Also included in this column:
• Dynamics Unlimited closes
its doors
• Mini Quaker is a replica of a
1930s FF model
• Polymicro film covering
GREETINGS, friends and followers of
RC micro flight. This has been a lean
month for reader contributions, so you
will have to suffer through more of my
projects and I will write about finishing
and covering techniques for the various
materials used with the small models.
We have lost one of our valued
vendors: Dynamics Unlimited. For
unspecified reasons the company has
closed permanently. You will be
missed!
We still have several vendors with
excellent lines. Bob and Janelle Selman
at www.bsdmicrorc.com/ and BP
Hobbies at www.bphobbies.com carry
a good selection of micro gear.
On a brighter note, John Worth is
publishing a magazine called RC Micro
World at www.cloud9rc.com. Visit the
Web site and look at John’s efforts. It
will be worth your while.
To kick off the discussion about
models and finishing, I will begin with
my latest project: an all-balsa BD-4
scale model of the kit-built aircraft
from the fertile mind of Jim Bede. It
has a 16-inch wingspan and an area of
42 square inches. With a finished
weight of 40 grams, it is not aerobatic
but flies smoothly in a realistic manner.
The equipment is all Dynamics
Unlimited. The receiver is a narrowband
RX-101, the two servos are the
Pin-Point 2.1-gram models, and the
drive is the M5-3-36 single-cell
brushless motor. A 250 mAh Li-Poly
cell powers the system. Dynamics
Unlimited is off the scene, but Bob
Selman carries equivalent equipment.
Concerning the finishing method,
the balsa is the soft and light variety
and soaks up paint like a sponge if you
are not careful. I have found that
rubbing drywall spackling compound
into the pores of block balsa around the
nose and then sanding it down to where
only the wood grain is filled provides a
nice surface for painting. The sheet
balsa seems to work fine with a bit of
sealing.
The sealing process is where Scott
Christensen made a “breakthrough”
discovery. There is a product in a
spray can sold by the Delta Company
called Stencil Magic Top Coat Satin
Spray. I found mine at a Ben Franklin
craft store. Two light coats of this
product and a light sanding prepare the
surface nicely for a paint finish.
Thanks, Scott!
Two views show
the author’s BD-4
scale model with a
16-inch wingspan.
Stencil Magic Top
Coat Satin Spray
prepared the surface
nicely for a paint
finish.
One of several new projects—the author’s Mini Quaker—is a replica of a 1930s FF
model. It has a lightweight stick-and-frame structure.
January 2007 89
The author’s lightweight Walker Jr. is an indoor living-room flyer with 60 square
inches of wing area, and it weighs less than 5 grams.
Working with tissue requires several materials. Clamping the flying surfaces to a flat
surface while they dry will prevent warping.
Working with films such as Polymicro covering requires special
techniques, tools, and materials.
3M 77 spray contact cement is used to adhere the Polymicro
film covering to the frames of the author’s Walker Jr.
Scott has been getting excellent
results from spraying thinned acrylic
paints on for the color. Anyone who
has seen his models or even pictures of
them will appreciate the results. This
technique requires a high-pressure
system (roughly 50 psi) with an
airbrush to work successfully.
I don’t have a system with pressure
that high, so I went in a different
direction. I have been using automobile
touch-up spray paint that I spray into a
container and then dilute
approximately 50% with slow-drying
automobile paint thinner. This has
worked well for me with my economy,
low-pressure airbrush system.
All these color paint systems have
the potential of adding excess weight,
so apply light coats and check the
results. Typically these systems do not
completely fill the wood grain, but the
bright, consistent colors compensate.
Shifting gears, let’s move to another
type of project altogether. One of the
photos shows my Mini Quaker: a
replica of a 1930s FF model. The
construction is similar to that of a
typical rubber-band-powered design,
with lightweight stick-and-frame
structure. The wingspan is 22 inches
and the weight is 30 grams.
The RC gear is the Plantraco HX-
900 900 MHz system with a 170 mAh
Li-Poly cell. I chose the GWJ 4:1 ballbearing
gear drive with a Super Slick
blue motor for power. This twirls a
GWS 5 x 3 propeller with authority.
All that equipment can be found at
www.bsdmicrorc.com.
The Mini Quaker is representative
of a broad variety of model choices,
whether scratch-built or converted
rubber-powered FF. The thing that
enhances the performance more than
any other is the use of an
undercambered airfoil with a
turbulator strip. I am fond of the
Benedek B6356b found at
www.profili2.com. This Profili
program is a free download with
more than 1,000 airfoils. It is a real
boon to scratch builders.
For covering and finishing these
lightweight models, I am fond of
tissue paper—especially the replica
type because it gives a more
authentic appearance. There is a
specific type of tissue I prefer called
Esaki. I got mine from Peck-
Polymers at www.peck-poly
mers.com/. Esaki is light and has
excellent working properties while
covering.
My favorite adhesive is Elmer’s
White Glue, spread thin before
applying the tissue. Remember that
when covering an undercambered
surface, the material must be fastened
to every rib.
After you have covered the model
with tissue, it needs to be shrunk. A
light mist of rubbing alcohol is
excellent for this. As shown in the
picture, it is important to clamp the
flying surfaces to a flat surface while
they are drying to avoid warping.
Shims under them promote drying.
I have had excellent results with
Krylon Crystal Clear spray paint as a
finish coat. It is thin and works the
same way as nitrate dope. Again, the
surfaces must be clamped down while
curing to avoid warps. Two coats will
usually give a nice sheen and keep
the weight reasonable. The Crystal
Clear spray paint is compatible with
the lacquer-based auto touch-up
paints when you want to add extra
color.
Moving to the light projects that fly
mostly indoors, my living-room flyer
(LRF)—the Walker Jr.—has 60
square inches of wing area and
weighs less than 5 grams. The
equipment came from
www.bsdmicrorc.com and is what is
sold for the Plantraco ARF Butterfly
LRF.
The construction is a mixture of
balsa, carbon fiber, and foam. The
covering is a light plastic film called
Polymicro. This material is available
through FF vendors who deal in
indoor models or www.homefly.com.
Working with thin plastic films
such as Polymicro requires some
special techniques. It is impractical to
try to cut it with scissors or a blade
because it tears too easily. The photo
shows some of the tools and methods
for using this fine covering.
I spread it out on a clean sheet of
construction paper. The first step is to
glue balsa “handles” to the section
you want to apply. A UHU-brand
glue stick works fine for this. A
pencil soldering iron is a fine tool for
cutting and trimming the plastic.
The preferred adhesive for
Polymicro is 3M 77 spray contact
cement. I spread newspaper on the
shop floor and place the frame to be
covered in the middle. Holding the
spray can roughly three feet above
the frame, I apply a light mist of the
adhesive to the frame. It is easy to
apply too much glue; take it lightly
here.
While the glue is still moist I lift
the frame and place it on the
construction paper. The next step is
to lift the section of Poymicro with
the balsa sticks and lower it onto the
frame. Smooth out wrinkles, slack,
and problems at this stage. Be sure to
rub all the areas where you want the
glue to stick with a clean fingertip.
Now you can use the soldering
iron to trim the excess from the
frame. Do this a few more times, and
you have a completely covered set of
parts. A picture shows the finished
sections of the Walker Jr. after
covering. With this material the
dihedral is added after the covering
has been applied.
For all of its apparent delicacy, the
covering on my Walker Jr. has
survived all sorts of bounces off
walls, furniture, and appliances. Any
modeler who flies Indoor FF
Duration will point out the same
durability. The slow-flying,
lightweight models lack the energy to
do significant damage.
The Walker Jr. and the Mini Quaker
were published in John Worth’s fine
RC Micro World. If you would like to
see something of yours in a national
magazine, send it to me. Don’t be
shy! All of us would enjoy seeing a
new project.
Thanks to those who do
contribute; after all, this is your
column.
Til next time.
Edition: Model Aviation - 2007/01
Page Numbers: 88,89,90
Edition: Model Aviation - 2007/01
Page Numbers: 88,89,90
Also included in this column:
• Dynamics Unlimited closes
its doors
• Mini Quaker is a replica of a
1930s FF model
• Polymicro film covering
GREETINGS, friends and followers of
RC micro flight. This has been a lean
month for reader contributions, so you
will have to suffer through more of my
projects and I will write about finishing
and covering techniques for the various
materials used with the small models.
We have lost one of our valued
vendors: Dynamics Unlimited. For
unspecified reasons the company has
closed permanently. You will be
missed!
We still have several vendors with
excellent lines. Bob and Janelle Selman
at www.bsdmicrorc.com/ and BP
Hobbies at www.bphobbies.com carry
a good selection of micro gear.
On a brighter note, John Worth is
publishing a magazine called RC Micro
World at www.cloud9rc.com. Visit the
Web site and look at John’s efforts. It
will be worth your while.
To kick off the discussion about
models and finishing, I will begin with
my latest project: an all-balsa BD-4
scale model of the kit-built aircraft
from the fertile mind of Jim Bede. It
has a 16-inch wingspan and an area of
42 square inches. With a finished
weight of 40 grams, it is not aerobatic
but flies smoothly in a realistic manner.
The equipment is all Dynamics
Unlimited. The receiver is a narrowband
RX-101, the two servos are the
Pin-Point 2.1-gram models, and the
drive is the M5-3-36 single-cell
brushless motor. A 250 mAh Li-Poly
cell powers the system. Dynamics
Unlimited is off the scene, but Bob
Selman carries equivalent equipment.
Concerning the finishing method,
the balsa is the soft and light variety
and soaks up paint like a sponge if you
are not careful. I have found that
rubbing drywall spackling compound
into the pores of block balsa around the
nose and then sanding it down to where
only the wood grain is filled provides a
nice surface for painting. The sheet
balsa seems to work fine with a bit of
sealing.
The sealing process is where Scott
Christensen made a “breakthrough”
discovery. There is a product in a
spray can sold by the Delta Company
called Stencil Magic Top Coat Satin
Spray. I found mine at a Ben Franklin
craft store. Two light coats of this
product and a light sanding prepare the
surface nicely for a paint finish.
Thanks, Scott!
Two views show
the author’s BD-4
scale model with a
16-inch wingspan.
Stencil Magic Top
Coat Satin Spray
prepared the surface
nicely for a paint
finish.
One of several new projects—the author’s Mini Quaker—is a replica of a 1930s FF
model. It has a lightweight stick-and-frame structure.
January 2007 89
The author’s lightweight Walker Jr. is an indoor living-room flyer with 60 square
inches of wing area, and it weighs less than 5 grams.
Working with tissue requires several materials. Clamping the flying surfaces to a flat
surface while they dry will prevent warping.
Working with films such as Polymicro covering requires special
techniques, tools, and materials.
3M 77 spray contact cement is used to adhere the Polymicro
film covering to the frames of the author’s Walker Jr.
Scott has been getting excellent
results from spraying thinned acrylic
paints on for the color. Anyone who
has seen his models or even pictures of
them will appreciate the results. This
technique requires a high-pressure
system (roughly 50 psi) with an
airbrush to work successfully.
I don’t have a system with pressure
that high, so I went in a different
direction. I have been using automobile
touch-up spray paint that I spray into a
container and then dilute
approximately 50% with slow-drying
automobile paint thinner. This has
worked well for me with my economy,
low-pressure airbrush system.
All these color paint systems have
the potential of adding excess weight,
so apply light coats and check the
results. Typically these systems do not
completely fill the wood grain, but the
bright, consistent colors compensate.
Shifting gears, let’s move to another
type of project altogether. One of the
photos shows my Mini Quaker: a
replica of a 1930s FF model. The
construction is similar to that of a
typical rubber-band-powered design,
with lightweight stick-and-frame
structure. The wingspan is 22 inches
and the weight is 30 grams.
The RC gear is the Plantraco HX-
900 900 MHz system with a 170 mAh
Li-Poly cell. I chose the GWJ 4:1 ballbearing
gear drive with a Super Slick
blue motor for power. This twirls a
GWS 5 x 3 propeller with authority.
All that equipment can be found at
www.bsdmicrorc.com.
The Mini Quaker is representative
of a broad variety of model choices,
whether scratch-built or converted
rubber-powered FF. The thing that
enhances the performance more than
any other is the use of an
undercambered airfoil with a
turbulator strip. I am fond of the
Benedek B6356b found at
www.profili2.com. This Profili
program is a free download with
more than 1,000 airfoils. It is a real
boon to scratch builders.
For covering and finishing these
lightweight models, I am fond of
tissue paper—especially the replica
type because it gives a more
authentic appearance. There is a
specific type of tissue I prefer called
Esaki. I got mine from Peck-
Polymers at www.peck-poly
mers.com/. Esaki is light and has
excellent working properties while
covering.
My favorite adhesive is Elmer’s
White Glue, spread thin before
applying the tissue. Remember that
when covering an undercambered
surface, the material must be fastened
to every rib.
After you have covered the model
with tissue, it needs to be shrunk. A
light mist of rubbing alcohol is
excellent for this. As shown in the
picture, it is important to clamp the
flying surfaces to a flat surface while
they are drying to avoid warping.
Shims under them promote drying.
I have had excellent results with
Krylon Crystal Clear spray paint as a
finish coat. It is thin and works the
same way as nitrate dope. Again, the
surfaces must be clamped down while
curing to avoid warps. Two coats will
usually give a nice sheen and keep
the weight reasonable. The Crystal
Clear spray paint is compatible with
the lacquer-based auto touch-up
paints when you want to add extra
color.
Moving to the light projects that fly
mostly indoors, my living-room flyer
(LRF)—the Walker Jr.—has 60
square inches of wing area and
weighs less than 5 grams. The
equipment came from
www.bsdmicrorc.com and is what is
sold for the Plantraco ARF Butterfly
LRF.
The construction is a mixture of
balsa, carbon fiber, and foam. The
covering is a light plastic film called
Polymicro. This material is available
through FF vendors who deal in
indoor models or www.homefly.com.
Working with thin plastic films
such as Polymicro requires some
special techniques. It is impractical to
try to cut it with scissors or a blade
because it tears too easily. The photo
shows some of the tools and methods
for using this fine covering.
I spread it out on a clean sheet of
construction paper. The first step is to
glue balsa “handles” to the section
you want to apply. A UHU-brand
glue stick works fine for this. A
pencil soldering iron is a fine tool for
cutting and trimming the plastic.
The preferred adhesive for
Polymicro is 3M 77 spray contact
cement. I spread newspaper on the
shop floor and place the frame to be
covered in the middle. Holding the
spray can roughly three feet above
the frame, I apply a light mist of the
adhesive to the frame. It is easy to
apply too much glue; take it lightly
here.
While the glue is still moist I lift
the frame and place it on the
construction paper. The next step is
to lift the section of Poymicro with
the balsa sticks and lower it onto the
frame. Smooth out wrinkles, slack,
and problems at this stage. Be sure to
rub all the areas where you want the
glue to stick with a clean fingertip.
Now you can use the soldering
iron to trim the excess from the
frame. Do this a few more times, and
you have a completely covered set of
parts. A picture shows the finished
sections of the Walker Jr. after
covering. With this material the
dihedral is added after the covering
has been applied.
For all of its apparent delicacy, the
covering on my Walker Jr. has
survived all sorts of bounces off
walls, furniture, and appliances. Any
modeler who flies Indoor FF
Duration will point out the same
durability. The slow-flying,
lightweight models lack the energy to
do significant damage.
The Walker Jr. and the Mini Quaker
were published in John Worth’s fine
RC Micro World. If you would like to
see something of yours in a national
magazine, send it to me. Don’t be
shy! All of us would enjoy seeing a
new project.
Thanks to those who do
contribute; after all, this is your
column.
Til next time.
Edition: Model Aviation - 2007/01
Page Numbers: 88,89,90
Also included in this column:
• Dynamics Unlimited closes
its doors
• Mini Quaker is a replica of a
1930s FF model
• Polymicro film covering
GREETINGS, friends and followers of
RC micro flight. This has been a lean
month for reader contributions, so you
will have to suffer through more of my
projects and I will write about finishing
and covering techniques for the various
materials used with the small models.
We have lost one of our valued
vendors: Dynamics Unlimited. For
unspecified reasons the company has
closed permanently. You will be
missed!
We still have several vendors with
excellent lines. Bob and Janelle Selman
at www.bsdmicrorc.com/ and BP
Hobbies at www.bphobbies.com carry
a good selection of micro gear.
On a brighter note, John Worth is
publishing a magazine called RC Micro
World at www.cloud9rc.com. Visit the
Web site and look at John’s efforts. It
will be worth your while.
To kick off the discussion about
models and finishing, I will begin with
my latest project: an all-balsa BD-4
scale model of the kit-built aircraft
from the fertile mind of Jim Bede. It
has a 16-inch wingspan and an area of
42 square inches. With a finished
weight of 40 grams, it is not aerobatic
but flies smoothly in a realistic manner.
The equipment is all Dynamics
Unlimited. The receiver is a narrowband
RX-101, the two servos are the
Pin-Point 2.1-gram models, and the
drive is the M5-3-36 single-cell
brushless motor. A 250 mAh Li-Poly
cell powers the system. Dynamics
Unlimited is off the scene, but Bob
Selman carries equivalent equipment.
Concerning the finishing method,
the balsa is the soft and light variety
and soaks up paint like a sponge if you
are not careful. I have found that
rubbing drywall spackling compound
into the pores of block balsa around the
nose and then sanding it down to where
only the wood grain is filled provides a
nice surface for painting. The sheet
balsa seems to work fine with a bit of
sealing.
The sealing process is where Scott
Christensen made a “breakthrough”
discovery. There is a product in a
spray can sold by the Delta Company
called Stencil Magic Top Coat Satin
Spray. I found mine at a Ben Franklin
craft store. Two light coats of this
product and a light sanding prepare the
surface nicely for a paint finish.
Thanks, Scott!
Two views show
the author’s BD-4
scale model with a
16-inch wingspan.
Stencil Magic Top
Coat Satin Spray
prepared the surface
nicely for a paint
finish.
One of several new projects—the author’s Mini Quaker—is a replica of a 1930s FF
model. It has a lightweight stick-and-frame structure.
January 2007 89
The author’s lightweight Walker Jr. is an indoor living-room flyer with 60 square
inches of wing area, and it weighs less than 5 grams.
Working with tissue requires several materials. Clamping the flying surfaces to a flat
surface while they dry will prevent warping.
Working with films such as Polymicro covering requires special
techniques, tools, and materials.
3M 77 spray contact cement is used to adhere the Polymicro
film covering to the frames of the author’s Walker Jr.
Scott has been getting excellent
results from spraying thinned acrylic
paints on for the color. Anyone who
has seen his models or even pictures of
them will appreciate the results. This
technique requires a high-pressure
system (roughly 50 psi) with an
airbrush to work successfully.
I don’t have a system with pressure
that high, so I went in a different
direction. I have been using automobile
touch-up spray paint that I spray into a
container and then dilute
approximately 50% with slow-drying
automobile paint thinner. This has
worked well for me with my economy,
low-pressure airbrush system.
All these color paint systems have
the potential of adding excess weight,
so apply light coats and check the
results. Typically these systems do not
completely fill the wood grain, but the
bright, consistent colors compensate.
Shifting gears, let’s move to another
type of project altogether. One of the
photos shows my Mini Quaker: a
replica of a 1930s FF model. The
construction is similar to that of a
typical rubber-band-powered design,
with lightweight stick-and-frame
structure. The wingspan is 22 inches
and the weight is 30 grams.
The RC gear is the Plantraco HX-
900 900 MHz system with a 170 mAh
Li-Poly cell. I chose the GWJ 4:1 ballbearing
gear drive with a Super Slick
blue motor for power. This twirls a
GWS 5 x 3 propeller with authority.
All that equipment can be found at
www.bsdmicrorc.com.
The Mini Quaker is representative
of a broad variety of model choices,
whether scratch-built or converted
rubber-powered FF. The thing that
enhances the performance more than
any other is the use of an
undercambered airfoil with a
turbulator strip. I am fond of the
Benedek B6356b found at
www.profili2.com. This Profili
program is a free download with
more than 1,000 airfoils. It is a real
boon to scratch builders.
For covering and finishing these
lightweight models, I am fond of
tissue paper—especially the replica
type because it gives a more
authentic appearance. There is a
specific type of tissue I prefer called
Esaki. I got mine from Peck-
Polymers at www.peck-poly
mers.com/. Esaki is light and has
excellent working properties while
covering.
My favorite adhesive is Elmer’s
White Glue, spread thin before
applying the tissue. Remember that
when covering an undercambered
surface, the material must be fastened
to every rib.
After you have covered the model
with tissue, it needs to be shrunk. A
light mist of rubbing alcohol is
excellent for this. As shown in the
picture, it is important to clamp the
flying surfaces to a flat surface while
they are drying to avoid warping.
Shims under them promote drying.
I have had excellent results with
Krylon Crystal Clear spray paint as a
finish coat. It is thin and works the
same way as nitrate dope. Again, the
surfaces must be clamped down while
curing to avoid warps. Two coats will
usually give a nice sheen and keep
the weight reasonable. The Crystal
Clear spray paint is compatible with
the lacquer-based auto touch-up
paints when you want to add extra
color.
Moving to the light projects that fly
mostly indoors, my living-room flyer
(LRF)—the Walker Jr.—has 60
square inches of wing area and
weighs less than 5 grams. The
equipment came from
www.bsdmicrorc.com and is what is
sold for the Plantraco ARF Butterfly
LRF.
The construction is a mixture of
balsa, carbon fiber, and foam. The
covering is a light plastic film called
Polymicro. This material is available
through FF vendors who deal in
indoor models or www.homefly.com.
Working with thin plastic films
such as Polymicro requires some
special techniques. It is impractical to
try to cut it with scissors or a blade
because it tears too easily. The photo
shows some of the tools and methods
for using this fine covering.
I spread it out on a clean sheet of
construction paper. The first step is to
glue balsa “handles” to the section
you want to apply. A UHU-brand
glue stick works fine for this. A
pencil soldering iron is a fine tool for
cutting and trimming the plastic.
The preferred adhesive for
Polymicro is 3M 77 spray contact
cement. I spread newspaper on the
shop floor and place the frame to be
covered in the middle. Holding the
spray can roughly three feet above
the frame, I apply a light mist of the
adhesive to the frame. It is easy to
apply too much glue; take it lightly
here.
While the glue is still moist I lift
the frame and place it on the
construction paper. The next step is
to lift the section of Poymicro with
the balsa sticks and lower it onto the
frame. Smooth out wrinkles, slack,
and problems at this stage. Be sure to
rub all the areas where you want the
glue to stick with a clean fingertip.
Now you can use the soldering
iron to trim the excess from the
frame. Do this a few more times, and
you have a completely covered set of
parts. A picture shows the finished
sections of the Walker Jr. after
covering. With this material the
dihedral is added after the covering
has been applied.
For all of its apparent delicacy, the
covering on my Walker Jr. has
survived all sorts of bounces off
walls, furniture, and appliances. Any
modeler who flies Indoor FF
Duration will point out the same
durability. The slow-flying,
lightweight models lack the energy to
do significant damage.
The Walker Jr. and the Mini Quaker
were published in John Worth’s fine
RC Micro World. If you would like to
see something of yours in a national
magazine, send it to me. Don’t be
shy! All of us would enjoy seeing a
new project.
Thanks to those who do
contribute; after all, this is your
column.
Til next time.