Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com
Edition: Model Aviation - 2012/05
Page Numbers: 28,29,30,31,32,33,34,35,36,37
Goose
Once dialed in, rising off the water took only a few feet with a little headwind.
The wind chop proved to be no problem. Flight photos by Bingo Kohlmann.
The Goose’s big rudder made lining up
photo passes such as this a breeze.
by Paul Kohlmann
28 Model Aviation May 2012 www.ModelAviation.com
In the world of aviation, icons can be found to represent
each of the categories of aircraft. For civil aviation there
are the ubiquitous J-3 Cubs and Cessna high-wing
aircraft, while for warbirds the P-51 Mustang is a standout.
In the RC world we often gravitate toward these iconic types, perhaps
because the full-scale designs were so well developed that they tend to
retain their successful attributes when scaled down for our use.
In the case of the flying boat, the Grumman Goose is one of these
icons. Starting life in 1936, the first Goose was built to transport wealthy
businessmen from Long Island, New York, to New York City.
By the onset of World War II, these “flying yachts” were serving more
pedestrian roles with commuter airlines, the U.S. Navy, and the Coast
Guard. Gooses, as Grumman called them, were flown by many nations
during the war, including Japan.
Grumman stopped production in 1945 after 345 were made, but the
Goose lives on. The Goose has been a staple of island-hopping, whether
that is along the rugged coast of Alaska or the sunny Caribbean.
The type is so well loved that in 2007, Antilles Seaplanes announced that
it would begin building new airframes to shore up the dwindling number of
originals. Familiarity and longevity are critical factors in the creation of an
icon, but a little limelight helps.
Hollywood has been kind, giving the Goose a central role in the TV cult
classic Tales of the Gold Monkey, a cameo in the opening of Fantasy Island,
and many other appearances.
Last fall I heard that MA editor, Jay Smith, was looking for a Goose
design in the 48-inch range to meet a demand from AMA’s Plans Service
customers.
electrified
The iconic
amphibian
The Grumman Goose is ready to
get its feet wet for the first time.
www.ModelAviation.com May 2012 Model Aviation 29
A Sullivan rod keeps the exposed elevator linkage as short as possible. CA hinges
were used for all control surfaces.
The fin and rudder are framed
and it’s up to the builder whether
to sheet the tail or keep it at its
lightest.
Jumping at the chance to model an
icon, I bumped the wingspan to 49
inches so that our Goose would settle
in at an even 1/12 scale.
Design
I’m partial to the classic stick-andtissue
genre, and this struck me as the
best way to produce a lightweight
aircraft that would come off of the
water easily. The design needed to
build quickly and a simple, open
structure supports that goal.
After studying photos and threeviews,
the design took root in
SolidWorks CAD. The Goose has such
great lines, there was no need to depart
from them. I created a solid rendering
by building a wireframe over a threeview
drawing.
The rendering was sent to the virtual
machine shop to be reduced to a
framework. The power of CAD can be
seen at this point as SolidWorks was
able to calculate weight and CG, and
configurations for hatches and such
could be quickly tested.
The center wing rip
is installed at an
angle using a gauge
to ensure that the
top of the wing will
be flat when joined.
Type: RC Scale model
Skill level: Intermediate builder,
intermediate pilot
Wingspan: 49 inches
Wing area: 396 square inches
Length: 393/8 inches
Weight: 34 to 40 ounces
Power: Two E-flite Power 370
1360 Kv motors, two 20- to 25-
amp ESC
Construction: Balsa and light
plywood
Covering/finish: Heat shrink
film with painted trim and
waterslide decals
Propeller: Two APC 8 x 3.6
30 Model Aviation May 2012 www.ModelAviation.com
Goose
For those who are
interested in amphibious
aircraft, Paul designed a
great model to build and
fly. To see a short video
of the Grumman Goose
flying from water, be
sure to check out
Left: The shear web,
aileron, and wingtip
parts are in place
and the next step is
to sheet between the
main spar and the LE.
Right: To avoid any exposed aileron
linkages, a central servo was installed
under the wing to actuate torque tubes
made from aluminum tubing and music
wire.
Left: The wingtip floats are
easy to shape by sanding
oversized balsa or foam fill
down to these scale plywood
outlines.
The port side of the fuselage is finished. When
the sheeting cures the structure becomes
extremely rigid.
the Online Features section
at www.ModelAviation.com.
Photos by the author except as noted
www.ModelAviation.com May 2012 Model Aviation 31
Right: Installing
the electronics is
straightforward,
although it’s possible
I could have saved an
ounce in wiring mine.
Goose6
This is what the Goose looks like when there are no
parts left in the kit.
Left: The assembly has been glued to its pad
and the lower pad, formers, and stringers are all
in place. Waxed paper over the wing allows the
nacelle to be removed for covering.
32 Model Aviation May 2012 www.ModelAviation.com
By the time I get a design reduced
to a cut file that a CNC laser can
read, I’m itching to build. So let’s go!
Construction
The first step is cutting forms for
the three-ply laminated tail group
outlines. I spray-tacked paper cutouts
onto 1-inch hard foam and then cut
the foam with a scroll saw.
Soften 1/16-inch balsa strip stock in
water overnight, then pin one strip
tightly against each form. Add two
more layers of balsa bonded with
carpentry glue to complete each
outline.
Packing tape between the template
and the balsa will keep the wood
from sticking to the forms. Let the
outlines cure completely and then pin
them in place over the plans.
Glue in the 1/8-inch laser-cut tail
parts in numerical order then add the
1/8 x 3/32-inch bracing. Sand the parts
then cut through the outlines to free
the rudder and elevators. Although
the tail group is built lightly, the
laminated outline provides for a
strong assembly.
The horizontal stabilizer and
vertical fin can be sheeted with 1/32
balsa to provide a more scalelike
appearance. I went this route in order
to duplicate the characteristic ribbing
and trim tab on the Goose’s rudder.
To prepare the hinges, I beveled
the hinge lines to allow ample
elevator and rudder deflection and
then installed CA hinges. In order to
keep the exposed linkage to the highmounted
stabilizer short, a Sullivan
rod was used to actuate a link silver
soldered to the elevator joiner rod.
Wing
The wing is a conventional open
structure with a sheeted upper LE
and center section. The main spar is
built from 1/8 x 3/32 balsa or basswood
(depending on your flying skills!).
The upper and lower main spar are
constructed from full vertical-grain
shear webbing.
Pin down the lower main spar and
the rear spar RS, then glue in ribs
W2 and W11. With these parts
aligned, glue in the TE, ribs W3
through W10, the LE, and then the
upper main spar.
Install the laser-cut shear webs. The
angle of center rib W1 determines
the dihedral, so it is glued in last at an
angle using a gauge.
Begin the ailerons by gluing doubler
A1 to the back of the rear spar
with the wing still pinned on top
of the plans. Pin aileron LE A2 into
place but do not glue. Glue in riblets
A3—they are all the same. Build the
wingtip by gluing W12 through W15
in order.
I prefer to install the 1/32 balsa
upper sheeting while the wing is
pinned down. Dampen the outer
surface lightly and it curves into place
for gluing. Once cured, unpin the
wing, flip it over, and sheet the lower
center section. Glue in the plywood
hard points for the wing floats and
bracing wires.
Sand the faces of the wing roots flat
and fit the plywood dihedral brace.
After everything is aligned, glue in the
brace and join the wings. The Goose
had no dihedral so the wing will be
flat across the upper main spars.
Glue soft 3/16 balsa to the face of
the LE and sand to shape. Trim the
LE away from the nacelle footings as
shown on the plans. Complete the
wing’s framework by sanding it with a
long block.
After the wing is sanded to shape,
cut the ailerons free by slicing
through the TE. Individual aileron
servos can be used to actuate them,
but to avoid exposed linkages, I used
a center-mounted servo and torque
tubes. The torque tubes were made
from .060 music wire Ls epoxied into
1/8 thin-wall aluminum tubing.
The wing floats are built from
foam or balsa fill glued over a lasercut
light-plywood framework. Sand
the excess fill to shape using the
framework as a template. Eyes for
the bracing wires are included in the
struts.
Fuselage
The fuselage is constructed using
the half-shell method. Begin by
pinning the keels K1 through K6 over
the plans. Add the “a” or port former
halves, working from nose to tail.
The battery tray is locked into
place by formers F2 through F5.
Formers B1 and B2 are part of the
battery hatch and should be glued
only to keel K1 at this time.
After all of the port formers are in
place, glue in side keels K7 through
K10; notice that K7/8 is a longeron
made by preassembling parts K7 and K8.
Glue the battery hatch side rail
B3 to formers B1, F2, and B2, but
be careful not to get glue on K7
or the other formers. Build up the
chine by gluing in the three stringers
then adding parts K11 and K12.
Dampening the stringers with water
before gluing into place will relieve
stress in the assembly.
Attach the side wall K13s. Add
enough additional stringers to give
some structural integrity when the
shell is unpinned.
The hull is covered by sheeting the
rear sections and planking the bow.
This isn’t as bad as it may sound; the
sheeted areas are simple rectangles.
The planked area is small and the
process goes quickly if the planks are
soaked in advance to soften them.
Sheeting the shell while it is
pinned down ensures that the
assembly will be straight when freed
from the board. I debated whether
to fiberglass the hull for added
durability, but decided to seal it with
water-based polyurethane.
The starboard half of the fuselage
goes quicker. Simply unpin and repeat
the steps taken so far. The servo tray
can be loaded with the rudder and
elevator servos and glued in now, as
can partial former F5A and the wingbolt
pad. Add any remaining stringers
and move on to the cockpit.
Start the cockpit by gluing ribs C2
through C4 to plywood former C1.
After it is cured, slide this assembly
into F5’s notches. Wet the outside of
each sidewall K11, bend them into
place, and glue them to C1.
Attach center rib C5 and the
windshield frames to complete
the structure. (Note: Covering the
area under the windshield first is
advisable.) Now that the cockpit is
done, it’s a good time to fit the wing
pin and wing bolts.
A battery hatch is designed into
the upper bow. To access it, carefully
cut through keel K1 and the hatch
stringers between formers F1 and
B1, and F3 and B2. This step can
be omitted and the battery can be
accessed by removing the wing if a
more watertight structure is desired.
The nose is made from soft balsa
and sanded to shape. Sand the fuselage
lightly and it is ready to cover.
Nacelles and Motors
The nacelles are designed to wrap
tightly around the wing and to align
themselves. Start by preassembling
the upper half parts N1 through N6
over the plans. Unpin this assembly
and glue in the plywood firewall and
N7. Remove and discard the pad at
the bottom of N4.
Join upper pad parts N8 and N9.
Once dry, pin this pad to the wing
with the front edge aligned to the
LE. Waxed paper under the pad will
prevent premature gluing of the
nacelle to the wing; dampening the
outside of N8/9 will help it match
the wing’s curvature.
Fit the nacelle assembly to the
wing with bulkhead N7 flush against
LE and the three nacelle keels
engaging the notches in N8/9. Glue
them together when you’re satisfied
they’re correctly positioned. Add
bottom pad N10/11 and parts N12
and N13. Fill in the stringers to lock
the pads into position.
When everything is completely
cured, pull the nacelles straight
forward to remove them for covering.
Use soft balsa or foam to fill the aft
ends. Assemble the motor mounts
from 1/8 balsa sides and plywood face.
Attach them to the firewalls and the
nacelles are complete.
Electronics
This Goose flew on a Hitec Micro
05S. I harvested the servos from a
recently deceased ParkZone T-28.
Two E-flite 370 1360 Kv motors and
20-amp ESCs powered the 8 x 6
APC propellers.
As is common with twins, the port
motor turned in reverse to neutralize
torque factors. This combination
produced 350 watts on a 2200 mAh
three-cell battery.
Finishing
Choosing a motif for your Goose
can be a challenging task. There
are enough fantastic military,
commercial, and private schemes
to satisfy anyone’s taste. I wanted
something simple using the Oracote
covering that I had in my box. The
teal-and-white paint scheme from
Catalina Airlines of the 1970s fit the
bill.
After covering, the tail was
assembled by locking the fin into
its notch and sliding the horizontal
stabilizer through its slot in the fin.
Control surfaces were mounted
with CA hinges. The nacelles were
epoxied onto the wing and the gaps
sealed with small beads of clear
silicone. After mounting the floats,
they were rigged with bracing wire
made from Kevlar fishing line.
I limited the details to the
horizontal stabilizer struts, a pilot,
and the engine exhausts, but a
builder could certainly go further. I
made waterslide decals for the logos,
passenger windows, and a few other
items.
The cowlings are vacuum-formed
parts from Park Flyer Plastics.
The dummy motor is a laminated
photograph filling the open cowling.
Flight Report
The prototype weighed 37 ounces
with a wing loading of only 13
ounces per square foot. The CG
was set to 25% Mean Aerodynamic
Chord and then the Goose was
prepared for a dry maiden flight.
The initial plan was to hand launch
it, but I thought I’d see if the Goose
would scoot over the wet grass on
the baseball field. Scoot it did—and 6
feet later the aircraft was airborne!
The Goose climbed out with
authority, and after some down
trim it was docile. The 370 motors
provided plenty of power for nonscale
flight but the low wing loading
and high drag from the fat fuselage
let the aircraft slow to a crawl.
For most of the flight, the Goose
looked like the full-scale aircraft,
flying low and slow, but the best part
was the landing. After riding out the
ground effect, it kissed the grass with
a soft shushing sound, giving the
impression that the lawn had turned
to water.
Next, I let the Goose loose on
the lake. Although there was only a
steady 5 mph wind, there was more
of a wind chop than I had hoped
for—particularly since that I had
never flown a flying boat from water
before.
Nevertheless, the Goose pushed
off. Its big tail kept it tracking
straight into the wind. It rode high
in the water, taking the small waves
well. The first attempt ended in a
pirouette after I sank the left tip float
before liftoff.
The next four attempts were
textbook flights, after I learned to
play with the rudder and aileron
together to get the Goose off of the
tip floats during the run-up. The
model is quite responsive to the
rudder, making it easy to line up.
After the routine was set, the
Goose popped off of the water
within a few feet and then
majestically climbed away, leaving a
trail of water droplets behind.
The learning curve for landing
was similar. I discovered after
coming in a little too hot that water
is bouncier than grass. Although
a splash-and-go would have been
prudent, I forced the Goose back
down, resulting in a spectacular
geyser. After applying some more
patience, the next three were a
piece of cake.
Conclusion
There is plenty of information
here, but don’t let it scare you
away from adding a legend to your
hangar. This build goes quickly,
thanks to a laser-cut kit, and no
specialized construction techniques
are required. Additionally, the power
system is economical and the flying
characteristics are docile.
If you have wanted to become
amphibious, this Goose is a great way
to go!
—Paul Kohlmann
[email protected]
Sources:
Manzano Lazer Works
(505) 286-2640
www.manzanolaser.com
E-flite
(800) 338-4639
www.e-fliterc.com
Hitec RCD
(858) 748-6948
www.hitecrcd.com
Park Flyer Plastics
(817) 233-1215
www.parkflyerplastics.com