CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
Edition: Model Aviation - 2007/12
Page Numbers: 36,37,38,39,40,41,42
CONTRARY TO popular belief, the Ares family of CL Aerobatics
models (Stunters) was not my first attempt at designing and building
original airplanes by a long shot. There were several notable models,
at least on the Midwest, local, and regional level, I designed that
might have become more famous if I had used them when I started
flying on a national level. Among those early designs were the
Lancer, Thor, Polaris, Comet, and Vulcan.
When I was a teenager I had lots of building time, and I used it to
produce as many as four new Stunt designs per year. Some of those
models were never named, but I learned a great deal, which (usually)
made each one better. Much of that development was educated trial
and error; I basically knew what I wanted and tried to make logical
choices and progressions toward an ever better-performing model.
Sometimes I built two or three versions of a particular design and
used a different type of wing construction in each. In that era
(approximately 1955-1958) I started using the light and mysterious
I-Beam type of wing construction.
I also tried D-Tube-, C-Tube-, and double-I-Beam-type wings in
the same basic design to see what effect they would have on
performance and weight. The subject of this article was originally
built in both C-Tube and I-Beam versions.
In 1984 I decided to build a totally accurate replica of one of my
“Classic” is the word for the shape of the Vulcan’s nose. Notice
the beautifully shaped cowl!
old .35-size Vulcans just to see how far we had really come in
airframe and engine development. I guess you could call it a sort of
benchmark check and nothing more; this model was not built with
the thought of ever using it in competition. In fact, the Classic
event did not exist, to my knowledge, and the Vintage Stunt
Championships (VSC) was not even a gleam in Mike Keville’s
eye.
I chose the Vulcan as the benchmark for several reasons, among
which was that I liked the overall appearance and the paint job that
was originally used. I “borrowed” the latter from one of Ray
Marlo’s models. To be truthful I also “borrowed” the Vulcan name
from Ray, but it was not the same design in any other respect.
The Design: The most significant difference about the Vulcan,
compared with most designs of the era, was the high amount of
forward sweep in the TE. This was done with two thoughts in
mind, one of which was that I wanted to keep the center of
pressure (CP) from moving aft on the wing when the flaps were
deployed.
With the forward-swept hinge line, the average flap position
Bill crisply pulls the Vulcan up into a Wingover maneuver on the way to another VSC victory. Will Hubin photo.
Notice the design’s gracefully rounded
wingtips and the swept-forward wing TE.
Bill tried several engines in the Vulcan, and he settled on the popular, powerful Aero
Tiger .36. Notice the “tongue” muffler and the lightweight Hobby Lobby plastic spinner.
Photos by Bob Hunt
The Vulcan sports a fantastic finish. Bill used modeling dope for the base coats.
Automotive polyurethane clear was applied over the top and rubbed out.
The Vulcan’s trim scheme seems to flow onto its fuselage. Streamlined wheel pants add
loads of character and reduce drag. This model has a balanced look.
Clockwise from bottom left: Phil Granderson, Glen Kaler, Bob Hazle,
Bill Werwage with their Vulcans at the VSC.
was ahead of the point where it would be
on a straight-hinge-line model. Therefore,
when deployed the flaps would not move
the CP as far aft. That had the effect of
not overstabilizing the model by moving
the CP too far back from the CG. The
model would not become as nose-heavy
with the flaps deployed.
One of this arrangement’s major
benefits is that the stick pressure felt in
the handle, especially in high-wind
conditions, is dramatically reduced. When
the flaps are moved up or down the airfoil
is changed to an undercamber type, which
increases the wing’s lift. It also changes
the point of the center of the lift, which is
also known as the CP.
When the flaps are deployed on a
straight-TE model, the CP moves a much
greater distance and overstabilization
occurs. The result is high stick pressure
and a model that requires more input to
achieve directional change. In calm
conditions this is almost unperceivable,
but in heavy wind it can be dramatic.
Another benefit of the forward sweep
in the TE hinge line is the effectively
longer tail moment. The moment is
measured from the average of the flap’s
position in relation to the
stabilizer/elevator hinge line.
The Vulcan was designed with largerthan-
average flaps, and that, combined
with the highly swept TE, would allow
me to use a thin-tip airfoil section. In
effect I was getting a model that had
plenty of lift, would be easy to turn in the
wind, and had less drag because of the
reduction in frontal area (average airfoil
thickness).
In those days we had limited power to
work with, and we had to optimize the
model to best utilize the power we did
have. The combination I have described
was a successful attempt at this.
Type: Classic CL Stunt
Wingspan: 50.25 inches
Wing area: 500 square inches
Length: 38.25 inches
Weight: 36 ounces
Engine: Aero Tiger .36
Construction: Balsa and plywood
Covering/finish: Silkspan and modeling dope
Bill prefers to use the Lost Foam method to construct his models’
wings. The TE, spars, and LE shims are shown pinned in the
building cradle.
The LEs are molded around a foam form and are then fitted to
the individual wing panels.
The ribs have been positioned and pinned in place. The top spar
and top TE edge pieces go in next.
The LE shells are joined to the wing panels and are held in place
accurately in the Lost Foam building cradle.
The Vulcan turned easily in the wind,
and the wing’s frontal area allowed the
available power to pull the model
effectively. All this proved to be a valid
concept that is still highly regarded today.
The original Vulcan was powered by a
Fox .35 engine swinging a 10 x 5 Y&O
wood propeller. I flew it on 60 feet of .015
cable. Surprisingly the C-Tube and IBeam
versions of the Vulcan flew
virtually alike. In either form it was a nice
combination, and that may also have had
something to do with my choosing to build
it as the benchmark check so many years
later.
The replica Vulcan did not disappoint
initially. I set it up as close to the original
as possible, including installing a Fox .35
from that time frame that I knew ran well.
I also used a vintage Y&O 10 x 5
propeller I had in my collection.
I flew the model on .015 lines, and
within a short amount of time I had it
performing great. I was really happy with
it! Then reality struck in the form of wind.
The power that was accepted as good
in the 1950s didn’t stand up to the power
to which I had become accustomed. As I
mentioned in the Ares article (in the July
2002 MA), these are the good, old days
when it comes to powerful model-airplane
engines. I felt like I was flying terrific
patterns, by any standard, with the Vulcan
in calm conditions, but performance
suffered when the wind came up to an
appreciable degree.
I decided to see what effect more power
would have on this excellent airframe. I
tried a Webra .28 with the same Y&O
propeller. I increased the rpm and went to
slightly longer .012 solid lines. This was an
improvement, but I still felt that I could get
more performance.
The next engine I tried was a drastic
improvement. I installed one of my
lightened SuperTigre. 46s and used an 11 x
5 Rev-Up propeller. Because of the linesize
rules I had to go to .014 solid lines. I
also increased the line length to 63 feet.
The airplane flew wonderfully with this
combination, but the model’s small size
did not allow proper vibration dampening
for the “hard-hitting” .46. I didn’t want to
age the airframe prematurely because of
the vibration, so I made yet another engine
change.
I tried the well-balanced O.S. .32,
which proved to be quite good, but, again,
I felt that more power was needed; the .46
had spoiled me! At this point I called
Randy Smith, of Aero Products, to see if
he could suggest an alternate path. Enter
the other Tiger ...
Randy suggested something that had
completely escaped me; Thunder Tiger had
introduced a new aluminum brass chrome
(ABC) .36 engine that seemed to have
considerable promise. It ran great in stock
form and was used in Stunt competition by
several Advanced fliers and a many-time
Junior National Champion, Dondy
Garrison, in his Randy Smith-designed
Vector 40.
The only problem with all these new
engines was weight. The ABC sleeve/
piston combination, dual-ball-bearing
configuration, larger diameter and heavier
crankshafts, and overall robust
construction added approximately 2.0-2.5
ounces compared with the original Fox’s 6-
ounce weight.
There’s more. Compounding that
problem is the fact that we now have to fly
two laps between maneuvers; only one was
required and flown in the 1950s and early
1960s. That means a larger, heavier fuel
load needs to be carried nowadays.
There were no muffler requirements in
the old days and none were used. Even
today’s lightest mufflers weigh something.
In addition, modern carbon-fiber
propellers—although more efficient—are
certainly heavier than the light wooden
propellers that were used then.
The result of all this is that the old
designs are not ideally suited to modern
power setups from strictly a balance
perspective. Some of this can be overcome
by using lightweight plastic tanks and by
moving them as far aft in the tank
compartment as possible. I use a
lightweight .007-.008 tin stock tank in my
Vulcan.
Another help is the availability of
lightweight plastic or composite spinners.
Extension shafts can be used in extreme
cases. These spinners must be properly
machined and balanced; they can do more
damage than good if they induce vibration.
Randy suggested that the Thunder Tiger
.36’s weight could be reduced significantly
by producing a custom-made aluminumaluminum
chrome (AAC) piston and liner.
That’s exactly what he did.
He also retimed the new, lighter sleeves
to our specifications for a good Stunt run.
The AAC-equipped “Aero Tiger” was
close to 0.7 ounce lighter than the stock
ABC version! And it ran great.
All the new ABC/AAC, Schnuerle
engines run and produce their power at a
higher rpm than the loop-scavenged
engines of the past; therefore, they require
far less pitch. Many of these setups are
running with propellers ranging in pitch
between 3.6 and 4.0, whereas the old
setups required 5.0-6.0 inches of pitch.
Lower-pitch propellers allow the
airplane to turn easier than the higher-pitch
varieties, and because of that these setups’
extra nose weight can be overcome. They
don’t feel nose-heavy—particularly in
wind!
During the development and
experimentation with engines in the Vulcan
that I have related, the Classic Stunt event
became popular and the VSC was
conceived. Even though the Vulcan was
not built to compete in these events, it was
a natural for them. Classic seemed like fun,
and I started flying it with the Vulcan.
I attended my first VSC with the
Vulcan in 1994, at which point it still had
the SuperTigre .46 for power. Things went
well and I had my first win with the Vulcan
design in 38 years.
Since that time I’ve flown it, the 1959
Ares, and the 1962 Ares at the VSC and
have been fortunate to win eight times. The
Vulcan captured four of those victories,
and the last three were with the Aero Tiger
.36 for power. The model also won the
Classic event in its only appearance at the
Nats, in 1996.
(Editor’s note: Bill has added a couple
more VSC wins since this article was
written!)
CONSTRUCTION
Building the Vulcan is not much
different from building any Stunt model of
that era. It is a smallish design, spanning
50 inches with 491.24 square inches of
wing area, so, as always, weight is a
consideration when building.
Use appropriate light materials with an
eye toward structural integrity. Think about
the part you are making and what its duty
is, and select materials accordingly.
The lightest piece of wood is not always
the right piece; it depends on its intended
use. Wing spars should be made from firm
material, but fuselage top and bottom
blocks can be made from the softest blocks
you can find.
The C-Tube version of the Vulcan is
presented here; it is the variation I built as
a replica in 1984. There are a number of
ways to build a C-Tube wing, but the
easiest and most accurate method is the
Lost Foam wing-building system; it keys in
on the outside shape of the wing.
The Lost Foam method also allows the
LEs to be accurately molded and installed.
This is a distinct advantage because it
guarantees a perfectly shaped LE radius—
something we have found to be extremely
important.
Lost Foam wing systems and LE mold
bucks for the Vulcan are available from
Robin’s View Productions. The company
also sells a set of comprehensive videos
that shows and explains, in detail, how to
build a wing using the Lost Foam system. I
highly recommend viewing them before
you begin construction.
One thing I’m often questioned about is
the use of a normal, straight control horn
on forward-swept hinge lines. The
geometry would seem to suggest that the
flaps would bind as they are deflected and
“spring” back to neutral. The degree of this
is negligible to the point of being a
nonissue if you adhere to the following
rules.
A flat must be sanded on the rear face
of the TEs that is exactly 90° to the wing
centerline as viewed from above. The
length of the arms of the horn from the
upright at the center must be the same.
The horn’s pivot point must be centered
and in line with the flap’s hinge center. I
also keep the flap-horn length as short as
possible. I have never had a problem with
binding using this method.
On the subject of flaps, I used the 3/16-
inch-thick ones shown on the plans when I
could find optimum firm, light “C”-grain
wood. Unless you have this perfect wood
stock for the flaps, I recommend that you
use light 1/4-inch stock.
I like to use cloth hinges on these
Classic-type models because they provide a
light way to achieve an almost perfectly
sealed hinge line. If you use pinned hinges
you will probably have to seal the hinge
line with tape, unless the gap is kept to a
minimum.
The plans presented with this article are
extraordinarily detailed. I thank Warren
Tiahrt for producing a great set of pencil
drawings from my original etchings and
Bob Sweitzer for doing such an
outstanding job of tracing and inking the
drawings.
There is an abundance of building notes
on the plans, and anyone who has built this
type of model should have no problem
reproducing it after studying them.
Finish: I covered the Vulcan with Japanese
tissue and applied the base and color coats
using modeling dope. I like to mix my own
colors by purchasing the color toners used
to mix auto paint.
I mix the toners in clear dope in a 1/3
toner-2/3 clear ratio. Then I thin the mixture
and spray it on the model. Auto toners
allow a wide range of color choices to be
used, and they generally cover better than
modeling dopes.
The Vulcan’s final topcoat is catalyzed
polyurethane clear. I have forgotten which
one I used, but there are so many new and
improved versions on the market that you
probably wouldn’t be able to find the exact
clear now anyway.
I do not advise using this type of clear
topcoat unless you have a modern spray
booth with an effective exhaust fan and at
least a good charcoal respirator. Catalyzed
polyurethane clears are extremely toxic and
should be handled with extreme care.
A good alternative is to use a quality
brand of clear modeling dope for the
topcoat. Even with that option you should
use an exhaust fan and a respirator!
Some of my friends have built several
Vulcans, and all of them appear to fly
wonderfully. Bob Hazle and Bill Little
have built I-Beam variants. Phil
Granderson, Glen Kaler, and Frank
MacMillan have campaigned C-Tube-wing
versions at the VSC.
Built light and straight and powered
properly, the Vulcan will reward you with
many happy flights and maybe more than a
few trophies. MA
Bill Werwage
Sources:
Aero Products
(678) 407-9376
www.aeroproduct.net
Robin’s View Productions
(610) 746-0106
E-mail: [email protected]
