Gene Smith, 1401 N. Husband St., Stillwater OK 74075; E-mail: [email protected]
FREE FLIGHT SPORT
TIPS FOR STRIPPERS: Stripping wood may seem quite simple, but
there are some basic techniques you need to know. Your first attempts
should be in the privacy of your shop—not at your model club’s demo
in a mall.
There are three reasons to make your own strip wood. First, you
can select the balsa for the proper weight and strength of wood for
your application. Second, it is less expensive to strip your own wood.
Third, you can cut sizes that are unavailable in the hobby shop.
I use two strippers. The Master Airscrew variety is inexpensive and
does a nice job for most modelers’ needs. It is readily available at your
hobby shop or by mail order. My other favorite—the Jim Jones
stripper—can strip wood that is up to 1⁄8-inch wide and is primarily for
Indoor-model use. Unfortunately it is no longer being produced.
If you want to make your own stripper, check out the Web site
www.mindspring.com/~thayer5/ and look under “tools.” And then
there is the old standby: a straightedge and a sharp #11 blade. I like the
This Sopwith Bee by Al Backstrom makes a cute Peanut Scale
model. Flight-trimming could be interesting.
Author’s Fw 190’s torque box and cowl. Nose plug with propeller
bearing is partially inserted into the torque box.
Although the framework of the author’s Fw 190 is covered, you
can see the lightened structure compared to the kit plans.
The finished Fw 190 spans 16.5 inches and weighs 17 grams
without the rubber motor. Flight times are roughly 30 seconds.
metal rulers with cork backing for “freehand” stripping. The cork
minimizes slippage.
My first mistake was trying to use wood that was too light.
Although 4- to 6-pound stock is fine for some structural use, it is too
weak for 1⁄16-inch stringers. I usually end up using 8- to 12-pound stock
for strip wood, depending on the quality of the wood and its intended
use. If the balsa is light yet stiff, it is “Indoor quality.”
If you are serious about it, you can determine the quality of your
balsa with a stiffness calculation. Don Slusarczyk’s Web site—
www.indoorfreeflight.com—features a stiffness calculator and
guidelines to let you know what a “good” value would be.
After selecting the proper weight of wood, make sure the stock is
straight-grained. If the sheet is otherwise satisfactory but the grain is at
a slight angle to the edge of the sheet, use a straightedge as a guide and
make a cut parallel to the grain so that the strip wood can be taken from
the new edge with straight grain. Be sure the blade is sharp.
If there is a little deviation in the grain, make the pass so that the
grain moves away from the free edge of the strip. Otherwise, the strip
will narrow as the blade tries to follow the grain.
When using the Master Airscrew stripper, make the first pass
using relatively little pressure so that the blade will not have a
tendency to wander with the grain. Each pass can be slightly deeper
until the cut is complete.Bob Schlosberg has created another beautiful aircraft. The Stinson SR-SE has a 31-inch
wingspan and is powered by a Brown B-200 twin CO2 motor.Howard Littman’s orange Stuka in
Japanese markings climbs out for another
great flight. Photo by Dave Boles.
When cutting 1⁄4 inch or thicker stock, flip
the sheet over to complete the cut. Rocky
Russo has found that the heavier #10 blade
gives a more accurate cut.
I strip all the wood for my models except
for the occasional kit-build. If you are using
kit strip wood, you still need to check the
strips before you use them. Some will be
stronger (heavier) than others. Use the
heavier stock for main stringers and the
lighter stock for the tail feathers. Another
nuance is that if your strip is heavier at one
end than the other, use the heavy end for the
front of the model so the lighter end is near
the tail.
Weighing sheet balsa has been a great
learning experience for me. With time you
can judge wood weight fairly well by just
looking at it. However, I still weigh every
sheet I buy. It is amazing to see how the
wood’s density can vary within a single
sheet. A sheet of 8-pound-stock wood can
actually be half 6-pound density and half 10-
pound density.
Develop the habit of holding the sheet
wood up to a light. You can see the areas of
lighter and heavier wood within the sheet, at
least up to 1⁄16 inch in thickness.
My friend Clarence Mather, an
experienced modeler who was on the US FF
Indoor team years ago and has published a
number of original designs, uses 1⁄32 square in
his Peanut-size models. He was often unable
to find light wood in his local hobby shop,
but they almost always had some heavy 1⁄32
sheet.
Clarence discovered that he could use the
hard 1⁄32 sheet in crossbracing and other
applications and achieve the same strength
and light weight of “better” wood. You can
see two of his models: a P-39 and P-51B in
the old Model Builder Flying Scale Models of
WWII plans book. He used 1⁄32 x 1⁄16 for the
fuselage stringers and 1⁄32 sheet for the wing
ribs.
Plastic Nose Surgery: Let’s say you bought
this neat-looking model kit, and it has a
molded plastic nose with provisions for a
small thrust button. Not only is the nose
opening too small for a decent rubber motor,
but trying to make thrust adjustments would
be a nightmare. You could improvise a built-
May 2005 137
up nose or carve a nose block, but there is that
nice-looking molded cowl, begging to be
used.
Enter Howard Littman with a neat
solution. He builds what he calls a “torque
box” in front of the number-one former. This
sheet-balsa box has an opening in the front for
a nose block that allows thrust adjustments.
The plastic cowl does not even have to be
glued to the torque box.
Howard also often adds a small ballast box
below the torque box. The ballast box, as the
name implies, holds BB shot as needed for
nose weight. A small hole in the box allows
shot to be added. Once the proper amount is
in place, a couple drops of cyanoacrylate glue
keep it from rattling around.
The Stuka did not need a separate box
because of the shape of the cowl. Howard put
a hole in the former behind the radiator
louvers and dropped the shot into the bottom
of the cowl from the back.
Another problem is that the small size of
the Guillow’s 500-series models leaves room
for only a 5⁄8-inch square torque box under the
cowl of the models of liquid-cooled-engined
airplanes such as the Stuka and the Spitfire.
That can result in the rubber climbing off the
propeller hook and binding inside the torque
box early in the power run.
This can be solved by using a sleeve of
shrink tubing over the first inch or so of the
motor. That also smooths the motor run and
allows for as short a propeller shaft as
possible to make the thrustline adjustments
more effective. The binding problem does not
exist in 500-series models of radial-enginepowered
airplanes or the larger Guillow’s kits
since those cowls have room for a larger
torque box.
The Stuka is resplendent in its orangeand-
black finish with Japanese markings.
Howard explains that the Japanese Stuka is
a “probably was.” Some sources say that
the Japanese had several Stukas supplied
by the Germans for testing with a view to
possible licensed production. The overall
orange with black cowling was a typical
experimental aircraft color scheme in
Japan during the period.
Howard built his model for the Guillow’s
Stuka Challenge (Yahoo group). Since the
rules stated that the color scheme could
represent “any operational Stuka that could
have existed,” he decided to have some fun
and use the orange scheme. It makes a
great-looking model.
Kit-Bashing the Guillow’s 500-Series Fw
190: The box art was irresistible, but the
realities of the heavy wood and “built for
stout” design kept the Fw 190 in the box for
years. After seeing Howard’s Stuka, I decided
to give the model a go.
The kit wood was discarded. Fortunately
138 MODEL AVIATION
Guillow’s puts patterns for the fuselage
formers on the plans. These were copied and
transferred to the balsa by putting the print
side down and rubbing acetone on the paper
with a cotton bud.
Light 1⁄20 sheet was used to strip the tailfeather
sticks and make the curved tips. A
torque box was built as described in the
preceding so that the plastic cowl could be
used. The wing was made per the plans outline
but using “cracked-rib” construction. If you
build this model, note that the space allowed
for the wing in the fuselage is 1⁄8-inch shorter
than the wing chord on the plans, so narrow
the wing in the center when you build it.
The finish was one thin coat of thin nitrate
brushed on, followed by a spray of 80%
nitrate/thinner with 20% white Floquil. The
propeller was made from old, thin, tough
cottage-cheese-container stock. The spinner is
balsa turned on a Dremel hand tool.
The model balanced at 30% of the chord
with no ballast and a 16-inch length of 1⁄8-inch
Tan rubber. A total of 3° right- and downthrust
were built into the nose block. Both wingtips
were washed out 1⁄32 inch.
Initial low-powered flights showed a dive.
The rear of the stabilizer was raised 1⁄64 inch.
More power caused a stall and a left turn, so
down- and right thrust were added. This gave
a safe, if somewhat wandering, flight pattern
that was good for more than 30 seconds. A
larger motor (two loops of .07 x 23 inches)
and 1,600 turns got a flight of 49 seconds. The
model’s parameters are similar to those of a
14-gram Bostonian.
Alcohol and Glue Stick Do Mix: Bill
Hancock mixes glue-stick material with
rubbing alcohol in a small jar (a prescription
bottle). He makes the mix relatively thick and
then brushes it onto the balsa to adhere tissue.
Tissue can be loosened and repositioned by
applying a bit of alcohol on a cotton ball to the
area that needs work.
You want wing area? We got wing area!
Cuter than a bumblebee, Al Backstrom’s
Peanut Scale Sopwith Bee was drawn with
help from Mike Roach of the United
Kingdom. Al did a beautiful job with this little
biplane. All of that wing area decreases the
wing loading but increases drag. Trimming
this cutie could be a chore. Use a relatively
low-pitch propeller.
Plans were published in the September
2004 Flying Aces newsletter. To subscribe,
send $15 to FAC-GHQ, 3301 Cindy Ln., Erie
PA 16506. That gets you six issues.
Good Deal From NFFS: The National Free
Flight Society (NFFS) has a sign-up offer for
new or past (not current) members. Visit
www.freeflight.org/jlf/NewMembers.htm for
the sign-up form or send me an SASE with a
request for the paper form.
In addition to membership and a
subscription to the NFFS Digest, you get a
$10 coupon for NFFS plans! The coupon
expires December 31, 2005. The digest
content is primarily contest FF. Dues are
$25 per year. MA
Edition: Model Aviation - 2005/05
Page Numbers: 135,136,137,138
Edition: Model Aviation - 2005/05
Page Numbers: 135,136,137,138
Gene Smith, 1401 N. Husband St., Stillwater OK 74075; E-mail: [email protected]
FREE FLIGHT SPORT
TIPS FOR STRIPPERS: Stripping wood may seem quite simple, but
there are some basic techniques you need to know. Your first attempts
should be in the privacy of your shop—not at your model club’s demo
in a mall.
There are three reasons to make your own strip wood. First, you
can select the balsa for the proper weight and strength of wood for
your application. Second, it is less expensive to strip your own wood.
Third, you can cut sizes that are unavailable in the hobby shop.
I use two strippers. The Master Airscrew variety is inexpensive and
does a nice job for most modelers’ needs. It is readily available at your
hobby shop or by mail order. My other favorite—the Jim Jones
stripper—can strip wood that is up to 1⁄8-inch wide and is primarily for
Indoor-model use. Unfortunately it is no longer being produced.
If you want to make your own stripper, check out the Web site
www.mindspring.com/~thayer5/ and look under “tools.” And then
there is the old standby: a straightedge and a sharp #11 blade. I like the
This Sopwith Bee by Al Backstrom makes a cute Peanut Scale
model. Flight-trimming could be interesting.
Author’s Fw 190’s torque box and cowl. Nose plug with propeller
bearing is partially inserted into the torque box.
Although the framework of the author’s Fw 190 is covered, you
can see the lightened structure compared to the kit plans.
The finished Fw 190 spans 16.5 inches and weighs 17 grams
without the rubber motor. Flight times are roughly 30 seconds.
metal rulers with cork backing for “freehand” stripping. The cork
minimizes slippage.
My first mistake was trying to use wood that was too light.
Although 4- to 6-pound stock is fine for some structural use, it is too
weak for 1⁄16-inch stringers. I usually end up using 8- to 12-pound stock
for strip wood, depending on the quality of the wood and its intended
use. If the balsa is light yet stiff, it is “Indoor quality.”
If you are serious about it, you can determine the quality of your
balsa with a stiffness calculation. Don Slusarczyk’s Web site—
www.indoorfreeflight.com—features a stiffness calculator and
guidelines to let you know what a “good” value would be.
After selecting the proper weight of wood, make sure the stock is
straight-grained. If the sheet is otherwise satisfactory but the grain is at
a slight angle to the edge of the sheet, use a straightedge as a guide and
make a cut parallel to the grain so that the strip wood can be taken from
the new edge with straight grain. Be sure the blade is sharp.
If there is a little deviation in the grain, make the pass so that the
grain moves away from the free edge of the strip. Otherwise, the strip
will narrow as the blade tries to follow the grain.
When using the Master Airscrew stripper, make the first pass
using relatively little pressure so that the blade will not have a
tendency to wander with the grain. Each pass can be slightly deeper
until the cut is complete.Bob Schlosberg has created another beautiful aircraft. The Stinson SR-SE has a 31-inch
wingspan and is powered by a Brown B-200 twin CO2 motor.Howard Littman’s orange Stuka in
Japanese markings climbs out for another
great flight. Photo by Dave Boles.
When cutting 1⁄4 inch or thicker stock, flip
the sheet over to complete the cut. Rocky
Russo has found that the heavier #10 blade
gives a more accurate cut.
I strip all the wood for my models except
for the occasional kit-build. If you are using
kit strip wood, you still need to check the
strips before you use them. Some will be
stronger (heavier) than others. Use the
heavier stock for main stringers and the
lighter stock for the tail feathers. Another
nuance is that if your strip is heavier at one
end than the other, use the heavy end for the
front of the model so the lighter end is near
the tail.
Weighing sheet balsa has been a great
learning experience for me. With time you
can judge wood weight fairly well by just
looking at it. However, I still weigh every
sheet I buy. It is amazing to see how the
wood’s density can vary within a single
sheet. A sheet of 8-pound-stock wood can
actually be half 6-pound density and half 10-
pound density.
Develop the habit of holding the sheet
wood up to a light. You can see the areas of
lighter and heavier wood within the sheet, at
least up to 1⁄16 inch in thickness.
My friend Clarence Mather, an
experienced modeler who was on the US FF
Indoor team years ago and has published a
number of original designs, uses 1⁄32 square in
his Peanut-size models. He was often unable
to find light wood in his local hobby shop,
but they almost always had some heavy 1⁄32
sheet.
Clarence discovered that he could use the
hard 1⁄32 sheet in crossbracing and other
applications and achieve the same strength
and light weight of “better” wood. You can
see two of his models: a P-39 and P-51B in
the old Model Builder Flying Scale Models of
WWII plans book. He used 1⁄32 x 1⁄16 for the
fuselage stringers and 1⁄32 sheet for the wing
ribs.
Plastic Nose Surgery: Let’s say you bought
this neat-looking model kit, and it has a
molded plastic nose with provisions for a
small thrust button. Not only is the nose
opening too small for a decent rubber motor,
but trying to make thrust adjustments would
be a nightmare. You could improvise a built-
May 2005 137
up nose or carve a nose block, but there is that
nice-looking molded cowl, begging to be
used.
Enter Howard Littman with a neat
solution. He builds what he calls a “torque
box” in front of the number-one former. This
sheet-balsa box has an opening in the front for
a nose block that allows thrust adjustments.
The plastic cowl does not even have to be
glued to the torque box.
Howard also often adds a small ballast box
below the torque box. The ballast box, as the
name implies, holds BB shot as needed for
nose weight. A small hole in the box allows
shot to be added. Once the proper amount is
in place, a couple drops of cyanoacrylate glue
keep it from rattling around.
The Stuka did not need a separate box
because of the shape of the cowl. Howard put
a hole in the former behind the radiator
louvers and dropped the shot into the bottom
of the cowl from the back.
Another problem is that the small size of
the Guillow’s 500-series models leaves room
for only a 5⁄8-inch square torque box under the
cowl of the models of liquid-cooled-engined
airplanes such as the Stuka and the Spitfire.
That can result in the rubber climbing off the
propeller hook and binding inside the torque
box early in the power run.
This can be solved by using a sleeve of
shrink tubing over the first inch or so of the
motor. That also smooths the motor run and
allows for as short a propeller shaft as
possible to make the thrustline adjustments
more effective. The binding problem does not
exist in 500-series models of radial-enginepowered
airplanes or the larger Guillow’s kits
since those cowls have room for a larger
torque box.
The Stuka is resplendent in its orangeand-
black finish with Japanese markings.
Howard explains that the Japanese Stuka is
a “probably was.” Some sources say that
the Japanese had several Stukas supplied
by the Germans for testing with a view to
possible licensed production. The overall
orange with black cowling was a typical
experimental aircraft color scheme in
Japan during the period.
Howard built his model for the Guillow’s
Stuka Challenge (Yahoo group). Since the
rules stated that the color scheme could
represent “any operational Stuka that could
have existed,” he decided to have some fun
and use the orange scheme. It makes a
great-looking model.
Kit-Bashing the Guillow’s 500-Series Fw
190: The box art was irresistible, but the
realities of the heavy wood and “built for
stout” design kept the Fw 190 in the box for
years. After seeing Howard’s Stuka, I decided
to give the model a go.
The kit wood was discarded. Fortunately
138 MODEL AVIATION
Guillow’s puts patterns for the fuselage
formers on the plans. These were copied and
transferred to the balsa by putting the print
side down and rubbing acetone on the paper
with a cotton bud.
Light 1⁄20 sheet was used to strip the tailfeather
sticks and make the curved tips. A
torque box was built as described in the
preceding so that the plastic cowl could be
used. The wing was made per the plans outline
but using “cracked-rib” construction. If you
build this model, note that the space allowed
for the wing in the fuselage is 1⁄8-inch shorter
than the wing chord on the plans, so narrow
the wing in the center when you build it.
The finish was one thin coat of thin nitrate
brushed on, followed by a spray of 80%
nitrate/thinner with 20% white Floquil. The
propeller was made from old, thin, tough
cottage-cheese-container stock. The spinner is
balsa turned on a Dremel hand tool.
The model balanced at 30% of the chord
with no ballast and a 16-inch length of 1⁄8-inch
Tan rubber. A total of 3° right- and downthrust
were built into the nose block. Both wingtips
were washed out 1⁄32 inch.
Initial low-powered flights showed a dive.
The rear of the stabilizer was raised 1⁄64 inch.
More power caused a stall and a left turn, so
down- and right thrust were added. This gave
a safe, if somewhat wandering, flight pattern
that was good for more than 30 seconds. A
larger motor (two loops of .07 x 23 inches)
and 1,600 turns got a flight of 49 seconds. The
model’s parameters are similar to those of a
14-gram Bostonian.
Alcohol and Glue Stick Do Mix: Bill
Hancock mixes glue-stick material with
rubbing alcohol in a small jar (a prescription
bottle). He makes the mix relatively thick and
then brushes it onto the balsa to adhere tissue.
Tissue can be loosened and repositioned by
applying a bit of alcohol on a cotton ball to the
area that needs work.
You want wing area? We got wing area!
Cuter than a bumblebee, Al Backstrom’s
Peanut Scale Sopwith Bee was drawn with
help from Mike Roach of the United
Kingdom. Al did a beautiful job with this little
biplane. All of that wing area decreases the
wing loading but increases drag. Trimming
this cutie could be a chore. Use a relatively
low-pitch propeller.
Plans were published in the September
2004 Flying Aces newsletter. To subscribe,
send $15 to FAC-GHQ, 3301 Cindy Ln., Erie
PA 16506. That gets you six issues.
Good Deal From NFFS: The National Free
Flight Society (NFFS) has a sign-up offer for
new or past (not current) members. Visit
www.freeflight.org/jlf/NewMembers.htm for
the sign-up form or send me an SASE with a
request for the paper form.
In addition to membership and a
subscription to the NFFS Digest, you get a
$10 coupon for NFFS plans! The coupon
expires December 31, 2005. The digest
content is primarily contest FF. Dues are
$25 per year. MA
Edition: Model Aviation - 2005/05
Page Numbers: 135,136,137,138
Gene Smith, 1401 N. Husband St., Stillwater OK 74075; E-mail: [email protected]
FREE FLIGHT SPORT
TIPS FOR STRIPPERS: Stripping wood may seem quite simple, but
there are some basic techniques you need to know. Your first attempts
should be in the privacy of your shop—not at your model club’s demo
in a mall.
There are three reasons to make your own strip wood. First, you
can select the balsa for the proper weight and strength of wood for
your application. Second, it is less expensive to strip your own wood.
Third, you can cut sizes that are unavailable in the hobby shop.
I use two strippers. The Master Airscrew variety is inexpensive and
does a nice job for most modelers’ needs. It is readily available at your
hobby shop or by mail order. My other favorite—the Jim Jones
stripper—can strip wood that is up to 1⁄8-inch wide and is primarily for
Indoor-model use. Unfortunately it is no longer being produced.
If you want to make your own stripper, check out the Web site
www.mindspring.com/~thayer5/ and look under “tools.” And then
there is the old standby: a straightedge and a sharp #11 blade. I like the
This Sopwith Bee by Al Backstrom makes a cute Peanut Scale
model. Flight-trimming could be interesting.
Author’s Fw 190’s torque box and cowl. Nose plug with propeller
bearing is partially inserted into the torque box.
Although the framework of the author’s Fw 190 is covered, you
can see the lightened structure compared to the kit plans.
The finished Fw 190 spans 16.5 inches and weighs 17 grams
without the rubber motor. Flight times are roughly 30 seconds.
metal rulers with cork backing for “freehand” stripping. The cork
minimizes slippage.
My first mistake was trying to use wood that was too light.
Although 4- to 6-pound stock is fine for some structural use, it is too
weak for 1⁄16-inch stringers. I usually end up using 8- to 12-pound stock
for strip wood, depending on the quality of the wood and its intended
use. If the balsa is light yet stiff, it is “Indoor quality.”
If you are serious about it, you can determine the quality of your
balsa with a stiffness calculation. Don Slusarczyk’s Web site—
www.indoorfreeflight.com—features a stiffness calculator and
guidelines to let you know what a “good” value would be.
After selecting the proper weight of wood, make sure the stock is
straight-grained. If the sheet is otherwise satisfactory but the grain is at
a slight angle to the edge of the sheet, use a straightedge as a guide and
make a cut parallel to the grain so that the strip wood can be taken from
the new edge with straight grain. Be sure the blade is sharp.
If there is a little deviation in the grain, make the pass so that the
grain moves away from the free edge of the strip. Otherwise, the strip
will narrow as the blade tries to follow the grain.
When using the Master Airscrew stripper, make the first pass
using relatively little pressure so that the blade will not have a
tendency to wander with the grain. Each pass can be slightly deeper
until the cut is complete.Bob Schlosberg has created another beautiful aircraft. The Stinson SR-SE has a 31-inch
wingspan and is powered by a Brown B-200 twin CO2 motor.Howard Littman’s orange Stuka in
Japanese markings climbs out for another
great flight. Photo by Dave Boles.
When cutting 1⁄4 inch or thicker stock, flip
the sheet over to complete the cut. Rocky
Russo has found that the heavier #10 blade
gives a more accurate cut.
I strip all the wood for my models except
for the occasional kit-build. If you are using
kit strip wood, you still need to check the
strips before you use them. Some will be
stronger (heavier) than others. Use the
heavier stock for main stringers and the
lighter stock for the tail feathers. Another
nuance is that if your strip is heavier at one
end than the other, use the heavy end for the
front of the model so the lighter end is near
the tail.
Weighing sheet balsa has been a great
learning experience for me. With time you
can judge wood weight fairly well by just
looking at it. However, I still weigh every
sheet I buy. It is amazing to see how the
wood’s density can vary within a single
sheet. A sheet of 8-pound-stock wood can
actually be half 6-pound density and half 10-
pound density.
Develop the habit of holding the sheet
wood up to a light. You can see the areas of
lighter and heavier wood within the sheet, at
least up to 1⁄16 inch in thickness.
My friend Clarence Mather, an
experienced modeler who was on the US FF
Indoor team years ago and has published a
number of original designs, uses 1⁄32 square in
his Peanut-size models. He was often unable
to find light wood in his local hobby shop,
but they almost always had some heavy 1⁄32
sheet.
Clarence discovered that he could use the
hard 1⁄32 sheet in crossbracing and other
applications and achieve the same strength
and light weight of “better” wood. You can
see two of his models: a P-39 and P-51B in
the old Model Builder Flying Scale Models of
WWII plans book. He used 1⁄32 x 1⁄16 for the
fuselage stringers and 1⁄32 sheet for the wing
ribs.
Plastic Nose Surgery: Let’s say you bought
this neat-looking model kit, and it has a
molded plastic nose with provisions for a
small thrust button. Not only is the nose
opening too small for a decent rubber motor,
but trying to make thrust adjustments would
be a nightmare. You could improvise a built-
May 2005 137
up nose or carve a nose block, but there is that
nice-looking molded cowl, begging to be
used.
Enter Howard Littman with a neat
solution. He builds what he calls a “torque
box” in front of the number-one former. This
sheet-balsa box has an opening in the front for
a nose block that allows thrust adjustments.
The plastic cowl does not even have to be
glued to the torque box.
Howard also often adds a small ballast box
below the torque box. The ballast box, as the
name implies, holds BB shot as needed for
nose weight. A small hole in the box allows
shot to be added. Once the proper amount is
in place, a couple drops of cyanoacrylate glue
keep it from rattling around.
The Stuka did not need a separate box
because of the shape of the cowl. Howard put
a hole in the former behind the radiator
louvers and dropped the shot into the bottom
of the cowl from the back.
Another problem is that the small size of
the Guillow’s 500-series models leaves room
for only a 5⁄8-inch square torque box under the
cowl of the models of liquid-cooled-engined
airplanes such as the Stuka and the Spitfire.
That can result in the rubber climbing off the
propeller hook and binding inside the torque
box early in the power run.
This can be solved by using a sleeve of
shrink tubing over the first inch or so of the
motor. That also smooths the motor run and
allows for as short a propeller shaft as
possible to make the thrustline adjustments
more effective. The binding problem does not
exist in 500-series models of radial-enginepowered
airplanes or the larger Guillow’s kits
since those cowls have room for a larger
torque box.
The Stuka is resplendent in its orangeand-
black finish with Japanese markings.
Howard explains that the Japanese Stuka is
a “probably was.” Some sources say that
the Japanese had several Stukas supplied
by the Germans for testing with a view to
possible licensed production. The overall
orange with black cowling was a typical
experimental aircraft color scheme in
Japan during the period.
Howard built his model for the Guillow’s
Stuka Challenge (Yahoo group). Since the
rules stated that the color scheme could
represent “any operational Stuka that could
have existed,” he decided to have some fun
and use the orange scheme. It makes a
great-looking model.
Kit-Bashing the Guillow’s 500-Series Fw
190: The box art was irresistible, but the
realities of the heavy wood and “built for
stout” design kept the Fw 190 in the box for
years. After seeing Howard’s Stuka, I decided
to give the model a go.
The kit wood was discarded. Fortunately
138 MODEL AVIATION
Guillow’s puts patterns for the fuselage
formers on the plans. These were copied and
transferred to the balsa by putting the print
side down and rubbing acetone on the paper
with a cotton bud.
Light 1⁄20 sheet was used to strip the tailfeather
sticks and make the curved tips. A
torque box was built as described in the
preceding so that the plastic cowl could be
used. The wing was made per the plans outline
but using “cracked-rib” construction. If you
build this model, note that the space allowed
for the wing in the fuselage is 1⁄8-inch shorter
than the wing chord on the plans, so narrow
the wing in the center when you build it.
The finish was one thin coat of thin nitrate
brushed on, followed by a spray of 80%
nitrate/thinner with 20% white Floquil. The
propeller was made from old, thin, tough
cottage-cheese-container stock. The spinner is
balsa turned on a Dremel hand tool.
The model balanced at 30% of the chord
with no ballast and a 16-inch length of 1⁄8-inch
Tan rubber. A total of 3° right- and downthrust
were built into the nose block. Both wingtips
were washed out 1⁄32 inch.
Initial low-powered flights showed a dive.
The rear of the stabilizer was raised 1⁄64 inch.
More power caused a stall and a left turn, so
down- and right thrust were added. This gave
a safe, if somewhat wandering, flight pattern
that was good for more than 30 seconds. A
larger motor (two loops of .07 x 23 inches)
and 1,600 turns got a flight of 49 seconds. The
model’s parameters are similar to those of a
14-gram Bostonian.
Alcohol and Glue Stick Do Mix: Bill
Hancock mixes glue-stick material with
rubbing alcohol in a small jar (a prescription
bottle). He makes the mix relatively thick and
then brushes it onto the balsa to adhere tissue.
Tissue can be loosened and repositioned by
applying a bit of alcohol on a cotton ball to the
area that needs work.
You want wing area? We got wing area!
Cuter than a bumblebee, Al Backstrom’s
Peanut Scale Sopwith Bee was drawn with
help from Mike Roach of the United
Kingdom. Al did a beautiful job with this little
biplane. All of that wing area decreases the
wing loading but increases drag. Trimming
this cutie could be a chore. Use a relatively
low-pitch propeller.
Plans were published in the September
2004 Flying Aces newsletter. To subscribe,
send $15 to FAC-GHQ, 3301 Cindy Ln., Erie
PA 16506. That gets you six issues.
Good Deal From NFFS: The National Free
Flight Society (NFFS) has a sign-up offer for
new or past (not current) members. Visit
www.freeflight.org/jlf/NewMembers.htm for
the sign-up form or send me an SASE with a
request for the paper form.
In addition to membership and a
subscription to the NFFS Digest, you get a
$10 coupon for NFFS plans! The coupon
expires December 31, 2005. The digest
content is primarily contest FF. Dues are
$25 per year. MA
Edition: Model Aviation - 2005/05
Page Numbers: 135,136,137,138
Gene Smith, 1401 N. Husband St., Stillwater OK 74075; E-mail: [email protected]
FREE FLIGHT SPORT
TIPS FOR STRIPPERS: Stripping wood may seem quite simple, but
there are some basic techniques you need to know. Your first attempts
should be in the privacy of your shop—not at your model club’s demo
in a mall.
There are three reasons to make your own strip wood. First, you
can select the balsa for the proper weight and strength of wood for
your application. Second, it is less expensive to strip your own wood.
Third, you can cut sizes that are unavailable in the hobby shop.
I use two strippers. The Master Airscrew variety is inexpensive and
does a nice job for most modelers’ needs. It is readily available at your
hobby shop or by mail order. My other favorite—the Jim Jones
stripper—can strip wood that is up to 1⁄8-inch wide and is primarily for
Indoor-model use. Unfortunately it is no longer being produced.
If you want to make your own stripper, check out the Web site
www.mindspring.com/~thayer5/ and look under “tools.” And then
there is the old standby: a straightedge and a sharp #11 blade. I like the
This Sopwith Bee by Al Backstrom makes a cute Peanut Scale
model. Flight-trimming could be interesting.
Author’s Fw 190’s torque box and cowl. Nose plug with propeller
bearing is partially inserted into the torque box.
Although the framework of the author’s Fw 190 is covered, you
can see the lightened structure compared to the kit plans.
The finished Fw 190 spans 16.5 inches and weighs 17 grams
without the rubber motor. Flight times are roughly 30 seconds.
metal rulers with cork backing for “freehand” stripping. The cork
minimizes slippage.
My first mistake was trying to use wood that was too light.
Although 4- to 6-pound stock is fine for some structural use, it is too
weak for 1⁄16-inch stringers. I usually end up using 8- to 12-pound stock
for strip wood, depending on the quality of the wood and its intended
use. If the balsa is light yet stiff, it is “Indoor quality.”
If you are serious about it, you can determine the quality of your
balsa with a stiffness calculation. Don Slusarczyk’s Web site—
www.indoorfreeflight.com—features a stiffness calculator and
guidelines to let you know what a “good” value would be.
After selecting the proper weight of wood, make sure the stock is
straight-grained. If the sheet is otherwise satisfactory but the grain is at
a slight angle to the edge of the sheet, use a straightedge as a guide and
make a cut parallel to the grain so that the strip wood can be taken from
the new edge with straight grain. Be sure the blade is sharp.
If there is a little deviation in the grain, make the pass so that the
grain moves away from the free edge of the strip. Otherwise, the strip
will narrow as the blade tries to follow the grain.
When using the Master Airscrew stripper, make the first pass
using relatively little pressure so that the blade will not have a
tendency to wander with the grain. Each pass can be slightly deeper
until the cut is complete.Bob Schlosberg has created another beautiful aircraft. The Stinson SR-SE has a 31-inch
wingspan and is powered by a Brown B-200 twin CO2 motor.Howard Littman’s orange Stuka in
Japanese markings climbs out for another
great flight. Photo by Dave Boles.
When cutting 1⁄4 inch or thicker stock, flip
the sheet over to complete the cut. Rocky
Russo has found that the heavier #10 blade
gives a more accurate cut.
I strip all the wood for my models except
for the occasional kit-build. If you are using
kit strip wood, you still need to check the
strips before you use them. Some will be
stronger (heavier) than others. Use the
heavier stock for main stringers and the
lighter stock for the tail feathers. Another
nuance is that if your strip is heavier at one
end than the other, use the heavy end for the
front of the model so the lighter end is near
the tail.
Weighing sheet balsa has been a great
learning experience for me. With time you
can judge wood weight fairly well by just
looking at it. However, I still weigh every
sheet I buy. It is amazing to see how the
wood’s density can vary within a single
sheet. A sheet of 8-pound-stock wood can
actually be half 6-pound density and half 10-
pound density.
Develop the habit of holding the sheet
wood up to a light. You can see the areas of
lighter and heavier wood within the sheet, at
least up to 1⁄16 inch in thickness.
My friend Clarence Mather, an
experienced modeler who was on the US FF
Indoor team years ago and has published a
number of original designs, uses 1⁄32 square in
his Peanut-size models. He was often unable
to find light wood in his local hobby shop,
but they almost always had some heavy 1⁄32
sheet.
Clarence discovered that he could use the
hard 1⁄32 sheet in crossbracing and other
applications and achieve the same strength
and light weight of “better” wood. You can
see two of his models: a P-39 and P-51B in
the old Model Builder Flying Scale Models of
WWII plans book. He used 1⁄32 x 1⁄16 for the
fuselage stringers and 1⁄32 sheet for the wing
ribs.
Plastic Nose Surgery: Let’s say you bought
this neat-looking model kit, and it has a
molded plastic nose with provisions for a
small thrust button. Not only is the nose
opening too small for a decent rubber motor,
but trying to make thrust adjustments would
be a nightmare. You could improvise a built-
May 2005 137
up nose or carve a nose block, but there is that
nice-looking molded cowl, begging to be
used.
Enter Howard Littman with a neat
solution. He builds what he calls a “torque
box” in front of the number-one former. This
sheet-balsa box has an opening in the front for
a nose block that allows thrust adjustments.
The plastic cowl does not even have to be
glued to the torque box.
Howard also often adds a small ballast box
below the torque box. The ballast box, as the
name implies, holds BB shot as needed for
nose weight. A small hole in the box allows
shot to be added. Once the proper amount is
in place, a couple drops of cyanoacrylate glue
keep it from rattling around.
The Stuka did not need a separate box
because of the shape of the cowl. Howard put
a hole in the former behind the radiator
louvers and dropped the shot into the bottom
of the cowl from the back.
Another problem is that the small size of
the Guillow’s 500-series models leaves room
for only a 5⁄8-inch square torque box under the
cowl of the models of liquid-cooled-engined
airplanes such as the Stuka and the Spitfire.
That can result in the rubber climbing off the
propeller hook and binding inside the torque
box early in the power run.
This can be solved by using a sleeve of
shrink tubing over the first inch or so of the
motor. That also smooths the motor run and
allows for as short a propeller shaft as
possible to make the thrustline adjustments
more effective. The binding problem does not
exist in 500-series models of radial-enginepowered
airplanes or the larger Guillow’s kits
since those cowls have room for a larger
torque box.
The Stuka is resplendent in its orangeand-
black finish with Japanese markings.
Howard explains that the Japanese Stuka is
a “probably was.” Some sources say that
the Japanese had several Stukas supplied
by the Germans for testing with a view to
possible licensed production. The overall
orange with black cowling was a typical
experimental aircraft color scheme in
Japan during the period.
Howard built his model for the Guillow’s
Stuka Challenge (Yahoo group). Since the
rules stated that the color scheme could
represent “any operational Stuka that could
have existed,” he decided to have some fun
and use the orange scheme. It makes a
great-looking model.
Kit-Bashing the Guillow’s 500-Series Fw
190: The box art was irresistible, but the
realities of the heavy wood and “built for
stout” design kept the Fw 190 in the box for
years. After seeing Howard’s Stuka, I decided
to give the model a go.
The kit wood was discarded. Fortunately
138 MODEL AVIATION
Guillow’s puts patterns for the fuselage
formers on the plans. These were copied and
transferred to the balsa by putting the print
side down and rubbing acetone on the paper
with a cotton bud.
Light 1⁄20 sheet was used to strip the tailfeather
sticks and make the curved tips. A
torque box was built as described in the
preceding so that the plastic cowl could be
used. The wing was made per the plans outline
but using “cracked-rib” construction. If you
build this model, note that the space allowed
for the wing in the fuselage is 1⁄8-inch shorter
than the wing chord on the plans, so narrow
the wing in the center when you build it.
The finish was one thin coat of thin nitrate
brushed on, followed by a spray of 80%
nitrate/thinner with 20% white Floquil. The
propeller was made from old, thin, tough
cottage-cheese-container stock. The spinner is
balsa turned on a Dremel hand tool.
The model balanced at 30% of the chord
with no ballast and a 16-inch length of 1⁄8-inch
Tan rubber. A total of 3° right- and downthrust
were built into the nose block. Both wingtips
were washed out 1⁄32 inch.
Initial low-powered flights showed a dive.
The rear of the stabilizer was raised 1⁄64 inch.
More power caused a stall and a left turn, so
down- and right thrust were added. This gave
a safe, if somewhat wandering, flight pattern
that was good for more than 30 seconds. A
larger motor (two loops of .07 x 23 inches)
and 1,600 turns got a flight of 49 seconds. The
model’s parameters are similar to those of a
14-gram Bostonian.
Alcohol and Glue Stick Do Mix: Bill
Hancock mixes glue-stick material with
rubbing alcohol in a small jar (a prescription
bottle). He makes the mix relatively thick and
then brushes it onto the balsa to adhere tissue.
Tissue can be loosened and repositioned by
applying a bit of alcohol on a cotton ball to the
area that needs work.
You want wing area? We got wing area!
Cuter than a bumblebee, Al Backstrom’s
Peanut Scale Sopwith Bee was drawn with
help from Mike Roach of the United
Kingdom. Al did a beautiful job with this little
biplane. All of that wing area decreases the
wing loading but increases drag. Trimming
this cutie could be a chore. Use a relatively
low-pitch propeller.
Plans were published in the September
2004 Flying Aces newsletter. To subscribe,
send $15 to FAC-GHQ, 3301 Cindy Ln., Erie
PA 16506. That gets you six issues.
Good Deal From NFFS: The National Free
Flight Society (NFFS) has a sign-up offer for
new or past (not current) members. Visit
www.freeflight.org/jlf/NewMembers.htm for
the sign-up form or send me an SASE with a
request for the paper form.
In addition to membership and a
subscription to the NFFS Digest, you get a
$10 coupon for NFFS plans! The coupon
expires December 31, 2005. The digest
content is primarily contest FF. Dues are
$25 per year. MA
