86 MODEL AVIATION
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]
ENDLESS POWER: When solar cells first emerged, I began
dreaming about the possibility of building a model airplane that could
fly all day long. That was long before practical electric-powered
Ralph Bradley’s purely solar-powered small-field flyer—the Sol
Mite—has 16 solar cells and a weight of 5.1 ounces.
A great new book by Keith Sparks on the market titled Building
With Foam puts special emphasis on beginners.
Pat Tritle has been retained to develop electric-powered RCconversion
packages for selected Dumas Models kits.
models and the associated radio gear we enjoy today were even a
concept in some designer’s imagination. The thought of getting
energy from the sun seemed to be a perfect way to power model
airplanes. Heck, it seemed like a perfect way to power the world!
Much has happened in the world of solar cells and their
respective applications since the early ones appeared. A number of
solar-powered, unmanned airplanes have been developed, including
some produced by modelers.
Solar cells are intriguing, but they are notorious for being
inefficient. If we want very much power, we need a number of
cells. The result is a fairly large model or solar-powered aircraft to
carry enough cells to produce the power needed for flight.
My dream of endless power from the sun for a model airplane is
also shared by my brother Ralph. “Large” and “model airplane” are
words that are mutually exclusive with him. He is devoted to small
and micro RC models.
Ralph decided to see if a small, practical, solar-powered model
could be developed—in other words, the perfect small-field flyer.
There would be no batteries, no charging, no fuel, no fuss, and no
muss. You would simply turn it on and fly as long as you wanted
(or until your transmitter battery was empty). It’s a nice goal, but as
you might expect, the path from the idea to the result was littered
with lessons learned.
Ralph did develop a solar-powered small-field flyer and learned
much while doing so. Called the Sol Mite, the aircraft is powered
with a custom-geared GWS EDF-50 ducted-fan motor. There are
no batteries of any type on the model. It is purely solar-powered.
The key to keeping it at the desired size was some higherefficiency
solar cells developed for the space industry and
obtainable by the general public. The cells Ralph used do not
represent the highest efficiency, but they are higher than those
commonly available to the home experimenter. The source for
these cells is given at the end of the column.
11sig3.QXD 8/23/04 12:24 pm Page 86
After much testing, Ralph determined that using 16 cells arranged
in two connected parallel banks of eight would work. The wing from
an SR Batteries Bantam kit adjusted to a 32-inch span is used to house
the cells and provide lift for the Sol Mite.
To keep the model’s basic weight to a minimum, the Sol Mite was
developed as a profile aircraft. The radio gear is what you would find
on a typical micromodel. It employs a narrow-band JMP microreceiver
intended for use with magnetic actuators. Bob Selman standard-sized
magnetic actuators are used for rudder and elevator control.
The model has rudder, elevator, and throttle control with no
batteries. The propeller is a GWS slow fly 6 x 5. The full flying weight
of the aircraft, including the 16 solar cells, is 144 grams (5.1 ounces).
The model has built-in ESC and BEC, so it was simply a matter of
plugging the solar-cell connector to the receiver and launching. It was
a real thrill when the model was flown for the first time. The Sol Mite
headed for the sky and flew beautifully. The weight of the solar cells in
the wings even offered some mass damping to make it easier to fly
such a lightweight model in a light breeze.
While the goal of flying a pure solar-powered small-field flyer was
realized, so were some other life lessons. One of the more important
things Ralph learned was that you can’t fly from dawn until dusk. With
the solar-cell technology available today, there is a rather narrow band
during the day that produces enough solar energy to make flyable
power.
That band of flying time is also dependent on the amount of stuff in
the air. High water vapor or days with a thin cloud cover will
dramatically reduce the power output of the cells. Ralph’s lightweight
model needs high solar output and limited winds, and that combination
does not happen on a regular basis in our area.
The solar-powered model achieved a longtime goal, but it can only
be flown when the weather gods make things just right. This was a
great project, but we need to see additional development in the solarcell
field before we can realistically have an everyday solar-powered
small-field model.
Do you build with foam? It is a material we see in many of the
commercially made small-field models on the market today. Plastic
foam is lightweight and makes it possible to produce some nicelooking
aircraft. It is no surprise that foam is also a popular material for
the scratch builder. For the models that we see in our small-field
venues, foam construction can offer many advantages and
opportunities for some highly creative airplanes.
For those of us who are inexperienced with foam construction
techniques, where do we get how-to information? Occasionally there
are articles on foam building methods, but until recently I was unaware
of a comprehensive book on the subject.
November 2004 87
Ed Couch has created a profile rendition of the 1950s Convair
Pogo that made vertical takeoffs and landings.
This is the prototype of a new micro-size brushless outrunner
motor that will be offered by Bob Selman Designs.
Jeremy Chinn brought his Cox .010-powered scratch-built
Chipmunk beauty to this summer’s SMALL event.
11sig3.QXD 8/23/04 12:24 pm Page 87
88 MODEL AVIATION
Keith Sparks, a master foam modeler, has
published a nice book titled Building With
Foam. It covers the full gamut of foambuilding
techniques with special emphasis on
the beginner. I highly recommend this book to
anyone who is interested in learning the art of
building model airplanes using plastic foam.
Ordering information is provided in the source
listing.
Awhile back I commented on using some of
the older FF designs for small-field RC
models. Unless you happen to have a number
of Old-Timer plans or kits lying around,
finding a source for these older models can be
a problem. Fortunately, Bob Holman Plans
offers an extensive list of plans and laser-cut
parts for some of the best vintage designs.
A review of Bob’s catalog reveals a
surprising number of excellent plans and lasercut
parts for models that would make great
small-field conversions. The nice thing about
the plans from Bob Holman is that each set
has been redrawn using CAD. This helps
ensure that they are accurate.
If you have experienced an urge for a
small-field flyer based on one of the vintage
FF designs, get a copy of the Bob Holman
Plans catalog. The plans list is free. Send an
SASE with a few stamps to the address in the
source listing.
Summer Flying Fun: It is hard to believe that
the cover date on this issue is November.
Where does the time go? The summer flying
months are just too short.
This year I had the opportunity to attend
the annual Small Aircraft Model Lover’s
League (SMALL) event in Little Rock,
Arkansas. This well-known event has taken
place for a number of years and represents a
wonderful collection of models that are
typically flown in the small-field venues.
I don’t have the space to provide a full
event report here, but there are several things
that I want to highlight and I’ll begin with Pat
Tritle.
You have probably seen Pat’s name and
his comments about model designs several
times in this column. He is the consummate
small-field-model designer, and many of his
works are available through the kits offered by
Dare Designs. For the past several years, Pat
has been concentrating on electric-powered
models. To say that he has accumulated an
extensive base of experience would be an
understatement.
While at the SMALL event, I learned that
Pat has been retained by the people at Dumas
Models to develop electric-power RC
conversion packages for many of the
company’s laser-cut, rubber-powered FF
model kits. This is great news.
A number of experienced electric-power
modelers have developed successful
conversions of the Dumas kits, but that can be
a daunting task for the less experienced.
Dumas has a nice line of laser-cut Scale
airplanes that are well suited to being flown as
electric-powered RC models. With the
conversion packages developed by Pat now
available, anyone who has given one of the
Dumas kits a longing look with RC in mind
can get on board. My hat is off to the people at
Dumas for taking this step.
By now you are probably aware that my
small-field models tend to be electricpowered,
but I still enjoy a great glowpowered
airplane. I have included a photo of
Jeremy Chinn of Cordova, Tennessee, with his
Cox .010-powered Chipmunk. This is a
scratch-built model featuring all control
functions and throttle.
You don’t fully appreciate this excellent
small aircraft until you see it in the air under
the control of Jeremy’s skilled hands. His little
Chipmunk is an excellent flyer with impressive
aerobatic qualities. It is a fine example of what
is possible when building smaller models.
Another effort that caught my eye at the
SMALL affair was a profile Convair Pogo,
designed and built by Ed Couch of the
Dallas/Fort Worth, Texas, area. He is a
longtime modeler who has a reputation for
taking on offbeat projects.
When Ed walked out to the flightline with
his Pogo, everyone stopped and said “Yes!” In
a world full of excellent-flying 3-D models,
something like the Convair Pogo may not seem
like such a big deal. Even with 3-D aircraft
flying everywhere around Ed and his Pogo, the
people appreciated his fine effort to reproduce
the flying qualities of the early 1950s full-scale
airplane that could take off vertically.
Using Dow BlueCor fan-fold foam, a GWS
300D motor package, a three-cell 1200 mAh
Li-Poly battery pack, and GWS radio gear, Ed
developed his 25-inch-wingspan Pogo. With a
flying weight of 12 ounces, it does beautiful
vertical takeoffs with a transition to horizontal
flight followed by a nice vertical landing as the
prototype did all those years ago. The Pogo
looks convincing in the air. Nice work, Ed.
There’s one more item from the SMALL
event that I want to share with you. Gary Jones,
who works with Bob Selman, has developed a
prototype micro brushless outrunner motor. At
7.2 grams, this is a great development for the
smaller small-field models. A photo of the
development unit is provided for your
reference. This micro power demon was
attached to a great little 18-inch foam 3-D
flyer.
Bob Selman plans to offer these micro
brushless outrunner motors in the not-toodistant
future. You may want to visit his Web
site occasionally to check on availability. The
source listing has the URL.
Wow! Once again, here we are at the end. You
should be starting your winter building projects
soon. Don’t be shy about sharing a picture or
two of your new small-field creations. MA
Sources:
Solar cells:
Spectrolab, a Boeing Company
12500 Gladstone Ave.
Sylmar CA 91342
(818) 365-4611
www.spectrolab.com
Micro radio gear:
Bob Selman Designs
9054 Gum Rd.
Carthage MO 64836
(417) 358-9521
www.bsdmicrorc.com
Building With Foam:
Parkflyer Plastics
7755 Noreast Dr.
Fort Worth TX 76180
www.parkflyerplastics.com
Old-Timer FF plans and laser-cut parts:
Bob Holman Plans
Box 741
San Bernardino CA 92402
[email protected]
www.bhplans.com
This month we list those who have donated $10 or more in support of the
Academy’s programs, the National Model Aviation Museum and the Aeromodeling
Center, and those organizations that have provided grants for which AMA has applied
and received. These people have made more than a donation—they have made an
investment in the future of aeromodeling.
When you see these folks, thank them! They are now among the thousands who
have given back to model aviation part of what model aviation has given to them.
Many things will be possible due to the their thoughtful giving and generosity.
We list our supporters monthly. These donations represent amounts processed in
the month of June 2004. If your name is not listed, please write to the Membership
Department and include a canceled check. We want to recognize all contributors!
Thank you.
$100 up to $500
Norbert E Auer - FL
James L Cromwell - OH
Jeffrey E Gagne - AZ
Paul Grant - OH
David Hallman - VA
Glen R Harrelson - OH
Arnold Jines - IN
David Johannesmeyer - CA
Pete Katsufrakis - MS
Todd W Londagin - NY
Stanley Luiz - OR
David Magee Sr - LA
C M Montplaisir - SC
John D Mulhorn - AZ
David Petit - OH
Karl Renaut - FL
Mike Upchurch - AL
$10 up to $100
Your Contributions do Make a Difference!
Aero Guidance Society Inc - NY John L Bentley - AZ
11sig3.QXD 8/23/04 12:25 pm Page 88
Edition: Model Aviation - 2004/11
Page Numbers: 86,87,88
Edition: Model Aviation - 2004/11
Page Numbers: 86,87,88
86 MODEL AVIATION
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]
ENDLESS POWER: When solar cells first emerged, I began
dreaming about the possibility of building a model airplane that could
fly all day long. That was long before practical electric-powered
Ralph Bradley’s purely solar-powered small-field flyer—the Sol
Mite—has 16 solar cells and a weight of 5.1 ounces.
A great new book by Keith Sparks on the market titled Building
With Foam puts special emphasis on beginners.
Pat Tritle has been retained to develop electric-powered RCconversion
packages for selected Dumas Models kits.
models and the associated radio gear we enjoy today were even a
concept in some designer’s imagination. The thought of getting
energy from the sun seemed to be a perfect way to power model
airplanes. Heck, it seemed like a perfect way to power the world!
Much has happened in the world of solar cells and their
respective applications since the early ones appeared. A number of
solar-powered, unmanned airplanes have been developed, including
some produced by modelers.
Solar cells are intriguing, but they are notorious for being
inefficient. If we want very much power, we need a number of
cells. The result is a fairly large model or solar-powered aircraft to
carry enough cells to produce the power needed for flight.
My dream of endless power from the sun for a model airplane is
also shared by my brother Ralph. “Large” and “model airplane” are
words that are mutually exclusive with him. He is devoted to small
and micro RC models.
Ralph decided to see if a small, practical, solar-powered model
could be developed—in other words, the perfect small-field flyer.
There would be no batteries, no charging, no fuel, no fuss, and no
muss. You would simply turn it on and fly as long as you wanted
(or until your transmitter battery was empty). It’s a nice goal, but as
you might expect, the path from the idea to the result was littered
with lessons learned.
Ralph did develop a solar-powered small-field flyer and learned
much while doing so. Called the Sol Mite, the aircraft is powered
with a custom-geared GWS EDF-50 ducted-fan motor. There are
no batteries of any type on the model. It is purely solar-powered.
The key to keeping it at the desired size was some higherefficiency
solar cells developed for the space industry and
obtainable by the general public. The cells Ralph used do not
represent the highest efficiency, but they are higher than those
commonly available to the home experimenter. The source for
these cells is given at the end of the column.
11sig3.QXD 8/23/04 12:24 pm Page 86
After much testing, Ralph determined that using 16 cells arranged
in two connected parallel banks of eight would work. The wing from
an SR Batteries Bantam kit adjusted to a 32-inch span is used to house
the cells and provide lift for the Sol Mite.
To keep the model’s basic weight to a minimum, the Sol Mite was
developed as a profile aircraft. The radio gear is what you would find
on a typical micromodel. It employs a narrow-band JMP microreceiver
intended for use with magnetic actuators. Bob Selman standard-sized
magnetic actuators are used for rudder and elevator control.
The model has rudder, elevator, and throttle control with no
batteries. The propeller is a GWS slow fly 6 x 5. The full flying weight
of the aircraft, including the 16 solar cells, is 144 grams (5.1 ounces).
The model has built-in ESC and BEC, so it was simply a matter of
plugging the solar-cell connector to the receiver and launching. It was
a real thrill when the model was flown for the first time. The Sol Mite
headed for the sky and flew beautifully. The weight of the solar cells in
the wings even offered some mass damping to make it easier to fly
such a lightweight model in a light breeze.
While the goal of flying a pure solar-powered small-field flyer was
realized, so were some other life lessons. One of the more important
things Ralph learned was that you can’t fly from dawn until dusk. With
the solar-cell technology available today, there is a rather narrow band
during the day that produces enough solar energy to make flyable
power.
That band of flying time is also dependent on the amount of stuff in
the air. High water vapor or days with a thin cloud cover will
dramatically reduce the power output of the cells. Ralph’s lightweight
model needs high solar output and limited winds, and that combination
does not happen on a regular basis in our area.
The solar-powered model achieved a longtime goal, but it can only
be flown when the weather gods make things just right. This was a
great project, but we need to see additional development in the solarcell
field before we can realistically have an everyday solar-powered
small-field model.
Do you build with foam? It is a material we see in many of the
commercially made small-field models on the market today. Plastic
foam is lightweight and makes it possible to produce some nicelooking
aircraft. It is no surprise that foam is also a popular material for
the scratch builder. For the models that we see in our small-field
venues, foam construction can offer many advantages and
opportunities for some highly creative airplanes.
For those of us who are inexperienced with foam construction
techniques, where do we get how-to information? Occasionally there
are articles on foam building methods, but until recently I was unaware
of a comprehensive book on the subject.
November 2004 87
Ed Couch has created a profile rendition of the 1950s Convair
Pogo that made vertical takeoffs and landings.
This is the prototype of a new micro-size brushless outrunner
motor that will be offered by Bob Selman Designs.
Jeremy Chinn brought his Cox .010-powered scratch-built
Chipmunk beauty to this summer’s SMALL event.
11sig3.QXD 8/23/04 12:24 pm Page 87
88 MODEL AVIATION
Keith Sparks, a master foam modeler, has
published a nice book titled Building With
Foam. It covers the full gamut of foambuilding
techniques with special emphasis on
the beginner. I highly recommend this book to
anyone who is interested in learning the art of
building model airplanes using plastic foam.
Ordering information is provided in the source
listing.
Awhile back I commented on using some of
the older FF designs for small-field RC
models. Unless you happen to have a number
of Old-Timer plans or kits lying around,
finding a source for these older models can be
a problem. Fortunately, Bob Holman Plans
offers an extensive list of plans and laser-cut
parts for some of the best vintage designs.
A review of Bob’s catalog reveals a
surprising number of excellent plans and lasercut
parts for models that would make great
small-field conversions. The nice thing about
the plans from Bob Holman is that each set
has been redrawn using CAD. This helps
ensure that they are accurate.
If you have experienced an urge for a
small-field flyer based on one of the vintage
FF designs, get a copy of the Bob Holman
Plans catalog. The plans list is free. Send an
SASE with a few stamps to the address in the
source listing.
Summer Flying Fun: It is hard to believe that
the cover date on this issue is November.
Where does the time go? The summer flying
months are just too short.
This year I had the opportunity to attend
the annual Small Aircraft Model Lover’s
League (SMALL) event in Little Rock,
Arkansas. This well-known event has taken
place for a number of years and represents a
wonderful collection of models that are
typically flown in the small-field venues.
I don’t have the space to provide a full
event report here, but there are several things
that I want to highlight and I’ll begin with Pat
Tritle.
You have probably seen Pat’s name and
his comments about model designs several
times in this column. He is the consummate
small-field-model designer, and many of his
works are available through the kits offered by
Dare Designs. For the past several years, Pat
has been concentrating on electric-powered
models. To say that he has accumulated an
extensive base of experience would be an
understatement.
While at the SMALL event, I learned that
Pat has been retained by the people at Dumas
Models to develop electric-power RC
conversion packages for many of the
company’s laser-cut, rubber-powered FF
model kits. This is great news.
A number of experienced electric-power
modelers have developed successful
conversions of the Dumas kits, but that can be
a daunting task for the less experienced.
Dumas has a nice line of laser-cut Scale
airplanes that are well suited to being flown as
electric-powered RC models. With the
conversion packages developed by Pat now
available, anyone who has given one of the
Dumas kits a longing look with RC in mind
can get on board. My hat is off to the people at
Dumas for taking this step.
By now you are probably aware that my
small-field models tend to be electricpowered,
but I still enjoy a great glowpowered
airplane. I have included a photo of
Jeremy Chinn of Cordova, Tennessee, with his
Cox .010-powered Chipmunk. This is a
scratch-built model featuring all control
functions and throttle.
You don’t fully appreciate this excellent
small aircraft until you see it in the air under
the control of Jeremy’s skilled hands. His little
Chipmunk is an excellent flyer with impressive
aerobatic qualities. It is a fine example of what
is possible when building smaller models.
Another effort that caught my eye at the
SMALL affair was a profile Convair Pogo,
designed and built by Ed Couch of the
Dallas/Fort Worth, Texas, area. He is a
longtime modeler who has a reputation for
taking on offbeat projects.
When Ed walked out to the flightline with
his Pogo, everyone stopped and said “Yes!” In
a world full of excellent-flying 3-D models,
something like the Convair Pogo may not seem
like such a big deal. Even with 3-D aircraft
flying everywhere around Ed and his Pogo, the
people appreciated his fine effort to reproduce
the flying qualities of the early 1950s full-scale
airplane that could take off vertically.
Using Dow BlueCor fan-fold foam, a GWS
300D motor package, a three-cell 1200 mAh
Li-Poly battery pack, and GWS radio gear, Ed
developed his 25-inch-wingspan Pogo. With a
flying weight of 12 ounces, it does beautiful
vertical takeoffs with a transition to horizontal
flight followed by a nice vertical landing as the
prototype did all those years ago. The Pogo
looks convincing in the air. Nice work, Ed.
There’s one more item from the SMALL
event that I want to share with you. Gary Jones,
who works with Bob Selman, has developed a
prototype micro brushless outrunner motor. At
7.2 grams, this is a great development for the
smaller small-field models. A photo of the
development unit is provided for your
reference. This micro power demon was
attached to a great little 18-inch foam 3-D
flyer.
Bob Selman plans to offer these micro
brushless outrunner motors in the not-toodistant
future. You may want to visit his Web
site occasionally to check on availability. The
source listing has the URL.
Wow! Once again, here we are at the end. You
should be starting your winter building projects
soon. Don’t be shy about sharing a picture or
two of your new small-field creations. MA
Sources:
Solar cells:
Spectrolab, a Boeing Company
12500 Gladstone Ave.
Sylmar CA 91342
(818) 365-4611
www.spectrolab.com
Micro radio gear:
Bob Selman Designs
9054 Gum Rd.
Carthage MO 64836
(417) 358-9521
www.bsdmicrorc.com
Building With Foam:
Parkflyer Plastics
7755 Noreast Dr.
Fort Worth TX 76180
www.parkflyerplastics.com
Old-Timer FF plans and laser-cut parts:
Bob Holman Plans
Box 741
San Bernardino CA 92402
[email protected]
www.bhplans.com
This month we list those who have donated $10 or more in support of the
Academy’s programs, the National Model Aviation Museum and the Aeromodeling
Center, and those organizations that have provided grants for which AMA has applied
and received. These people have made more than a donation—they have made an
investment in the future of aeromodeling.
When you see these folks, thank them! They are now among the thousands who
have given back to model aviation part of what model aviation has given to them.
Many things will be possible due to the their thoughtful giving and generosity.
We list our supporters monthly. These donations represent amounts processed in
the month of June 2004. If your name is not listed, please write to the Membership
Department and include a canceled check. We want to recognize all contributors!
Thank you.
$100 up to $500
Norbert E Auer - FL
James L Cromwell - OH
Jeffrey E Gagne - AZ
Paul Grant - OH
David Hallman - VA
Glen R Harrelson - OH
Arnold Jines - IN
David Johannesmeyer - CA
Pete Katsufrakis - MS
Todd W Londagin - NY
Stanley Luiz - OR
David Magee Sr - LA
C M Montplaisir - SC
John D Mulhorn - AZ
David Petit - OH
Karl Renaut - FL
Mike Upchurch - AL
$10 up to $100
Your Contributions do Make a Difference!
Aero Guidance Society Inc - NY John L Bentley - AZ
11sig3.QXD 8/23/04 12:25 pm Page 88
Edition: Model Aviation - 2004/11
Page Numbers: 86,87,88
86 MODEL AVIATION
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]
ENDLESS POWER: When solar cells first emerged, I began
dreaming about the possibility of building a model airplane that could
fly all day long. That was long before practical electric-powered
Ralph Bradley’s purely solar-powered small-field flyer—the Sol
Mite—has 16 solar cells and a weight of 5.1 ounces.
A great new book by Keith Sparks on the market titled Building
With Foam puts special emphasis on beginners.
Pat Tritle has been retained to develop electric-powered RCconversion
packages for selected Dumas Models kits.
models and the associated radio gear we enjoy today were even a
concept in some designer’s imagination. The thought of getting
energy from the sun seemed to be a perfect way to power model
airplanes. Heck, it seemed like a perfect way to power the world!
Much has happened in the world of solar cells and their
respective applications since the early ones appeared. A number of
solar-powered, unmanned airplanes have been developed, including
some produced by modelers.
Solar cells are intriguing, but they are notorious for being
inefficient. If we want very much power, we need a number of
cells. The result is a fairly large model or solar-powered aircraft to
carry enough cells to produce the power needed for flight.
My dream of endless power from the sun for a model airplane is
also shared by my brother Ralph. “Large” and “model airplane” are
words that are mutually exclusive with him. He is devoted to small
and micro RC models.
Ralph decided to see if a small, practical, solar-powered model
could be developed—in other words, the perfect small-field flyer.
There would be no batteries, no charging, no fuel, no fuss, and no
muss. You would simply turn it on and fly as long as you wanted
(or until your transmitter battery was empty). It’s a nice goal, but as
you might expect, the path from the idea to the result was littered
with lessons learned.
Ralph did develop a solar-powered small-field flyer and learned
much while doing so. Called the Sol Mite, the aircraft is powered
with a custom-geared GWS EDF-50 ducted-fan motor. There are
no batteries of any type on the model. It is purely solar-powered.
The key to keeping it at the desired size was some higherefficiency
solar cells developed for the space industry and
obtainable by the general public. The cells Ralph used do not
represent the highest efficiency, but they are higher than those
commonly available to the home experimenter. The source for
these cells is given at the end of the column.
11sig3.QXD 8/23/04 12:24 pm Page 86
After much testing, Ralph determined that using 16 cells arranged
in two connected parallel banks of eight would work. The wing from
an SR Batteries Bantam kit adjusted to a 32-inch span is used to house
the cells and provide lift for the Sol Mite.
To keep the model’s basic weight to a minimum, the Sol Mite was
developed as a profile aircraft. The radio gear is what you would find
on a typical micromodel. It employs a narrow-band JMP microreceiver
intended for use with magnetic actuators. Bob Selman standard-sized
magnetic actuators are used for rudder and elevator control.
The model has rudder, elevator, and throttle control with no
batteries. The propeller is a GWS slow fly 6 x 5. The full flying weight
of the aircraft, including the 16 solar cells, is 144 grams (5.1 ounces).
The model has built-in ESC and BEC, so it was simply a matter of
plugging the solar-cell connector to the receiver and launching. It was
a real thrill when the model was flown for the first time. The Sol Mite
headed for the sky and flew beautifully. The weight of the solar cells in
the wings even offered some mass damping to make it easier to fly
such a lightweight model in a light breeze.
While the goal of flying a pure solar-powered small-field flyer was
realized, so were some other life lessons. One of the more important
things Ralph learned was that you can’t fly from dawn until dusk. With
the solar-cell technology available today, there is a rather narrow band
during the day that produces enough solar energy to make flyable
power.
That band of flying time is also dependent on the amount of stuff in
the air. High water vapor or days with a thin cloud cover will
dramatically reduce the power output of the cells. Ralph’s lightweight
model needs high solar output and limited winds, and that combination
does not happen on a regular basis in our area.
The solar-powered model achieved a longtime goal, but it can only
be flown when the weather gods make things just right. This was a
great project, but we need to see additional development in the solarcell
field before we can realistically have an everyday solar-powered
small-field model.
Do you build with foam? It is a material we see in many of the
commercially made small-field models on the market today. Plastic
foam is lightweight and makes it possible to produce some nicelooking
aircraft. It is no surprise that foam is also a popular material for
the scratch builder. For the models that we see in our small-field
venues, foam construction can offer many advantages and
opportunities for some highly creative airplanes.
For those of us who are inexperienced with foam construction
techniques, where do we get how-to information? Occasionally there
are articles on foam building methods, but until recently I was unaware
of a comprehensive book on the subject.
November 2004 87
Ed Couch has created a profile rendition of the 1950s Convair
Pogo that made vertical takeoffs and landings.
This is the prototype of a new micro-size brushless outrunner
motor that will be offered by Bob Selman Designs.
Jeremy Chinn brought his Cox .010-powered scratch-built
Chipmunk beauty to this summer’s SMALL event.
11sig3.QXD 8/23/04 12:24 pm Page 87
88 MODEL AVIATION
Keith Sparks, a master foam modeler, has
published a nice book titled Building With
Foam. It covers the full gamut of foambuilding
techniques with special emphasis on
the beginner. I highly recommend this book to
anyone who is interested in learning the art of
building model airplanes using plastic foam.
Ordering information is provided in the source
listing.
Awhile back I commented on using some of
the older FF designs for small-field RC
models. Unless you happen to have a number
of Old-Timer plans or kits lying around,
finding a source for these older models can be
a problem. Fortunately, Bob Holman Plans
offers an extensive list of plans and laser-cut
parts for some of the best vintage designs.
A review of Bob’s catalog reveals a
surprising number of excellent plans and lasercut
parts for models that would make great
small-field conversions. The nice thing about
the plans from Bob Holman is that each set
has been redrawn using CAD. This helps
ensure that they are accurate.
If you have experienced an urge for a
small-field flyer based on one of the vintage
FF designs, get a copy of the Bob Holman
Plans catalog. The plans list is free. Send an
SASE with a few stamps to the address in the
source listing.
Summer Flying Fun: It is hard to believe that
the cover date on this issue is November.
Where does the time go? The summer flying
months are just too short.
This year I had the opportunity to attend
the annual Small Aircraft Model Lover’s
League (SMALL) event in Little Rock,
Arkansas. This well-known event has taken
place for a number of years and represents a
wonderful collection of models that are
typically flown in the small-field venues.
I don’t have the space to provide a full
event report here, but there are several things
that I want to highlight and I’ll begin with Pat
Tritle.
You have probably seen Pat’s name and
his comments about model designs several
times in this column. He is the consummate
small-field-model designer, and many of his
works are available through the kits offered by
Dare Designs. For the past several years, Pat
has been concentrating on electric-powered
models. To say that he has accumulated an
extensive base of experience would be an
understatement.
While at the SMALL event, I learned that
Pat has been retained by the people at Dumas
Models to develop electric-power RC
conversion packages for many of the
company’s laser-cut, rubber-powered FF
model kits. This is great news.
A number of experienced electric-power
modelers have developed successful
conversions of the Dumas kits, but that can be
a daunting task for the less experienced.
Dumas has a nice line of laser-cut Scale
airplanes that are well suited to being flown as
electric-powered RC models. With the
conversion packages developed by Pat now
available, anyone who has given one of the
Dumas kits a longing look with RC in mind
can get on board. My hat is off to the people at
Dumas for taking this step.
By now you are probably aware that my
small-field models tend to be electricpowered,
but I still enjoy a great glowpowered
airplane. I have included a photo of
Jeremy Chinn of Cordova, Tennessee, with his
Cox .010-powered Chipmunk. This is a
scratch-built model featuring all control
functions and throttle.
You don’t fully appreciate this excellent
small aircraft until you see it in the air under
the control of Jeremy’s skilled hands. His little
Chipmunk is an excellent flyer with impressive
aerobatic qualities. It is a fine example of what
is possible when building smaller models.
Another effort that caught my eye at the
SMALL affair was a profile Convair Pogo,
designed and built by Ed Couch of the
Dallas/Fort Worth, Texas, area. He is a
longtime modeler who has a reputation for
taking on offbeat projects.
When Ed walked out to the flightline with
his Pogo, everyone stopped and said “Yes!” In
a world full of excellent-flying 3-D models,
something like the Convair Pogo may not seem
like such a big deal. Even with 3-D aircraft
flying everywhere around Ed and his Pogo, the
people appreciated his fine effort to reproduce
the flying qualities of the early 1950s full-scale
airplane that could take off vertically.
Using Dow BlueCor fan-fold foam, a GWS
300D motor package, a three-cell 1200 mAh
Li-Poly battery pack, and GWS radio gear, Ed
developed his 25-inch-wingspan Pogo. With a
flying weight of 12 ounces, it does beautiful
vertical takeoffs with a transition to horizontal
flight followed by a nice vertical landing as the
prototype did all those years ago. The Pogo
looks convincing in the air. Nice work, Ed.
There’s one more item from the SMALL
event that I want to share with you. Gary Jones,
who works with Bob Selman, has developed a
prototype micro brushless outrunner motor. At
7.2 grams, this is a great development for the
smaller small-field models. A photo of the
development unit is provided for your
reference. This micro power demon was
attached to a great little 18-inch foam 3-D
flyer.
Bob Selman plans to offer these micro
brushless outrunner motors in the not-toodistant
future. You may want to visit his Web
site occasionally to check on availability. The
source listing has the URL.
Wow! Once again, here we are at the end. You
should be starting your winter building projects
soon. Don’t be shy about sharing a picture or
two of your new small-field creations. MA
Sources:
Solar cells:
Spectrolab, a Boeing Company
12500 Gladstone Ave.
Sylmar CA 91342
(818) 365-4611
www.spectrolab.com
Micro radio gear:
Bob Selman Designs
9054 Gum Rd.
Carthage MO 64836
(417) 358-9521
www.bsdmicrorc.com
Building With Foam:
Parkflyer Plastics
7755 Noreast Dr.
Fort Worth TX 76180
www.parkflyerplastics.com
Old-Timer FF plans and laser-cut parts:
Bob Holman Plans
Box 741
San Bernardino CA 92402
[email protected]
www.bhplans.com
This month we list those who have donated $10 or more in support of the
Academy’s programs, the National Model Aviation Museum and the Aeromodeling
Center, and those organizations that have provided grants for which AMA has applied
and received. These people have made more than a donation—they have made an
investment in the future of aeromodeling.
When you see these folks, thank them! They are now among the thousands who
have given back to model aviation part of what model aviation has given to them.
Many things will be possible due to the their thoughtful giving and generosity.
We list our supporters monthly. These donations represent amounts processed in
the month of June 2004. If your name is not listed, please write to the Membership
Department and include a canceled check. We want to recognize all contributors!
Thank you.
$100 up to $500
Norbert E Auer - FL
James L Cromwell - OH
Jeffrey E Gagne - AZ
Paul Grant - OH
David Hallman - VA
Glen R Harrelson - OH
Arnold Jines - IN
David Johannesmeyer - CA
Pete Katsufrakis - MS
Todd W Londagin - NY
Stanley Luiz - OR
David Magee Sr - LA
C M Montplaisir - SC
John D Mulhorn - AZ
David Petit - OH
Karl Renaut - FL
Mike Upchurch - AL
$10 up to $100
Your Contributions do Make a Difference!
Aero Guidance Society Inc - NY John L Bentley - AZ
11sig3.QXD 8/23/04 12:25 pm Page 88