Foam wing-construction options for any model-airplane build
[[email protected]]
Control Line Aerobatics Bob Hunt
Bob uses 1/16 plywood for his foam cutting templates. They are set
up for internal coring. Two holes must be drilled through the core
before cutting the airfoil shapes.
Bob draws the heated nichrome wire over the two plywood
templates, to achieve a perfect airfoil. Note that the foam LE is
fully rounded. A molded balsa cap will be attached to the LE later.
The cut panel. Only one side has been cut; the template will be
inverted and reattached to the foam panel, and the other side will
be cut.
AS YOU MIGHT have figured out by now, the Project Hole Shot
model is a convenient way to introduce the new CL Precision
Aerobatics (Stunt) enthusiast to “accepted” building practices, the
required tools and materials, and the various products that are
available.
With the fuselage and tail assemblies complete, it is time to think
about a wing. And here’s where we need to pause and take some time
to examine the different types of wing construction and determine the
pros and cons of each type.
The original Hole Shot was constructed using a foam-core wing,
but several have used built-up wings. That type has been with us since
the beginning of the Stunt event. Foam wings came onto the scene in
approximately 1965, but they didn’t become a widely accepted
alternative to the built-up wing for competitive CL use until the early
1970s.
Each type of wing has its merits. On the up side, built-up wings are
less expensive to construct and are generally lighter than an equivalentdesign/
size foam wing. On the downside, built-up wings are more
difficult to build straight and warp free, they are not as strong as foam
wings, they are prone to move around with temperature and humidity
changes, and they are generally more labor-intensive to cover and
finish.
The positives of foam-core wings are that, if properly cut and
covered, they are and will remain warp free. They are durable and will
resist dents and dings. They are much quicker and easier to construct,
and they are easier to repair.
The negatives are that foam wings are more expensive—especially
if you opt to purchase a core or sheeted wing from a commercial
source. “Foamers” are also a bit heavier than an equivalent-size builtup
wing.
I can’t and won’t recommend one type of wing over the other. You
need to evaluate which one is best suited to your needs and skills. I
suggest building one of each, and then you will know which one is best
for you!
The history of the built-up wing goes back a long way. Many types of
wing construction can be utilized with a built-up wing. The one used
on the Hole Shot is the tried-and-proven C-Tube method, with sheet
ribs and a sheeted LE. It’s not fancy, but it is easy to do. Let’s look at a
bit of the foam wing’s history and the path of its development for CL
Stunt use.
The first use of foam for model-airplane wings can be traced back
to a June 1964 Model Airplane News article that Ed Izzo and Ray
Olson co-wrote, titled “Styrofoam, a giant step forward.” The foam
they initially used was a product of the Dow Chemical company,
which owns the rights to the name “Styrofoam.” It was an extruded
type of polystyrene foam, but it could easily be “cut” using a heated
nichrome wire and a bow.
Ed and Ray’s article inspired many modelers to experiment with
foam components in their modeling. I remember reading that article
repeatedly, coming to the conclusion that there was real value in giving
foam a try.
The first foam-winged Stunt model I ever saw fly was Gene
Schaffer’s white-and-orange Jet in 1965. (He never did actually name
that airplane.) Apparently Gene built it quickly to evaluate the use of
foam components in his models. The fact that he used that aircraft in
competition right away certainly indicated that he liked it.
The earliest CL foam wings were cut from 1-pound-per-cubic-foot
foam and were not “cored out.” The entire wing was solid foam
September 2008 139
covered with 1/16 sheet balsa. Clearance holes
were drilled in the inboard panel to allow
passage for the leadouts. Predictably, these
wings were quite a bit heavier than an
equivalent built-up balsa wing.
The first manufacturer to supply the CL
fraternity with commercial foam-core wings
was Arnold and Mike Stott’s Foam Flite,
based in Mankato, Minnesota. Mike was an
accomplished Stunt flier, and he too had read
Ed and Ray’s landmark article.
Even though the solid-core foam wings
suffered a significant weight penalty, they
began showing up in more and more Stunt
models in the mid- to late 1960s. Why? The
reason is simple. A properly cut and covered
foam wing proved to be extremely accurate,
warp free, and quick to assemble. You were
basically guaranteed a straight model that
would fly well.
Many resisted changing to foam because
of the weight penalty. Ed and Ray’s article
addressed internal coring to reduce weight,
but the earliest CL foam wings did not take
advantage of this feature.
By the end of the 1960s, Arnold and Mike
had begun to use two-section coring in their
wings, to reduce the weight. Foam quickly
became more popular after that.
I started experimenting with foam wings
in 1968 and opened a company—Controline
Specialties Corporation (CSC)—in 1969 that
produced them for both RC and CL use. My
company and Arnold and Mike’s Foam Flite
immediately entered some good-natured
competition to see who could produce the
lightest foam-core wings for CL modelers.
They had two-section coring, so I began
cutting a third section.
It was great fun, and the result of our
“competition” was rapid development of the
foam-core wing for CL Stunt use. Throughout
the 1970s, the foam wing became
increasingly popular and allowed many
modelers to rapidly build accurate and
competitive CL Stunt models.
The preceding is an extremely abbreviated
history of the CL foam wing. Through the
years, many additional developments were
pioneered by many innovative modelers.
Perhaps I’ll be able to cover them in detail at a
later date.
The message is clear. Foam provides a
viable, durable, accurate, and easy-toconstruct
wing option for our purposes.
If you have foam-cutting equipment, you
can make the cores for the Hole Shot. If you
do not, you can order the cores from a custom
wing-cutting service.
I own a company called Robin’s View
Productions, which can provide cores for the
Hole Shot and even provide covered and
sanded wings. Another good source for CL
foam wing cores is Crist Rigotti. See the
“Sources” listing at the end of this column for
contact information.
The early foam wing cores were cut in
such a manner that a balsa block had to be glued to the front of each panel after covering
so that a rounded LE could be achieved. This
practice proved to be inaccurate in many
cases. It was found that improper rounding of
the LE would cause all sorts of trim and flying
problems.
For that reason, I recommend that you cut
or purchase cores with rounded foam LEs. If
the core is properly cut from an accurate
template, an equally accurate LE cap can be
molded and applied.
So we have new techniques to discuss:
foam-wing cutting and covering and balsa
molding.
The term “foam” in this case refers to EPS
(Expanded Polystyrene), which is the type
that is typically used for flotation, packaging,
and insulation. It is usually formed in large
rectangular molds into billets, although
custom-shaped pieces can be made in
custom-shaped molds.
Foam planks can be cut from the billet in
whatever thickness is required. This “cutting”
process is actually a “melting” process.
Nichrome resistance wire attached to a
cutting “bow” on one end and to a safe power
supply at the other is used to slice the foam in
much the same manner as a cheese slicer.
Only, heat does the job in the foam cutter’s
case.
A set of foam wing-core blanks is cut
from one of the planks. A set of templates is
attached to these foam blanks. One template
attaches to the root end, and the other
attaches to the tip end of the blank. On a
constant-chord wing, such as the Hole
Shot’s, these templates are identical.
The templates are aligned to a centerline
that is drawn accurately on either end of the
blank. This ensures that there will be no
warps in the resulting core when it is cut.
The hot-wire bow is usually suspended
above the cutting area via springs, so both
hands are free to guide the bow accurately
over the templates. Most cutting setups also
employ a footswitch so the operator has only
to depress it to turn on the power supply and
heat the wire.
The cutting is quite simple. The hot wire
is drawn from front to rear across the
template to achieve the airfoil shape. The rate
of movement of the bow and the amount of
heat used are important, and the operator will
learn how much of each is required only
through experimentation.
After the core is cut, the surfaces are
sanded smooth and then vacuumed clean.
Then the covering procedure can begin.
Next time we’ll look at covering, or
“skinning,” a foam core and discuss molded
LEs. Till then, fly Stunt! MA
Sources:
Robin’s View Productions
[email protected]
Crist Rigotti
www.clguy.com/
Edition: Model Aviation - 2008/09
Page Numbers: 139,141,142
Edition: Model Aviation - 2008/09
Page Numbers: 139,141,142
Foam wing-construction options for any model-airplane build
[[email protected]]
Control Line Aerobatics Bob Hunt
Bob uses 1/16 plywood for his foam cutting templates. They are set
up for internal coring. Two holes must be drilled through the core
before cutting the airfoil shapes.
Bob draws the heated nichrome wire over the two plywood
templates, to achieve a perfect airfoil. Note that the foam LE is
fully rounded. A molded balsa cap will be attached to the LE later.
The cut panel. Only one side has been cut; the template will be
inverted and reattached to the foam panel, and the other side will
be cut.
AS YOU MIGHT have figured out by now, the Project Hole Shot
model is a convenient way to introduce the new CL Precision
Aerobatics (Stunt) enthusiast to “accepted” building practices, the
required tools and materials, and the various products that are
available.
With the fuselage and tail assemblies complete, it is time to think
about a wing. And here’s where we need to pause and take some time
to examine the different types of wing construction and determine the
pros and cons of each type.
The original Hole Shot was constructed using a foam-core wing,
but several have used built-up wings. That type has been with us since
the beginning of the Stunt event. Foam wings came onto the scene in
approximately 1965, but they didn’t become a widely accepted
alternative to the built-up wing for competitive CL use until the early
1970s.
Each type of wing has its merits. On the up side, built-up wings are
less expensive to construct and are generally lighter than an equivalentdesign/
size foam wing. On the downside, built-up wings are more
difficult to build straight and warp free, they are not as strong as foam
wings, they are prone to move around with temperature and humidity
changes, and they are generally more labor-intensive to cover and
finish.
The positives of foam-core wings are that, if properly cut and
covered, they are and will remain warp free. They are durable and will
resist dents and dings. They are much quicker and easier to construct,
and they are easier to repair.
The negatives are that foam wings are more expensive—especially
if you opt to purchase a core or sheeted wing from a commercial
source. “Foamers” are also a bit heavier than an equivalent-size builtup
wing.
I can’t and won’t recommend one type of wing over the other. You
need to evaluate which one is best suited to your needs and skills. I
suggest building one of each, and then you will know which one is best
for you!
The history of the built-up wing goes back a long way. Many types of
wing construction can be utilized with a built-up wing. The one used
on the Hole Shot is the tried-and-proven C-Tube method, with sheet
ribs and a sheeted LE. It’s not fancy, but it is easy to do. Let’s look at a
bit of the foam wing’s history and the path of its development for CL
Stunt use.
The first use of foam for model-airplane wings can be traced back
to a June 1964 Model Airplane News article that Ed Izzo and Ray
Olson co-wrote, titled “Styrofoam, a giant step forward.” The foam
they initially used was a product of the Dow Chemical company,
which owns the rights to the name “Styrofoam.” It was an extruded
type of polystyrene foam, but it could easily be “cut” using a heated
nichrome wire and a bow.
Ed and Ray’s article inspired many modelers to experiment with
foam components in their modeling. I remember reading that article
repeatedly, coming to the conclusion that there was real value in giving
foam a try.
The first foam-winged Stunt model I ever saw fly was Gene
Schaffer’s white-and-orange Jet in 1965. (He never did actually name
that airplane.) Apparently Gene built it quickly to evaluate the use of
foam components in his models. The fact that he used that aircraft in
competition right away certainly indicated that he liked it.
The earliest CL foam wings were cut from 1-pound-per-cubic-foot
foam and were not “cored out.” The entire wing was solid foam
September 2008 139
covered with 1/16 sheet balsa. Clearance holes
were drilled in the inboard panel to allow
passage for the leadouts. Predictably, these
wings were quite a bit heavier than an
equivalent built-up balsa wing.
The first manufacturer to supply the CL
fraternity with commercial foam-core wings
was Arnold and Mike Stott’s Foam Flite,
based in Mankato, Minnesota. Mike was an
accomplished Stunt flier, and he too had read
Ed and Ray’s landmark article.
Even though the solid-core foam wings
suffered a significant weight penalty, they
began showing up in more and more Stunt
models in the mid- to late 1960s. Why? The
reason is simple. A properly cut and covered
foam wing proved to be extremely accurate,
warp free, and quick to assemble. You were
basically guaranteed a straight model that
would fly well.
Many resisted changing to foam because
of the weight penalty. Ed and Ray’s article
addressed internal coring to reduce weight,
but the earliest CL foam wings did not take
advantage of this feature.
By the end of the 1960s, Arnold and Mike
had begun to use two-section coring in their
wings, to reduce the weight. Foam quickly
became more popular after that.
I started experimenting with foam wings
in 1968 and opened a company—Controline
Specialties Corporation (CSC)—in 1969 that
produced them for both RC and CL use. My
company and Arnold and Mike’s Foam Flite
immediately entered some good-natured
competition to see who could produce the
lightest foam-core wings for CL modelers.
They had two-section coring, so I began
cutting a third section.
It was great fun, and the result of our
“competition” was rapid development of the
foam-core wing for CL Stunt use. Throughout
the 1970s, the foam wing became
increasingly popular and allowed many
modelers to rapidly build accurate and
competitive CL Stunt models.
The preceding is an extremely abbreviated
history of the CL foam wing. Through the
years, many additional developments were
pioneered by many innovative modelers.
Perhaps I’ll be able to cover them in detail at a
later date.
The message is clear. Foam provides a
viable, durable, accurate, and easy-toconstruct
wing option for our purposes.
If you have foam-cutting equipment, you
can make the cores for the Hole Shot. If you
do not, you can order the cores from a custom
wing-cutting service.
I own a company called Robin’s View
Productions, which can provide cores for the
Hole Shot and even provide covered and
sanded wings. Another good source for CL
foam wing cores is Crist Rigotti. See the
“Sources” listing at the end of this column for
contact information.
The early foam wing cores were cut in
such a manner that a balsa block had to be glued to the front of each panel after covering
so that a rounded LE could be achieved. This
practice proved to be inaccurate in many
cases. It was found that improper rounding of
the LE would cause all sorts of trim and flying
problems.
For that reason, I recommend that you cut
or purchase cores with rounded foam LEs. If
the core is properly cut from an accurate
template, an equally accurate LE cap can be
molded and applied.
So we have new techniques to discuss:
foam-wing cutting and covering and balsa
molding.
The term “foam” in this case refers to EPS
(Expanded Polystyrene), which is the type
that is typically used for flotation, packaging,
and insulation. It is usually formed in large
rectangular molds into billets, although
custom-shaped pieces can be made in
custom-shaped molds.
Foam planks can be cut from the billet in
whatever thickness is required. This “cutting”
process is actually a “melting” process.
Nichrome resistance wire attached to a
cutting “bow” on one end and to a safe power
supply at the other is used to slice the foam in
much the same manner as a cheese slicer.
Only, heat does the job in the foam cutter’s
case.
A set of foam wing-core blanks is cut
from one of the planks. A set of templates is
attached to these foam blanks. One template
attaches to the root end, and the other
attaches to the tip end of the blank. On a
constant-chord wing, such as the Hole
Shot’s, these templates are identical.
The templates are aligned to a centerline
that is drawn accurately on either end of the
blank. This ensures that there will be no
warps in the resulting core when it is cut.
The hot-wire bow is usually suspended
above the cutting area via springs, so both
hands are free to guide the bow accurately
over the templates. Most cutting setups also
employ a footswitch so the operator has only
to depress it to turn on the power supply and
heat the wire.
The cutting is quite simple. The hot wire
is drawn from front to rear across the
template to achieve the airfoil shape. The rate
of movement of the bow and the amount of
heat used are important, and the operator will
learn how much of each is required only
through experimentation.
After the core is cut, the surfaces are
sanded smooth and then vacuumed clean.
Then the covering procedure can begin.
Next time we’ll look at covering, or
“skinning,” a foam core and discuss molded
LEs. Till then, fly Stunt! MA
Sources:
Robin’s View Productions
[email protected]
Crist Rigotti
www.clguy.com/
Edition: Model Aviation - 2008/09
Page Numbers: 139,141,142
Foam wing-construction options for any model-airplane build
[[email protected]]
Control Line Aerobatics Bob Hunt
Bob uses 1/16 plywood for his foam cutting templates. They are set
up for internal coring. Two holes must be drilled through the core
before cutting the airfoil shapes.
Bob draws the heated nichrome wire over the two plywood
templates, to achieve a perfect airfoil. Note that the foam LE is
fully rounded. A molded balsa cap will be attached to the LE later.
The cut panel. Only one side has been cut; the template will be
inverted and reattached to the foam panel, and the other side will
be cut.
AS YOU MIGHT have figured out by now, the Project Hole Shot
model is a convenient way to introduce the new CL Precision
Aerobatics (Stunt) enthusiast to “accepted” building practices, the
required tools and materials, and the various products that are
available.
With the fuselage and tail assemblies complete, it is time to think
about a wing. And here’s where we need to pause and take some time
to examine the different types of wing construction and determine the
pros and cons of each type.
The original Hole Shot was constructed using a foam-core wing,
but several have used built-up wings. That type has been with us since
the beginning of the Stunt event. Foam wings came onto the scene in
approximately 1965, but they didn’t become a widely accepted
alternative to the built-up wing for competitive CL use until the early
1970s.
Each type of wing has its merits. On the up side, built-up wings are
less expensive to construct and are generally lighter than an equivalentdesign/
size foam wing. On the downside, built-up wings are more
difficult to build straight and warp free, they are not as strong as foam
wings, they are prone to move around with temperature and humidity
changes, and they are generally more labor-intensive to cover and
finish.
The positives of foam-core wings are that, if properly cut and
covered, they are and will remain warp free. They are durable and will
resist dents and dings. They are much quicker and easier to construct,
and they are easier to repair.
The negatives are that foam wings are more expensive—especially
if you opt to purchase a core or sheeted wing from a commercial
source. “Foamers” are also a bit heavier than an equivalent-size builtup
wing.
I can’t and won’t recommend one type of wing over the other. You
need to evaluate which one is best suited to your needs and skills. I
suggest building one of each, and then you will know which one is best
for you!
The history of the built-up wing goes back a long way. Many types of
wing construction can be utilized with a built-up wing. The one used
on the Hole Shot is the tried-and-proven C-Tube method, with sheet
ribs and a sheeted LE. It’s not fancy, but it is easy to do. Let’s look at a
bit of the foam wing’s history and the path of its development for CL
Stunt use.
The first use of foam for model-airplane wings can be traced back
to a June 1964 Model Airplane News article that Ed Izzo and Ray
Olson co-wrote, titled “Styrofoam, a giant step forward.” The foam
they initially used was a product of the Dow Chemical company,
which owns the rights to the name “Styrofoam.” It was an extruded
type of polystyrene foam, but it could easily be “cut” using a heated
nichrome wire and a bow.
Ed and Ray’s article inspired many modelers to experiment with
foam components in their modeling. I remember reading that article
repeatedly, coming to the conclusion that there was real value in giving
foam a try.
The first foam-winged Stunt model I ever saw fly was Gene
Schaffer’s white-and-orange Jet in 1965. (He never did actually name
that airplane.) Apparently Gene built it quickly to evaluate the use of
foam components in his models. The fact that he used that aircraft in
competition right away certainly indicated that he liked it.
The earliest CL foam wings were cut from 1-pound-per-cubic-foot
foam and were not “cored out.” The entire wing was solid foam
September 2008 139
covered with 1/16 sheet balsa. Clearance holes
were drilled in the inboard panel to allow
passage for the leadouts. Predictably, these
wings were quite a bit heavier than an
equivalent built-up balsa wing.
The first manufacturer to supply the CL
fraternity with commercial foam-core wings
was Arnold and Mike Stott’s Foam Flite,
based in Mankato, Minnesota. Mike was an
accomplished Stunt flier, and he too had read
Ed and Ray’s landmark article.
Even though the solid-core foam wings
suffered a significant weight penalty, they
began showing up in more and more Stunt
models in the mid- to late 1960s. Why? The
reason is simple. A properly cut and covered
foam wing proved to be extremely accurate,
warp free, and quick to assemble. You were
basically guaranteed a straight model that
would fly well.
Many resisted changing to foam because
of the weight penalty. Ed and Ray’s article
addressed internal coring to reduce weight,
but the earliest CL foam wings did not take
advantage of this feature.
By the end of the 1960s, Arnold and Mike
had begun to use two-section coring in their
wings, to reduce the weight. Foam quickly
became more popular after that.
I started experimenting with foam wings
in 1968 and opened a company—Controline
Specialties Corporation (CSC)—in 1969 that
produced them for both RC and CL use. My
company and Arnold and Mike’s Foam Flite
immediately entered some good-natured
competition to see who could produce the
lightest foam-core wings for CL modelers.
They had two-section coring, so I began
cutting a third section.
It was great fun, and the result of our
“competition” was rapid development of the
foam-core wing for CL Stunt use. Throughout
the 1970s, the foam wing became
increasingly popular and allowed many
modelers to rapidly build accurate and
competitive CL Stunt models.
The preceding is an extremely abbreviated
history of the CL foam wing. Through the
years, many additional developments were
pioneered by many innovative modelers.
Perhaps I’ll be able to cover them in detail at a
later date.
The message is clear. Foam provides a
viable, durable, accurate, and easy-toconstruct
wing option for our purposes.
If you have foam-cutting equipment, you
can make the cores for the Hole Shot. If you
do not, you can order the cores from a custom
wing-cutting service.
I own a company called Robin’s View
Productions, which can provide cores for the
Hole Shot and even provide covered and
sanded wings. Another good source for CL
foam wing cores is Crist Rigotti. See the
“Sources” listing at the end of this column for
contact information.
The early foam wing cores were cut in
such a manner that a balsa block had to be glued to the front of each panel after covering
so that a rounded LE could be achieved. This
practice proved to be inaccurate in many
cases. It was found that improper rounding of
the LE would cause all sorts of trim and flying
problems.
For that reason, I recommend that you cut
or purchase cores with rounded foam LEs. If
the core is properly cut from an accurate
template, an equally accurate LE cap can be
molded and applied.
So we have new techniques to discuss:
foam-wing cutting and covering and balsa
molding.
The term “foam” in this case refers to EPS
(Expanded Polystyrene), which is the type
that is typically used for flotation, packaging,
and insulation. It is usually formed in large
rectangular molds into billets, although
custom-shaped pieces can be made in
custom-shaped molds.
Foam planks can be cut from the billet in
whatever thickness is required. This “cutting”
process is actually a “melting” process.
Nichrome resistance wire attached to a
cutting “bow” on one end and to a safe power
supply at the other is used to slice the foam in
much the same manner as a cheese slicer.
Only, heat does the job in the foam cutter’s
case.
A set of foam wing-core blanks is cut
from one of the planks. A set of templates is
attached to these foam blanks. One template
attaches to the root end, and the other
attaches to the tip end of the blank. On a
constant-chord wing, such as the Hole
Shot’s, these templates are identical.
The templates are aligned to a centerline
that is drawn accurately on either end of the
blank. This ensures that there will be no
warps in the resulting core when it is cut.
The hot-wire bow is usually suspended
above the cutting area via springs, so both
hands are free to guide the bow accurately
over the templates. Most cutting setups also
employ a footswitch so the operator has only
to depress it to turn on the power supply and
heat the wire.
The cutting is quite simple. The hot wire
is drawn from front to rear across the
template to achieve the airfoil shape. The rate
of movement of the bow and the amount of
heat used are important, and the operator will
learn how much of each is required only
through experimentation.
After the core is cut, the surfaces are
sanded smooth and then vacuumed clean.
Then the covering procedure can begin.
Next time we’ll look at covering, or
“skinning,” a foam core and discuss molded
LEs. Till then, fly Stunt! MA
Sources:
Robin’s View Productions
[email protected]
Crist Rigotti
www.clguy.com/