124 MODEL AVIATION
[[email protected]]
Radio Control Slope Soaring Dave Garwood
Rudder-only slope-flying challenge
Also included in this column:
• Ten foam building tips
Bonus foamie-building tip 11: Dave’s EPP-foam Leading Edge Gliders P-80 gave a smooth
surface for a panel-line pen, because it had two spackle applications after final-shaping
and before taping and covering.
Below: The Sig Riser, with rudder and elevator, is flown
in light air by Tom Wild during the 2008 Midwest Slope
Challenge.
Left: Tom Wild recovers his polyhedral Sig Riser,
controlled by rudder and elevator. Who can re-create the
early Slope Soaring days by building and flying a rudderonly
slope glider? A challenge is issued in the text.
Precision EPP-foam shaping tools. The cylindrical cutter in the
rotary tool shaped the cavity around the elevator control horn.
Use the rotary tool or bullet-shaped soldering-iron tip to shape
the channel for a pushrod-cable installation.
Dave Garwood flies his Leading Edge Gliders P-80 at the coast. Is
it a rudder-only challenge candidate? That’s doubtful, since it does
not have enough dihedral and no rudder. Jim Harrigan photo.
MANY SLOPE SOARING models run
aileron and elevator control. Some add rudder
control, and a few feature flaps or spoilers.
Think for a minute; what would be the
smallest number of control surfaces needed to
complete a flight and land back on top of the
hill under pilot control?
If your answer is one, you’re right, but
which surface would it be? If your answer is
rudder, right again, but what would it be like
to fly a “rudder-only” Slope sailplane.
How smoothly could you fly without
elevator control? Would it even be possible to
06sig4.QXD 4/23/09 12:08 PM Page 124
June 2009 125
Photograph the component layout before closing the fuselage. If you have to replace
something, the photo will help you locate it. The charge switch, just in front of the canopy
outline, makes for a clean installation of the on/off switch and charge connection.
launch, fly, and land back at the top using
only rudder control, with no other control
surfaces?
Not only is it possible, but it has been
done. Not only has it been done, but in the
early days of Slope Soaring, it was the only
way to fly RC for both power airplanes and
for gliders.
John Hackert has done it. He is a longtime
modeler who is president of the Electric
Powered Aeromodelers in Scotia, New York.
We rode together on a bus trip to the WRAM
Show earlier this year, and he told me stories
about CL flying in 1961 at La Cumbre Junior
High School and rudder-only Slope Soaring
with early RC equipment at Henry’s Beach in
Santa Barbara, California.
John remembers that during his freshman
and sophomore years in high school, he and
schoolmates flew CL models at the school all
day on Sundays.
“I had a buddy who had a balsa glider,
built from a kit, built up from sticks,” said
John. “The glider carried a single-channel
radio receiver—one of the first to use
transistors. He had remote control of rudder
only.”
The RC site featured a cliff overlooking
the ocean, and John’s buddy launched the
model into slope lift. John explained:
“It was remarkable that a model airplane
could be controlled by radio, and it was
amazing that a model glider could go up in
slope lift. The transmitter had a single button.
Press once to swing the rudder to the right;
press again to center it. Press twice to give
left rudder, and once again to return it to
center.”
Servos had yet to be introduced into
model flight; this airplane used rubber-bandpowered
escapements. John explained
further:
“Our frequency was on the citizen’s band,
between a couple of CB voice channels. We
had all kinds of interference, and it was
unusual to complete a flight without crashing.
We crashed plenty, but we also flew.”
John Hackert’s recollections started me
wondering if any of us are tough enough to
launch a rudder-only-controlled Slope Soarer
today. The brief time I’ve flown while
intentionally not touching the elevator
control, imagining that I was flying a rudderonly
sailplane, has convinced me that this is a
substantial task.
I’d like to hear the experiences of any RC
pilot who is willing to build, prep, and launch
a rudder-only sailplane into slope lift. I’ll run
photos and the stories of any of us who can
complete such a flight and manage to land
shiny-side up.
Are we tough enough to re-create the
early days of radio-controlled slope flight?
It’s something like the days of iron men in
wooden ships, it seems. Send in your stories
and pictures.
Foam Aircraft Building Tips: The
introduction of EPP foam in Slope Soarers in
the mid-1990s boosted their damage
resistance and heightened their crash
tolerance. This nigh-indestructible foam
attracted newcomers, sped up aerobatics
training, and offered us landing areas that
were previously considered too gnarly to put a
model down in, thus making more slopes
flyable.
The following is from Wikipedia, an
online encyclopedia (March 7, 2009).
“Expanded Polypropylene (EPP) is a foam
form of polypropylene. EPP has very good
impact characteristics due to its low stiffness,
this allows EPP to resume its shape after
impacts.
“EPP is extensively used in model aircraft
and other radio controlled vehicles by
hobbyists. This is mainly due to its ability to
absorb impacts, making this an ideal material
for RC aircraft for beginners and amateurs.”
Incorporating EPP foam into model
aircraft required that designers work to stiffen
wings and fuselages and that builders perfect
techniques to build with this miracle material.
There’s a necessary adjustment period for oldschool
modelers who are used to working
with wood and fiberglass.
“Sanding EPP foam is like sanding bubble
gum,” quipped Carl Maas Sr., who is a
legendary master Scale builder.
We did learn to sand and shape and finish
EPP foam and build some good-looking
sailplanes with it. Following are some foamaircraft
building tips I learned on my path to
constructing bounceable gliders.
1. Read the instructions before you start.
Aeromodeller Dec 1952
Used with permission
Subscribe to our magazine and receive full size plans in every issue
FULL SIZE PLANS - 1640C Kellogg Street - Galesburg, Illinois 61401
Do you like to look at model airplane plans and dream
about those you’d like to build?
Are you tired of ARFs and would you like to build
something yourself?
Would you like to build a model with a grandkid or
with your own children?
Do you remember when model magazines actually
printed plans in each issue?
Do you have a list of old classic RC, FF, RUBBER or UC
models you would like to build?
Do you have fond memories of that one special model
you first built as a kid?
Well, help is on the way. Our magazine specializes
in bringing back those fondly remembered oldies and
classics for you.
Send $4.00 now for a sample issue and full information
We find and restore the plans from old kits and magazines,
have them reprinted on high speed presses, and send them out to our
subscribers 6 times each year for their enjoyment, all at prices much less than
buying plans any other way.
06sig4.QXD 4/23/09 1:45 PM Page 125
Sure, this applies to wood and fiberglass
models too, but for foamies it especially
helps to make sure you have the right
adhesives, tape, and finishing materials for
the project.
Will you be using epoxy, Gorilla Glue,
3M 77 spray contact cement, hot-melt glue,
or all four? Will you use 1-inch- or 2-inchwide
filament tape?
Are you going to finish the model with
low-temperature film such as UltraCote or
iron-on fabric such as Solartex? Or will you
try something new, such as tool-handle dip
or temperature-sensitive plastic designed for
laminating ID cards (which a flying buddy
showed me, and it looks promising)?
2. Order tools, parts, and materials early
in the build process, so you’ll have them on
hand and save interruptions to the workflow.
Get the correct-size servos and battery packs
so that fuselage construction will proceed
without interruption.
Make sure you have sufficient tape and
covering material at your disposal, to
complete the project without a delay at a late
stage when you might be anxious to get the
model in the air. Do you need to order
decals or special spray-paint colors?
3. Remove the hot-wire-cutter “hairs”
from wing and fuselage parts with a block of
EPP foam. It’s quicker than picking off the
strands with fingers, and it’s gentler on the
foam parts than using a sanding block.
4. I prefer to join wood parts with wood
glue. It’s light and strong, and it sands more
easily than epoxy or cyanoacrylate glue.
Elmer’s ProBond Interior Wood Glue
(yellow carpenter’s glue) or any brand of
aliphatic resin will do the trick, and it is
inexpensive.
5. I like setting spars into a foam wing
with polyurethane adhesive. I’ve used both
Gorilla Glue and Borden Ultimate Glue
Polyurethane, which is available from
Elmer’s.
When these adhesives are exposed to a
slight amount of water, they foam slightly
and expand, thus filling pores in wood and
nooks and crannies in foam, locking them
together in a tight bond. A polyurethane glue
joint is lighter than an equivalent epoxy or
hot-melt-glue joint, and it has a longer
working time than the hot-glue method.
Using polyurethane adhesive is different
from using most other glues. Some moisture
is needed as a catalyst to start the curing
process. It can be moisture in the air on a
humid day.
In dry air, wipe one part with a damp
paper towel. You’ll have 10-15 minutes to
assemble and clamp the parts, and I like to
let them cure overnight to develop
maximum strength.
This glue is exceedingly sticky before
curing. Clean up your hands and tools with
mineral spirits before curing, and remove
the adhesive from finished parts with a
sanding block after curing.
6. There’s a method I use to make
accurate cutouts for servos, receivers, and
battery packs. Position the part on the foam
and draw around it with a Sharpie marker.
Cut the sides of the cavity with a blade,
using tape on the blade as a depth gauge.
Remove the excess foam by chunking it out
with long-nose pliers or by grinding with a
rotary tool using a cylinder-shaped cutter.
For a sturdy servo mount, “pot” the
servos in an epoxy-and-microballoon mix,
as described in the August 2008 MA Slope
Soaring column, for a rigid and easily
removable servo mount.
7. Useful tools for cutting out channels
for pushrods, antenna tubes, and stiffener
tubes in a fuselage are a cylindrical cutter
tool used on a rotary tool and a special tip on
a soldering iron.
8. Install a charge switch if your model
can handle the weight. Slope Soarers with
spans exceeding 48 inches should hardly
notice the slight extra weight. You’ll find
the charge switch to be a cleaner installation
than a standard switch with charging pigtail
hanging out.
Charge switches are available from ATS
RC Planes, Horizon Hobby,
ElectroDynamics, and Maxx Products
International. Also available from Maxx
Products is a charge switch with LEDs to
show the state of your onboard battery
pack’s charge under load.
9. Use MonoKote hinges wherever you
can. They are stronger, more flexible, and
last longer than any other hinging technique
I’ve used in building 115 models.
I learned this while building a Gentle
Lady kit decades ago. The “film covering
hinge technique” is described and
diagrammed on page 17 of the Gentle Lady
Glider Kit instruction manual, which is
available for download on the Carl Goldberg
Products Web site.
10. Photograph the location of internal
components before closing or taping up the
fuselage. I hope you’ll never need them, but
the picture will make it easier to locate the
component if you have to excavate a broken
radio component for replacement.
For many more foam building hints, tips,
and ideas, order a copy of “The EPP
Building Clinic” four-disc DVD set. It is
available from Leading Edge Gliders and
slopeflyer.com. MA
Sources:
Elmer’s
(800) 848-9400
www.elmers.com
Gorilla Glue
(800) 966-3458
www.gorillaglue.com
ATS RC Planes
Box 95
Hartford OH 44424
www.atsrcplanes.com
ElectroDynamics
(734) 422-5420
www.electrodynam.com
Horizon Hobby
(800) 338-4639
www.horizonhobby.com
Maxx Products International
(847) 438-2233
www.maxxprod.com
Carl Goldberg Products
(217) 398-8970
www.carlgoldbergproducts.com
Leading Edge Gliders
(785) 525-6263
www.leadingedgegliders.com
slopeflyer.com
www.slopeflyer.com
Edition: Model Aviation - 2009/06
Page Numbers: 124,125,126
Edition: Model Aviation - 2009/06
Page Numbers: 124,125,126
124 MODEL AVIATION
[[email protected]]
Radio Control Slope Soaring Dave Garwood
Rudder-only slope-flying challenge
Also included in this column:
• Ten foam building tips
Bonus foamie-building tip 11: Dave’s EPP-foam Leading Edge Gliders P-80 gave a smooth
surface for a panel-line pen, because it had two spackle applications after final-shaping
and before taping and covering.
Below: The Sig Riser, with rudder and elevator, is flown
in light air by Tom Wild during the 2008 Midwest Slope
Challenge.
Left: Tom Wild recovers his polyhedral Sig Riser,
controlled by rudder and elevator. Who can re-create the
early Slope Soaring days by building and flying a rudderonly
slope glider? A challenge is issued in the text.
Precision EPP-foam shaping tools. The cylindrical cutter in the
rotary tool shaped the cavity around the elevator control horn.
Use the rotary tool or bullet-shaped soldering-iron tip to shape
the channel for a pushrod-cable installation.
Dave Garwood flies his Leading Edge Gliders P-80 at the coast. Is
it a rudder-only challenge candidate? That’s doubtful, since it does
not have enough dihedral and no rudder. Jim Harrigan photo.
MANY SLOPE SOARING models run
aileron and elevator control. Some add rudder
control, and a few feature flaps or spoilers.
Think for a minute; what would be the
smallest number of control surfaces needed to
complete a flight and land back on top of the
hill under pilot control?
If your answer is one, you’re right, but
which surface would it be? If your answer is
rudder, right again, but what would it be like
to fly a “rudder-only” Slope sailplane.
How smoothly could you fly without
elevator control? Would it even be possible to
06sig4.QXD 4/23/09 12:08 PM Page 124
June 2009 125
Photograph the component layout before closing the fuselage. If you have to replace
something, the photo will help you locate it. The charge switch, just in front of the canopy
outline, makes for a clean installation of the on/off switch and charge connection.
launch, fly, and land back at the top using
only rudder control, with no other control
surfaces?
Not only is it possible, but it has been
done. Not only has it been done, but in the
early days of Slope Soaring, it was the only
way to fly RC for both power airplanes and
for gliders.
John Hackert has done it. He is a longtime
modeler who is president of the Electric
Powered Aeromodelers in Scotia, New York.
We rode together on a bus trip to the WRAM
Show earlier this year, and he told me stories
about CL flying in 1961 at La Cumbre Junior
High School and rudder-only Slope Soaring
with early RC equipment at Henry’s Beach in
Santa Barbara, California.
John remembers that during his freshman
and sophomore years in high school, he and
schoolmates flew CL models at the school all
day on Sundays.
“I had a buddy who had a balsa glider,
built from a kit, built up from sticks,” said
John. “The glider carried a single-channel
radio receiver—one of the first to use
transistors. He had remote control of rudder
only.”
The RC site featured a cliff overlooking
the ocean, and John’s buddy launched the
model into slope lift. John explained:
“It was remarkable that a model airplane
could be controlled by radio, and it was
amazing that a model glider could go up in
slope lift. The transmitter had a single button.
Press once to swing the rudder to the right;
press again to center it. Press twice to give
left rudder, and once again to return it to
center.”
Servos had yet to be introduced into
model flight; this airplane used rubber-bandpowered
escapements. John explained
further:
“Our frequency was on the citizen’s band,
between a couple of CB voice channels. We
had all kinds of interference, and it was
unusual to complete a flight without crashing.
We crashed plenty, but we also flew.”
John Hackert’s recollections started me
wondering if any of us are tough enough to
launch a rudder-only-controlled Slope Soarer
today. The brief time I’ve flown while
intentionally not touching the elevator
control, imagining that I was flying a rudderonly
sailplane, has convinced me that this is a
substantial task.
I’d like to hear the experiences of any RC
pilot who is willing to build, prep, and launch
a rudder-only sailplane into slope lift. I’ll run
photos and the stories of any of us who can
complete such a flight and manage to land
shiny-side up.
Are we tough enough to re-create the
early days of radio-controlled slope flight?
It’s something like the days of iron men in
wooden ships, it seems. Send in your stories
and pictures.
Foam Aircraft Building Tips: The
introduction of EPP foam in Slope Soarers in
the mid-1990s boosted their damage
resistance and heightened their crash
tolerance. This nigh-indestructible foam
attracted newcomers, sped up aerobatics
training, and offered us landing areas that
were previously considered too gnarly to put a
model down in, thus making more slopes
flyable.
The following is from Wikipedia, an
online encyclopedia (March 7, 2009).
“Expanded Polypropylene (EPP) is a foam
form of polypropylene. EPP has very good
impact characteristics due to its low stiffness,
this allows EPP to resume its shape after
impacts.
“EPP is extensively used in model aircraft
and other radio controlled vehicles by
hobbyists. This is mainly due to its ability to
absorb impacts, making this an ideal material
for RC aircraft for beginners and amateurs.”
Incorporating EPP foam into model
aircraft required that designers work to stiffen
wings and fuselages and that builders perfect
techniques to build with this miracle material.
There’s a necessary adjustment period for oldschool
modelers who are used to working
with wood and fiberglass.
“Sanding EPP foam is like sanding bubble
gum,” quipped Carl Maas Sr., who is a
legendary master Scale builder.
We did learn to sand and shape and finish
EPP foam and build some good-looking
sailplanes with it. Following are some foamaircraft
building tips I learned on my path to
constructing bounceable gliders.
1. Read the instructions before you start.
Aeromodeller Dec 1952
Used with permission
Subscribe to our magazine and receive full size plans in every issue
FULL SIZE PLANS - 1640C Kellogg Street - Galesburg, Illinois 61401
Do you like to look at model airplane plans and dream
about those you’d like to build?
Are you tired of ARFs and would you like to build
something yourself?
Would you like to build a model with a grandkid or
with your own children?
Do you remember when model magazines actually
printed plans in each issue?
Do you have a list of old classic RC, FF, RUBBER or UC
models you would like to build?
Do you have fond memories of that one special model
you first built as a kid?
Well, help is on the way. Our magazine specializes
in bringing back those fondly remembered oldies and
classics for you.
Send $4.00 now for a sample issue and full information
We find and restore the plans from old kits and magazines,
have them reprinted on high speed presses, and send them out to our
subscribers 6 times each year for their enjoyment, all at prices much less than
buying plans any other way.
06sig4.QXD 4/23/09 1:45 PM Page 125
Sure, this applies to wood and fiberglass
models too, but for foamies it especially
helps to make sure you have the right
adhesives, tape, and finishing materials for
the project.
Will you be using epoxy, Gorilla Glue,
3M 77 spray contact cement, hot-melt glue,
or all four? Will you use 1-inch- or 2-inchwide
filament tape?
Are you going to finish the model with
low-temperature film such as UltraCote or
iron-on fabric such as Solartex? Or will you
try something new, such as tool-handle dip
or temperature-sensitive plastic designed for
laminating ID cards (which a flying buddy
showed me, and it looks promising)?
2. Order tools, parts, and materials early
in the build process, so you’ll have them on
hand and save interruptions to the workflow.
Get the correct-size servos and battery packs
so that fuselage construction will proceed
without interruption.
Make sure you have sufficient tape and
covering material at your disposal, to
complete the project without a delay at a late
stage when you might be anxious to get the
model in the air. Do you need to order
decals or special spray-paint colors?
3. Remove the hot-wire-cutter “hairs”
from wing and fuselage parts with a block of
EPP foam. It’s quicker than picking off the
strands with fingers, and it’s gentler on the
foam parts than using a sanding block.
4. I prefer to join wood parts with wood
glue. It’s light and strong, and it sands more
easily than epoxy or cyanoacrylate glue.
Elmer’s ProBond Interior Wood Glue
(yellow carpenter’s glue) or any brand of
aliphatic resin will do the trick, and it is
inexpensive.
5. I like setting spars into a foam wing
with polyurethane adhesive. I’ve used both
Gorilla Glue and Borden Ultimate Glue
Polyurethane, which is available from
Elmer’s.
When these adhesives are exposed to a
slight amount of water, they foam slightly
and expand, thus filling pores in wood and
nooks and crannies in foam, locking them
together in a tight bond. A polyurethane glue
joint is lighter than an equivalent epoxy or
hot-melt-glue joint, and it has a longer
working time than the hot-glue method.
Using polyurethane adhesive is different
from using most other glues. Some moisture
is needed as a catalyst to start the curing
process. It can be moisture in the air on a
humid day.
In dry air, wipe one part with a damp
paper towel. You’ll have 10-15 minutes to
assemble and clamp the parts, and I like to
let them cure overnight to develop
maximum strength.
This glue is exceedingly sticky before
curing. Clean up your hands and tools with
mineral spirits before curing, and remove
the adhesive from finished parts with a
sanding block after curing.
6. There’s a method I use to make
accurate cutouts for servos, receivers, and
battery packs. Position the part on the foam
and draw around it with a Sharpie marker.
Cut the sides of the cavity with a blade,
using tape on the blade as a depth gauge.
Remove the excess foam by chunking it out
with long-nose pliers or by grinding with a
rotary tool using a cylinder-shaped cutter.
For a sturdy servo mount, “pot” the
servos in an epoxy-and-microballoon mix,
as described in the August 2008 MA Slope
Soaring column, for a rigid and easily
removable servo mount.
7. Useful tools for cutting out channels
for pushrods, antenna tubes, and stiffener
tubes in a fuselage are a cylindrical cutter
tool used on a rotary tool and a special tip on
a soldering iron.
8. Install a charge switch if your model
can handle the weight. Slope Soarers with
spans exceeding 48 inches should hardly
notice the slight extra weight. You’ll find
the charge switch to be a cleaner installation
than a standard switch with charging pigtail
hanging out.
Charge switches are available from ATS
RC Planes, Horizon Hobby,
ElectroDynamics, and Maxx Products
International. Also available from Maxx
Products is a charge switch with LEDs to
show the state of your onboard battery
pack’s charge under load.
9. Use MonoKote hinges wherever you
can. They are stronger, more flexible, and
last longer than any other hinging technique
I’ve used in building 115 models.
I learned this while building a Gentle
Lady kit decades ago. The “film covering
hinge technique” is described and
diagrammed on page 17 of the Gentle Lady
Glider Kit instruction manual, which is
available for download on the Carl Goldberg
Products Web site.
10. Photograph the location of internal
components before closing or taping up the
fuselage. I hope you’ll never need them, but
the picture will make it easier to locate the
component if you have to excavate a broken
radio component for replacement.
For many more foam building hints, tips,
and ideas, order a copy of “The EPP
Building Clinic” four-disc DVD set. It is
available from Leading Edge Gliders and
slopeflyer.com. MA
Sources:
Elmer’s
(800) 848-9400
www.elmers.com
Gorilla Glue
(800) 966-3458
www.gorillaglue.com
ATS RC Planes
Box 95
Hartford OH 44424
www.atsrcplanes.com
ElectroDynamics
(734) 422-5420
www.electrodynam.com
Horizon Hobby
(800) 338-4639
www.horizonhobby.com
Maxx Products International
(847) 438-2233
www.maxxprod.com
Carl Goldberg Products
(217) 398-8970
www.carlgoldbergproducts.com
Leading Edge Gliders
(785) 525-6263
www.leadingedgegliders.com
slopeflyer.com
www.slopeflyer.com
Edition: Model Aviation - 2009/06
Page Numbers: 124,125,126
124 MODEL AVIATION
[[email protected]]
Radio Control Slope Soaring Dave Garwood
Rudder-only slope-flying challenge
Also included in this column:
• Ten foam building tips
Bonus foamie-building tip 11: Dave’s EPP-foam Leading Edge Gliders P-80 gave a smooth
surface for a panel-line pen, because it had two spackle applications after final-shaping
and before taping and covering.
Below: The Sig Riser, with rudder and elevator, is flown
in light air by Tom Wild during the 2008 Midwest Slope
Challenge.
Left: Tom Wild recovers his polyhedral Sig Riser,
controlled by rudder and elevator. Who can re-create the
early Slope Soaring days by building and flying a rudderonly
slope glider? A challenge is issued in the text.
Precision EPP-foam shaping tools. The cylindrical cutter in the
rotary tool shaped the cavity around the elevator control horn.
Use the rotary tool or bullet-shaped soldering-iron tip to shape
the channel for a pushrod-cable installation.
Dave Garwood flies his Leading Edge Gliders P-80 at the coast. Is
it a rudder-only challenge candidate? That’s doubtful, since it does
not have enough dihedral and no rudder. Jim Harrigan photo.
MANY SLOPE SOARING models run
aileron and elevator control. Some add rudder
control, and a few feature flaps or spoilers.
Think for a minute; what would be the
smallest number of control surfaces needed to
complete a flight and land back on top of the
hill under pilot control?
If your answer is one, you’re right, but
which surface would it be? If your answer is
rudder, right again, but what would it be like
to fly a “rudder-only” Slope sailplane.
How smoothly could you fly without
elevator control? Would it even be possible to
06sig4.QXD 4/23/09 12:08 PM Page 124
June 2009 125
Photograph the component layout before closing the fuselage. If you have to replace
something, the photo will help you locate it. The charge switch, just in front of the canopy
outline, makes for a clean installation of the on/off switch and charge connection.
launch, fly, and land back at the top using
only rudder control, with no other control
surfaces?
Not only is it possible, but it has been
done. Not only has it been done, but in the
early days of Slope Soaring, it was the only
way to fly RC for both power airplanes and
for gliders.
John Hackert has done it. He is a longtime
modeler who is president of the Electric
Powered Aeromodelers in Scotia, New York.
We rode together on a bus trip to the WRAM
Show earlier this year, and he told me stories
about CL flying in 1961 at La Cumbre Junior
High School and rudder-only Slope Soaring
with early RC equipment at Henry’s Beach in
Santa Barbara, California.
John remembers that during his freshman
and sophomore years in high school, he and
schoolmates flew CL models at the school all
day on Sundays.
“I had a buddy who had a balsa glider,
built from a kit, built up from sticks,” said
John. “The glider carried a single-channel
radio receiver—one of the first to use
transistors. He had remote control of rudder
only.”
The RC site featured a cliff overlooking
the ocean, and John’s buddy launched the
model into slope lift. John explained:
“It was remarkable that a model airplane
could be controlled by radio, and it was
amazing that a model glider could go up in
slope lift. The transmitter had a single button.
Press once to swing the rudder to the right;
press again to center it. Press twice to give
left rudder, and once again to return it to
center.”
Servos had yet to be introduced into
model flight; this airplane used rubber-bandpowered
escapements. John explained
further:
“Our frequency was on the citizen’s band,
between a couple of CB voice channels. We
had all kinds of interference, and it was
unusual to complete a flight without crashing.
We crashed plenty, but we also flew.”
John Hackert’s recollections started me
wondering if any of us are tough enough to
launch a rudder-only-controlled Slope Soarer
today. The brief time I’ve flown while
intentionally not touching the elevator
control, imagining that I was flying a rudderonly
sailplane, has convinced me that this is a
substantial task.
I’d like to hear the experiences of any RC
pilot who is willing to build, prep, and launch
a rudder-only sailplane into slope lift. I’ll run
photos and the stories of any of us who can
complete such a flight and manage to land
shiny-side up.
Are we tough enough to re-create the
early days of radio-controlled slope flight?
It’s something like the days of iron men in
wooden ships, it seems. Send in your stories
and pictures.
Foam Aircraft Building Tips: The
introduction of EPP foam in Slope Soarers in
the mid-1990s boosted their damage
resistance and heightened their crash
tolerance. This nigh-indestructible foam
attracted newcomers, sped up aerobatics
training, and offered us landing areas that
were previously considered too gnarly to put a
model down in, thus making more slopes
flyable.
The following is from Wikipedia, an
online encyclopedia (March 7, 2009).
“Expanded Polypropylene (EPP) is a foam
form of polypropylene. EPP has very good
impact characteristics due to its low stiffness,
this allows EPP to resume its shape after
impacts.
“EPP is extensively used in model aircraft
and other radio controlled vehicles by
hobbyists. This is mainly due to its ability to
absorb impacts, making this an ideal material
for RC aircraft for beginners and amateurs.”
Incorporating EPP foam into model
aircraft required that designers work to stiffen
wings and fuselages and that builders perfect
techniques to build with this miracle material.
There’s a necessary adjustment period for oldschool
modelers who are used to working
with wood and fiberglass.
“Sanding EPP foam is like sanding bubble
gum,” quipped Carl Maas Sr., who is a
legendary master Scale builder.
We did learn to sand and shape and finish
EPP foam and build some good-looking
sailplanes with it. Following are some foamaircraft
building tips I learned on my path to
constructing bounceable gliders.
1. Read the instructions before you start.
Aeromodeller Dec 1952
Used with permission
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06sig4.QXD 4/23/09 1:45 PM Page 125
Sure, this applies to wood and fiberglass
models too, but for foamies it especially
helps to make sure you have the right
adhesives, tape, and finishing materials for
the project.
Will you be using epoxy, Gorilla Glue,
3M 77 spray contact cement, hot-melt glue,
or all four? Will you use 1-inch- or 2-inchwide
filament tape?
Are you going to finish the model with
low-temperature film such as UltraCote or
iron-on fabric such as Solartex? Or will you
try something new, such as tool-handle dip
or temperature-sensitive plastic designed for
laminating ID cards (which a flying buddy
showed me, and it looks promising)?
2. Order tools, parts, and materials early
in the build process, so you’ll have them on
hand and save interruptions to the workflow.
Get the correct-size servos and battery packs
so that fuselage construction will proceed
without interruption.
Make sure you have sufficient tape and
covering material at your disposal, to
complete the project without a delay at a late
stage when you might be anxious to get the
model in the air. Do you need to order
decals or special spray-paint colors?
3. Remove the hot-wire-cutter “hairs”
from wing and fuselage parts with a block of
EPP foam. It’s quicker than picking off the
strands with fingers, and it’s gentler on the
foam parts than using a sanding block.
4. I prefer to join wood parts with wood
glue. It’s light and strong, and it sands more
easily than epoxy or cyanoacrylate glue.
Elmer’s ProBond Interior Wood Glue
(yellow carpenter’s glue) or any brand of
aliphatic resin will do the trick, and it is
inexpensive.
5. I like setting spars into a foam wing
with polyurethane adhesive. I’ve used both
Gorilla Glue and Borden Ultimate Glue
Polyurethane, which is available from
Elmer’s.
When these adhesives are exposed to a
slight amount of water, they foam slightly
and expand, thus filling pores in wood and
nooks and crannies in foam, locking them
together in a tight bond. A polyurethane glue
joint is lighter than an equivalent epoxy or
hot-melt-glue joint, and it has a longer
working time than the hot-glue method.
Using polyurethane adhesive is different
from using most other glues. Some moisture
is needed as a catalyst to start the curing
process. It can be moisture in the air on a
humid day.
In dry air, wipe one part with a damp
paper towel. You’ll have 10-15 minutes to
assemble and clamp the parts, and I like to
let them cure overnight to develop
maximum strength.
This glue is exceedingly sticky before
curing. Clean up your hands and tools with
mineral spirits before curing, and remove
the adhesive from finished parts with a
sanding block after curing.
6. There’s a method I use to make
accurate cutouts for servos, receivers, and
battery packs. Position the part on the foam
and draw around it with a Sharpie marker.
Cut the sides of the cavity with a blade,
using tape on the blade as a depth gauge.
Remove the excess foam by chunking it out
with long-nose pliers or by grinding with a
rotary tool using a cylinder-shaped cutter.
For a sturdy servo mount, “pot” the
servos in an epoxy-and-microballoon mix,
as described in the August 2008 MA Slope
Soaring column, for a rigid and easily
removable servo mount.
7. Useful tools for cutting out channels
for pushrods, antenna tubes, and stiffener
tubes in a fuselage are a cylindrical cutter
tool used on a rotary tool and a special tip on
a soldering iron.
8. Install a charge switch if your model
can handle the weight. Slope Soarers with
spans exceeding 48 inches should hardly
notice the slight extra weight. You’ll find
the charge switch to be a cleaner installation
than a standard switch with charging pigtail
hanging out.
Charge switches are available from ATS
RC Planes, Horizon Hobby,
ElectroDynamics, and Maxx Products
International. Also available from Maxx
Products is a charge switch with LEDs to
show the state of your onboard battery
pack’s charge under load.
9. Use MonoKote hinges wherever you
can. They are stronger, more flexible, and
last longer than any other hinging technique
I’ve used in building 115 models.
I learned this while building a Gentle
Lady kit decades ago. The “film covering
hinge technique” is described and
diagrammed on page 17 of the Gentle Lady
Glider Kit instruction manual, which is
available for download on the Carl Goldberg
Products Web site.
10. Photograph the location of internal
components before closing or taping up the
fuselage. I hope you’ll never need them, but
the picture will make it easier to locate the
component if you have to excavate a broken
radio component for replacement.
For many more foam building hints, tips,
and ideas, order a copy of “The EPP
Building Clinic” four-disc DVD set. It is
available from Leading Edge Gliders and
slopeflyer.com. MA
Sources:
Elmer’s
(800) 848-9400
www.elmers.com
Gorilla Glue
(800) 966-3458
www.gorillaglue.com
ATS RC Planes
Box 95
Hartford OH 44424
www.atsrcplanes.com
ElectroDynamics
(734) 422-5420
www.electrodynam.com
Horizon Hobby
(800) 338-4639
www.horizonhobby.com
Maxx Products International
(847) 438-2233
www.maxxprod.com
Carl Goldberg Products
(217) 398-8970
www.carlgoldbergproducts.com
Leading Edge Gliders
(785) 525-6263
www.leadingedgegliders.com
slopeflyer.com
www.slopeflyer.com