98 MODEL AVIATION
ONE FACET OF this hobby that I really enjoy is scheduled flying
events. This can be in the form of a competition or a fun-fly. Being
able to see what other people are doing, sharing airspace, and
swapping stories makes for an enjoyable time. Such events are
normally held at larger flying sites but do provide an opportunity to
showcase some of the models intended for small-field flying.
That was the setup at the October 2002 Dallas Electric Aircraft
Flyers (DEAF) annual fly-in—a relaxed two-day gathering
emphasizing fun-flying with a few competitive events thrown in to add
a little spice. One event is All-Up/Last-Down, or AULD.
As the name implies, AULD is a mass-launch event in which all
the participants release their models at the same time. Talk about a few
moments of excitement! There is nothing like watching a group of a
dozen or more models take to the air at once, especially if you’re
guiding one of the models with your trusty transmitter in hand.
Amazingly enough, there are few midairs. The goal is to be the last
person standing—I mean the last to land.
It’s a simple enough concept, but like most simple concepts there
are many ways to skin the proverbial cat. The most common approach
to the AULD event is to use a model that can climb to thermal height
quickly then hunt for those magic rising bubbles of air. If high enough,
all you need to do is move from thermal to thermal and your model
stays up forever. Yeah, right.
To make things interesting, the DEAF group runs its AULD event
with no restrictions; truly, anything goes. That means you are free to
use any airframe, any electric motor, and any battery technology. This
produces an interesting range of models. The most common are the
electric-powered sailplanes, but there are a few who walk to a different
beat.
Pat Tritle, who does many of the Dare kit designs, enters some of
his small-field Scale models. Ralph Bradley is another entrant who
likes to depart from the norm and also uses his small-field models. Pat
and Ralph take the approach of not depending on thermal help, but
rather continuous motor runs. Mix in a little thermal help, and you get
some interesting results. Pat has placed in the money on several
occasions with his lovely small-field Scale models.
First place in 2002, though, went to Ralph. Using a pure smallfield
flyer and taking full advantage of having no limit on battery
technology, he won the event with his 24-inch Lithium-Ionbattery-
powered Pipsqueak.
Paul Bradley
S m a l l - F i e l d F l y i n g
32238 Spinnaker Run, Magnolia TX 77354; E-mail: [email protected]
Small-field flier Ralph Bradley (L) flew his Dave Robelen-designed
Pipsqueak to first place in the 2002 DEAF fly-in AULD event.
1⁄2A Texaco models, such as the author’s Speed 300-powered
Kerswap, make great small-field thermal-riding models.
Climb-and-glide-type soaring is practical at small fields. Ralph
Bradley’s Termite is used for thermal-hunting expeditions.
This Free Flight proof model is for the author’s Jigtime Rascal 18
reproduction and electric RC conversion project.
03sig4.QXD 12.20.02 8:33 am Page 98
100 MODEL AVIATION
In case you don’t recognize it, the Pipsqueak design comes from
well-known pioneer of small-field flying and Model Aviation
columnist Dave Robelen. In April 1966 Dave had the Pipsqueak
design published in Radio Control Modeler. The plan is available as
number 162 from RCM.
Based on the Midwest Esquire, the Pipsqueak was designed for
glow-engine power. Ralph’s rendition of Dave’s design is powered
with a GWS ducted-fan motor mated to a home-brew gear drive. This
setup produces plenty of flying power on a single Lithium-Ion cell.
With two 830 mAh cells in parallel, Ralph’s model was up for more
than an hour when second-place finisher Jason Nowell’s had to land.
Watch out for the small-field-flying crowd; you just don’t know
what strategy it might throw at you.
At first blush, we might not think small-field soaring is practical for
small-field flyers. Thermal-chasing often requires covering a lot of
ground and seems to require fairly wide-open spaces. It is certainly
true that soaring in the most open sense does entail large venues and
models capable of flying at great distances from the pilot, but thermal
flying and soaring can be enjoyed by the small-field flyer. You just go
about it a bit differently.
Choose something with a wingspan a bit smaller than 2.0 or 3.0
meters—probably something more like just less than 1.0 meter to
maybe 1.5 meters. There are many choices. If you like Old-Time Free
Flight designs, the ones sized for 1⁄2A Texaco competition flying
make great small-field flyers. With wing areas typically near 288
square inches (2 square feet) and weights in the 16- to 18-ounce
range, the 1⁄2A Texaco models are lightly loaded and require little
power to stay up. I mention the latter because I want to take you down
a path like the one Pat Tritle and Ralph Bradley used for their AULD
entries.
I have the pleasure of owning a 1⁄2A Texaco Kerswap that was
built from a superb Balsa Products kit. The kit is no longer in
production, but the model is a good example of what we can do to
enjoy soaring-type flight in small flying fields. My Kerswap is
powered by a geared Speed 300 rather than a glow motor. It is flown
just for fun, so I don’t have to worry about meeting restrictions
imposed by competition flying.
Using seven 600 mAh Ni-Cd cells, I let the Kerswap climb
aggressively to an altitude of roughly 100 feet, then I throttle back
until the model is holding its own. I can then orbit around the small
field and wait for a passing bit of lift. If it comes along, it is possible
to ride it for several circuits then let it go as the model reaches the
boundary of the flying area. With no lift at all, the model can easily
stay up for 15 minutes. With any passing thermal help, duration is
extended proportionally. This is not pure soaring, but it helps to
practice recognizing the presence of lift and working smaller
thermals. It’s fun if you like soaring-type flying.
Although the Balsa Products Kerswap kit is no longer available,
you can get several 1⁄2A Texaco Old-Timer plans from Bob Holman,
These are the guts of the RC conversion. Text has details.
The homemade gear drive has been arranged to let everything fit
in the nose of the TopFlite Rascal 18.
including a Kerswap. Contact information is at the end of the column.
Cruising around on low power is not the only way you can enjoy
some small-field soaring-type flight. An alternative is to follow the
format of larger sailplanes that climb and glide. The availability of
good, lightweight radio systems and strong small electric motors
makes building a small-field climb-and-glide model practical.
Again, I’ll use a model Ralph Bradley built as an example. Ralph
has been an avid slope-glider flier and a Free Flight Duration modeler.
As a result, he has a large interest in gliders and fast-climbing
powered models. Since he is now pretty much a small-field flier
because of available flying sites, he decided to design a small-field
climb-and-glide model.
The result of Ralph’s efforts—the Termite—is shown in the
photos. His Free Flight heritage shows in the design. The wing is
made from solid balsa airfoil-shaped balsa stock typically used for
Free Flight Hand-Launched Gliders.
With a span of 36 inches and powered with an Astro brushless 010
motor on eight 270 mAh NiMH cells, his Termite has an aggressive
climb. Normally a 20-second or so burst of power will get the model
to a nice thermal-hunting height, then Ralph does circuits around the
small-field patch looking for lift.
If no lift is found by the time the model is at low altitude again,
Ralph applies another burst of power. So goes the cycle until the
battery gives up. He typically gets 20-minute flights with little or no
help from nature. It’s another way to enjoy some soaring fun in a
small-field venue.
Before I forget, I did promise to bring you up to date on the project I
mentioned in the January 2003 column: my effort to reproduce an old
boyhood favorite—the TopFlite Jigtime Rascal 18.
My goal for this project was to not only reproduce the balsa parts
that had all the color-and-markings, but to add radio control and
transform the model into a small-field flyer. Actually, it was already a
small-field flyer. I guess I should specify an electric-powered Radio
Control (RC) small-field flyer.
I do need to ask for Dave Robelen’s forgiveness in discussing this
project. It is probably more a micro-RC model and encroaches on the
material in his excellent Model Aviation column.
My progress on the project has been hampered by life events
(work and all that stuff), so I can’t report on the final product. That is
still waiting for me to complete on my far too idle building board.
I can report, though, that I built a proof-of-concept model in its
original Free Flight form. I did this to verify my parts fit and to relive
that old boyhood dream to get one of these models to fly as I had
always imagined. The result is shown in the photos.
Printing the parts directly on balsa using my ink-jet printer went
much better than I had expected. Everything went together like it
should have, and I ended up with a pretty little model that flies better
than I could have ever hoped for all those years ago.
03sig4.QXD 12.20.02 8:34 am Page 100
In addition to getting a proof model built,
I was able to get the guts for the RC version
together. For a model this size you need
some really light components. Hence my
encroachment into Dave Robelen’s territory.
The radio is a beautiful little unit from
Dynamic Web Enterprises. The RFFS-100
provides two channels and a built-in
Electronic Speed Control, all for a weight of
just less than 2 grams. This radio is designed
to work with magnetic actuators. These
actuators work in principal like the old
Galloping Ghost actuators, but they take
advantage of modern electronics. That
means they are fully proportional and the
flight surfaces don’t flutter back and forth.
To keep the actuators’ weight near the
model’s center of gravity, I chose units that
Bob Selman offers. The Selman actuators
provide pull-pull type outputs rather than
directly driving the control surfaces. They
weigh approximately 2 grams each.
Last, I twisted Ralph Bradley’s arm to
get him to build me a custom geared
Mabuchi M-20 motor setup. The photos
show the components and how the motor
will fit into the model’s nose. As you can
see, the spur gear has been placed at the rear
of the motor so everything can fit inside that
rather small area.
What appears to be a fat collar around the
front of the propeller shaft is a piece of
dowel that is glued to the model’s nose
block. The motor assembly can then be
plugged into the dowel collar or just as
easily slipped out. The friction fit is plenty to
keep everything in place while flying.
I should be able to report on the
completed RC version of the Rascal 18 and
its flying qualities in the next column.
I have reached the end of this installment of
“Small-Field Flying.” Keep ’em flying
safely in small spaces. MA
Sources:
1⁄2A Texaco plans:
Bob Holman Plans
Box 741
San Bernardino CA 92402
(909) 885-3959
www.bhplans.com
RFFS-100 receiver:
Dynamic Web Enterprises
159 Little Robin Rd.
Amherst NY 14228
(866) Fly-Micro
www.smallrc.com
Magnetic actuators:
Bob Selman Designs
9054 Gum Rd.
Carthage MO 64836
(417) 358-9521 after 6 p.m. CST
http://users.joplin.com/~bselman
Pipsqueak plan (number 162):
Radio Control Modeler
(800) 523-1736
www.rcmmagazine.com
Edition: Model Aviation - 2003/03
Page Numbers: 98,100,102
Edition: Model Aviation - 2003/03
Page Numbers: 98,100,102
98 MODEL AVIATION
ONE FACET OF this hobby that I really enjoy is scheduled flying
events. This can be in the form of a competition or a fun-fly. Being
able to see what other people are doing, sharing airspace, and
swapping stories makes for an enjoyable time. Such events are
normally held at larger flying sites but do provide an opportunity to
showcase some of the models intended for small-field flying.
That was the setup at the October 2002 Dallas Electric Aircraft
Flyers (DEAF) annual fly-in—a relaxed two-day gathering
emphasizing fun-flying with a few competitive events thrown in to add
a little spice. One event is All-Up/Last-Down, or AULD.
As the name implies, AULD is a mass-launch event in which all
the participants release their models at the same time. Talk about a few
moments of excitement! There is nothing like watching a group of a
dozen or more models take to the air at once, especially if you’re
guiding one of the models with your trusty transmitter in hand.
Amazingly enough, there are few midairs. The goal is to be the last
person standing—I mean the last to land.
It’s a simple enough concept, but like most simple concepts there
are many ways to skin the proverbial cat. The most common approach
to the AULD event is to use a model that can climb to thermal height
quickly then hunt for those magic rising bubbles of air. If high enough,
all you need to do is move from thermal to thermal and your model
stays up forever. Yeah, right.
To make things interesting, the DEAF group runs its AULD event
with no restrictions; truly, anything goes. That means you are free to
use any airframe, any electric motor, and any battery technology. This
produces an interesting range of models. The most common are the
electric-powered sailplanes, but there are a few who walk to a different
beat.
Pat Tritle, who does many of the Dare kit designs, enters some of
his small-field Scale models. Ralph Bradley is another entrant who
likes to depart from the norm and also uses his small-field models. Pat
and Ralph take the approach of not depending on thermal help, but
rather continuous motor runs. Mix in a little thermal help, and you get
some interesting results. Pat has placed in the money on several
occasions with his lovely small-field Scale models.
First place in 2002, though, went to Ralph. Using a pure smallfield
flyer and taking full advantage of having no limit on battery
technology, he won the event with his 24-inch Lithium-Ionbattery-
powered Pipsqueak.
Paul Bradley
S m a l l - F i e l d F l y i n g
32238 Spinnaker Run, Magnolia TX 77354; E-mail: [email protected]
Small-field flier Ralph Bradley (L) flew his Dave Robelen-designed
Pipsqueak to first place in the 2002 DEAF fly-in AULD event.
1⁄2A Texaco models, such as the author’s Speed 300-powered
Kerswap, make great small-field thermal-riding models.
Climb-and-glide-type soaring is practical at small fields. Ralph
Bradley’s Termite is used for thermal-hunting expeditions.
This Free Flight proof model is for the author’s Jigtime Rascal 18
reproduction and electric RC conversion project.
03sig4.QXD 12.20.02 8:33 am Page 98
100 MODEL AVIATION
In case you don’t recognize it, the Pipsqueak design comes from
well-known pioneer of small-field flying and Model Aviation
columnist Dave Robelen. In April 1966 Dave had the Pipsqueak
design published in Radio Control Modeler. The plan is available as
number 162 from RCM.
Based on the Midwest Esquire, the Pipsqueak was designed for
glow-engine power. Ralph’s rendition of Dave’s design is powered
with a GWS ducted-fan motor mated to a home-brew gear drive. This
setup produces plenty of flying power on a single Lithium-Ion cell.
With two 830 mAh cells in parallel, Ralph’s model was up for more
than an hour when second-place finisher Jason Nowell’s had to land.
Watch out for the small-field-flying crowd; you just don’t know
what strategy it might throw at you.
At first blush, we might not think small-field soaring is practical for
small-field flyers. Thermal-chasing often requires covering a lot of
ground and seems to require fairly wide-open spaces. It is certainly
true that soaring in the most open sense does entail large venues and
models capable of flying at great distances from the pilot, but thermal
flying and soaring can be enjoyed by the small-field flyer. You just go
about it a bit differently.
Choose something with a wingspan a bit smaller than 2.0 or 3.0
meters—probably something more like just less than 1.0 meter to
maybe 1.5 meters. There are many choices. If you like Old-Time Free
Flight designs, the ones sized for 1⁄2A Texaco competition flying
make great small-field flyers. With wing areas typically near 288
square inches (2 square feet) and weights in the 16- to 18-ounce
range, the 1⁄2A Texaco models are lightly loaded and require little
power to stay up. I mention the latter because I want to take you down
a path like the one Pat Tritle and Ralph Bradley used for their AULD
entries.
I have the pleasure of owning a 1⁄2A Texaco Kerswap that was
built from a superb Balsa Products kit. The kit is no longer in
production, but the model is a good example of what we can do to
enjoy soaring-type flight in small flying fields. My Kerswap is
powered by a geared Speed 300 rather than a glow motor. It is flown
just for fun, so I don’t have to worry about meeting restrictions
imposed by competition flying.
Using seven 600 mAh Ni-Cd cells, I let the Kerswap climb
aggressively to an altitude of roughly 100 feet, then I throttle back
until the model is holding its own. I can then orbit around the small
field and wait for a passing bit of lift. If it comes along, it is possible
to ride it for several circuits then let it go as the model reaches the
boundary of the flying area. With no lift at all, the model can easily
stay up for 15 minutes. With any passing thermal help, duration is
extended proportionally. This is not pure soaring, but it helps to
practice recognizing the presence of lift and working smaller
thermals. It’s fun if you like soaring-type flying.
Although the Balsa Products Kerswap kit is no longer available,
you can get several 1⁄2A Texaco Old-Timer plans from Bob Holman,
These are the guts of the RC conversion. Text has details.
The homemade gear drive has been arranged to let everything fit
in the nose of the TopFlite Rascal 18.
including a Kerswap. Contact information is at the end of the column.
Cruising around on low power is not the only way you can enjoy
some small-field soaring-type flight. An alternative is to follow the
format of larger sailplanes that climb and glide. The availability of
good, lightweight radio systems and strong small electric motors
makes building a small-field climb-and-glide model practical.
Again, I’ll use a model Ralph Bradley built as an example. Ralph
has been an avid slope-glider flier and a Free Flight Duration modeler.
As a result, he has a large interest in gliders and fast-climbing
powered models. Since he is now pretty much a small-field flier
because of available flying sites, he decided to design a small-field
climb-and-glide model.
The result of Ralph’s efforts—the Termite—is shown in the
photos. His Free Flight heritage shows in the design. The wing is
made from solid balsa airfoil-shaped balsa stock typically used for
Free Flight Hand-Launched Gliders.
With a span of 36 inches and powered with an Astro brushless 010
motor on eight 270 mAh NiMH cells, his Termite has an aggressive
climb. Normally a 20-second or so burst of power will get the model
to a nice thermal-hunting height, then Ralph does circuits around the
small-field patch looking for lift.
If no lift is found by the time the model is at low altitude again,
Ralph applies another burst of power. So goes the cycle until the
battery gives up. He typically gets 20-minute flights with little or no
help from nature. It’s another way to enjoy some soaring fun in a
small-field venue.
Before I forget, I did promise to bring you up to date on the project I
mentioned in the January 2003 column: my effort to reproduce an old
boyhood favorite—the TopFlite Jigtime Rascal 18.
My goal for this project was to not only reproduce the balsa parts
that had all the color-and-markings, but to add radio control and
transform the model into a small-field flyer. Actually, it was already a
small-field flyer. I guess I should specify an electric-powered Radio
Control (RC) small-field flyer.
I do need to ask for Dave Robelen’s forgiveness in discussing this
project. It is probably more a micro-RC model and encroaches on the
material in his excellent Model Aviation column.
My progress on the project has been hampered by life events
(work and all that stuff), so I can’t report on the final product. That is
still waiting for me to complete on my far too idle building board.
I can report, though, that I built a proof-of-concept model in its
original Free Flight form. I did this to verify my parts fit and to relive
that old boyhood dream to get one of these models to fly as I had
always imagined. The result is shown in the photos.
Printing the parts directly on balsa using my ink-jet printer went
much better than I had expected. Everything went together like it
should have, and I ended up with a pretty little model that flies better
than I could have ever hoped for all those years ago.
03sig4.QXD 12.20.02 8:34 am Page 100
In addition to getting a proof model built,
I was able to get the guts for the RC version
together. For a model this size you need
some really light components. Hence my
encroachment into Dave Robelen’s territory.
The radio is a beautiful little unit from
Dynamic Web Enterprises. The RFFS-100
provides two channels and a built-in
Electronic Speed Control, all for a weight of
just less than 2 grams. This radio is designed
to work with magnetic actuators. These
actuators work in principal like the old
Galloping Ghost actuators, but they take
advantage of modern electronics. That
means they are fully proportional and the
flight surfaces don’t flutter back and forth.
To keep the actuators’ weight near the
model’s center of gravity, I chose units that
Bob Selman offers. The Selman actuators
provide pull-pull type outputs rather than
directly driving the control surfaces. They
weigh approximately 2 grams each.
Last, I twisted Ralph Bradley’s arm to
get him to build me a custom geared
Mabuchi M-20 motor setup. The photos
show the components and how the motor
will fit into the model’s nose. As you can
see, the spur gear has been placed at the rear
of the motor so everything can fit inside that
rather small area.
What appears to be a fat collar around the
front of the propeller shaft is a piece of
dowel that is glued to the model’s nose
block. The motor assembly can then be
plugged into the dowel collar or just as
easily slipped out. The friction fit is plenty to
keep everything in place while flying.
I should be able to report on the
completed RC version of the Rascal 18 and
its flying qualities in the next column.
I have reached the end of this installment of
“Small-Field Flying.” Keep ’em flying
safely in small spaces. MA
Sources:
1⁄2A Texaco plans:
Bob Holman Plans
Box 741
San Bernardino CA 92402
(909) 885-3959
www.bhplans.com
RFFS-100 receiver:
Dynamic Web Enterprises
159 Little Robin Rd.
Amherst NY 14228
(866) Fly-Micro
www.smallrc.com
Magnetic actuators:
Bob Selman Designs
9054 Gum Rd.
Carthage MO 64836
(417) 358-9521 after 6 p.m. CST
http://users.joplin.com/~bselman
Pipsqueak plan (number 162):
Radio Control Modeler
(800) 523-1736
www.rcmmagazine.com
Edition: Model Aviation - 2003/03
Page Numbers: 98,100,102
98 MODEL AVIATION
ONE FACET OF this hobby that I really enjoy is scheduled flying
events. This can be in the form of a competition or a fun-fly. Being
able to see what other people are doing, sharing airspace, and
swapping stories makes for an enjoyable time. Such events are
normally held at larger flying sites but do provide an opportunity to
showcase some of the models intended for small-field flying.
That was the setup at the October 2002 Dallas Electric Aircraft
Flyers (DEAF) annual fly-in—a relaxed two-day gathering
emphasizing fun-flying with a few competitive events thrown in to add
a little spice. One event is All-Up/Last-Down, or AULD.
As the name implies, AULD is a mass-launch event in which all
the participants release their models at the same time. Talk about a few
moments of excitement! There is nothing like watching a group of a
dozen or more models take to the air at once, especially if you’re
guiding one of the models with your trusty transmitter in hand.
Amazingly enough, there are few midairs. The goal is to be the last
person standing—I mean the last to land.
It’s a simple enough concept, but like most simple concepts there
are many ways to skin the proverbial cat. The most common approach
to the AULD event is to use a model that can climb to thermal height
quickly then hunt for those magic rising bubbles of air. If high enough,
all you need to do is move from thermal to thermal and your model
stays up forever. Yeah, right.
To make things interesting, the DEAF group runs its AULD event
with no restrictions; truly, anything goes. That means you are free to
use any airframe, any electric motor, and any battery technology. This
produces an interesting range of models. The most common are the
electric-powered sailplanes, but there are a few who walk to a different
beat.
Pat Tritle, who does many of the Dare kit designs, enters some of
his small-field Scale models. Ralph Bradley is another entrant who
likes to depart from the norm and also uses his small-field models. Pat
and Ralph take the approach of not depending on thermal help, but
rather continuous motor runs. Mix in a little thermal help, and you get
some interesting results. Pat has placed in the money on several
occasions with his lovely small-field Scale models.
First place in 2002, though, went to Ralph. Using a pure smallfield
flyer and taking full advantage of having no limit on battery
technology, he won the event with his 24-inch Lithium-Ionbattery-
powered Pipsqueak.
Paul Bradley
S m a l l - F i e l d F l y i n g
32238 Spinnaker Run, Magnolia TX 77354; E-mail: [email protected]
Small-field flier Ralph Bradley (L) flew his Dave Robelen-designed
Pipsqueak to first place in the 2002 DEAF fly-in AULD event.
1⁄2A Texaco models, such as the author’s Speed 300-powered
Kerswap, make great small-field thermal-riding models.
Climb-and-glide-type soaring is practical at small fields. Ralph
Bradley’s Termite is used for thermal-hunting expeditions.
This Free Flight proof model is for the author’s Jigtime Rascal 18
reproduction and electric RC conversion project.
03sig4.QXD 12.20.02 8:33 am Page 98
100 MODEL AVIATION
In case you don’t recognize it, the Pipsqueak design comes from
well-known pioneer of small-field flying and Model Aviation
columnist Dave Robelen. In April 1966 Dave had the Pipsqueak
design published in Radio Control Modeler. The plan is available as
number 162 from RCM.
Based on the Midwest Esquire, the Pipsqueak was designed for
glow-engine power. Ralph’s rendition of Dave’s design is powered
with a GWS ducted-fan motor mated to a home-brew gear drive. This
setup produces plenty of flying power on a single Lithium-Ion cell.
With two 830 mAh cells in parallel, Ralph’s model was up for more
than an hour when second-place finisher Jason Nowell’s had to land.
Watch out for the small-field-flying crowd; you just don’t know
what strategy it might throw at you.
At first blush, we might not think small-field soaring is practical for
small-field flyers. Thermal-chasing often requires covering a lot of
ground and seems to require fairly wide-open spaces. It is certainly
true that soaring in the most open sense does entail large venues and
models capable of flying at great distances from the pilot, but thermal
flying and soaring can be enjoyed by the small-field flyer. You just go
about it a bit differently.
Choose something with a wingspan a bit smaller than 2.0 or 3.0
meters—probably something more like just less than 1.0 meter to
maybe 1.5 meters. There are many choices. If you like Old-Time Free
Flight designs, the ones sized for 1⁄2A Texaco competition flying
make great small-field flyers. With wing areas typically near 288
square inches (2 square feet) and weights in the 16- to 18-ounce
range, the 1⁄2A Texaco models are lightly loaded and require little
power to stay up. I mention the latter because I want to take you down
a path like the one Pat Tritle and Ralph Bradley used for their AULD
entries.
I have the pleasure of owning a 1⁄2A Texaco Kerswap that was
built from a superb Balsa Products kit. The kit is no longer in
production, but the model is a good example of what we can do to
enjoy soaring-type flight in small flying fields. My Kerswap is
powered by a geared Speed 300 rather than a glow motor. It is flown
just for fun, so I don’t have to worry about meeting restrictions
imposed by competition flying.
Using seven 600 mAh Ni-Cd cells, I let the Kerswap climb
aggressively to an altitude of roughly 100 feet, then I throttle back
until the model is holding its own. I can then orbit around the small
field and wait for a passing bit of lift. If it comes along, it is possible
to ride it for several circuits then let it go as the model reaches the
boundary of the flying area. With no lift at all, the model can easily
stay up for 15 minutes. With any passing thermal help, duration is
extended proportionally. This is not pure soaring, but it helps to
practice recognizing the presence of lift and working smaller
thermals. It’s fun if you like soaring-type flying.
Although the Balsa Products Kerswap kit is no longer available,
you can get several 1⁄2A Texaco Old-Timer plans from Bob Holman,
These are the guts of the RC conversion. Text has details.
The homemade gear drive has been arranged to let everything fit
in the nose of the TopFlite Rascal 18.
including a Kerswap. Contact information is at the end of the column.
Cruising around on low power is not the only way you can enjoy
some small-field soaring-type flight. An alternative is to follow the
format of larger sailplanes that climb and glide. The availability of
good, lightweight radio systems and strong small electric motors
makes building a small-field climb-and-glide model practical.
Again, I’ll use a model Ralph Bradley built as an example. Ralph
has been an avid slope-glider flier and a Free Flight Duration modeler.
As a result, he has a large interest in gliders and fast-climbing
powered models. Since he is now pretty much a small-field flier
because of available flying sites, he decided to design a small-field
climb-and-glide model.
The result of Ralph’s efforts—the Termite—is shown in the
photos. His Free Flight heritage shows in the design. The wing is
made from solid balsa airfoil-shaped balsa stock typically used for
Free Flight Hand-Launched Gliders.
With a span of 36 inches and powered with an Astro brushless 010
motor on eight 270 mAh NiMH cells, his Termite has an aggressive
climb. Normally a 20-second or so burst of power will get the model
to a nice thermal-hunting height, then Ralph does circuits around the
small-field patch looking for lift.
If no lift is found by the time the model is at low altitude again,
Ralph applies another burst of power. So goes the cycle until the
battery gives up. He typically gets 20-minute flights with little or no
help from nature. It’s another way to enjoy some soaring fun in a
small-field venue.
Before I forget, I did promise to bring you up to date on the project I
mentioned in the January 2003 column: my effort to reproduce an old
boyhood favorite—the TopFlite Jigtime Rascal 18.
My goal for this project was to not only reproduce the balsa parts
that had all the color-and-markings, but to add radio control and
transform the model into a small-field flyer. Actually, it was already a
small-field flyer. I guess I should specify an electric-powered Radio
Control (RC) small-field flyer.
I do need to ask for Dave Robelen’s forgiveness in discussing this
project. It is probably more a micro-RC model and encroaches on the
material in his excellent Model Aviation column.
My progress on the project has been hampered by life events
(work and all that stuff), so I can’t report on the final product. That is
still waiting for me to complete on my far too idle building board.
I can report, though, that I built a proof-of-concept model in its
original Free Flight form. I did this to verify my parts fit and to relive
that old boyhood dream to get one of these models to fly as I had
always imagined. The result is shown in the photos.
Printing the parts directly on balsa using my ink-jet printer went
much better than I had expected. Everything went together like it
should have, and I ended up with a pretty little model that flies better
than I could have ever hoped for all those years ago.
03sig4.QXD 12.20.02 8:34 am Page 100
In addition to getting a proof model built,
I was able to get the guts for the RC version
together. For a model this size you need
some really light components. Hence my
encroachment into Dave Robelen’s territory.
The radio is a beautiful little unit from
Dynamic Web Enterprises. The RFFS-100
provides two channels and a built-in
Electronic Speed Control, all for a weight of
just less than 2 grams. This radio is designed
to work with magnetic actuators. These
actuators work in principal like the old
Galloping Ghost actuators, but they take
advantage of modern electronics. That
means they are fully proportional and the
flight surfaces don’t flutter back and forth.
To keep the actuators’ weight near the
model’s center of gravity, I chose units that
Bob Selman offers. The Selman actuators
provide pull-pull type outputs rather than
directly driving the control surfaces. They
weigh approximately 2 grams each.
Last, I twisted Ralph Bradley’s arm to
get him to build me a custom geared
Mabuchi M-20 motor setup. The photos
show the components and how the motor
will fit into the model’s nose. As you can
see, the spur gear has been placed at the rear
of the motor so everything can fit inside that
rather small area.
What appears to be a fat collar around the
front of the propeller shaft is a piece of
dowel that is glued to the model’s nose
block. The motor assembly can then be
plugged into the dowel collar or just as
easily slipped out. The friction fit is plenty to
keep everything in place while flying.
I should be able to report on the
completed RC version of the Rascal 18 and
its flying qualities in the next column.
I have reached the end of this installment of
“Small-Field Flying.” Keep ’em flying
safely in small spaces. MA
Sources:
1⁄2A Texaco plans:
Bob Holman Plans
Box 741
San Bernardino CA 92402
(909) 885-3959
www.bhplans.com
RFFS-100 receiver:
Dynamic Web Enterprises
159 Little Robin Rd.
Amherst NY 14228
(866) Fly-Micro
www.smallrc.com
Magnetic actuators:
Bob Selman Designs
9054 Gum Rd.
Carthage MO 64836
(417) 358-9521 after 6 p.m. CST
http://users.joplin.com/~bselman
Pipsqueak plan (number 162):
Radio Control Modeler
(800) 523-1736
www.rcmmagazine.com
