1922 Stahlwerk Mark III - 2008/01

January 2008 31
ALTHOUGH IT’S virtually unknown in
the US, other than by historical-aviation
enthusiasts, the Stahlwerk Mark III was a
popular and successful sport aviation design
in Europe during the 1920s and 1930s.
Walter Rieseler designed the airplane in
1922, and it is sometimes referred to as the
Rieseler R III.
Rieseler, a gifted German airplane
pioneer and designer, has been all but
forgotten in aviation history in spite of his
numerous accomplishments. The Stahlwerk
Mark III was one of his earliest aircraft. He
became better known for his innovative
autogiros and was credited in 1935 with
designing and producing the world’s first
helicopter that featured twin counterrotating
blades.
In 1920 Rieseler, in partnership with his
brother, formed a small aircraft
manufacturing company in Breslau,
Germany, called Stahlwerk. The Mark III,
which was preceded by the Mark II and
Mark I, was offered for sale in 1922, and it
rapidly became popular among the sportaviation
community in Germany.
The Mark III was a small, single-place
design with a fuselage length of 17 feet
and a wingspan of 25 feet. It was
powered with several different air-cooled
engines, the most popular of which were
the Haacke HFM two-cylinder flat
opposed type that produced 26
horsepower and the Anzani three-cylinder
Fly the Stahlwerk indoors or out. The outrunner motor system is quiet and provides
enough power for a five-minute flight on a two-cell Li-Poly battery pack.
1922 Stahlwerk Mark III
BY BOB WALLACE
A semiscale
park flyer of
the golden-age
German sport
aircraft
radial that produced 30 horsepower.
The airplane’s maximum speed near sea
level was 66 mph, and it had a 62 mph
cruise speed. With its low wing loading the
Mark III had great short-field takeoff-andlanding
capabilities. It could be airborne in
slightly more than 100 feet, and it could be
put back on the ground in an even shorter
distance since its landing speed was just less
than 30 mph. Its large-diameter landing-gear
wheels were well suited to grass fields.
In 1923 a publicity seeker named
Antonius Raab made one of the Mark III’s
most publicized flights. He landed his
01sig1.QXD 11/19/07 1:14 PM Page 31
32 MODEL AVIATION
The constant-chord wing uses the same rib shape at each station. The flat-bottom
airfoil can be built on a flat surface with no fixturing required. Notice how the top
spars meet the wingtip.
It’s easier to install the rudder and elevator servos and control rods before the model
is covered. A 6-gram submicroservo with roughly 10 inch-ounce of torque is all that is
required.
Before sheeting the top of the fuselage, temporarily glue an incidence template in place
to build the wing support. Round all balsa parts before assembling the structure.
aircraft on the Unter den Linden, which is a
main thoroughfare in Berlin, Germany. The
police promptly arrested him.
At least one Mark III still exists. It is on
display at the Arlanda Aerospace Museum
in Stockholm, Sweden.
I selected the Stahlwerk Mark III as an
RC modeling project because it’s unique.
More importantly, it produced dimensions
and a planform that I hoped would result in
a model that would be easy to build and fly
and offer good flight characteristics.
Perhaps RC modelers who have never
built a stick-and-tissue-type model will find
this construction project to be one of interest
and give it a try. It uses simple, proven
building methods that require no unique
tools or building skills. Older modelers who
grew up eagerly constructing Comet and
Megow kits and chewing Lepage’s or
Ambroid glue off their fingers may find the
Mark III to be a trip down memory lane.
The intent in designing this model was to
keep it simple using inexpensive and readily
available construction materials most hobby
shops should have in stock. My Stahlwerk
Mark III is powered by a Baby Bullet
Double Cool Wind brushless outrunner
motor from CustomCDR.
CONSTRUCTION
As with any plans- or scratch-building
project, it helps to fabricate all the shaped or
formed parts before starting the assembly
Info
box
1922
Stahlwerk Mark III
Static shots by the author; flight shots by Lloyd Burnham
Type: Small vintage sport scale
Wingspan: 24 inches
Flying weight: 116 grams (4.1 ounces)
Wing area: 105 square inches
Length: 16.5 inches
Motor: Small microsize brushless
outrunner
Propeller: GWS 6 x 3
Battery: Two-cell, 300 mAh Li-Poly
Construction: Balsa and plywood
Covering/finish: Polyester tissue
(Litespan)
01sig1.QXD 11/19/07 1:18 PM Page 32
January 2008 33
The landing gear is stitched to the airframe with button thread.
The axle is attached with fine copper wrapping wire and solder.
The CustomCDR Baby Bullet (Cool Wind) brushless motor weighs
just 16 grams and has a thrust output of approximately 12 ounces.
The number of shaped or formed parts required to construct a
Stahlwerk Mark III is minimal.
Cutting the 11 balsa wing ribs is easy and
rapid if you first make a rib master
template from plywood, aluminum, or
plastic.
The landing-gear structure is fabricated from two pieces of .047
(3/64 inch) music wire. Guillow’s 2-inch lightweight plastic wheels
are used.
process. That way the model’s construction
seems to go more smoothly and
uninterrupted.
I did not prepare a list of required
materials because most modelers who possess
at least some building experience will have
most, if not all, of the various-size wood
pieces in their spare-wood supply box. Some
of the sizes indicated do not require a full
sheet, and the hardware needed is minimal.
Some modelers with built-up model
construction experience know that using a
balsa stripper greatly simplifies the
material-acquisition process. With this tool
all the stick stock can be cut easily from
sheet stock to any custom width needed. I
used a Jones balsa stripper, which is
considered to be the Rolls-Royce of balsa
strippers, but an inexpensive version such
as Master Airscrew’s will work fine.
01sig2.QXD 11/19/07 2:03 PM Page 33
34 MODEL AVIATION
Although it is optional, you can give your model a more
scalelike appearance by adding 1/16 x 3/16 balsa to the landinggear
assembly legs.
The author made the decals on his Stahlwerk using a homecomputer
ink-jet printer and water-transfer decal sheets.
The tail surfaces are constructed from balsa stick and sheet stock. The curved perimeter pieces are made from laminated 1/32 balsa sheet.
Scale Documentation Sources
• www.histaviation.com/Mark_R_III_colour_profile.jpg
• http://aircraftwalkaround.hobbyvista.com/rieseler/rieseler.htm
• www.histaviation.com/Stahlwerk_Mark_III.html MA
—Bob Wallace
The number of shaped or formed parts required to construct a
Stahlwerk Mark III is minimal. Since the wing is a constantchord
type, cutting the 11 balsa wing ribs is easy and fast if you
make a master template from a scrap piece of 1/32 plywood, thin
sheet aluminum, or plastic.
The motor-mount former is cut from 1/8 light plywood. Its
height and width may vary a bit depending on what type of motor
you use and where that former will be positioned within the nose
portion of the fuselage.
The only other shaped parts that need to be cut are the 1/16
plywood tail skid, two 1/16 plywood landing-gear mounting
crossbraces, three 3/32 sheet top fuselage formers, and the 1/16
plywood wing-spar brace.
The main components are constructed directly over the plans
sheet placed on a flat building surface. Fledgling builders are
reminded to place a sheet of clear vinyl plastic (backing from
many heat-shrinkable film-type covering materials works well for
this) or good, old kitchen-variety waxed paper over the plans
sheet to permit easy separation of the assembled part from the
sheet.
Wing: To construct each wing panel, pin the 1/8 x 1/4 main spar in
place along with the 1/8 x 3/8 TE. Use the wing ribs to achieve the
proper lateral spacing. Pin all the wing ribs in place. Be sure to
cant the 1/8 center-section rib using the wing-dihedral-angle
template as a guide. Glue these pieces together with thin
cyanoacrylate adhesive, and then pin and glue the 1/8 x 1/4 LE and
01sig2.QXD 11/19/07 2:35 PM Page 34
Any lightweight film-type covering, such as silkspan, or tissue-type materials can be used.
A Williams Brothers 1/12th scale racing pilot bust was cut down to fit and painted.
Three Williams Brothers plastic Gnome engine cylinders (item 206) were trimmed
and mounted to resemble the Anzani engine used on most Stahlwerk Mark III aircraft
that were produced.
Using Litespan
requires that a heatsensitive
adhesive
be applied to the
various components
before covering.
two 3/32 square top spars in place.
Pin and glue the 1/8 x 1/4 wingtip pieces
in place. The two 3/32 square top spars are
cut at the outer W2 rib and angled
downward to the 1/8 x 1/4 tip; see Section BB
on the plans sheet.
Glue the gussets and 1/16 x 1/8 wing-strut
attachment pieces in place. It is easier to
install the center-section cockpit-recess 1/16
sheet trim pieces after the two wing panels
have been joined.
After both wing panels have been
fabricated, lightly block-sand the faces of
the canted center-section W1 ribs and trialfit
them to ensure that the indicated dihedral
angle (3/4 inch under each tip) is produced.
Glue the two wing panels together, and then
install the 1/16 plywood DB1 brace.
Install the 1/16 sheet cockpit-recess pieces
in the aft center-section recess. The
completed wing assembly can be sanded
and contoured to the indicated airfoil and
planform.
Tail: The tail surfaces are constructed from
balsa stick and sheet stock. The curved
perimeter pieces are made from laminated
1/32 balsa sheet.
Three pieces of 1/32 balsa sheet are glued
together, with the center piece positioned
cross-grain to provide additional strength,
and then the curved perimeter tail-surface
pieces are cut from this laminated balsa
sheet stock.
Fuselage: The basic fuselage is a box-type
structure that is composed primarily of 1/8
square balsa to make its open framework.
The two fuselage sides are constructed
directly over the plans sheet side view, and
then the various 1/8 square crossbraces are
installed using the plans sheet top view as a
guide.
As I mentioned, the size and position of
the 1/8 light-plywood motor bulkhead may
vary depending on what type of motor,
propeller mounting adapter, and motor
mount you choose. I also mentioned that I
used a Baby Bullet brushless motor, but a
January 2008 35
01sig2.QXD 11/19/07 2:36 PM Page 35
variety of other motors can be employed.
Mine weighs 16 grams and has a thrust output
of roughly 12 ounces using a 2S Li-Poly
battery source and 7-inch propeller.
After installing the motor-mount
bulkhead, 1/16 nose-sheeting inlays, and 1/8
scrap bulkhead gussets, fit and secure the
fuselage F1 and F2 top formers, 1/16 square
stringer, and 1/16 top sheeting.
To ensure that the wing-mounting pylon
structure is constructed at the proper
incidence angle and aligned correctly, use the
incidence template shown on the plans sheet
as a guide.
Using a piece of string or thread, along
with a couple pins or a flexible straightedge,
determine the fuselage centerline and lightly
mark it along the top sheeting between the F2
fuselage top formers. Pin the 1/8 sheet
incidence template onto the fuselage top
sheeting along the marked fuselage centerline
between the F2 formers.
Once the 1/8 x 1/4 wing-support portion of
the pylon is pinned in place on top of the
template, the 1/8 and 1/16 square pylon support
pieces can be cut, fitted (notching the top
sheeting as required), and glued in place.
Since the full-scale Stahlwerk’s pylon support
pieces were made from welded steel tubing, it
is easier to sand the 1/8 and 1/16 square pieces
round before cutting them and fitting them in
place.
36 MODEL AVIATION
Full-Size Plans Available—See Page 199
After you have glued the wing pylon
structure in place, remove and discard the
incidence template.
The landing-gear structure is fabricated
from two pieces of .047 (3/64 inch) music
wire. One piece is the 4-inch-long axle that
will ultimately be trimmed to accommodate
whatever type of wheel you choose. I used
Guillow’s 2-inch lightweight plastic wheels
on my Stahlwerk.
The main landing-gear structure is bent
to shape using the detail shown on the plans
sheet. Then the landing-gear structure is
mounted on the two 1/16 plywood
crossbraces using button thread and
cyanoacrylate adhesive.
A 1/16 cap piece of balsa is applied over
the laced-on landing-gear/plywood
crosspieces to provide a finished appearance
after being installed on the fuselage. The
axle is attached to the main landing gear
with fine copper wrapping wire and solder.
Although optional, you can attain a more
scalelike appearance by adding 1/16 x 3/16
balsa to the landing-gear-assembly legs. I did
this by cutting a small channel along the
balsa strips and then gluing them in place
with cyanoacrylate. After sanding a radius
on the legs, I painted the landing-gear
assembly with satin-finish black paint.
The fuselage bottom access hatch is
fabricated using the hatch detail shown on
the plans sheet, and it is held in place with a
small magnet. Glue the 1/4 sheet nose block
in place and sand the fuselage assembly to
the indicated contours.
Notch the fuselage to accept the 1/16
plywood tail skid, but do not permanently
install the tail skid until after you cover the
model. Also, it is easier to install the rudder
and elevator servos and control rods now
rather than after the model has been covered.
The wing struts are made from 3/32 x 3/16
balsa and have their edges rounded. The
wing, tail surfaces, and fuselage assembly
can be fine-sanded in preparation for
covering. Any minor surface imperfections
can be filled with lightweight filler.
Covering: Any lightweight film-type
covering, such as silkspan or tissue-type
materials, can be used to cover this model. I
used buff-colored Litespan, which is a
lightweight, heat-shrinkable polyester tissuetype
covering that closely resembles the
natural linen-type material used on many
aircraft during the 1920s, including the
Stahlwerk.
Using Litespan requires that a heatsensitive
adhesive be applied to the various
components before covering. I used Coverite
Balsarite. The adhesive is brushed onto the
various subassemblies wherever the
covering material needs to be heat-fastened.
Once the Balsarite has dried, the Litespan
can be applied in the same manner as any
other heat-shrinkable covering material. In
areas where covering material overlaps, the
joint needs to be coated with Balsarite.
The decals shown on my Stahlwerk were
made using a home-computer ink-jet printer
01sig2.QXD 11/19/07 2:04 PM Page 36
38 MODEL AVIATION
and water-transfer decal sheets. These decal
sheets are readily available at graphic-arts
supply outlets or from a variety of Internet
sources. The sheets I used were purchased on
eBay and cost roughly one dollar each.
I trimmed three Williams Brothers plastic
Gnome engine cylinders and mounted them
on my model to resemble the Anzani engine
that was used in most of the Stahlwerk Mark
IIIs. Although they are not true scale, the
World War I-era Gnome cylinders resemble
those on the Anzani; I do believe they
enhance the model’s overall scale
appearance.
To complete the power package I
equipped the Baby Bullet brushless motor
with a GWS 6 x 3 propeller (item
GW/EP6030), a Castle Creations
Thunderbird-9 ESC, and an Apache 7.4-volt,
300 mAh 20C Li-Poly battery pack. I used
an Airtronics RD6000 transmitter, and the
airborne radio system consisted of a Corona
RS410 single-conversion microreceiver and
two Blue Bird BMS-303 microservos.
I achieved the indicated CG on my model
by positioning the operating components as
shown on the plans sheet. My Stahlwerk,
ready to fly, weighed 116 grams (4.1
ounces).
Flying: A beautiful, mild spring day with
sunny skies and only a wisp of a breeze
proved to be ideal conditions for my
Stahlwerk’s test flights. Since our club flying
field is all grass, and the Stahlwerk is
equipped with relatively small-diameter
wheels, I decided to hand launch for the
maiden flight.
After a usual radio range check and final
inspection, it was flip-and-fly time. Standing
stationary with approximately two-thirds
throttle introduced, a light, straight-out toss
was all that was necessary for the Stahlwerk
to climb out nicely.
After gaining roughly 75 feet of altitude,
a few blips of right rudder and down-elevator
trim correction made the Stahlwerk fly hands
off. I spent the next several minutes flying
about, performing mild maneuvers at various
throttle settings to assess the model’s inflight
capabilities. It became apparent that a
bit more rudder and slightly less elevator
control-surface movement were needed.
The first landing was easy and
uneventful. With the motor throttled back to
approximately one-quarter power, I made a
shallow, gentle approach until the Stahlwerk
was a few feet above the grass surface. The
landing stall occurred predictably after
easing back the throttle to idle, which
resulted in a soft landing.
Since the Stahlwerk is a small,
lightweight aircraft with a low wing loading,
landing on grass could best be described as a
three-point plop rather than a conventional
landing. There is no rollout once the wheels
make contact with the grass!
After making the required controlsurface-
movement adjustments, I installed a
fresh battery pack and the Stahlwerk was
airborne again and flying quite nicely. It is
easy to fly and forgiving, with no bad in-
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01sig2.QXD 11/19/07 2:04 PM Page 38
flight characteristics. Its mild aerobatic
capability proved to be suitable for this type of
model. The well-built Baby Bullet proved to
be an ideal choice, with outstanding power.
Subsequent flights were in the 10- to 12-
minute range using an Apache two-cell, 300
mAh Li-Poly battery pack. The recommended
control-surface travel limits, in each direction,
are three-eights rudder and one-quarter
elevator. Those are suggested starting points,
and those who decide to build a Stahlwerk
may ultimately decide to alter them a bit to
suit their flying preferences.
Although I have not had the opportunity to
fly my Stahlwerk indoors, I am sure I will
when what is referred to as the “building
season” (winter) arrives in New England.
Since it is slow-flying, docile, and easy to fly,
it should be well suited for indoor flying.
The Stahlwerk is an easy-to-build sport-scale
model that is a bit different. It is well suited to
those who would like to try a traditional stickand-
tissue-type built-up model. Experienced
modelers who are looking for a project that
will renew pleasant memories of a time that
may well become known as the golden age of
model aviation should also find this to be a
worthy subject.
If I can be of help in answering any
questions relative to how I built my
Stahlwerk, I will be most willing to do so. My
address is 91 Sylvan St., Avon CT 06001. MA
Bob Wallace
[email protected]
Sources:
Baby Bullet Double Cool Wind motor:
CustomCDR
1215 Diamondback Dr. NE
Albuquerque NM 87113
www.customcdr.com
Castle Creations Thunderbird-9 ESC:
(913) 390-6939
www.castlecreations.com
Battery pack, servos, receiver, covering
material:
BP Hobbies
(732) 287-3933
www.bphobbies.com
Master Airscrew Balsa Stripper:
(916) 631-8385
www.masterairscrew.com
Jim Jones Design Balsa Stripper:
A2Z CNC
(877) 754-7465
www.a2zcnc.com/airplane.asp
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40 MODEL AVIATION
01sig2.QXD 11/19/07 2:04 PM Page 40

January 2008 31
ALTHOUGH IT’S virtually unknown in
the US, other than by historical-aviation
enthusiasts, the Stahlwerk Mark III was a
popular and successful sport aviation design
in Europe during the 1920s and 1930s.
Walter Rieseler designed the airplane in
1922, and it is sometimes referred to as the
Rieseler R III.
Rieseler, a gifted German airplane
pioneer and designer, has been all but
forgotten in aviation history in spite of his
numerous accomplishments. The Stahlwerk
Mark III was one of his earliest aircraft. He
became better known for his innovative
autogiros and was credited in 1935 with
designing and producing the world’s first
helicopter that featured twin counterrotating
blades.
In 1920 Rieseler, in partnership with his
brother, formed a small aircraft
manufacturing company in Breslau,
Germany, called Stahlwerk. The Mark III,
which was preceded by the Mark II and
Mark I, was offered for sale in 1922, and it
rapidly became popular among the sportaviation
community in Germany.
The Mark III was a small, single-place
design with a fuselage length of 17 feet
and a wingspan of 25 feet. It was
powered with several different air-cooled
engines, the most popular of which were
the Haacke HFM two-cylinder flat
opposed type that produced 26
horsepower and the Anzani three-cylinder
Fly the Stahlwerk indoors or out. The outrunner motor system is quiet and provides
enough power for a five-minute flight on a two-cell Li-Poly battery pack.
1922 Stahlwerk Mark III
BY BOB WALLACE
A semiscale
park flyer of
the golden-age
German sport
aircraft
radial that produced 30 horsepower.
The airplane’s maximum speed near sea
level was 66 mph, and it had a 62 mph
cruise speed. With its low wing loading the
Mark III had great short-field takeoff-andlanding
capabilities. It could be airborne in
slightly more than 100 feet, and it could be
put back on the ground in an even shorter
distance since its landing speed was just less
than 30 mph. Its large-diameter landing-gear
wheels were well suited to grass fields.
In 1923 a publicity seeker named
Antonius Raab made one of the Mark III’s
most publicized flights. He landed his
01sig1.QXD 11/19/07 1:14 PM Page 31
32 MODEL AVIATION
The constant-chord wing uses the same rib shape at each station. The flat-bottom
airfoil can be built on a flat surface with no fixturing required. Notice how the top
spars meet the wingtip.
It’s easier to install the rudder and elevator servos and control rods before the model
is covered. A 6-gram submicroservo with roughly 10 inch-ounce of torque is all that is
required.
Before sheeting the top of the fuselage, temporarily glue an incidence template in place
to build the wing support. Round all balsa parts before assembling the structure.
aircraft on the Unter den Linden, which is a
main thoroughfare in Berlin, Germany. The
police promptly arrested him.
At least one Mark III still exists. It is on
display at the Arlanda Aerospace Museum
in Stockholm, Sweden.
I selected the Stahlwerk Mark III as an
RC modeling project because it’s unique.
More importantly, it produced dimensions
and a planform that I hoped would result in
a model that would be easy to build and fly
and offer good flight characteristics.
Perhaps RC modelers who have never
built a stick-and-tissue-type model will find
this construction project to be one of interest
and give it a try. It uses simple, proven
building methods that require no unique
tools or building skills. Older modelers who
grew up eagerly constructing Comet and
Megow kits and chewing Lepage’s or
Ambroid glue off their fingers may find the
Mark III to be a trip down memory lane.
The intent in designing this model was to
keep it simple using inexpensive and readily
available construction materials most hobby
shops should have in stock. My Stahlwerk
Mark III is powered by a Baby Bullet
Double Cool Wind brushless outrunner
motor from CustomCDR.
CONSTRUCTION
As with any plans- or scratch-building
project, it helps to fabricate all the shaped or
formed parts before starting the assembly
Info
box
1922
Stahlwerk Mark III
Static shots by the author; flight shots by Lloyd Burnham
Type: Small vintage sport scale
Wingspan: 24 inches
Flying weight: 116 grams (4.1 ounces)
Wing area: 105 square inches
Length: 16.5 inches
Motor: Small microsize brushless
outrunner
Propeller: GWS 6 x 3
Battery: Two-cell, 300 mAh Li-Poly
Construction: Balsa and plywood
Covering/finish: Polyester tissue
(Litespan)
01sig1.QXD 11/19/07 1:18 PM Page 32
January 2008 33
The landing gear is stitched to the airframe with button thread.
The axle is attached with fine copper wrapping wire and solder.
The CustomCDR Baby Bullet (Cool Wind) brushless motor weighs
just 16 grams and has a thrust output of approximately 12 ounces.
The number of shaped or formed parts required to construct a
Stahlwerk Mark III is minimal.
Cutting the 11 balsa wing ribs is easy and
rapid if you first make a rib master
template from plywood, aluminum, or
plastic.
The landing-gear structure is fabricated from two pieces of .047
(3/64 inch) music wire. Guillow’s 2-inch lightweight plastic wheels
are used.
process. That way the model’s construction
seems to go more smoothly and
uninterrupted.
I did not prepare a list of required
materials because most modelers who possess
at least some building experience will have
most, if not all, of the various-size wood
pieces in their spare-wood supply box. Some
of the sizes indicated do not require a full
sheet, and the hardware needed is minimal.
Some modelers with built-up model
construction experience know that using a
balsa stripper greatly simplifies the
material-acquisition process. With this tool
all the stick stock can be cut easily from
sheet stock to any custom width needed. I
used a Jones balsa stripper, which is
considered to be the Rolls-Royce of balsa
strippers, but an inexpensive version such
as Master Airscrew’s will work fine.
01sig2.QXD 11/19/07 2:03 PM Page 33
34 MODEL AVIATION
Although it is optional, you can give your model a more
scalelike appearance by adding 1/16 x 3/16 balsa to the landinggear
assembly legs.
The author made the decals on his Stahlwerk using a homecomputer
ink-jet printer and water-transfer decal sheets.
The tail surfaces are constructed from balsa stick and sheet stock. The curved perimeter pieces are made from laminated 1/32 balsa sheet.
Scale Documentation Sources
• www.histaviation.com/Mark_R_III_colour_profile.jpg
• http://aircraftwalkaround.hobbyvista.com/rieseler/rieseler.htm
• www.histaviation.com/Stahlwerk_Mark_III.html MA
—Bob Wallace
The number of shaped or formed parts required to construct a
Stahlwerk Mark III is minimal. Since the wing is a constantchord
type, cutting the 11 balsa wing ribs is easy and fast if you
make a master template from a scrap piece of 1/32 plywood, thin
sheet aluminum, or plastic.
The motor-mount former is cut from 1/8 light plywood. Its
height and width may vary a bit depending on what type of motor
you use and where that former will be positioned within the nose
portion of the fuselage.
The only other shaped parts that need to be cut are the 1/16
plywood tail skid, two 1/16 plywood landing-gear mounting
crossbraces, three 3/32 sheet top fuselage formers, and the 1/16
plywood wing-spar brace.
The main components are constructed directly over the plans
sheet placed on a flat building surface. Fledgling builders are
reminded to place a sheet of clear vinyl plastic (backing from
many heat-shrinkable film-type covering materials works well for
this) or good, old kitchen-variety waxed paper over the plans
sheet to permit easy separation of the assembled part from the
sheet.
Wing: To construct each wing panel, pin the 1/8 x 1/4 main spar in
place along with the 1/8 x 3/8 TE. Use the wing ribs to achieve the
proper lateral spacing. Pin all the wing ribs in place. Be sure to
cant the 1/8 center-section rib using the wing-dihedral-angle
template as a guide. Glue these pieces together with thin
cyanoacrylate adhesive, and then pin and glue the 1/8 x 1/4 LE and
01sig2.QXD 11/19/07 2:35 PM Page 34
Any lightweight film-type covering, such as silkspan, or tissue-type materials can be used.
A Williams Brothers 1/12th scale racing pilot bust was cut down to fit and painted.
Three Williams Brothers plastic Gnome engine cylinders (item 206) were trimmed
and mounted to resemble the Anzani engine used on most Stahlwerk Mark III aircraft
that were produced.
Using Litespan
requires that a heatsensitive
adhesive
be applied to the
various components
before covering.
two 3/32 square top spars in place.
Pin and glue the 1/8 x 1/4 wingtip pieces
in place. The two 3/32 square top spars are
cut at the outer W2 rib and angled
downward to the 1/8 x 1/4 tip; see Section BB
on the plans sheet.
Glue the gussets and 1/16 x 1/8 wing-strut
attachment pieces in place. It is easier to
install the center-section cockpit-recess 1/16
sheet trim pieces after the two wing panels
have been joined.
After both wing panels have been
fabricated, lightly block-sand the faces of
the canted center-section W1 ribs and trialfit
them to ensure that the indicated dihedral
angle (3/4 inch under each tip) is produced.
Glue the two wing panels together, and then
install the 1/16 plywood DB1 brace.
Install the 1/16 sheet cockpit-recess pieces
in the aft center-section recess. The
completed wing assembly can be sanded
and contoured to the indicated airfoil and
planform.
Tail: The tail surfaces are constructed from
balsa stick and sheet stock. The curved
perimeter pieces are made from laminated
1/32 balsa sheet.
Three pieces of 1/32 balsa sheet are glued
together, with the center piece positioned
cross-grain to provide additional strength,
and then the curved perimeter tail-surface
pieces are cut from this laminated balsa
sheet stock.
Fuselage: The basic fuselage is a box-type
structure that is composed primarily of 1/8
square balsa to make its open framework.
The two fuselage sides are constructed
directly over the plans sheet side view, and
then the various 1/8 square crossbraces are
installed using the plans sheet top view as a
guide.
As I mentioned, the size and position of
the 1/8 light-plywood motor bulkhead may
vary depending on what type of motor,
propeller mounting adapter, and motor
mount you choose. I also mentioned that I
used a Baby Bullet brushless motor, but a
January 2008 35
01sig2.QXD 11/19/07 2:36 PM Page 35
variety of other motors can be employed.
Mine weighs 16 grams and has a thrust output
of roughly 12 ounces using a 2S Li-Poly
battery source and 7-inch propeller.
After installing the motor-mount
bulkhead, 1/16 nose-sheeting inlays, and 1/8
scrap bulkhead gussets, fit and secure the
fuselage F1 and F2 top formers, 1/16 square
stringer, and 1/16 top sheeting.
To ensure that the wing-mounting pylon
structure is constructed at the proper
incidence angle and aligned correctly, use the
incidence template shown on the plans sheet
as a guide.
Using a piece of string or thread, along
with a couple pins or a flexible straightedge,
determine the fuselage centerline and lightly
mark it along the top sheeting between the F2
fuselage top formers. Pin the 1/8 sheet
incidence template onto the fuselage top
sheeting along the marked fuselage centerline
between the F2 formers.
Once the 1/8 x 1/4 wing-support portion of
the pylon is pinned in place on top of the
template, the 1/8 and 1/16 square pylon support
pieces can be cut, fitted (notching the top
sheeting as required), and glued in place.
Since the full-scale Stahlwerk’s pylon support
pieces were made from welded steel tubing, it
is easier to sand the 1/8 and 1/16 square pieces
round before cutting them and fitting them in
place.
36 MODEL AVIATION
Full-Size Plans Available—See Page 199
After you have glued the wing pylon
structure in place, remove and discard the
incidence template.
The landing-gear structure is fabricated
from two pieces of .047 (3/64 inch) music
wire. One piece is the 4-inch-long axle that
will ultimately be trimmed to accommodate
whatever type of wheel you choose. I used
Guillow’s 2-inch lightweight plastic wheels
on my Stahlwerk.
The main landing-gear structure is bent
to shape using the detail shown on the plans
sheet. Then the landing-gear structure is
mounted on the two 1/16 plywood
crossbraces using button thread and
cyanoacrylate adhesive.
A 1/16 cap piece of balsa is applied over
the laced-on landing-gear/plywood
crosspieces to provide a finished appearance
after being installed on the fuselage. The
axle is attached to the main landing gear
with fine copper wrapping wire and solder.
Although optional, you can attain a more
scalelike appearance by adding 1/16 x 3/16
balsa to the landing-gear-assembly legs. I did
this by cutting a small channel along the
balsa strips and then gluing them in place
with cyanoacrylate. After sanding a radius
on the legs, I painted the landing-gear
assembly with satin-finish black paint.
The fuselage bottom access hatch is
fabricated using the hatch detail shown on
the plans sheet, and it is held in place with a
small magnet. Glue the 1/4 sheet nose block
in place and sand the fuselage assembly to
the indicated contours.
Notch the fuselage to accept the 1/16
plywood tail skid, but do not permanently
install the tail skid until after you cover the
model. Also, it is easier to install the rudder
and elevator servos and control rods now
rather than after the model has been covered.
The wing struts are made from 3/32 x 3/16
balsa and have their edges rounded. The
wing, tail surfaces, and fuselage assembly
can be fine-sanded in preparation for
covering. Any minor surface imperfections
can be filled with lightweight filler.
Covering: Any lightweight film-type
covering, such as silkspan or tissue-type
materials, can be used to cover this model. I
used buff-colored Litespan, which is a
lightweight, heat-shrinkable polyester tissuetype
covering that closely resembles the
natural linen-type material used on many
aircraft during the 1920s, including the
Stahlwerk.
Using Litespan requires that a heatsensitive
adhesive be applied to the various
components before covering. I used Coverite
Balsarite. The adhesive is brushed onto the
various subassemblies wherever the
covering material needs to be heat-fastened.
Once the Balsarite has dried, the Litespan
can be applied in the same manner as any
other heat-shrinkable covering material. In
areas where covering material overlaps, the
joint needs to be coated with Balsarite.
The decals shown on my Stahlwerk were
made using a home-computer ink-jet printer
01sig2.QXD 11/19/07 2:04 PM Page 36
38 MODEL AVIATION
and water-transfer decal sheets. These decal
sheets are readily available at graphic-arts
supply outlets or from a variety of Internet
sources. The sheets I used were purchased on
eBay and cost roughly one dollar each.
I trimmed three Williams Brothers plastic
Gnome engine cylinders and mounted them
on my model to resemble the Anzani engine
that was used in most of the Stahlwerk Mark
IIIs. Although they are not true scale, the
World War I-era Gnome cylinders resemble
those on the Anzani; I do believe they
enhance the model’s overall scale
appearance.
To complete the power package I
equipped the Baby Bullet brushless motor
with a GWS 6 x 3 propeller (item
GW/EP6030), a Castle Creations
Thunderbird-9 ESC, and an Apache 7.4-volt,
300 mAh 20C Li-Poly battery pack. I used
an Airtronics RD6000 transmitter, and the
airborne radio system consisted of a Corona
RS410 single-conversion microreceiver and
two Blue Bird BMS-303 microservos.
I achieved the indicated CG on my model
by positioning the operating components as
shown on the plans sheet. My Stahlwerk,
ready to fly, weighed 116 grams (4.1
ounces).
Flying: A beautiful, mild spring day with
sunny skies and only a wisp of a breeze
proved to be ideal conditions for my
Stahlwerk’s test flights. Since our club flying
field is all grass, and the Stahlwerk is
equipped with relatively small-diameter
wheels, I decided to hand launch for the
maiden flight.
After a usual radio range check and final
inspection, it was flip-and-fly time. Standing
stationary with approximately two-thirds
throttle introduced, a light, straight-out toss
was all that was necessary for the Stahlwerk
to climb out nicely.
After gaining roughly 75 feet of altitude,
a few blips of right rudder and down-elevator
trim correction made the Stahlwerk fly hands
off. I spent the next several minutes flying
about, performing mild maneuvers at various
throttle settings to assess the model’s inflight
capabilities. It became apparent that a
bit more rudder and slightly less elevator
control-surface movement were needed.
The first landing was easy and
uneventful. With the motor throttled back to
approximately one-quarter power, I made a
shallow, gentle approach until the Stahlwerk
was a few feet above the grass surface. The
landing stall occurred predictably after
easing back the throttle to idle, which
resulted in a soft landing.
Since the Stahlwerk is a small,
lightweight aircraft with a low wing loading,
landing on grass could best be described as a
three-point plop rather than a conventional
landing. There is no rollout once the wheels
make contact with the grass!
After making the required controlsurface-
movement adjustments, I installed a
fresh battery pack and the Stahlwerk was
airborne again and flying quite nicely. It is
easy to fly and forgiving, with no bad in-
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■ Red LED when driver on
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01sig2.QXD 11/19/07 2:04 PM Page 38
flight characteristics. Its mild aerobatic
capability proved to be suitable for this type of
model. The well-built Baby Bullet proved to
be an ideal choice, with outstanding power.
Subsequent flights were in the 10- to 12-
minute range using an Apache two-cell, 300
mAh Li-Poly battery pack. The recommended
control-surface travel limits, in each direction,
are three-eights rudder and one-quarter
elevator. Those are suggested starting points,
and those who decide to build a Stahlwerk
may ultimately decide to alter them a bit to
suit their flying preferences.
Although I have not had the opportunity to
fly my Stahlwerk indoors, I am sure I will
when what is referred to as the “building
season” (winter) arrives in New England.
Since it is slow-flying, docile, and easy to fly,
it should be well suited for indoor flying.
The Stahlwerk is an easy-to-build sport-scale
model that is a bit different. It is well suited to
those who would like to try a traditional stickand-
tissue-type built-up model. Experienced
modelers who are looking for a project that
will renew pleasant memories of a time that
may well become known as the golden age of
model aviation should also find this to be a
worthy subject.
If I can be of help in answering any
questions relative to how I built my
Stahlwerk, I will be most willing to do so. My
address is 91 Sylvan St., Avon CT 06001. MA
Bob Wallace
[email protected]
Sources:
Baby Bullet Double Cool Wind motor:
CustomCDR
1215 Diamondback Dr. NE
Albuquerque NM 87113
www.customcdr.com
Castle Creations Thunderbird-9 ESC:
(913) 390-6939
www.castlecreations.com
Battery pack, servos, receiver, covering
material:
BP Hobbies
(732) 287-3933
www.bphobbies.com
Master Airscrew Balsa Stripper:
(916) 631-8385
www.masterairscrew.com
Jim Jones Design Balsa Stripper:
A2Z CNC
(877) 754-7465
www.a2zcnc.com/airplane.asp
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40 MODEL AVIATION
01sig2.QXD 11/19/07 2:04 PM Page 40

January 2008 31
ALTHOUGH IT’S virtually unknown in
the US, other than by historical-aviation
enthusiasts, the Stahlwerk Mark III was a
popular and successful sport aviation design
in Europe during the 1920s and 1930s.
Walter Rieseler designed the airplane in
1922, and it is sometimes referred to as the
Rieseler R III.
Rieseler, a gifted German airplane
pioneer and designer, has been all but
forgotten in aviation history in spite of his
numerous accomplishments. The Stahlwerk
Mark III was one of his earliest aircraft. He
became better known for his innovative
autogiros and was credited in 1935 with
designing and producing the world’s first
helicopter that featured twin counterrotating
blades.
In 1920 Rieseler, in partnership with his
brother, formed a small aircraft
manufacturing company in Breslau,
Germany, called Stahlwerk. The Mark III,
which was preceded by the Mark II and
Mark I, was offered for sale in 1922, and it
rapidly became popular among the sportaviation
community in Germany.
The Mark III was a small, single-place
design with a fuselage length of 17 feet
and a wingspan of 25 feet. It was
powered with several different air-cooled
engines, the most popular of which were
the Haacke HFM two-cylinder flat
opposed type that produced 26
horsepower and the Anzani three-cylinder
Fly the Stahlwerk indoors or out. The outrunner motor system is quiet and provides
enough power for a five-minute flight on a two-cell Li-Poly battery pack.
1922 Stahlwerk Mark III
BY BOB WALLACE
A semiscale
park flyer of
the golden-age
German sport
aircraft
radial that produced 30 horsepower.
The airplane’s maximum speed near sea
level was 66 mph, and it had a 62 mph
cruise speed. With its low wing loading the
Mark III had great short-field takeoff-andlanding
capabilities. It could be airborne in
slightly more than 100 feet, and it could be
put back on the ground in an even shorter
distance since its landing speed was just less
than 30 mph. Its large-diameter landing-gear
wheels were well suited to grass fields.
In 1923 a publicity seeker named
Antonius Raab made one of the Mark III’s
most publicized flights. He landed his
01sig1.QXD 11/19/07 1:14 PM Page 31
32 MODEL AVIATION
The constant-chord wing uses the same rib shape at each station. The flat-bottom
airfoil can be built on a flat surface with no fixturing required. Notice how the top
spars meet the wingtip.
It’s easier to install the rudder and elevator servos and control rods before the model
is covered. A 6-gram submicroservo with roughly 10 inch-ounce of torque is all that is
required.
Before sheeting the top of the fuselage, temporarily glue an incidence template in place
to build the wing support. Round all balsa parts before assembling the structure.
aircraft on the Unter den Linden, which is a
main thoroughfare in Berlin, Germany. The
police promptly arrested him.
At least one Mark III still exists. It is on
display at the Arlanda Aerospace Museum
in Stockholm, Sweden.
I selected the Stahlwerk Mark III as an
RC modeling project because it’s unique.
More importantly, it produced dimensions
and a planform that I hoped would result in
a model that would be easy to build and fly
and offer good flight characteristics.
Perhaps RC modelers who have never
built a stick-and-tissue-type model will find
this construction project to be one of interest
and give it a try. It uses simple, proven
building methods that require no unique
tools or building skills. Older modelers who
grew up eagerly constructing Comet and
Megow kits and chewing Lepage’s or
Ambroid glue off their fingers may find the
Mark III to be a trip down memory lane.
The intent in designing this model was to
keep it simple using inexpensive and readily
available construction materials most hobby
shops should have in stock. My Stahlwerk
Mark III is powered by a Baby Bullet
Double Cool Wind brushless outrunner
motor from CustomCDR.
CONSTRUCTION
As with any plans- or scratch-building
project, it helps to fabricate all the shaped or
formed parts before starting the assembly
Info
box
1922
Stahlwerk Mark III
Static shots by the author; flight shots by Lloyd Burnham
Type: Small vintage sport scale
Wingspan: 24 inches
Flying weight: 116 grams (4.1 ounces)
Wing area: 105 square inches
Length: 16.5 inches
Motor: Small microsize brushless
outrunner
Propeller: GWS 6 x 3
Battery: Two-cell, 300 mAh Li-Poly
Construction: Balsa and plywood
Covering/finish: Polyester tissue
(Litespan)
01sig1.QXD 11/19/07 1:18 PM Page 32
January 2008 33
The landing gear is stitched to the airframe with button thread.
The axle is attached with fine copper wrapping wire and solder.
The CustomCDR Baby Bullet (Cool Wind) brushless motor weighs
just 16 grams and has a thrust output of approximately 12 ounces.
The number of shaped or formed parts required to construct a
Stahlwerk Mark III is minimal.
Cutting the 11 balsa wing ribs is easy and
rapid if you first make a rib master
template from plywood, aluminum, or
plastic.
The landing-gear structure is fabricated from two pieces of .047
(3/64 inch) music wire. Guillow’s 2-inch lightweight plastic wheels
are used.
process. That way the model’s construction
seems to go more smoothly and
uninterrupted.
I did not prepare a list of required
materials because most modelers who possess
at least some building experience will have
most, if not all, of the various-size wood
pieces in their spare-wood supply box. Some
of the sizes indicated do not require a full
sheet, and the hardware needed is minimal.
Some modelers with built-up model
construction experience know that using a
balsa stripper greatly simplifies the
material-acquisition process. With this tool
all the stick stock can be cut easily from
sheet stock to any custom width needed. I
used a Jones balsa stripper, which is
considered to be the Rolls-Royce of balsa
strippers, but an inexpensive version such
as Master Airscrew’s will work fine.
01sig2.QXD 11/19/07 2:03 PM Page 33
34 MODEL AVIATION
Although it is optional, you can give your model a more
scalelike appearance by adding 1/16 x 3/16 balsa to the landinggear
assembly legs.
The author made the decals on his Stahlwerk using a homecomputer
ink-jet printer and water-transfer decal sheets.
The tail surfaces are constructed from balsa stick and sheet stock. The curved perimeter pieces are made from laminated 1/32 balsa sheet.
Scale Documentation Sources
• www.histaviation.com/Mark_R_III_colour_profile.jpg
• http://aircraftwalkaround.hobbyvista.com/rieseler/rieseler.htm
• www.histaviation.com/Stahlwerk_Mark_III.html MA
—Bob Wallace
The number of shaped or formed parts required to construct a
Stahlwerk Mark III is minimal. Since the wing is a constantchord
type, cutting the 11 balsa wing ribs is easy and fast if you
make a master template from a scrap piece of 1/32 plywood, thin
sheet aluminum, or plastic.
The motor-mount former is cut from 1/8 light plywood. Its
height and width may vary a bit depending on what type of motor
you use and where that former will be positioned within the nose
portion of the fuselage.
The only other shaped parts that need to be cut are the 1/16
plywood tail skid, two 1/16 plywood landing-gear mounting
crossbraces, three 3/32 sheet top fuselage formers, and the 1/16
plywood wing-spar brace.
The main components are constructed directly over the plans
sheet placed on a flat building surface. Fledgling builders are
reminded to place a sheet of clear vinyl plastic (backing from
many heat-shrinkable film-type covering materials works well for
this) or good, old kitchen-variety waxed paper over the plans
sheet to permit easy separation of the assembled part from the
sheet.
Wing: To construct each wing panel, pin the 1/8 x 1/4 main spar in
place along with the 1/8 x 3/8 TE. Use the wing ribs to achieve the
proper lateral spacing. Pin all the wing ribs in place. Be sure to
cant the 1/8 center-section rib using the wing-dihedral-angle
template as a guide. Glue these pieces together with thin
cyanoacrylate adhesive, and then pin and glue the 1/8 x 1/4 LE and
01sig2.QXD 11/19/07 2:35 PM Page 34
Any lightweight film-type covering, such as silkspan, or tissue-type materials can be used.
A Williams Brothers 1/12th scale racing pilot bust was cut down to fit and painted.
Three Williams Brothers plastic Gnome engine cylinders (item 206) were trimmed
and mounted to resemble the Anzani engine used on most Stahlwerk Mark III aircraft
that were produced.
Using Litespan
requires that a heatsensitive
adhesive
be applied to the
various components
before covering.
two 3/32 square top spars in place.
Pin and glue the 1/8 x 1/4 wingtip pieces
in place. The two 3/32 square top spars are
cut at the outer W2 rib and angled
downward to the 1/8 x 1/4 tip; see Section BB
on the plans sheet.
Glue the gussets and 1/16 x 1/8 wing-strut
attachment pieces in place. It is easier to
install the center-section cockpit-recess 1/16
sheet trim pieces after the two wing panels
have been joined.
After both wing panels have been
fabricated, lightly block-sand the faces of
the canted center-section W1 ribs and trialfit
them to ensure that the indicated dihedral
angle (3/4 inch under each tip) is produced.
Glue the two wing panels together, and then
install the 1/16 plywood DB1 brace.
Install the 1/16 sheet cockpit-recess pieces
in the aft center-section recess. The
completed wing assembly can be sanded
and contoured to the indicated airfoil and
planform.
Tail: The tail surfaces are constructed from
balsa stick and sheet stock. The curved
perimeter pieces are made from laminated
1/32 balsa sheet.
Three pieces of 1/32 balsa sheet are glued
together, with the center piece positioned
cross-grain to provide additional strength,
and then the curved perimeter tail-surface
pieces are cut from this laminated balsa
sheet stock.
Fuselage: The basic fuselage is a box-type
structure that is composed primarily of 1/8
square balsa to make its open framework.
The two fuselage sides are constructed
directly over the plans sheet side view, and
then the various 1/8 square crossbraces are
installed using the plans sheet top view as a
guide.
As I mentioned, the size and position of
the 1/8 light-plywood motor bulkhead may
vary depending on what type of motor,
propeller mounting adapter, and motor
mount you choose. I also mentioned that I
used a Baby Bullet brushless motor, but a
January 2008 35
01sig2.QXD 11/19/07 2:36 PM Page 35
variety of other motors can be employed.
Mine weighs 16 grams and has a thrust output
of roughly 12 ounces using a 2S Li-Poly
battery source and 7-inch propeller.
After installing the motor-mount
bulkhead, 1/16 nose-sheeting inlays, and 1/8
scrap bulkhead gussets, fit and secure the
fuselage F1 and F2 top formers, 1/16 square
stringer, and 1/16 top sheeting.
To ensure that the wing-mounting pylon
structure is constructed at the proper
incidence angle and aligned correctly, use the
incidence template shown on the plans sheet
as a guide.
Using a piece of string or thread, along
with a couple pins or a flexible straightedge,
determine the fuselage centerline and lightly
mark it along the top sheeting between the F2
fuselage top formers. Pin the 1/8 sheet
incidence template onto the fuselage top
sheeting along the marked fuselage centerline
between the F2 formers.
Once the 1/8 x 1/4 wing-support portion of
the pylon is pinned in place on top of the
template, the 1/8 and 1/16 square pylon support
pieces can be cut, fitted (notching the top
sheeting as required), and glued in place.
Since the full-scale Stahlwerk’s pylon support
pieces were made from welded steel tubing, it
is easier to sand the 1/8 and 1/16 square pieces
round before cutting them and fitting them in
place.
36 MODEL AVIATION
Full-Size Plans Available—See Page 199
After you have glued the wing pylon
structure in place, remove and discard the
incidence template.
The landing-gear structure is fabricated
from two pieces of .047 (3/64 inch) music
wire. One piece is the 4-inch-long axle that
will ultimately be trimmed to accommodate
whatever type of wheel you choose. I used
Guillow’s 2-inch lightweight plastic wheels
on my Stahlwerk.
The main landing-gear structure is bent
to shape using the detail shown on the plans
sheet. Then the landing-gear structure is
mounted on the two 1/16 plywood
crossbraces using button thread and
cyanoacrylate adhesive.
A 1/16 cap piece of balsa is applied over
the laced-on landing-gear/plywood
crosspieces to provide a finished appearance
after being installed on the fuselage. The
axle is attached to the main landing gear
with fine copper wrapping wire and solder.
Although optional, you can attain a more
scalelike appearance by adding 1/16 x 3/16
balsa to the landing-gear-assembly legs. I did
this by cutting a small channel along the
balsa strips and then gluing them in place
with cyanoacrylate. After sanding a radius
on the legs, I painted the landing-gear
assembly with satin-finish black paint.
The fuselage bottom access hatch is
fabricated using the hatch detail shown on
the plans sheet, and it is held in place with a
small magnet. Glue the 1/4 sheet nose block
in place and sand the fuselage assembly to
the indicated contours.
Notch the fuselage to accept the 1/16
plywood tail skid, but do not permanently
install the tail skid until after you cover the
model. Also, it is easier to install the rudder
and elevator servos and control rods now
rather than after the model has been covered.
The wing struts are made from 3/32 x 3/16
balsa and have their edges rounded. The
wing, tail surfaces, and fuselage assembly
can be fine-sanded in preparation for
covering. Any minor surface imperfections
can be filled with lightweight filler.
Covering: Any lightweight film-type
covering, such as silkspan or tissue-type
materials, can be used to cover this model. I
used buff-colored Litespan, which is a
lightweight, heat-shrinkable polyester tissuetype
covering that closely resembles the
natural linen-type material used on many
aircraft during the 1920s, including the
Stahlwerk.
Using Litespan requires that a heatsensitive
adhesive be applied to the various
components before covering. I used Coverite
Balsarite. The adhesive is brushed onto the
various subassemblies wherever the
covering material needs to be heat-fastened.
Once the Balsarite has dried, the Litespan
can be applied in the same manner as any
other heat-shrinkable covering material. In
areas where covering material overlaps, the
joint needs to be coated with Balsarite.
The decals shown on my Stahlwerk were
made using a home-computer ink-jet printer
01sig2.QXD 11/19/07 2:04 PM Page 36
38 MODEL AVIATION
and water-transfer decal sheets. These decal
sheets are readily available at graphic-arts
supply outlets or from a variety of Internet
sources. The sheets I used were purchased on
eBay and cost roughly one dollar each.
I trimmed three Williams Brothers plastic
Gnome engine cylinders and mounted them
on my model to resemble the Anzani engine
that was used in most of the Stahlwerk Mark
IIIs. Although they are not true scale, the
World War I-era Gnome cylinders resemble
those on the Anzani; I do believe they
enhance the model’s overall scale
appearance.
To complete the power package I
equipped the Baby Bullet brushless motor
with a GWS 6 x 3 propeller (item
GW/EP6030), a Castle Creations
Thunderbird-9 ESC, and an Apache 7.4-volt,
300 mAh 20C Li-Poly battery pack. I used
an Airtronics RD6000 transmitter, and the
airborne radio system consisted of a Corona
RS410 single-conversion microreceiver and
two Blue Bird BMS-303 microservos.
I achieved the indicated CG on my model
by positioning the operating components as
shown on the plans sheet. My Stahlwerk,
ready to fly, weighed 116 grams (4.1
ounces).
Flying: A beautiful, mild spring day with
sunny skies and only a wisp of a breeze
proved to be ideal conditions for my
Stahlwerk’s test flights. Since our club flying
field is all grass, and the Stahlwerk is
equipped with relatively small-diameter
wheels, I decided to hand launch for the
maiden flight.
After a usual radio range check and final
inspection, it was flip-and-fly time. Standing
stationary with approximately two-thirds
throttle introduced, a light, straight-out toss
was all that was necessary for the Stahlwerk
to climb out nicely.
After gaining roughly 75 feet of altitude,
a few blips of right rudder and down-elevator
trim correction made the Stahlwerk fly hands
off. I spent the next several minutes flying
about, performing mild maneuvers at various
throttle settings to assess the model’s inflight
capabilities. It became apparent that a
bit more rudder and slightly less elevator
control-surface movement were needed.
The first landing was easy and
uneventful. With the motor throttled back to
approximately one-quarter power, I made a
shallow, gentle approach until the Stahlwerk
was a few feet above the grass surface. The
landing stall occurred predictably after
easing back the throttle to idle, which
resulted in a soft landing.
Since the Stahlwerk is a small,
lightweight aircraft with a low wing loading,
landing on grass could best be described as a
three-point plop rather than a conventional
landing. There is no rollout once the wheels
make contact with the grass!
After making the required controlsurface-
movement adjustments, I installed a
fresh battery pack and the Stahlwerk was
airborne again and flying quite nicely. It is
easy to fly and forgiving, with no bad in-
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01sig2.QXD 11/19/07 2:04 PM Page 38
flight characteristics. Its mild aerobatic
capability proved to be suitable for this type of
model. The well-built Baby Bullet proved to
be an ideal choice, with outstanding power.
Subsequent flights were in the 10- to 12-
minute range using an Apache two-cell, 300
mAh Li-Poly battery pack. The recommended
control-surface travel limits, in each direction,
are three-eights rudder and one-quarter
elevator. Those are suggested starting points,
and those who decide to build a Stahlwerk
may ultimately decide to alter them a bit to
suit their flying preferences.
Although I have not had the opportunity to
fly my Stahlwerk indoors, I am sure I will
when what is referred to as the “building
season” (winter) arrives in New England.
Since it is slow-flying, docile, and easy to fly,
it should be well suited for indoor flying.
The Stahlwerk is an easy-to-build sport-scale
model that is a bit different. It is well suited to
those who would like to try a traditional stickand-
tissue-type built-up model. Experienced
modelers who are looking for a project that
will renew pleasant memories of a time that
may well become known as the golden age of
model aviation should also find this to be a
worthy subject.
If I can be of help in answering any
questions relative to how I built my
Stahlwerk, I will be most willing to do so. My
address is 91 Sylvan St., Avon CT 06001. MA
Bob Wallace
[email protected]
Sources:
Baby Bullet Double Cool Wind motor:
CustomCDR
1215 Diamondback Dr. NE
Albuquerque NM 87113
www.customcdr.com
Castle Creations Thunderbird-9 ESC:
(913) 390-6939
www.castlecreations.com
Battery pack, servos, receiver, covering
material:
BP Hobbies
(732) 287-3933
www.bphobbies.com
Master Airscrew Balsa Stripper:
(916) 631-8385
www.masterairscrew.com
Jim Jones Design Balsa Stripper:
A2Z CNC
(877) 754-7465
www.a2zcnc.com/airplane.asp
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01sig2.QXD 11/19/07 2:04 PM Page 40