battery box is located directly under the motor mounting
box. The three-cell Li-Poly battery pack I selected weighed 5.7
ounces. This was close to the recommended 2100 mAh battery
pack.
If a lower-capacity and lighter-weight pack were used, the
model could come out tail-heavy. Be sure to consider that when
you select the battery for this application. The current version of
the Gee Bee has a much larger battery-compartment cover,
making it easy to remove the battery for charging purposes
without having to remove the wing.
I did find that the motor rubbed against the forward portion of
the cowl. The opening had to be opened somewhat using a
Dremel tool and a drum-sander attachment. This also provided
more cooling air to enter the front of the motor, which was a
bonus.
The two main landing-gear struts must be installed exactly per
the instructions. The U-shaped wire strut top goes into a slot that
is precut in the wing. You actually remove the wire from the top
of the strut assembly.
After pressing it into the slot, pass the remainder of the
landing gear (with the shock-absorbing spring) up through the
wheel pant and out the top. Then engage the landing-gear
assembly into the protruding wire. Move the pant in place and
screw it to the lower side of the wing in two places.
Take particular note of the tail-wheel bracket. There is a metal
bracket that attaches to the lower rear of the fuselage that is most
important. It acts as a bearing and eliminates any stress placed on
the hinges. Failure to use that bracket could result in the rudder’s
falling off the aircraft.
When I ran up the brushless motor the first time on the
recommended APC 10 x 4.7SF propeller, it drew 23 amps and
258 watts of input power, which is at the upper end of what this
unit can handle. That particular propeller should not be run at that
power level. I decided to switch to an APC 9 x 6E (a high-rpm
propeller) and got the current down to 18 amps and the input
power to just less than 200 watts.
The resulting power loading is still a respectable 92 watts per
pound, which can make for some aggressive flying at full throttle.
With the 2200 mAh battery pack, I was able to obtain flights
exceeding 10 minutes with some throttling.
My Gee Bee’s final weight was at the upper end: 34 ounces.
The CG ended up slightly forward of the recommended 60mm
(23/8 inches, or 28% of the chord) from the wing LE. That
location worked well for me and being that it was so close to the
recommendation, I did not change the location.
Final control throws worked out to 7/8 inch on either side of
the neutral position for the ailerons and elevator and 11/4 inches
on either side for the rudder.
Flying: I finished the Gee Bee’s assembly in late January. Since I
was heading south to Florida during February and March, I
passed the model on to Tom Hunt, fellow Model Aviation Hall of
Famer and NEAT [Northeast Electric Aircraft Technology] Fair
director, who volunteered to do the initial flight tests. Ray
Juschkus, a professional photographer and AMA District II
associate vice president, took all the flight photos shown in this
review.
The Gee Bee certainly isn’t a candidate for hand launching, but
it can take off from rough fields with comparative ease, thanks to
that pair of shock-absorbing landing-gear struts. Make sure there is
enough clearance between the wheels and the fiberglass pants for
movement and a freely rotating wheel.
The Gee Bee flew great. It has plenty of power for all kinds of
aerobatics. Because of the speed at full throttle, consider adding
some exponential rate control (if you have it on your transmitter) to
the ailerons, elevator, and rudder. I used roughly 20% exponential
rate on all three flight controls to smooth things out a little.
This Gee Bee proved to be a wonderful experience. My prototype
ARF took a little longer to assemble. The new version, now being
sold, eliminates some of the “start-up” problems I found. The
assembly job should prove to be easy and fast.
I would have no problem assembling and flying other Green
RC Models aircraft, and the price tag is well worth it. Had I built
this Gee Bee from scratch, I estimate that it would have cost
much more than the current street price and might have taken
several months to construct. With this ARF, an RC pilot can be at
the flying field in less than a week. Best of all was the model’s
great performance in the air. It’s a totally worthwhile project! MA
Bob Aberle
[email protected]
Manufacturer/Distributor:
Green Models/Maxford USA
(866) 706-8288
www.maxfordusa.com/gm-gb-ep-wr.aspx
Sources:
Granville Brothers information
http://en.wikipedia.org/wiki/Granville_Brothers_Aircraft
Landing Products (APC propellers)
(530) 661-0399
www.apcprop.com
Polk’s Hobby
(973) 351-9800
www.polkshobby.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Other Reviews:
Model Airplane News: January 2008
RC Sport Flyer: June 2008
Fly RC: April 2008
Left: The front
portion of the
battery box had to
be trimmed to
provide clearance
for the ring cowl.
The battery box
will suit a 3S 1300-
2100 mAh Li-Poly
pack.
Once the two upper wing
struts are attached, you
are likely not to touch
the wing again. The 40-
inch span makes it easy
to transport with the
wing in place.
Above: The Gee Bee’s
empennage houses a
steerable, spring-loaded
tail-wheel assembly. All
control-surface hinging
is done at the factory.
Above: The molded-fiberglass wheel
pants add so much to the overall scale
appearance. There are two aileron
servos—one in each wing.
September 2008 63
Edition: Model Aviation - 2008/09
Page Numbers: 60,61,62,63
60 MODEL AVIATION
BOB ABERLE
Static photos by the author
Flight photos by Ray Juschkus This electric-powered racer features
high-end extras and color options
Pluses and Minuses
+
• Shock-absorbing main landing gears
with wheels.
• Steerable, shock-absorbing tail-wheel
assembly.
• Molded-fiberglass wheel pants and
cowl with scale radial engine cylinders.
• Scale wing struts.
• All control surfaces are hinged with
provided control rods and hardware.
• Completely covered model with
certain areas spray-painted.
-• Prototype assembly manual was not
particularly helpful, but this has been
updated making assembly much easier.
The Gee Bee is eye-catching in
the air. Tom Hunt performed all
the flight-testing and gave the
thumbs-up afterward.
GRANVILLE BROTHERS Aircraft’s
series of full-scale racing airplanes dates
back to the early 1930s. The company
built a total of 24 aircraft, and only three
of the originals are known to exist today.
(For more information about the Granville
brothers’ aircraft, see the source list at the
end of this article.)
Through the years, many of the
Granville designs have been featured as
scale RC models in various hobby
publications. The AMA Plans Service has
several pages of model plans for many of
the company’s various aircraft.
The Granville airplanes’ sleek lines
make them popular modeling subjects that
have earned the reputation of being good
fliers. Most of these designs were
characterized by large engine cowls,
streamlined wheel pants, and wing struts
mounted on top of low wings.
Green RC Models (based in China)
designed and constructed the Gee Bee
Model Y Senior Sportster I have reviewed
for this article. The model is distributed in
the US by Maxford USA. (See the source
list for contact information.) On the Web
site you can access an excellent set of
detailed photos by clicking on “View
More Images.” There is also a link to a
flight video.
Be advised that the particular kit I
reviewed was an early prototype model
and has been replaced with an improved
version that is easier to assemble and is
supplemented with the updated instruction
sheet, just mentioned. But understand that
this prototype ARF was still an excellentflying
aircraft.
The electric-powered Model Y is
slightly larger than an average park flyer.
It is constructed from laser-cut balsa and
plywood that is factory covered and spraypainted
in some areas. There is a choice of
three color schemes: red/black, red/white,
and yellow/black.
The Gee Bee ARF includes everything
except the motor, ESC, battery, and RC
system. There is also a combo deal, which
includes the airplane, brushless outrunner
motor, and ESC, for $209.99. Then you
will need to buy only a battery and supply
the RC system (which needs a receiver
and four servos).
The model has a 40-inch wingspan,
306 square inches of wing area, and
weighs 28-34 ounces. The recommended
motor is the Uranus 28309 (from Maxford
USA), running on a three-cell Li-Poly
battery pack at approximately 18-23 amps
and 200-250 watts of input power. This
will provide power loadings in the range
of 100-130 watts per pound, making it an
aggressive aerobatic performer (at full
throttle).
This Gee Bee seems to have been crafted
by people who understand model
building. Thanks to precision lasercutting,
all major parts fit easily. Both the
Park View: Green RC Models Gee Bee Model Y Senior Sportster
Test-Model Details
Specifications
Type: Park Pilot Program-legal
semiscale ARF
Skill level: Intermediate builder and
pilot
Wingspan: 40 inches
Wing area: 306 square inches
Length: 30 inches
Weight: 28-34 ounces
Wing loading: 16 ounces/square
foot
Power (recommended): 275-
watt motor, 11.1-volt Li-Poly
battery, 25-amp ESC
Radio: Four channels (minimum),
four miniservos
Construction: Balsa, light plywood,
fiberglass cowling and wheel spats
Covering/finish: Heat-shrink film,
high-gloss paint
Price: $145.99
Motor: Uranus 28309 brushless
outrunner
Battery: Three-cell, 2200 mAh with
15C load capability
Propeller: APC 9 x 6E
Motor current: 18 amps
Power loading: 92 watts/pound
Motor output: 197 watts input
Radio system: Polk’s Hobby
Tracker III transmitter, Polk’s Hobby
Seeker 6 receiver, four Hitec HS-81
servos, two 6-inch extensions, one Y
harness, one 25-amp ESC
Ready-to-fly weight: 34 ounces
Flight duration: Seven to 10
minutes
Above: The Gee Bee is available in a
choice of three color schemes, as
shown on the side of the box.
Left: The balsa and plywood has
iron-on covering. All hinges are
already in place. The cowl and wheel
pants are spray-painted.
scale engine cowl and the large wheel
pants are made from molded fiberglass
that has been spray-painted to match the
color of the covering material exactly.
Equally impressive are the scalelike
shock-absorbing main landing-gear
assemblies. Even the steerable tail-wheel
assembly has a shock-absorbing spring.
Totally impressive is the best way to
describe the construction.
Your RC system will require a receiver
and four servos (one for the elevator, one
for the rudder, and two for the ailerons). I
selected Hitec HS-81 servos, which were
larger than the openings provided in the
wing. This required some “surgery” to get
them mounted in place. Choosing a
smaller servo, like the HS-65 or even the
HS-55, would provide more than enough
power and eliminate the time-consuming
step I took of enlarging the pockets in the
wing.
Since the wing arrives covered, the
manufacturer thoughtfully provided a
length of string so you can pull the aileron
servo cables through a series of holes in
the wing ribs and then out through the top
center-section. I needed a 6-inch aileron
extension cable on each servo, and then in
the center-section I combined the two
extensions with a Y-harness cable that
allowed both aileron servos to plug into
one port on the receiver.
The rudder is controlled by two cables
for a pull-pull-type installation. The trick
is to get these cables through holes in the
rear of the fuselage and then bring them
forward into the RC compartment.
Clip connectors are preinstalled on one
side of these cables. Put the other end of
the cables (no connector) in the
preinstalled wire tubes that exit at the rear
of the fuselage, on both sides. The cables
then come out inside of the fuselage,
where they can be brought forward to the
rudder-servo output arm. The final step is
to use the little metal tube and clip to
attach the cables to both sides of the servo
arm.
You can mount the motor directly to
the plywood box, without using the
adapter plate. The only problem is that the
four screws are slightly short. So I
countersunk each hole from the rear,
September 2008 61
62 MODEL AVIATION
Left: The power-system air-cooling holes
in the front of the cowl are more than
adequate. The air passes out through the
open cockpit. A neat and practical idea!
Above: The stabilizer
has been cemented in
place; the vertical
fin/rudder goes next.
Notice the tabs and
slots that add strength
and make aligning
these tail surfaces easy.
Right: Be careful when
installing the two main
landing-gear struts. The
shock-absorbing spring
must face the rear of
the aircraft or it won’t
fit into the wheel pant.
Above: The rudder
servo is located aft of
the elevator servo and
in the center of the
RC compartment. A
separate cable goes to
each side of the
rudder; equal tension
on these control wires
is essential.
Above: The first step in the landing-gear
installation is to place the small plywood
insert in the end of the wire strut. No glue
is necessary.
allowing the screws to go a bit deeper, and it worked. Once
mounted to the plywood box, the motor will have a slight amount
of down and right thrust.
A battery box is located directly under the motor mounting
box. The three-cell Li-Poly battery pack I selected weighed 5.7
ounces. This was close to the recommended 2100 mAh battery
pack.
If a lower-capacity and lighter-weight pack were used, the
model could come out tail-heavy. Be sure to consider that when
you select the battery for this application. The current version of
the Gee Bee has a much larger battery-compartment cover,
making it easy to remove the battery for charging purposes
without having to remove the wing.
I did find that the motor rubbed against the forward portion of
the cowl. The opening had to be opened somewhat using a
Dremel tool and a drum-sander attachment. This also provided
more cooling air to enter the front of the motor, which was a
bonus.
The two main landing-gear struts must be installed exactly per
the instructions. The U-shaped wire strut top goes into a slot that
is precut in the wing. You actually remove the wire from the top
of the strut assembly.
After pressing it into the slot, pass the remainder of the
landing gear (with the shock-absorbing spring) up through the
wheel pant and out the top. Then engage the landing-gear
assembly into the protruding wire. Move the pant in place and
screw it to the lower side of the wing in two places.
Take particular note of the tail-wheel bracket. There is a metal
bracket that attaches to the lower rear of the fuselage that is most
important. It acts as a bearing and eliminates any stress placed on
the hinges. Failure to use that bracket could result in the rudder’s
falling off the aircraft.
When I ran up the brushless motor the first time on the
recommended APC 10 x 4.7SF propeller, it drew 23 amps and
258 watts of input power, which is at the upper end of what this
unit can handle. That particular propeller should not be run at that
power level. I decided to switch to an APC 9 x 6E (a high-rpm
propeller) and got the current down to 18 amps and the input
power to just less than 200 watts.
The resulting power loading is still a respectable 92 watts per
pound, which can make for some aggressive flying at full throttle.
With the 2200 mAh battery pack, I was able to obtain flights
exceeding 10 minutes with some throttling.
My Gee Bee’s final weight was at the upper end: 34 ounces.
The CG ended up slightly forward of the recommended 60mm
(23/8 inches, or 28% of the chord) from the wing LE. That
location worked well for me and being that it was so close to the
recommendation, I did not change the location.
Final control throws worked out to 7/8 inch on either side of
the neutral position for the ailerons and elevator and 11/4 inches
on either side for the rudder.
Flying: I finished the Gee Bee’s assembly in late January. Since I
was heading south to Florida during February and March, I
passed the model on to Tom Hunt, fellow Model Aviation Hall of
Famer and NEAT [Northeast Electric Aircraft Technology] Fair
director, who volunteered to do the initial flight tests. Ray
Juschkus, a professional photographer and AMA District II
associate vice president, took all the flight photos shown in this
review.
The Gee Bee certainly isn’t a candidate for hand launching, but
it can take off from rough fields with comparative ease, thanks to
that pair of shock-absorbing landing-gear struts. Make sure there is
enough clearance between the wheels and the fiberglass pants for
movement and a freely rotating wheel.
The Gee Bee flew great. It has plenty of power for all kinds of
aerobatics. Because of the speed at full throttle, consider adding
some exponential rate control (if you have it on your transmitter) to
the ailerons, elevator, and rudder. I used roughly 20% exponential
rate on all three flight controls to smooth things out a little.
This Gee Bee proved to be a wonderful experience. My prototype
ARF took a little longer to assemble. The new version, now being
sold, eliminates some of the “start-up” problems I found. The
assembly job should prove to be easy and fast.
I would have no problem assembling and flying other Green
RC Models aircraft, and the price tag is well worth it. Had I built
this Gee Bee from scratch, I estimate that it would have cost
much more than the current street price and might have taken
several months to construct. With this ARF, an RC pilot can be at
the flying field in less than a week. Best of all was the model’s
great performance in the air. It’s a totally worthwhile project! MA
Bob Aberle
[email protected]
Manufacturer/Distributor:
Green Models/Maxford USA
(866) 706-8288
www.maxfordusa.com/gm-gb-ep-wr.aspx
Sources:
Granville Brothers information
http://en.wikipedia.org/wiki/Granville_Brothers_Aircraft
Landing Products (APC propellers)
(530) 661-0399
www.apcprop.com
Polk’s Hobby
(973) 351-9800
www.polkshobby.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Other Reviews:
Model Airplane News: January 2008
RC Sport Flyer: June 2008
Fly RC: April 2008
Left: The front
portion of the
battery box had to
be trimmed to
provide clearance
for the ring cowl.
The battery box
will suit a 3S 1300-
2100 mAh Li-Poly
pack.
Once the two upper wing
struts are attached, you
are likely not to touch
the wing again. The 40-
inch span makes it easy
to transport with the
wing in place.
Above: The Gee Bee’s
empennage houses a
steerable, spring-loaded
tail-wheel assembly. All
control-surface hinging
is done at the factory.
Above: The molded-fiberglass wheel
pants add so much to the overall scale
appearance. There are two aileron
servos—one in each wing.
September 2008 63