Years ago, one of the model magazines published a Hand-Launched Glider that
featured an interesting wing construction. Instead of the usual solid piece of
3/16- or 1/4-inch sheet, the wing consisted of a piece of 1/16 balsa with a large
cutout in the middle of each panel.
Ribs glued on the underside of the sheet gave it camber. Both top and bottom
were covered with tissue. I’m not sure there was much savings in weight or time, but
it did eliminate the shavings and sanding dust.
More recently, some large
discus-launched models have
used built-up construction
in an effort to keep weight
down. These typically use a
solid balsa front section back
to roughly 30% chord, and a
wide balsa TE with connected
ribs. The entire wing is covered
with tissue or plastic film. In
addition to saving some weight,
easier-to-find balsa is used.
For small catapult gliders,
built-up construction also
offers a way to use some of
those scraps of lightweight
C-grain balsa left over from
building a larger glider.
At a recent contest, Joe
Hurdle showed me two
catapult gliders with built-up
wings. One featured a striking
bird-feather color scheme
airbrushed on the top of
the wing. The other slightly
smaller model had an elegant elliptical planform and “V” dihedral.
The wing consisted of a 3/16 balsa LE and 1/8 balsa TE connected by 1/16 ribs.
A wide center rib and filler blocks at the tips complete the wing structure. After
assembly, the wing is planed and sanded to the desired airfoil as is a solid balsa wing.
Instead of covering the entire wing, Joe only covered the open areas with carefully
shaped pieces of plastic film.
Remote Dethermalizer
Remote dethermalizer (RDT) systems allow the modeler to activate the DT
remotely at any time during the flight. It can be used to save a power model that
goes off pattern and is heading straight for the ground, to prevent a fly-away when a
model booms out in a thermal, or to keep a model out of the trees when flying from
a small field. When test flying, it allows the pilot to cut a flight short and make trim
adjustments.
The simplest RDTs are stand-alone systems that consist of a receiver, battery, and
microservo that activates the DT. A small transmitter sends the activation signal
Below: Another of Joe’s gliders uses an
elliptical wing planform and “V” dihedral.
Only the open sections of the built-up
wing are covered.
The fuselage is 1/8-inch spruce with balsa
cheeks at the front to hide the nose weight.
Careful craftsmanship and an airbrushed avian color
scheme lifts Joe Hurdle’s catapult glider out of the ordinary.
The wing features a built-up structure.
when the flier pushes the button. Similar
to a garage door opener, the signal is
encrypted to eliminate the chance of
activating another model’s RDT. Systems
that can share the battery power of a
host electronic timer are also available.
Two popular RDT systems are the
Airtek unit from Ken Bauer at Airtek
Free Flight Electronics and the Aeris
system available from Starlink Flitetech
Models or from the manufacturer, Free
Flight Electronics. Both the Airtek and Aeris systems are
available as stand-alone or as host versions.
Kit Bays showed me the RDT on his tip-launched glider. It
is the Bauer Airtek stand-alone system fitted into the nose of
the glider instead of lead, so there is no weight penalty (typical
stand-alone systems
weigh roughly 8 grams).
The microservo is located
closest to the front of the
model, with a small LiPo
battery next, and the
receiver behind that. Kit
has fitted the transmitter
with an armband so it is
always accessible.
As a batteryconservation
measure,
the receiver in the Airtek
unit that Kit uses cycles
on and off. “Sometimes
you have to wait a
couple of seconds for it
to react,” says Kit. He
has purchased a second
Airtek receiver that
is always on and provides instant DT. He plans to use that
receiver in a scaled-up Civy Boy 61. “It sucks up a little more
current,” he says, “but it could save the model.”
Although a stand-alone RDT setup sells for approximately
$300, it reduces the chance of losing a model. Kit has set up all
four of his tip-launched gliders for RDT. Each model is fitted
with a microservo and a simple mousetrap lever to reduce the
loads on the servo arm.
“I move the receiver and battery between models,” he
mentioned. On his next model, Kit plans to try a linear servo,
which is slightly narrower than the servos he is using. This will
allow him to slightly reduce the front fuselage width slightly.
RDT also opens up FF to sites that would not be suitable
for a conventional timer or fuse-activated DT. “It’s really
handy for a small field,” says Kit. “The practice fields I have are
so small.”
Book Review
The Compressed Air Engine Book, edited by Sergio Montes
and Chris Stoddart, provides an in-depth look at one of the
earliest forms of FF propulsion. Dating back to before the turn
of the century, compressed air motors (similar to steam and
CO2) provided a quiet, compact power source.
Although supplanted by internal combustion engines and
more recently by electric power, compressed air motors
A microservo
in the model’s
nose activates
the model’s DT.
The small wire
antenna in front
of the wing shows
the receiver’s
location. A
mousetrap device
reduces the load
on the servo arm.
Kit Bays’ own-design tip-launch glider utilizes an RDT system that allows
him to terminate the flight at will. The transmitter, which sends out an
encrypted signal to the receiver in the model, is worn on his arm.
have endured throughout the last
100-plus years in a variety of forms,
both homebuilt and manufactured.
The ready-to-fly Air Hog is one recent
example of a compressed air model for
mass consumption.
Published by Free Flight Quarterly, the
book explores the history, design, and
construction of compressed air motors.
Detailed drawings and instructions
for building compressed air motors
are included. One, designed by David
Kerzel, can be built with only a drill
press and hand tools utilizing brass
tubing, rod, and sheet from the local
hobby shop.
Constructing John Morril’s .015 cu. in.
Zephyr motor requires a small lathe and
milling attachment. Most of the parts
are aluminum, with Delrin used for the
piston and drill rod for the crankshaft.
His plans also detail construction of air
tanks from two small aluminum juice
cans.
Also included are small-scale plans for
Jim Sprenger’s Scirocco, a 30-inch span
Sport model utilizing the Zephyr motor.
The model uses traditional stick-andtissue
and the book includes full-size
patterns for wing and stabilizer ribs,
propeller blank, and fuselage formers.
Another motor plan is from a 1928
issue of The Modelmaker magazine and
was designed by Ed Packard, founder of
Cleveland Model Supply. This opposed
twin design uses brass tubing and sheet
for most of the parts. The original plans
called for a 14-inch propeller; Roger
Schroeder constructed one that turned
a 7 x 3 propeller at 2,000 rpm on 60
pounds of air pressure.
Information about ordering The
Compressed Air Engine Book
can be found on Free Flight
Quarterly’s website listed in
“Sources.” The 84-page book is
$25.
FAI Model Supply
In the mid-1990s, John Clapp
and his wife, Sally, purchased FAI
Model Supply from Ed Dolby,
who had started the mail-order
company roughly 50 years ago. At
that time, the company’s major
product was rubber strip for FF
models.
John worked closely with the
manufacturer to develop rubber
of consistently high quality and
power output. Now FAI Super
Sport rubber is used by virtually
every competition Rubber flier in
the world. In addition, the Clapps
have expanded the company to include
a wide variety of kits and FF supplies.
This past summer, John and Sally
decided to sell FAI Model Supply
to another husband-and-wife team:
Charlie and Geralyn Jones. Charlie is an
active F1B and F1G modeler as are the
couple’s two sons, Ryan and Kyle. The
new contact information for FAI Model
Supply is listed in “Sources.” Best wishes
to the Jones family in its new venture.
All Rubber fliers owe John and Sally
a big thanks for their work keeping us
supplied with quality rubber strip and
hundreds of hard-to-find FF items.
Retrieval Pole
Getting a model out of a tree has
always been a part of FF. Throughout the
A small LiPo cell powers the RDT system in the model.
The battery can handle up to 500 flights without
recharging. Its line-of-sight range is roughly 3 miles.
The Sablier two-cylinder compressed air motor
that ran in a French model magazine in 1938
is featured in The Compressed Air Book. The
publication features photos and construction
drawings of a variety of motors.
years, many methods have been tried,
but the two that seem to have survived
are the tall pole and a professional tree
climber.
The late Tommy McLaughlan had a
homemade retrieval pole of telescoping
sections of aluminum and magnesium
tubing. Everyone who flew at Tommy’s
Pensacola, Florida, contests probably
used his retrieval pole at least once.
For the last 20 years or so, the retrieval
pole of choice has been the telescoping
fiberglass one used by power company
linemen. The Telescoping Hot Stick,
made by Hastings and sold through local
dealers, is available in extended lengths
from 12 to 40 feet.
At the Carolina Free Flight
Association contest last summer, CD
John Diebolt showed me a lighter
alternative to the industrial-strength
lineman’s pole. It’s a fiberglass pole used
for flying decorative kites.
Sold by Jackite, Inc., the pole measures
46 inches collapsed and extends to 31
feet. At 5 pounds, it weighs much less
than a Hastings pole. Although the
Jackite comes in green, the orange one
makes the most sense for our intended
use in the trees. The price for the 31-
foot model is approximately $70 plus
shipping. Shorter ones are also available.
As with any pole, the Jackite product
should be used from directly below the
model. This makes handling much easier
and prevents the pole from bending
excessively.
You will need to fit the end of the
pole with some sort of hook or fork so
you can carefully move the model from
the tree limb.
SOURCES:
Airtek Free Flight Electronics
[email protected]
http://mysite.verizon.net/resrqa3z/airtek/index.
html
Free Flight Electronics
[email protected]
www.ffelectronics.com
Starlink Flitetech Models
(858) 231-4994
www.starlink-flitetech.com
Free Flight Quarterly
http://freeflightquarterly.com/wordpress
FAI Model Supply
(440) 930-2114
www.faimodelsupply.com
Hastings Hot Line Tools & Equipment
(269) 945-9541
www.hfgp.com
Jackite Inc.
(877) 522-5483
www.jackite.com
National Free Flight Society
www.freeflight.org
Edition: Model Aviation - 2012/11
Page Numbers: 115,116,117,118
Edition: Model Aviation - 2012/11
Page Numbers: 115,116,117,118
Years ago, one of the model magazines published a Hand-Launched Glider that
featured an interesting wing construction. Instead of the usual solid piece of
3/16- or 1/4-inch sheet, the wing consisted of a piece of 1/16 balsa with a large
cutout in the middle of each panel.
Ribs glued on the underside of the sheet gave it camber. Both top and bottom
were covered with tissue. I’m not sure there was much savings in weight or time, but
it did eliminate the shavings and sanding dust.
More recently, some large
discus-launched models have
used built-up construction
in an effort to keep weight
down. These typically use a
solid balsa front section back
to roughly 30% chord, and a
wide balsa TE with connected
ribs. The entire wing is covered
with tissue or plastic film. In
addition to saving some weight,
easier-to-find balsa is used.
For small catapult gliders,
built-up construction also
offers a way to use some of
those scraps of lightweight
C-grain balsa left over from
building a larger glider.
At a recent contest, Joe
Hurdle showed me two
catapult gliders with built-up
wings. One featured a striking
bird-feather color scheme
airbrushed on the top of
the wing. The other slightly
smaller model had an elegant elliptical planform and “V” dihedral.
The wing consisted of a 3/16 balsa LE and 1/8 balsa TE connected by 1/16 ribs.
A wide center rib and filler blocks at the tips complete the wing structure. After
assembly, the wing is planed and sanded to the desired airfoil as is a solid balsa wing.
Instead of covering the entire wing, Joe only covered the open areas with carefully
shaped pieces of plastic film.
Remote Dethermalizer
Remote dethermalizer (RDT) systems allow the modeler to activate the DT
remotely at any time during the flight. It can be used to save a power model that
goes off pattern and is heading straight for the ground, to prevent a fly-away when a
model booms out in a thermal, or to keep a model out of the trees when flying from
a small field. When test flying, it allows the pilot to cut a flight short and make trim
adjustments.
The simplest RDTs are stand-alone systems that consist of a receiver, battery, and
microservo that activates the DT. A small transmitter sends the activation signal
Below: Another of Joe’s gliders uses an
elliptical wing planform and “V” dihedral.
Only the open sections of the built-up
wing are covered.
The fuselage is 1/8-inch spruce with balsa
cheeks at the front to hide the nose weight.
Careful craftsmanship and an airbrushed avian color
scheme lifts Joe Hurdle’s catapult glider out of the ordinary.
The wing features a built-up structure.
when the flier pushes the button. Similar
to a garage door opener, the signal is
encrypted to eliminate the chance of
activating another model’s RDT. Systems
that can share the battery power of a
host electronic timer are also available.
Two popular RDT systems are the
Airtek unit from Ken Bauer at Airtek
Free Flight Electronics and the Aeris
system available from Starlink Flitetech
Models or from the manufacturer, Free
Flight Electronics. Both the Airtek and Aeris systems are
available as stand-alone or as host versions.
Kit Bays showed me the RDT on his tip-launched glider. It
is the Bauer Airtek stand-alone system fitted into the nose of
the glider instead of lead, so there is no weight penalty (typical
stand-alone systems
weigh roughly 8 grams).
The microservo is located
closest to the front of the
model, with a small LiPo
battery next, and the
receiver behind that. Kit
has fitted the transmitter
with an armband so it is
always accessible.
As a batteryconservation
measure,
the receiver in the Airtek
unit that Kit uses cycles
on and off. “Sometimes
you have to wait a
couple of seconds for it
to react,” says Kit. He
has purchased a second
Airtek receiver that
is always on and provides instant DT. He plans to use that
receiver in a scaled-up Civy Boy 61. “It sucks up a little more
current,” he says, “but it could save the model.”
Although a stand-alone RDT setup sells for approximately
$300, it reduces the chance of losing a model. Kit has set up all
four of his tip-launched gliders for RDT. Each model is fitted
with a microservo and a simple mousetrap lever to reduce the
loads on the servo arm.
“I move the receiver and battery between models,” he
mentioned. On his next model, Kit plans to try a linear servo,
which is slightly narrower than the servos he is using. This will
allow him to slightly reduce the front fuselage width slightly.
RDT also opens up FF to sites that would not be suitable
for a conventional timer or fuse-activated DT. “It’s really
handy for a small field,” says Kit. “The practice fields I have are
so small.”
Book Review
The Compressed Air Engine Book, edited by Sergio Montes
and Chris Stoddart, provides an in-depth look at one of the
earliest forms of FF propulsion. Dating back to before the turn
of the century, compressed air motors (similar to steam and
CO2) provided a quiet, compact power source.
Although supplanted by internal combustion engines and
more recently by electric power, compressed air motors
A microservo
in the model’s
nose activates
the model’s DT.
The small wire
antenna in front
of the wing shows
the receiver’s
location. A
mousetrap device
reduces the load
on the servo arm.
Kit Bays’ own-design tip-launch glider utilizes an RDT system that allows
him to terminate the flight at will. The transmitter, which sends out an
encrypted signal to the receiver in the model, is worn on his arm.
have endured throughout the last
100-plus years in a variety of forms,
both homebuilt and manufactured.
The ready-to-fly Air Hog is one recent
example of a compressed air model for
mass consumption.
Published by Free Flight Quarterly, the
book explores the history, design, and
construction of compressed air motors.
Detailed drawings and instructions
for building compressed air motors
are included. One, designed by David
Kerzel, can be built with only a drill
press and hand tools utilizing brass
tubing, rod, and sheet from the local
hobby shop.
Constructing John Morril’s .015 cu. in.
Zephyr motor requires a small lathe and
milling attachment. Most of the parts
are aluminum, with Delrin used for the
piston and drill rod for the crankshaft.
His plans also detail construction of air
tanks from two small aluminum juice
cans.
Also included are small-scale plans for
Jim Sprenger’s Scirocco, a 30-inch span
Sport model utilizing the Zephyr motor.
The model uses traditional stick-andtissue
and the book includes full-size
patterns for wing and stabilizer ribs,
propeller blank, and fuselage formers.
Another motor plan is from a 1928
issue of The Modelmaker magazine and
was designed by Ed Packard, founder of
Cleveland Model Supply. This opposed
twin design uses brass tubing and sheet
for most of the parts. The original plans
called for a 14-inch propeller; Roger
Schroeder constructed one that turned
a 7 x 3 propeller at 2,000 rpm on 60
pounds of air pressure.
Information about ordering The
Compressed Air Engine Book
can be found on Free Flight
Quarterly’s website listed in
“Sources.” The 84-page book is
$25.
FAI Model Supply
In the mid-1990s, John Clapp
and his wife, Sally, purchased FAI
Model Supply from Ed Dolby,
who had started the mail-order
company roughly 50 years ago. At
that time, the company’s major
product was rubber strip for FF
models.
John worked closely with the
manufacturer to develop rubber
of consistently high quality and
power output. Now FAI Super
Sport rubber is used by virtually
every competition Rubber flier in
the world. In addition, the Clapps
have expanded the company to include
a wide variety of kits and FF supplies.
This past summer, John and Sally
decided to sell FAI Model Supply
to another husband-and-wife team:
Charlie and Geralyn Jones. Charlie is an
active F1B and F1G modeler as are the
couple’s two sons, Ryan and Kyle. The
new contact information for FAI Model
Supply is listed in “Sources.” Best wishes
to the Jones family in its new venture.
All Rubber fliers owe John and Sally
a big thanks for their work keeping us
supplied with quality rubber strip and
hundreds of hard-to-find FF items.
Retrieval Pole
Getting a model out of a tree has
always been a part of FF. Throughout the
A small LiPo cell powers the RDT system in the model.
The battery can handle up to 500 flights without
recharging. Its line-of-sight range is roughly 3 miles.
The Sablier two-cylinder compressed air motor
that ran in a French model magazine in 1938
is featured in The Compressed Air Book. The
publication features photos and construction
drawings of a variety of motors.
years, many methods have been tried,
but the two that seem to have survived
are the tall pole and a professional tree
climber.
The late Tommy McLaughlan had a
homemade retrieval pole of telescoping
sections of aluminum and magnesium
tubing. Everyone who flew at Tommy’s
Pensacola, Florida, contests probably
used his retrieval pole at least once.
For the last 20 years or so, the retrieval
pole of choice has been the telescoping
fiberglass one used by power company
linemen. The Telescoping Hot Stick,
made by Hastings and sold through local
dealers, is available in extended lengths
from 12 to 40 feet.
At the Carolina Free Flight
Association contest last summer, CD
John Diebolt showed me a lighter
alternative to the industrial-strength
lineman’s pole. It’s a fiberglass pole used
for flying decorative kites.
Sold by Jackite, Inc., the pole measures
46 inches collapsed and extends to 31
feet. At 5 pounds, it weighs much less
than a Hastings pole. Although the
Jackite comes in green, the orange one
makes the most sense for our intended
use in the trees. The price for the 31-
foot model is approximately $70 plus
shipping. Shorter ones are also available.
As with any pole, the Jackite product
should be used from directly below the
model. This makes handling much easier
and prevents the pole from bending
excessively.
You will need to fit the end of the
pole with some sort of hook or fork so
you can carefully move the model from
the tree limb.
SOURCES:
Airtek Free Flight Electronics
[email protected]
http://mysite.verizon.net/resrqa3z/airtek/index.
html
Free Flight Electronics
[email protected]
www.ffelectronics.com
Starlink Flitetech Models
(858) 231-4994
www.starlink-flitetech.com
Free Flight Quarterly
http://freeflightquarterly.com/wordpress
FAI Model Supply
(440) 930-2114
www.faimodelsupply.com
Hastings Hot Line Tools & Equipment
(269) 945-9541
www.hfgp.com
Jackite Inc.
(877) 522-5483
www.jackite.com
National Free Flight Society
www.freeflight.org
Edition: Model Aviation - 2012/11
Page Numbers: 115,116,117,118
Years ago, one of the model magazines published a Hand-Launched Glider that
featured an interesting wing construction. Instead of the usual solid piece of
3/16- or 1/4-inch sheet, the wing consisted of a piece of 1/16 balsa with a large
cutout in the middle of each panel.
Ribs glued on the underside of the sheet gave it camber. Both top and bottom
were covered with tissue. I’m not sure there was much savings in weight or time, but
it did eliminate the shavings and sanding dust.
More recently, some large
discus-launched models have
used built-up construction
in an effort to keep weight
down. These typically use a
solid balsa front section back
to roughly 30% chord, and a
wide balsa TE with connected
ribs. The entire wing is covered
with tissue or plastic film. In
addition to saving some weight,
easier-to-find balsa is used.
For small catapult gliders,
built-up construction also
offers a way to use some of
those scraps of lightweight
C-grain balsa left over from
building a larger glider.
At a recent contest, Joe
Hurdle showed me two
catapult gliders with built-up
wings. One featured a striking
bird-feather color scheme
airbrushed on the top of
the wing. The other slightly
smaller model had an elegant elliptical planform and “V” dihedral.
The wing consisted of a 3/16 balsa LE and 1/8 balsa TE connected by 1/16 ribs.
A wide center rib and filler blocks at the tips complete the wing structure. After
assembly, the wing is planed and sanded to the desired airfoil as is a solid balsa wing.
Instead of covering the entire wing, Joe only covered the open areas with carefully
shaped pieces of plastic film.
Remote Dethermalizer
Remote dethermalizer (RDT) systems allow the modeler to activate the DT
remotely at any time during the flight. It can be used to save a power model that
goes off pattern and is heading straight for the ground, to prevent a fly-away when a
model booms out in a thermal, or to keep a model out of the trees when flying from
a small field. When test flying, it allows the pilot to cut a flight short and make trim
adjustments.
The simplest RDTs are stand-alone systems that consist of a receiver, battery, and
microservo that activates the DT. A small transmitter sends the activation signal
Below: Another of Joe’s gliders uses an
elliptical wing planform and “V” dihedral.
Only the open sections of the built-up
wing are covered.
The fuselage is 1/8-inch spruce with balsa
cheeks at the front to hide the nose weight.
Careful craftsmanship and an airbrushed avian color
scheme lifts Joe Hurdle’s catapult glider out of the ordinary.
The wing features a built-up structure.
when the flier pushes the button. Similar
to a garage door opener, the signal is
encrypted to eliminate the chance of
activating another model’s RDT. Systems
that can share the battery power of a
host electronic timer are also available.
Two popular RDT systems are the
Airtek unit from Ken Bauer at Airtek
Free Flight Electronics and the Aeris
system available from Starlink Flitetech
Models or from the manufacturer, Free
Flight Electronics. Both the Airtek and Aeris systems are
available as stand-alone or as host versions.
Kit Bays showed me the RDT on his tip-launched glider. It
is the Bauer Airtek stand-alone system fitted into the nose of
the glider instead of lead, so there is no weight penalty (typical
stand-alone systems
weigh roughly 8 grams).
The microservo is located
closest to the front of the
model, with a small LiPo
battery next, and the
receiver behind that. Kit
has fitted the transmitter
with an armband so it is
always accessible.
As a batteryconservation
measure,
the receiver in the Airtek
unit that Kit uses cycles
on and off. “Sometimes
you have to wait a
couple of seconds for it
to react,” says Kit. He
has purchased a second
Airtek receiver that
is always on and provides instant DT. He plans to use that
receiver in a scaled-up Civy Boy 61. “It sucks up a little more
current,” he says, “but it could save the model.”
Although a stand-alone RDT setup sells for approximately
$300, it reduces the chance of losing a model. Kit has set up all
four of his tip-launched gliders for RDT. Each model is fitted
with a microservo and a simple mousetrap lever to reduce the
loads on the servo arm.
“I move the receiver and battery between models,” he
mentioned. On his next model, Kit plans to try a linear servo,
which is slightly narrower than the servos he is using. This will
allow him to slightly reduce the front fuselage width slightly.
RDT also opens up FF to sites that would not be suitable
for a conventional timer or fuse-activated DT. “It’s really
handy for a small field,” says Kit. “The practice fields I have are
so small.”
Book Review
The Compressed Air Engine Book, edited by Sergio Montes
and Chris Stoddart, provides an in-depth look at one of the
earliest forms of FF propulsion. Dating back to before the turn
of the century, compressed air motors (similar to steam and
CO2) provided a quiet, compact power source.
Although supplanted by internal combustion engines and
more recently by electric power, compressed air motors
A microservo
in the model’s
nose activates
the model’s DT.
The small wire
antenna in front
of the wing shows
the receiver’s
location. A
mousetrap device
reduces the load
on the servo arm.
Kit Bays’ own-design tip-launch glider utilizes an RDT system that allows
him to terminate the flight at will. The transmitter, which sends out an
encrypted signal to the receiver in the model, is worn on his arm.
have endured throughout the last
100-plus years in a variety of forms,
both homebuilt and manufactured.
The ready-to-fly Air Hog is one recent
example of a compressed air model for
mass consumption.
Published by Free Flight Quarterly, the
book explores the history, design, and
construction of compressed air motors.
Detailed drawings and instructions
for building compressed air motors
are included. One, designed by David
Kerzel, can be built with only a drill
press and hand tools utilizing brass
tubing, rod, and sheet from the local
hobby shop.
Constructing John Morril’s .015 cu. in.
Zephyr motor requires a small lathe and
milling attachment. Most of the parts
are aluminum, with Delrin used for the
piston and drill rod for the crankshaft.
His plans also detail construction of air
tanks from two small aluminum juice
cans.
Also included are small-scale plans for
Jim Sprenger’s Scirocco, a 30-inch span
Sport model utilizing the Zephyr motor.
The model uses traditional stick-andtissue
and the book includes full-size
patterns for wing and stabilizer ribs,
propeller blank, and fuselage formers.
Another motor plan is from a 1928
issue of The Modelmaker magazine and
was designed by Ed Packard, founder of
Cleveland Model Supply. This opposed
twin design uses brass tubing and sheet
for most of the parts. The original plans
called for a 14-inch propeller; Roger
Schroeder constructed one that turned
a 7 x 3 propeller at 2,000 rpm on 60
pounds of air pressure.
Information about ordering The
Compressed Air Engine Book
can be found on Free Flight
Quarterly’s website listed in
“Sources.” The 84-page book is
$25.
FAI Model Supply
In the mid-1990s, John Clapp
and his wife, Sally, purchased FAI
Model Supply from Ed Dolby,
who had started the mail-order
company roughly 50 years ago. At
that time, the company’s major
product was rubber strip for FF
models.
John worked closely with the
manufacturer to develop rubber
of consistently high quality and
power output. Now FAI Super
Sport rubber is used by virtually
every competition Rubber flier in
the world. In addition, the Clapps
have expanded the company to include
a wide variety of kits and FF supplies.
This past summer, John and Sally
decided to sell FAI Model Supply
to another husband-and-wife team:
Charlie and Geralyn Jones. Charlie is an
active F1B and F1G modeler as are the
couple’s two sons, Ryan and Kyle. The
new contact information for FAI Model
Supply is listed in “Sources.” Best wishes
to the Jones family in its new venture.
All Rubber fliers owe John and Sally
a big thanks for their work keeping us
supplied with quality rubber strip and
hundreds of hard-to-find FF items.
Retrieval Pole
Getting a model out of a tree has
always been a part of FF. Throughout the
A small LiPo cell powers the RDT system in the model.
The battery can handle up to 500 flights without
recharging. Its line-of-sight range is roughly 3 miles.
The Sablier two-cylinder compressed air motor
that ran in a French model magazine in 1938
is featured in The Compressed Air Book. The
publication features photos and construction
drawings of a variety of motors.
years, many methods have been tried,
but the two that seem to have survived
are the tall pole and a professional tree
climber.
The late Tommy McLaughlan had a
homemade retrieval pole of telescoping
sections of aluminum and magnesium
tubing. Everyone who flew at Tommy’s
Pensacola, Florida, contests probably
used his retrieval pole at least once.
For the last 20 years or so, the retrieval
pole of choice has been the telescoping
fiberglass one used by power company
linemen. The Telescoping Hot Stick,
made by Hastings and sold through local
dealers, is available in extended lengths
from 12 to 40 feet.
At the Carolina Free Flight
Association contest last summer, CD
John Diebolt showed me a lighter
alternative to the industrial-strength
lineman’s pole. It’s a fiberglass pole used
for flying decorative kites.
Sold by Jackite, Inc., the pole measures
46 inches collapsed and extends to 31
feet. At 5 pounds, it weighs much less
than a Hastings pole. Although the
Jackite comes in green, the orange one
makes the most sense for our intended
use in the trees. The price for the 31-
foot model is approximately $70 plus
shipping. Shorter ones are also available.
As with any pole, the Jackite product
should be used from directly below the
model. This makes handling much easier
and prevents the pole from bending
excessively.
You will need to fit the end of the
pole with some sort of hook or fork so
you can carefully move the model from
the tree limb.
SOURCES:
Airtek Free Flight Electronics
[email protected]
http://mysite.verizon.net/resrqa3z/airtek/index.
html
Free Flight Electronics
[email protected]
www.ffelectronics.com
Starlink Flitetech Models
(858) 231-4994
www.starlink-flitetech.com
Free Flight Quarterly
http://freeflightquarterly.com/wordpress
FAI Model Supply
(440) 930-2114
www.faimodelsupply.com
Hastings Hot Line Tools & Equipment
(269) 945-9541
www.hfgp.com
Jackite Inc.
(877) 522-5483
www.jackite.com
National Free Flight Society
www.freeflight.org
Edition: Model Aviation - 2012/11
Page Numbers: 115,116,117,118
Years ago, one of the model magazines published a Hand-Launched Glider that
featured an interesting wing construction. Instead of the usual solid piece of
3/16- or 1/4-inch sheet, the wing consisted of a piece of 1/16 balsa with a large
cutout in the middle of each panel.
Ribs glued on the underside of the sheet gave it camber. Both top and bottom
were covered with tissue. I’m not sure there was much savings in weight or time, but
it did eliminate the shavings and sanding dust.
More recently, some large
discus-launched models have
used built-up construction
in an effort to keep weight
down. These typically use a
solid balsa front section back
to roughly 30% chord, and a
wide balsa TE with connected
ribs. The entire wing is covered
with tissue or plastic film. In
addition to saving some weight,
easier-to-find balsa is used.
For small catapult gliders,
built-up construction also
offers a way to use some of
those scraps of lightweight
C-grain balsa left over from
building a larger glider.
At a recent contest, Joe
Hurdle showed me two
catapult gliders with built-up
wings. One featured a striking
bird-feather color scheme
airbrushed on the top of
the wing. The other slightly
smaller model had an elegant elliptical planform and “V” dihedral.
The wing consisted of a 3/16 balsa LE and 1/8 balsa TE connected by 1/16 ribs.
A wide center rib and filler blocks at the tips complete the wing structure. After
assembly, the wing is planed and sanded to the desired airfoil as is a solid balsa wing.
Instead of covering the entire wing, Joe only covered the open areas with carefully
shaped pieces of plastic film.
Remote Dethermalizer
Remote dethermalizer (RDT) systems allow the modeler to activate the DT
remotely at any time during the flight. It can be used to save a power model that
goes off pattern and is heading straight for the ground, to prevent a fly-away when a
model booms out in a thermal, or to keep a model out of the trees when flying from
a small field. When test flying, it allows the pilot to cut a flight short and make trim
adjustments.
The simplest RDTs are stand-alone systems that consist of a receiver, battery, and
microservo that activates the DT. A small transmitter sends the activation signal
Below: Another of Joe’s gliders uses an
elliptical wing planform and “V” dihedral.
Only the open sections of the built-up
wing are covered.
The fuselage is 1/8-inch spruce with balsa
cheeks at the front to hide the nose weight.
Careful craftsmanship and an airbrushed avian color
scheme lifts Joe Hurdle’s catapult glider out of the ordinary.
The wing features a built-up structure.
when the flier pushes the button. Similar
to a garage door opener, the signal is
encrypted to eliminate the chance of
activating another model’s RDT. Systems
that can share the battery power of a
host electronic timer are also available.
Two popular RDT systems are the
Airtek unit from Ken Bauer at Airtek
Free Flight Electronics and the Aeris
system available from Starlink Flitetech
Models or from the manufacturer, Free
Flight Electronics. Both the Airtek and Aeris systems are
available as stand-alone or as host versions.
Kit Bays showed me the RDT on his tip-launched glider. It
is the Bauer Airtek stand-alone system fitted into the nose of
the glider instead of lead, so there is no weight penalty (typical
stand-alone systems
weigh roughly 8 grams).
The microservo is located
closest to the front of the
model, with a small LiPo
battery next, and the
receiver behind that. Kit
has fitted the transmitter
with an armband so it is
always accessible.
As a batteryconservation
measure,
the receiver in the Airtek
unit that Kit uses cycles
on and off. “Sometimes
you have to wait a
couple of seconds for it
to react,” says Kit. He
has purchased a second
Airtek receiver that
is always on and provides instant DT. He plans to use that
receiver in a scaled-up Civy Boy 61. “It sucks up a little more
current,” he says, “but it could save the model.”
Although a stand-alone RDT setup sells for approximately
$300, it reduces the chance of losing a model. Kit has set up all
four of his tip-launched gliders for RDT. Each model is fitted
with a microservo and a simple mousetrap lever to reduce the
loads on the servo arm.
“I move the receiver and battery between models,” he
mentioned. On his next model, Kit plans to try a linear servo,
which is slightly narrower than the servos he is using. This will
allow him to slightly reduce the front fuselage width slightly.
RDT also opens up FF to sites that would not be suitable
for a conventional timer or fuse-activated DT. “It’s really
handy for a small field,” says Kit. “The practice fields I have are
so small.”
Book Review
The Compressed Air Engine Book, edited by Sergio Montes
and Chris Stoddart, provides an in-depth look at one of the
earliest forms of FF propulsion. Dating back to before the turn
of the century, compressed air motors (similar to steam and
CO2) provided a quiet, compact power source.
Although supplanted by internal combustion engines and
more recently by electric power, compressed air motors
A microservo
in the model’s
nose activates
the model’s DT.
The small wire
antenna in front
of the wing shows
the receiver’s
location. A
mousetrap device
reduces the load
on the servo arm.
Kit Bays’ own-design tip-launch glider utilizes an RDT system that allows
him to terminate the flight at will. The transmitter, which sends out an
encrypted signal to the receiver in the model, is worn on his arm.
have endured throughout the last
100-plus years in a variety of forms,
both homebuilt and manufactured.
The ready-to-fly Air Hog is one recent
example of a compressed air model for
mass consumption.
Published by Free Flight Quarterly, the
book explores the history, design, and
construction of compressed air motors.
Detailed drawings and instructions
for building compressed air motors
are included. One, designed by David
Kerzel, can be built with only a drill
press and hand tools utilizing brass
tubing, rod, and sheet from the local
hobby shop.
Constructing John Morril’s .015 cu. in.
Zephyr motor requires a small lathe and
milling attachment. Most of the parts
are aluminum, with Delrin used for the
piston and drill rod for the crankshaft.
His plans also detail construction of air
tanks from two small aluminum juice
cans.
Also included are small-scale plans for
Jim Sprenger’s Scirocco, a 30-inch span
Sport model utilizing the Zephyr motor.
The model uses traditional stick-andtissue
and the book includes full-size
patterns for wing and stabilizer ribs,
propeller blank, and fuselage formers.
Another motor plan is from a 1928
issue of The Modelmaker magazine and
was designed by Ed Packard, founder of
Cleveland Model Supply. This opposed
twin design uses brass tubing and sheet
for most of the parts. The original plans
called for a 14-inch propeller; Roger
Schroeder constructed one that turned
a 7 x 3 propeller at 2,000 rpm on 60
pounds of air pressure.
Information about ordering The
Compressed Air Engine Book
can be found on Free Flight
Quarterly’s website listed in
“Sources.” The 84-page book is
$25.
FAI Model Supply
In the mid-1990s, John Clapp
and his wife, Sally, purchased FAI
Model Supply from Ed Dolby,
who had started the mail-order
company roughly 50 years ago. At
that time, the company’s major
product was rubber strip for FF
models.
John worked closely with the
manufacturer to develop rubber
of consistently high quality and
power output. Now FAI Super
Sport rubber is used by virtually
every competition Rubber flier in
the world. In addition, the Clapps
have expanded the company to include
a wide variety of kits and FF supplies.
This past summer, John and Sally
decided to sell FAI Model Supply
to another husband-and-wife team:
Charlie and Geralyn Jones. Charlie is an
active F1B and F1G modeler as are the
couple’s two sons, Ryan and Kyle. The
new contact information for FAI Model
Supply is listed in “Sources.” Best wishes
to the Jones family in its new venture.
All Rubber fliers owe John and Sally
a big thanks for their work keeping us
supplied with quality rubber strip and
hundreds of hard-to-find FF items.
Retrieval Pole
Getting a model out of a tree has
always been a part of FF. Throughout the
A small LiPo cell powers the RDT system in the model.
The battery can handle up to 500 flights without
recharging. Its line-of-sight range is roughly 3 miles.
The Sablier two-cylinder compressed air motor
that ran in a French model magazine in 1938
is featured in The Compressed Air Book. The
publication features photos and construction
drawings of a variety of motors.
years, many methods have been tried,
but the two that seem to have survived
are the tall pole and a professional tree
climber.
The late Tommy McLaughlan had a
homemade retrieval pole of telescoping
sections of aluminum and magnesium
tubing. Everyone who flew at Tommy’s
Pensacola, Florida, contests probably
used his retrieval pole at least once.
For the last 20 years or so, the retrieval
pole of choice has been the telescoping
fiberglass one used by power company
linemen. The Telescoping Hot Stick,
made by Hastings and sold through local
dealers, is available in extended lengths
from 12 to 40 feet.
At the Carolina Free Flight
Association contest last summer, CD
John Diebolt showed me a lighter
alternative to the industrial-strength
lineman’s pole. It’s a fiberglass pole used
for flying decorative kites.
Sold by Jackite, Inc., the pole measures
46 inches collapsed and extends to 31
feet. At 5 pounds, it weighs much less
than a Hastings pole. Although the
Jackite comes in green, the orange one
makes the most sense for our intended
use in the trees. The price for the 31-
foot model is approximately $70 plus
shipping. Shorter ones are also available.
As with any pole, the Jackite product
should be used from directly below the
model. This makes handling much easier
and prevents the pole from bending
excessively.
You will need to fit the end of the
pole with some sort of hook or fork so
you can carefully move the model from
the tree limb.
SOURCES:
Airtek Free Flight Electronics
[email protected]
http://mysite.verizon.net/resrqa3z/airtek/index.
html
Free Flight Electronics
[email protected]
www.ffelectronics.com
Starlink Flitetech Models
(858) 231-4994
www.starlink-flitetech.com
Free Flight Quarterly
http://freeflightquarterly.com/wordpress
FAI Model Supply
(440) 930-2114
www.faimodelsupply.com
Hastings Hot Line Tools & Equipment
(269) 945-9541
www.hfgp.com
Jackite Inc.
(877) 522-5483
www.jackite.com
National Free Flight Society
www.freeflight.org
