October 2010 29
WHILE BROWSING in a used-book store I
saw a pocket encyclopedia of world aircraft in
color. Authored by Kenneth Munson and
titled Private Aircraft Business and General
Purpose, it had a number of nice color twoviews.
(Macmillan published this book in 1967. I
suspect you can purchase it from booksellers
that specialize in used aviation volumes.)
The price was right, so I purchased the
book. Since then I have looked through it
many times, to see whether or not any of the
airplanes featured would ignite a creative
spark.
I kept coming back to an aircraft similar to
a Piper Cub. A Danish design, the
Skandinavisk KZ III Laerke (Lark) looked
like it would be a good flier and had an
interesting history.
Design began on the airplane in 1943
Denmark, under Nazi occupation.
Development was
allowed to proceed
because the KZ III
was intended for use
by the Danish Air
Ambulance Service.
The aircraft’s maiden
flight was in 1944.
Production continued
until 1947. Of the 64 Larks built,
three were delivered to the
ambulance service.
The aircraft had excellent
STOL (Short Takeoff & Landing)
performance. The civilian version that I
modeled was equipped with a 100-horsepower
Cirrus Minor engine.
CONSTRUCTION
Fuselage: There is no way around it; lighter
models fly better. You can use 1/16 square
balsa to frame the fuselage, but I recommend
1/20.
A 1/20 square side brace extends from the
back of the cabin area to the tail. Do not add it
until the fuselage sides have been joined.
When framing the rear of the fuselage, use
a spacer that you will remove later to enable
the stabilizer to slide into position. Be sure to
allow a little “wiggle room” for the front of
the stabilizer, in case you need to shim it up
or down for flight-trimming.
The fuselage narrows at the nose. Joining
the nose can be made easier by using 1/20 x 1/8
rather than 1/20 square for the front vertical
brace.
Instead of joining the nose with 1/20
square, make a full front former (F1) from
soft 1/8 sheet. This gives you plenty of gluing
area and helps square the nose.
Add top and bottom formers, including
the “instrument panel.” Select soft 1/32 sheet,
and sand it a bit thinner so it will wrap easily
around the top and bottom of the cowl. You
do not need to sheet the sides of the cowl.
Once the top and bottom cowl sheeting
are in place, the nose will be strong enough to
remove the center of F1. Use a sharp #11
blade to cut out the center of the front former.
That can be used as the plug for the nose
block. Notice on the plans that you will also
remove a bit of former T1 for prop shaft
clearance.
The bottom formers aft of
the landing gear are triangles
with a single central spar.
There is also a single
central spar on top of the
fuselage that begins at the
wing spar, rides on the top
crossbraces, and
provides a mount
surface for the fin.
The landing
gear wire is .025 stock, and it
attaches to the front of B3. The landing gear
fairing attaches to the front of the wire and is
not glued to the fuselage. This allows the
by Gene Smiitth
Skandinavisk KZ.III
This particular model has been flown only
indoors but should also be a good outdoor
subject. The full-scale design was originally
intended to be a STOL ambulance airplane
for the Dutch Army, but only a few were
used in that capacity.
10sig1.QXD_00MSTRPG.QXD 8/20/10 10:47 AM Page 29
structure to flex back slightly, to absorb
landing shock.
When drilling the nose block for the prop
shaft bearing, aim for 3° of right thrust and 2°
of downthrust. I used a Peck-Polymers
bearing but removed part of the front of the
button so that the propeller would not stick
out so far from the nose.
The propeller is 51/2 inches in diameter,
with a 7-inch pitch. The shaft is a round
toothpick. Blades are 1/64 plywood, soaked in
water overnight. Wrapped onto a can, the
blades are tilted 15° to the left. Use a plastic
commercial propeller if you prefer. The
spinner is balsa.
Wing: I built the model’s wing with split rib
construction, using a 1/16 x 3/32 LE and a 1/20 x
1/8 main spar. If you want a simpler approach,
you could make the ribs from 1/32 balsa.
Notice that the LE angles toward the cabin
near the cabin junction. This LE splice should
be approximately 1/8 inch thick, to properly
join the wing root rib.
The root rib is 1/20 sheet—not a split rib.
Dihedral is 5/16 inch for each panel measured
at the last rib.
Tail: The tail surfaces were laminated
from 1/32 x 1/16 strips using Titebond. The
form was made from 1/16 balsa that was
too heavy to use for construction.
After the strips dried, I used 1/20
crossbraces to complete the internal
framing. Then I sanded the stabilizer and
fin to 1/20 inch in thickness.
Flap hinges and aileron counterbalance
weight were made from gray construction
paper. The legs were left slightly long,
slits were cut in the tissue, and the hinges
and counterbalances were glued into the
slits.
Hinges and flap counterbalance
locations are shown on the plans. They are
on the underside of the wing. The next-tolast
outboard fixture is the counterbalance.
Covering: The Skandinavisk is yellow
overall, with light-blue registration and trim. I
simulated the wing slots with black domestic
tissue cut into strips and attached them with
white glue.
The registration numbers and blue wing,
stabilizer, and fuselage trim strips were cut
from light-blue Japanese tissue, which I had
sprayed with Floquil to accentuate the color. I
preshrunk and lightly sprayed all of the tissue
covering with Floquil before I applied it to the
model.
Flying: I anticipated flying the model to the
right and built 1/16 inch of washin into the
right wing. This proved to be too much and
induced a stalling right climb that would
dampen as the power decreased. Flights have
been much better since I removed almost all
washin.
Start with the CG at the back edge of the
spar and adjust as needed. My airplane now
balances 1/8 inch to the rear of the spar. To
date, the model has been flown only indoors
under a 38-foot ceiling.
A 20-inch loop of .080-inch-diameter Tan
II rubber wound to 1,800 turns and 0.6 inchounce
of torque has given a respectable flight
of 1 minute, 42 seconds. If flying outdoors, a
16-inch loop of .100-.125 should be a good
starting point.
Enjoy your Danish! MA
Gene Smith
[email protected]
Edition: Model Aviation - 2010/10
Page Numbers: 29,30,31,32
Edition: Model Aviation - 2010/10
Page Numbers: 29,30,31,32
October 2010 29
WHILE BROWSING in a used-book store I
saw a pocket encyclopedia of world aircraft in
color. Authored by Kenneth Munson and
titled Private Aircraft Business and General
Purpose, it had a number of nice color twoviews.
(Macmillan published this book in 1967. I
suspect you can purchase it from booksellers
that specialize in used aviation volumes.)
The price was right, so I purchased the
book. Since then I have looked through it
many times, to see whether or not any of the
airplanes featured would ignite a creative
spark.
I kept coming back to an aircraft similar to
a Piper Cub. A Danish design, the
Skandinavisk KZ III Laerke (Lark) looked
like it would be a good flier and had an
interesting history.
Design began on the airplane in 1943
Denmark, under Nazi occupation.
Development was
allowed to proceed
because the KZ III
was intended for use
by the Danish Air
Ambulance Service.
The aircraft’s maiden
flight was in 1944.
Production continued
until 1947. Of the 64 Larks built,
three were delivered to the
ambulance service.
The aircraft had excellent
STOL (Short Takeoff & Landing)
performance. The civilian version that I
modeled was equipped with a 100-horsepower
Cirrus Minor engine.
CONSTRUCTION
Fuselage: There is no way around it; lighter
models fly better. You can use 1/16 square
balsa to frame the fuselage, but I recommend
1/20.
A 1/20 square side brace extends from the
back of the cabin area to the tail. Do not add it
until the fuselage sides have been joined.
When framing the rear of the fuselage, use
a spacer that you will remove later to enable
the stabilizer to slide into position. Be sure to
allow a little “wiggle room” for the front of
the stabilizer, in case you need to shim it up
or down for flight-trimming.
The fuselage narrows at the nose. Joining
the nose can be made easier by using 1/20 x 1/8
rather than 1/20 square for the front vertical
brace.
Instead of joining the nose with 1/20
square, make a full front former (F1) from
soft 1/8 sheet. This gives you plenty of gluing
area and helps square the nose.
Add top and bottom formers, including
the “instrument panel.” Select soft 1/32 sheet,
and sand it a bit thinner so it will wrap easily
around the top and bottom of the cowl. You
do not need to sheet the sides of the cowl.
Once the top and bottom cowl sheeting
are in place, the nose will be strong enough to
remove the center of F1. Use a sharp #11
blade to cut out the center of the front former.
That can be used as the plug for the nose
block. Notice on the plans that you will also
remove a bit of former T1 for prop shaft
clearance.
The bottom formers aft of
the landing gear are triangles
with a single central spar.
There is also a single
central spar on top of the
fuselage that begins at the
wing spar, rides on the top
crossbraces, and
provides a mount
surface for the fin.
The landing
gear wire is .025 stock, and it
attaches to the front of B3. The landing gear
fairing attaches to the front of the wire and is
not glued to the fuselage. This allows the
by Gene Smiitth
Skandinavisk KZ.III
This particular model has been flown only
indoors but should also be a good outdoor
subject. The full-scale design was originally
intended to be a STOL ambulance airplane
for the Dutch Army, but only a few were
used in that capacity.
10sig1.QXD_00MSTRPG.QXD 8/20/10 10:47 AM Page 29
structure to flex back slightly, to absorb
landing shock.
When drilling the nose block for the prop
shaft bearing, aim for 3° of right thrust and 2°
of downthrust. I used a Peck-Polymers
bearing but removed part of the front of the
button so that the propeller would not stick
out so far from the nose.
The propeller is 51/2 inches in diameter,
with a 7-inch pitch. The shaft is a round
toothpick. Blades are 1/64 plywood, soaked in
water overnight. Wrapped onto a can, the
blades are tilted 15° to the left. Use a plastic
commercial propeller if you prefer. The
spinner is balsa.
Wing: I built the model’s wing with split rib
construction, using a 1/16 x 3/32 LE and a 1/20 x
1/8 main spar. If you want a simpler approach,
you could make the ribs from 1/32 balsa.
Notice that the LE angles toward the cabin
near the cabin junction. This LE splice should
be approximately 1/8 inch thick, to properly
join the wing root rib.
The root rib is 1/20 sheet—not a split rib.
Dihedral is 5/16 inch for each panel measured
at the last rib.
Tail: The tail surfaces were laminated
from 1/32 x 1/16 strips using Titebond. The
form was made from 1/16 balsa that was
too heavy to use for construction.
After the strips dried, I used 1/20
crossbraces to complete the internal
framing. Then I sanded the stabilizer and
fin to 1/20 inch in thickness.
Flap hinges and aileron counterbalance
weight were made from gray construction
paper. The legs were left slightly long,
slits were cut in the tissue, and the hinges
and counterbalances were glued into the
slits.
Hinges and flap counterbalance
locations are shown on the plans. They are
on the underside of the wing. The next-tolast
outboard fixture is the counterbalance.
Covering: The Skandinavisk is yellow
overall, with light-blue registration and trim. I
simulated the wing slots with black domestic
tissue cut into strips and attached them with
white glue.
The registration numbers and blue wing,
stabilizer, and fuselage trim strips were cut
from light-blue Japanese tissue, which I had
sprayed with Floquil to accentuate the color. I
preshrunk and lightly sprayed all of the tissue
covering with Floquil before I applied it to the
model.
Flying: I anticipated flying the model to the
right and built 1/16 inch of washin into the
right wing. This proved to be too much and
induced a stalling right climb that would
dampen as the power decreased. Flights have
been much better since I removed almost all
washin.
Start with the CG at the back edge of the
spar and adjust as needed. My airplane now
balances 1/8 inch to the rear of the spar. To
date, the model has been flown only indoors
under a 38-foot ceiling.
A 20-inch loop of .080-inch-diameter Tan
II rubber wound to 1,800 turns and 0.6 inchounce
of torque has given a respectable flight
of 1 minute, 42 seconds. If flying outdoors, a
16-inch loop of .100-.125 should be a good
starting point.
Enjoy your Danish! MA
Gene Smith
[email protected]
Edition: Model Aviation - 2010/10
Page Numbers: 29,30,31,32
October 2010 29
WHILE BROWSING in a used-book store I
saw a pocket encyclopedia of world aircraft in
color. Authored by Kenneth Munson and
titled Private Aircraft Business and General
Purpose, it had a number of nice color twoviews.
(Macmillan published this book in 1967. I
suspect you can purchase it from booksellers
that specialize in used aviation volumes.)
The price was right, so I purchased the
book. Since then I have looked through it
many times, to see whether or not any of the
airplanes featured would ignite a creative
spark.
I kept coming back to an aircraft similar to
a Piper Cub. A Danish design, the
Skandinavisk KZ III Laerke (Lark) looked
like it would be a good flier and had an
interesting history.
Design began on the airplane in 1943
Denmark, under Nazi occupation.
Development was
allowed to proceed
because the KZ III
was intended for use
by the Danish Air
Ambulance Service.
The aircraft’s maiden
flight was in 1944.
Production continued
until 1947. Of the 64 Larks built,
three were delivered to the
ambulance service.
The aircraft had excellent
STOL (Short Takeoff & Landing)
performance. The civilian version that I
modeled was equipped with a 100-horsepower
Cirrus Minor engine.
CONSTRUCTION
Fuselage: There is no way around it; lighter
models fly better. You can use 1/16 square
balsa to frame the fuselage, but I recommend
1/20.
A 1/20 square side brace extends from the
back of the cabin area to the tail. Do not add it
until the fuselage sides have been joined.
When framing the rear of the fuselage, use
a spacer that you will remove later to enable
the stabilizer to slide into position. Be sure to
allow a little “wiggle room” for the front of
the stabilizer, in case you need to shim it up
or down for flight-trimming.
The fuselage narrows at the nose. Joining
the nose can be made easier by using 1/20 x 1/8
rather than 1/20 square for the front vertical
brace.
Instead of joining the nose with 1/20
square, make a full front former (F1) from
soft 1/8 sheet. This gives you plenty of gluing
area and helps square the nose.
Add top and bottom formers, including
the “instrument panel.” Select soft 1/32 sheet,
and sand it a bit thinner so it will wrap easily
around the top and bottom of the cowl. You
do not need to sheet the sides of the cowl.
Once the top and bottom cowl sheeting
are in place, the nose will be strong enough to
remove the center of F1. Use a sharp #11
blade to cut out the center of the front former.
That can be used as the plug for the nose
block. Notice on the plans that you will also
remove a bit of former T1 for prop shaft
clearance.
The bottom formers aft of
the landing gear are triangles
with a single central spar.
There is also a single
central spar on top of the
fuselage that begins at the
wing spar, rides on the top
crossbraces, and
provides a mount
surface for the fin.
The landing
gear wire is .025 stock, and it
attaches to the front of B3. The landing gear
fairing attaches to the front of the wire and is
not glued to the fuselage. This allows the
by Gene Smiitth
Skandinavisk KZ.III
This particular model has been flown only
indoors but should also be a good outdoor
subject. The full-scale design was originally
intended to be a STOL ambulance airplane
for the Dutch Army, but only a few were
used in that capacity.
10sig1.QXD_00MSTRPG.QXD 8/20/10 10:47 AM Page 29
structure to flex back slightly, to absorb
landing shock.
When drilling the nose block for the prop
shaft bearing, aim for 3° of right thrust and 2°
of downthrust. I used a Peck-Polymers
bearing but removed part of the front of the
button so that the propeller would not stick
out so far from the nose.
The propeller is 51/2 inches in diameter,
with a 7-inch pitch. The shaft is a round
toothpick. Blades are 1/64 plywood, soaked in
water overnight. Wrapped onto a can, the
blades are tilted 15° to the left. Use a plastic
commercial propeller if you prefer. The
spinner is balsa.
Wing: I built the model’s wing with split rib
construction, using a 1/16 x 3/32 LE and a 1/20 x
1/8 main spar. If you want a simpler approach,
you could make the ribs from 1/32 balsa.
Notice that the LE angles toward the cabin
near the cabin junction. This LE splice should
be approximately 1/8 inch thick, to properly
join the wing root rib.
The root rib is 1/20 sheet—not a split rib.
Dihedral is 5/16 inch for each panel measured
at the last rib.
Tail: The tail surfaces were laminated
from 1/32 x 1/16 strips using Titebond. The
form was made from 1/16 balsa that was
too heavy to use for construction.
After the strips dried, I used 1/20
crossbraces to complete the internal
framing. Then I sanded the stabilizer and
fin to 1/20 inch in thickness.
Flap hinges and aileron counterbalance
weight were made from gray construction
paper. The legs were left slightly long,
slits were cut in the tissue, and the hinges
and counterbalances were glued into the
slits.
Hinges and flap counterbalance
locations are shown on the plans. They are
on the underside of the wing. The next-tolast
outboard fixture is the counterbalance.
Covering: The Skandinavisk is yellow
overall, with light-blue registration and trim. I
simulated the wing slots with black domestic
tissue cut into strips and attached them with
white glue.
The registration numbers and blue wing,
stabilizer, and fuselage trim strips were cut
from light-blue Japanese tissue, which I had
sprayed with Floquil to accentuate the color. I
preshrunk and lightly sprayed all of the tissue
covering with Floquil before I applied it to the
model.
Flying: I anticipated flying the model to the
right and built 1/16 inch of washin into the
right wing. This proved to be too much and
induced a stalling right climb that would
dampen as the power decreased. Flights have
been much better since I removed almost all
washin.
Start with the CG at the back edge of the
spar and adjust as needed. My airplane now
balances 1/8 inch to the rear of the spar. To
date, the model has been flown only indoors
under a 38-foot ceiling.
A 20-inch loop of .080-inch-diameter Tan
II rubber wound to 1,800 turns and 0.6 inchounce
of torque has given a respectable flight
of 1 minute, 42 seconds. If flying outdoors, a
16-inch loop of .100-.125 should be a good
starting point.
Enjoy your Danish! MA
Gene Smith
[email protected]
Edition: Model Aviation - 2010/10
Page Numbers: 29,30,31,32
October 2010 29
WHILE BROWSING in a used-book store I
saw a pocket encyclopedia of world aircraft in
color. Authored by Kenneth Munson and
titled Private Aircraft Business and General
Purpose, it had a number of nice color twoviews.
(Macmillan published this book in 1967. I
suspect you can purchase it from booksellers
that specialize in used aviation volumes.)
The price was right, so I purchased the
book. Since then I have looked through it
many times, to see whether or not any of the
airplanes featured would ignite a creative
spark.
I kept coming back to an aircraft similar to
a Piper Cub. A Danish design, the
Skandinavisk KZ III Laerke (Lark) looked
like it would be a good flier and had an
interesting history.
Design began on the airplane in 1943
Denmark, under Nazi occupation.
Development was
allowed to proceed
because the KZ III
was intended for use
by the Danish Air
Ambulance Service.
The aircraft’s maiden
flight was in 1944.
Production continued
until 1947. Of the 64 Larks built,
three were delivered to the
ambulance service.
The aircraft had excellent
STOL (Short Takeoff & Landing)
performance. The civilian version that I
modeled was equipped with a 100-horsepower
Cirrus Minor engine.
CONSTRUCTION
Fuselage: There is no way around it; lighter
models fly better. You can use 1/16 square
balsa to frame the fuselage, but I recommend
1/20.
A 1/20 square side brace extends from the
back of the cabin area to the tail. Do not add it
until the fuselage sides have been joined.
When framing the rear of the fuselage, use
a spacer that you will remove later to enable
the stabilizer to slide into position. Be sure to
allow a little “wiggle room” for the front of
the stabilizer, in case you need to shim it up
or down for flight-trimming.
The fuselage narrows at the nose. Joining
the nose can be made easier by using 1/20 x 1/8
rather than 1/20 square for the front vertical
brace.
Instead of joining the nose with 1/20
square, make a full front former (F1) from
soft 1/8 sheet. This gives you plenty of gluing
area and helps square the nose.
Add top and bottom formers, including
the “instrument panel.” Select soft 1/32 sheet,
and sand it a bit thinner so it will wrap easily
around the top and bottom of the cowl. You
do not need to sheet the sides of the cowl.
Once the top and bottom cowl sheeting
are in place, the nose will be strong enough to
remove the center of F1. Use a sharp #11
blade to cut out the center of the front former.
That can be used as the plug for the nose
block. Notice on the plans that you will also
remove a bit of former T1 for prop shaft
clearance.
The bottom formers aft of
the landing gear are triangles
with a single central spar.
There is also a single
central spar on top of the
fuselage that begins at the
wing spar, rides on the top
crossbraces, and
provides a mount
surface for the fin.
The landing
gear wire is .025 stock, and it
attaches to the front of B3. The landing gear
fairing attaches to the front of the wire and is
not glued to the fuselage. This allows the
by Gene Smiitth
Skandinavisk KZ.III
This particular model has been flown only
indoors but should also be a good outdoor
subject. The full-scale design was originally
intended to be a STOL ambulance airplane
for the Dutch Army, but only a few were
used in that capacity.
10sig1.QXD_00MSTRPG.QXD 8/20/10 10:47 AM Page 29
structure to flex back slightly, to absorb
landing shock.
When drilling the nose block for the prop
shaft bearing, aim for 3° of right thrust and 2°
of downthrust. I used a Peck-Polymers
bearing but removed part of the front of the
button so that the propeller would not stick
out so far from the nose.
The propeller is 51/2 inches in diameter,
with a 7-inch pitch. The shaft is a round
toothpick. Blades are 1/64 plywood, soaked in
water overnight. Wrapped onto a can, the
blades are tilted 15° to the left. Use a plastic
commercial propeller if you prefer. The
spinner is balsa.
Wing: I built the model’s wing with split rib
construction, using a 1/16 x 3/32 LE and a 1/20 x
1/8 main spar. If you want a simpler approach,
you could make the ribs from 1/32 balsa.
Notice that the LE angles toward the cabin
near the cabin junction. This LE splice should
be approximately 1/8 inch thick, to properly
join the wing root rib.
The root rib is 1/20 sheet—not a split rib.
Dihedral is 5/16 inch for each panel measured
at the last rib.
Tail: The tail surfaces were laminated
from 1/32 x 1/16 strips using Titebond. The
form was made from 1/16 balsa that was
too heavy to use for construction.
After the strips dried, I used 1/20
crossbraces to complete the internal
framing. Then I sanded the stabilizer and
fin to 1/20 inch in thickness.
Flap hinges and aileron counterbalance
weight were made from gray construction
paper. The legs were left slightly long,
slits were cut in the tissue, and the hinges
and counterbalances were glued into the
slits.
Hinges and flap counterbalance
locations are shown on the plans. They are
on the underside of the wing. The next-tolast
outboard fixture is the counterbalance.
Covering: The Skandinavisk is yellow
overall, with light-blue registration and trim. I
simulated the wing slots with black domestic
tissue cut into strips and attached them with
white glue.
The registration numbers and blue wing,
stabilizer, and fuselage trim strips were cut
from light-blue Japanese tissue, which I had
sprayed with Floquil to accentuate the color. I
preshrunk and lightly sprayed all of the tissue
covering with Floquil before I applied it to the
model.
Flying: I anticipated flying the model to the
right and built 1/16 inch of washin into the
right wing. This proved to be too much and
induced a stalling right climb that would
dampen as the power decreased. Flights have
been much better since I removed almost all
washin.
Start with the CG at the back edge of the
spar and adjust as needed. My airplane now
balances 1/8 inch to the rear of the spar. To
date, the model has been flown only indoors
under a 38-foot ceiling.
A 20-inch loop of .080-inch-diameter Tan
II rubber wound to 1,800 turns and 0.6 inchounce
of torque has given a respectable flight
of 1 minute, 42 seconds. If flying outdoors, a
16-inch loop of .100-.125 should be a good
starting point.
Enjoy your Danish! MA
Gene Smith
[email protected]
