[[email protected]]
Radio Control Soaring Darwin Barrie
The project hybrid 2-meter model gets some wings
A frontal view of the author’s hybrid 2-meter model. The lower-aspect-ratio wing
provides more wing area than many conventional 2-meter sailplanes have.
The winglets also add wing area. The tail surfaces are small but very effective.
I PROMISED TO have a full flight report
on the hybrid 2-meter I’ve been building for
the past few months. Unfortunately, because
of a death in the family and other obstacles
in life, I didn’t get to explore the full flight
envelope. I promise to have the complete
flight report in the next column. That is the
bad news.
The good news is that I’ve been able to
launch the sailplane on a small hi-start and
can provide a preliminary flight report. But
first we have to finish the model.
The wings were the remaining piece of the
puzzle. As I have noted, Jerry Robertson
and I collaborated on this project.
His idea was to use the outer panels of
the AVA Rudder-Elevator-Spoiler (RES)
sailplane as the starting point. From there
the panels would eventually be joined in the
center, the outer ribs would be removed to
get to the 2 meters, the ailerons and flaps
would be constructed, and winglets would
be added.
Jerry used the AVA panels while I used
panels from the Buzzard. In comparing the
two, the only real difference was how the
panels were joined to the center panel of the
RES model. The AVA used a square-type
joiner and the Buzzard used a round rod.
They look like they came from the same
factory.
The AVA panels are available new from
Barry Kennedy at Kennedy Composites. I
posted a note on the Radio Control Soaring
Exchange (RCSE) indicating that I was
searching for used panels from the AVA or
a similar sailplane. It doesn’t matter if the
panels are the same color or even damaged
as long as you get a right and a left from the
same design.
The process begins with cutting the
panels to the proper size. I sawed off five
rib bays from the tip, which provided ample
room to build the optional winglets.
Conventional tips can certainly be added to
get the full 2-meter span.
Next is the tedious task of removing the
covering. The process is made easier by
using a heat gun, an X-Acto knife, and time.
No matter how hard you try, there will
be some pieces adhered to the ribs or other
structure. Since the ribs are carbon capped
and the TE is carbon, light sanding can
remove stubborn covering. Heat can also be
applied and the X-Acto knife can be used.
With the covering removed it is time to
lay out the flaps and ailerons. Jerry and I
decided to use flaps and ailerons with a
chord of 25% of the overall chord. This was
marked at the root and the tip and a line was
drawn.
Because this was a first-time project, we
were concerned about the rigidity and
torsional ability of the flaps and ailerons if
we used just a capped LE. We decided that
aluminum tube would be built into the LE of
the structure of the flaps and ailerons. This
was completed and a rigid structure was
produced.
In review I don’t believe the added work
of the aluminum tube is necessary. The
same rigidity can be achieved by using
fairly hard stock balsa. For your purposes
use a capped LE of the flap and aileron
without aluminum tubing. The TE of the
wing panels is capped with hard balsa.
We’ve already drawn a line that
established the chord (in essence, the hinge
line). The LE and TE will be capped with 1/4
hard balsa. The LE and TE caps will be
notched 1/8 inch to increase the integrity of
the bond.
To keep the proper chord, 1/8 inch of
each rib will need to be removed from the
ailerons, flaps, and wing panels. Measure
and mark 1/8 inch on each side of the hingeline
top and bottom. I drew a line with a
straightedge and then applied tape as a cut
guide.
Once completed and all measurements
confirmed, I used my band saw to cut the
ailerons and flaps loose. I finished the
process by doing the other wing panel.
I used 1/4 sheet balsa for the cap and cut
the taper to minimize sanding. I taped the
caps in place and marked the rib locations.
Since I am going to notch the LE and
TE, a centerline needs to be drawn on the
top of the caps. That represents the center of
110 MODEL AVIATION
11sig4.QXD 9/21/07 10:04 AM Page 110
Aileron radial drive system with Futaba 3154 micro digital for
drive. Note capped LE of flap and aileron and TE of wing. Each is
notched 1/8 inch.
The flap RDS with Futaba 3150 digital servo. The flaps are large
and extraordinarily effective.
the notch. I used my band saw to cut the
notches and fine-tuned each notch with a
flat, thin file. A Dremel can be used, with a
file used for cleanup.
I test-fit each piece and used a
straightedge to true the cap. When I was
satisfied I glued the caps in place and sanded
them to match the ribs. I installed corner
gussets at each corner of the cap, tip, and
root.
The flaps will be hinged on the bottom and
the ailerons on the top. I sanded a slight bevel
into the flap cap to allow approximately 1/8
inch of up flap travel. A bevel was sanded
into the bottom of each aileron. You can
determine how much to sand, but you need
only what you think your max downward
deflection might be. After the servo
locations were established I Dremeled
holes into the ribs for the servo wires (near
the spar).
I used a full radial drive system (RDS)
for actuating both the ailerons and the
flaps. This presented considerable extra
work, but the results were a completely
“clean” wing surface.
If I did this again I’d do the RDS on the
ailerons and not the flaps. Considerable
tinkering is necessary with the flaps to get
full down deflection. You can find details
about the RDS on Harley Michaelis’s Web
site. Look at File 06.
I used the Futaba 3154 micro digital
servo for the ailerons. The RDS provides a
slop-free linkage and the 3154 has 23
ounces of torque on 6 volts, so I believed
this would be more than sufficient. On flaps
I used the Futaba 3150 servo. It is thin and
fits nicely in virtually any wing.
Before joining the wing panels I
determined the bolt-hole locations and
Dremeled a “half round” into each panel.
This was necessary because the root ribs
were carbon capped and would have been
difficult to drill without a guide hole. Once
joined, I drilled the true 1/4-inch hole,
applied cyanoacrylate glue, and drilled the
hole again.
The wing rod at the center was a stock
aluminum 1/2-inch joiner rod I obtained from
Don Richmond at Hilaunch.com. Since the
wing panels are the outer panels of a larger
model, there are only a few inches on each
side of center to insert the rod. I cut the rod
to the proper length and fit it to the wings.
The dihedral was perfect.
I also built a 1/4-inch carbon-rod
alignment pin forward of the TE. Once all
the servo detail was completed, the wings
were joined.
I used epoxy and micro filler for the job
and thoroughly coated the main wing rod.
But first I scuffed it with 80-grit sandpaper
and cleaned it. The center was covered with
2-ounce fiberglass cloth that was 2 inches
wide. The cloth aft of the spar was trimmed
to the ribs after curing.
The main structure was complete. I
attached the wing to the fuselage with 1/4-20
nylon bolts. The rudder and elevator were
made operational and the CG was checked. I
used an initial CG of 35% of the chord. I
knew that would be safe.
I wasn’t sure what to do about towhook
location on a new model with no history.
Jerry said he uses a removable towhook
until he has established the CG. This
involves making a molded fixture that is
taped to the fuselage.
He tapes waxed paper to the bottom of
the fuselage in the range where the CG will
be located. Two layers of 4- to 6-ounce cloth
are epoxied in place.
After that cures Jerry epoxies a towhook
in place and secures it with a buildup of
epoxy and micro filler. He forms the fill
with a finger and alcohol before it cures.
When it has cured he adds a couple more
layers of cloth over the entire structure.
Then he trims it and sands it to final form.
Initial test tosses showed the CG to be too
far forward. I removed nose weight until the
hand tosses felt comfortable.
I taped on the towhook fixture with
fiberglass-stranded tape, approximately 1/8
inch in front of the CG. My small-length histart
is perfect for 150-foot launches, which
is ideal for initial flights.
I launched the sailplane and the
trajectory was nearly ideal. The CG was still
forward and more weight was removed. I
moved the towhook back slightly.
The next launch was perfect. I felt a
bump on the way up, and the model
immediately caught a thermal for a 10-
minute ride. During the flight I was able to
determine what settings I needed to modify.
After a couple more launches the
flap/elevator landing compensation was set.
What a great-flying airplane!
Next month I’ll wrap it up with a full flying
report and some contest reports. MA
Sources:
Harley Michaelis
http://genie.rchomepage.com
Hilaunch.com
(858) 539-6029
www.hilaunch.com
Kennedy Composites
(972) 602-3144
www.kennedycomposites.com
Radio Control Soaring Exchange
www.eclipse.net/~mikel/rcse/rcse.htm
Edition: Model Aviation - 2007/11
Page Numbers: 110,112,114
Edition: Model Aviation - 2007/11
Page Numbers: 110,112,114
[[email protected]]
Radio Control Soaring Darwin Barrie
The project hybrid 2-meter model gets some wings
A frontal view of the author’s hybrid 2-meter model. The lower-aspect-ratio wing
provides more wing area than many conventional 2-meter sailplanes have.
The winglets also add wing area. The tail surfaces are small but very effective.
I PROMISED TO have a full flight report
on the hybrid 2-meter I’ve been building for
the past few months. Unfortunately, because
of a death in the family and other obstacles
in life, I didn’t get to explore the full flight
envelope. I promise to have the complete
flight report in the next column. That is the
bad news.
The good news is that I’ve been able to
launch the sailplane on a small hi-start and
can provide a preliminary flight report. But
first we have to finish the model.
The wings were the remaining piece of the
puzzle. As I have noted, Jerry Robertson
and I collaborated on this project.
His idea was to use the outer panels of
the AVA Rudder-Elevator-Spoiler (RES)
sailplane as the starting point. From there
the panels would eventually be joined in the
center, the outer ribs would be removed to
get to the 2 meters, the ailerons and flaps
would be constructed, and winglets would
be added.
Jerry used the AVA panels while I used
panels from the Buzzard. In comparing the
two, the only real difference was how the
panels were joined to the center panel of the
RES model. The AVA used a square-type
joiner and the Buzzard used a round rod.
They look like they came from the same
factory.
The AVA panels are available new from
Barry Kennedy at Kennedy Composites. I
posted a note on the Radio Control Soaring
Exchange (RCSE) indicating that I was
searching for used panels from the AVA or
a similar sailplane. It doesn’t matter if the
panels are the same color or even damaged
as long as you get a right and a left from the
same design.
The process begins with cutting the
panels to the proper size. I sawed off five
rib bays from the tip, which provided ample
room to build the optional winglets.
Conventional tips can certainly be added to
get the full 2-meter span.
Next is the tedious task of removing the
covering. The process is made easier by
using a heat gun, an X-Acto knife, and time.
No matter how hard you try, there will
be some pieces adhered to the ribs or other
structure. Since the ribs are carbon capped
and the TE is carbon, light sanding can
remove stubborn covering. Heat can also be
applied and the X-Acto knife can be used.
With the covering removed it is time to
lay out the flaps and ailerons. Jerry and I
decided to use flaps and ailerons with a
chord of 25% of the overall chord. This was
marked at the root and the tip and a line was
drawn.
Because this was a first-time project, we
were concerned about the rigidity and
torsional ability of the flaps and ailerons if
we used just a capped LE. We decided that
aluminum tube would be built into the LE of
the structure of the flaps and ailerons. This
was completed and a rigid structure was
produced.
In review I don’t believe the added work
of the aluminum tube is necessary. The
same rigidity can be achieved by using
fairly hard stock balsa. For your purposes
use a capped LE of the flap and aileron
without aluminum tubing. The TE of the
wing panels is capped with hard balsa.
We’ve already drawn a line that
established the chord (in essence, the hinge
line). The LE and TE will be capped with 1/4
hard balsa. The LE and TE caps will be
notched 1/8 inch to increase the integrity of
the bond.
To keep the proper chord, 1/8 inch of
each rib will need to be removed from the
ailerons, flaps, and wing panels. Measure
and mark 1/8 inch on each side of the hingeline
top and bottom. I drew a line with a
straightedge and then applied tape as a cut
guide.
Once completed and all measurements
confirmed, I used my band saw to cut the
ailerons and flaps loose. I finished the
process by doing the other wing panel.
I used 1/4 sheet balsa for the cap and cut
the taper to minimize sanding. I taped the
caps in place and marked the rib locations.
Since I am going to notch the LE and
TE, a centerline needs to be drawn on the
top of the caps. That represents the center of
110 MODEL AVIATION
11sig4.QXD 9/21/07 10:04 AM Page 110
Aileron radial drive system with Futaba 3154 micro digital for
drive. Note capped LE of flap and aileron and TE of wing. Each is
notched 1/8 inch.
The flap RDS with Futaba 3150 digital servo. The flaps are large
and extraordinarily effective.
the notch. I used my band saw to cut the
notches and fine-tuned each notch with a
flat, thin file. A Dremel can be used, with a
file used for cleanup.
I test-fit each piece and used a
straightedge to true the cap. When I was
satisfied I glued the caps in place and sanded
them to match the ribs. I installed corner
gussets at each corner of the cap, tip, and
root.
The flaps will be hinged on the bottom and
the ailerons on the top. I sanded a slight bevel
into the flap cap to allow approximately 1/8
inch of up flap travel. A bevel was sanded
into the bottom of each aileron. You can
determine how much to sand, but you need
only what you think your max downward
deflection might be. After the servo
locations were established I Dremeled
holes into the ribs for the servo wires (near
the spar).
I used a full radial drive system (RDS)
for actuating both the ailerons and the
flaps. This presented considerable extra
work, but the results were a completely
“clean” wing surface.
If I did this again I’d do the RDS on the
ailerons and not the flaps. Considerable
tinkering is necessary with the flaps to get
full down deflection. You can find details
about the RDS on Harley Michaelis’s Web
site. Look at File 06.
I used the Futaba 3154 micro digital
servo for the ailerons. The RDS provides a
slop-free linkage and the 3154 has 23
ounces of torque on 6 volts, so I believed
this would be more than sufficient. On flaps
I used the Futaba 3150 servo. It is thin and
fits nicely in virtually any wing.
Before joining the wing panels I
determined the bolt-hole locations and
Dremeled a “half round” into each panel.
This was necessary because the root ribs
were carbon capped and would have been
difficult to drill without a guide hole. Once
joined, I drilled the true 1/4-inch hole,
applied cyanoacrylate glue, and drilled the
hole again.
The wing rod at the center was a stock
aluminum 1/2-inch joiner rod I obtained from
Don Richmond at Hilaunch.com. Since the
wing panels are the outer panels of a larger
model, there are only a few inches on each
side of center to insert the rod. I cut the rod
to the proper length and fit it to the wings.
The dihedral was perfect.
I also built a 1/4-inch carbon-rod
alignment pin forward of the TE. Once all
the servo detail was completed, the wings
were joined.
I used epoxy and micro filler for the job
and thoroughly coated the main wing rod.
But first I scuffed it with 80-grit sandpaper
and cleaned it. The center was covered with
2-ounce fiberglass cloth that was 2 inches
wide. The cloth aft of the spar was trimmed
to the ribs after curing.
The main structure was complete. I
attached the wing to the fuselage with 1/4-20
nylon bolts. The rudder and elevator were
made operational and the CG was checked. I
used an initial CG of 35% of the chord. I
knew that would be safe.
I wasn’t sure what to do about towhook
location on a new model with no history.
Jerry said he uses a removable towhook
until he has established the CG. This
involves making a molded fixture that is
taped to the fuselage.
He tapes waxed paper to the bottom of
the fuselage in the range where the CG will
be located. Two layers of 4- to 6-ounce cloth
are epoxied in place.
After that cures Jerry epoxies a towhook
in place and secures it with a buildup of
epoxy and micro filler. He forms the fill
with a finger and alcohol before it cures.
When it has cured he adds a couple more
layers of cloth over the entire structure.
Then he trims it and sands it to final form.
Initial test tosses showed the CG to be too
far forward. I removed nose weight until the
hand tosses felt comfortable.
I taped on the towhook fixture with
fiberglass-stranded tape, approximately 1/8
inch in front of the CG. My small-length histart
is perfect for 150-foot launches, which
is ideal for initial flights.
I launched the sailplane and the
trajectory was nearly ideal. The CG was still
forward and more weight was removed. I
moved the towhook back slightly.
The next launch was perfect. I felt a
bump on the way up, and the model
immediately caught a thermal for a 10-
minute ride. During the flight I was able to
determine what settings I needed to modify.
After a couple more launches the
flap/elevator landing compensation was set.
What a great-flying airplane!
Next month I’ll wrap it up with a full flying
report and some contest reports. MA
Sources:
Harley Michaelis
http://genie.rchomepage.com
Hilaunch.com
(858) 539-6029
www.hilaunch.com
Kennedy Composites
(972) 602-3144
www.kennedycomposites.com
Radio Control Soaring Exchange
www.eclipse.net/~mikel/rcse/rcse.htm
Edition: Model Aviation - 2007/11
Page Numbers: 110,112,114
[[email protected]]
Radio Control Soaring Darwin Barrie
The project hybrid 2-meter model gets some wings
A frontal view of the author’s hybrid 2-meter model. The lower-aspect-ratio wing
provides more wing area than many conventional 2-meter sailplanes have.
The winglets also add wing area. The tail surfaces are small but very effective.
I PROMISED TO have a full flight report
on the hybrid 2-meter I’ve been building for
the past few months. Unfortunately, because
of a death in the family and other obstacles
in life, I didn’t get to explore the full flight
envelope. I promise to have the complete
flight report in the next column. That is the
bad news.
The good news is that I’ve been able to
launch the sailplane on a small hi-start and
can provide a preliminary flight report. But
first we have to finish the model.
The wings were the remaining piece of the
puzzle. As I have noted, Jerry Robertson
and I collaborated on this project.
His idea was to use the outer panels of
the AVA Rudder-Elevator-Spoiler (RES)
sailplane as the starting point. From there
the panels would eventually be joined in the
center, the outer ribs would be removed to
get to the 2 meters, the ailerons and flaps
would be constructed, and winglets would
be added.
Jerry used the AVA panels while I used
panels from the Buzzard. In comparing the
two, the only real difference was how the
panels were joined to the center panel of the
RES model. The AVA used a square-type
joiner and the Buzzard used a round rod.
They look like they came from the same
factory.
The AVA panels are available new from
Barry Kennedy at Kennedy Composites. I
posted a note on the Radio Control Soaring
Exchange (RCSE) indicating that I was
searching for used panels from the AVA or
a similar sailplane. It doesn’t matter if the
panels are the same color or even damaged
as long as you get a right and a left from the
same design.
The process begins with cutting the
panels to the proper size. I sawed off five
rib bays from the tip, which provided ample
room to build the optional winglets.
Conventional tips can certainly be added to
get the full 2-meter span.
Next is the tedious task of removing the
covering. The process is made easier by
using a heat gun, an X-Acto knife, and time.
No matter how hard you try, there will
be some pieces adhered to the ribs or other
structure. Since the ribs are carbon capped
and the TE is carbon, light sanding can
remove stubborn covering. Heat can also be
applied and the X-Acto knife can be used.
With the covering removed it is time to
lay out the flaps and ailerons. Jerry and I
decided to use flaps and ailerons with a
chord of 25% of the overall chord. This was
marked at the root and the tip and a line was
drawn.
Because this was a first-time project, we
were concerned about the rigidity and
torsional ability of the flaps and ailerons if
we used just a capped LE. We decided that
aluminum tube would be built into the LE of
the structure of the flaps and ailerons. This
was completed and a rigid structure was
produced.
In review I don’t believe the added work
of the aluminum tube is necessary. The
same rigidity can be achieved by using
fairly hard stock balsa. For your purposes
use a capped LE of the flap and aileron
without aluminum tubing. The TE of the
wing panels is capped with hard balsa.
We’ve already drawn a line that
established the chord (in essence, the hinge
line). The LE and TE will be capped with 1/4
hard balsa. The LE and TE caps will be
notched 1/8 inch to increase the integrity of
the bond.
To keep the proper chord, 1/8 inch of
each rib will need to be removed from the
ailerons, flaps, and wing panels. Measure
and mark 1/8 inch on each side of the hingeline
top and bottom. I drew a line with a
straightedge and then applied tape as a cut
guide.
Once completed and all measurements
confirmed, I used my band saw to cut the
ailerons and flaps loose. I finished the
process by doing the other wing panel.
I used 1/4 sheet balsa for the cap and cut
the taper to minimize sanding. I taped the
caps in place and marked the rib locations.
Since I am going to notch the LE and
TE, a centerline needs to be drawn on the
top of the caps. That represents the center of
110 MODEL AVIATION
11sig4.QXD 9/21/07 10:04 AM Page 110
Aileron radial drive system with Futaba 3154 micro digital for
drive. Note capped LE of flap and aileron and TE of wing. Each is
notched 1/8 inch.
The flap RDS with Futaba 3150 digital servo. The flaps are large
and extraordinarily effective.
the notch. I used my band saw to cut the
notches and fine-tuned each notch with a
flat, thin file. A Dremel can be used, with a
file used for cleanup.
I test-fit each piece and used a
straightedge to true the cap. When I was
satisfied I glued the caps in place and sanded
them to match the ribs. I installed corner
gussets at each corner of the cap, tip, and
root.
The flaps will be hinged on the bottom and
the ailerons on the top. I sanded a slight bevel
into the flap cap to allow approximately 1/8
inch of up flap travel. A bevel was sanded
into the bottom of each aileron. You can
determine how much to sand, but you need
only what you think your max downward
deflection might be. After the servo
locations were established I Dremeled
holes into the ribs for the servo wires (near
the spar).
I used a full radial drive system (RDS)
for actuating both the ailerons and the
flaps. This presented considerable extra
work, but the results were a completely
“clean” wing surface.
If I did this again I’d do the RDS on the
ailerons and not the flaps. Considerable
tinkering is necessary with the flaps to get
full down deflection. You can find details
about the RDS on Harley Michaelis’s Web
site. Look at File 06.
I used the Futaba 3154 micro digital
servo for the ailerons. The RDS provides a
slop-free linkage and the 3154 has 23
ounces of torque on 6 volts, so I believed
this would be more than sufficient. On flaps
I used the Futaba 3150 servo. It is thin and
fits nicely in virtually any wing.
Before joining the wing panels I
determined the bolt-hole locations and
Dremeled a “half round” into each panel.
This was necessary because the root ribs
were carbon capped and would have been
difficult to drill without a guide hole. Once
joined, I drilled the true 1/4-inch hole,
applied cyanoacrylate glue, and drilled the
hole again.
The wing rod at the center was a stock
aluminum 1/2-inch joiner rod I obtained from
Don Richmond at Hilaunch.com. Since the
wing panels are the outer panels of a larger
model, there are only a few inches on each
side of center to insert the rod. I cut the rod
to the proper length and fit it to the wings.
The dihedral was perfect.
I also built a 1/4-inch carbon-rod
alignment pin forward of the TE. Once all
the servo detail was completed, the wings
were joined.
I used epoxy and micro filler for the job
and thoroughly coated the main wing rod.
But first I scuffed it with 80-grit sandpaper
and cleaned it. The center was covered with
2-ounce fiberglass cloth that was 2 inches
wide. The cloth aft of the spar was trimmed
to the ribs after curing.
The main structure was complete. I
attached the wing to the fuselage with 1/4-20
nylon bolts. The rudder and elevator were
made operational and the CG was checked. I
used an initial CG of 35% of the chord. I
knew that would be safe.
I wasn’t sure what to do about towhook
location on a new model with no history.
Jerry said he uses a removable towhook
until he has established the CG. This
involves making a molded fixture that is
taped to the fuselage.
He tapes waxed paper to the bottom of
the fuselage in the range where the CG will
be located. Two layers of 4- to 6-ounce cloth
are epoxied in place.
After that cures Jerry epoxies a towhook
in place and secures it with a buildup of
epoxy and micro filler. He forms the fill
with a finger and alcohol before it cures.
When it has cured he adds a couple more
layers of cloth over the entire structure.
Then he trims it and sands it to final form.
Initial test tosses showed the CG to be too
far forward. I removed nose weight until the
hand tosses felt comfortable.
I taped on the towhook fixture with
fiberglass-stranded tape, approximately 1/8
inch in front of the CG. My small-length histart
is perfect for 150-foot launches, which
is ideal for initial flights.
I launched the sailplane and the
trajectory was nearly ideal. The CG was still
forward and more weight was removed. I
moved the towhook back slightly.
The next launch was perfect. I felt a
bump on the way up, and the model
immediately caught a thermal for a 10-
minute ride. During the flight I was able to
determine what settings I needed to modify.
After a couple more launches the
flap/elevator landing compensation was set.
What a great-flying airplane!
Next month I’ll wrap it up with a full flying
report and some contest reports. MA
Sources:
Harley Michaelis
http://genie.rchomepage.com
Hilaunch.com
(858) 539-6029
www.hilaunch.com
Kennedy Composites
(972) 602-3144
www.kennedycomposites.com
Radio Control Soaring Exchange
www.eclipse.net/~mikel/rcse/rcse.htm
