154 MODEL AVIATION
types are high wing,
low wing, midwing,
and biplane.
When installing
leadouts, we make
every effort to create
a straight line from
the bellcrank
through the leadouts
and from the flying
lines to the control
handle. Properly
supporting the
leadouts at or near
the wingtip of the
inboard wing will
ensure that the
airplane maintains
the proper flight
attitude and control.
If the leadouts
are not properly supported at, or near, the
inboard wingtip, the aircraft could yaw from
side to side or take on an undesirable flight
attitude and have poor control.
The accompanying sketch shows some
In the OctOber column I wrote about
the three-line control system and the
necessity of having a balanced setup to
provide maximum safety and good flight
performance. I also mentioned that the
control handle and bellcrank must
complement each other or be a
matched set, to obtain maximum
throw for proper engine throttle
control and prevent slack in the
flying lines.
This month I will continue with
control-system basics, concerning
leadouts, their installation, and their
means of support. I suspect that there
are many ways to install and support
leadouts, but for purposes of this
column I will cover the three or four
basic methods.
Some of what follows might be
useful to newcomers as well as some
of the old-timers. A review is good
for everybody.
What is the purpose of the
leadouts? How must they be installed
and supported to keep the model in
stable flight? What are the rules
governing the use of external
removable guides, so that an airplane
has a clean look during Scale static
judging?
Leadouts are a means of
connecting the flying lines to the
aircraft bellcrank, and the placement
of the leadouts depends on the type
of model you are building. Basic
Also included in this column:
• Contest reminder
Leadout installations
[[email protected]]
Control Line Scale Bill Boss
This shows a few ways that leadouts and leadout guides can be installed. Also shown are a
couple of methods to make leadout guides removable, for better static judging scores. Author
sketch.
Lou Wolgast’s Profile de Havilland D.H.88 Comet represents one
of three full-scale wood-framed racers that entered the Englandto-
Australia MacRobertson Air Race in 1934. The model is
powered by two .049 engines. Wolgast photo.
basic methods of installing leadouts. For
low-wing and midwing subjects, Low
Wing-A and Low Wing-B are representative
methods.
In the former, the bellcrank is located in
the core of the wing and the leadouts exit
the bottom of the wing. They are supported
near the bottom of the wingtip. This
technique would be used on a low-wing
Scale model when full cockpit details would
be installed.
Low Wing-B is for the fuselage-mounted
bellcrank, as in a sport model with which
there is little concern about cockpit detail. In
this configuration the leadouts are supported
with a guide on top of the wing.
The High Wing sketch shows the leadout
guide, made from formed piano wire, that is
attached to the bottom of the wing near the
wingtip. Leadouts on the Biplane are
supported with a plywood or sheet-metal
guide that is attached to the upper and lower
wing struts of the airplane.
I have described supporting the leadouts
with a guide located at the wingtip, but there
is an alternative for low-wing and midwing
12sig5x.QXD_00MSTRPG.QXD 10/22/10 9:07 AM Page 154
aircraft that many Scale modelers have used
successfully. In spite of a couple degrees of
dihedral, the leadouts can be concealed
inside the wing.
This method does away with the need for
exit holes in the bottom of the wing and a
guide at the wingtip. The concealment
technique certainly enhances the appearance
of the airplane for static judging.
Alongside the Low Wing-A and Low
Wing-B sketches I have shown possible
methods of making the leadout guides
removable. The former has an 8-32 screw
drilled with a small hole and a piece of thin
piano wire formed into a loop and soldered
into the screw. The screw is threaded into a
mount in the wing and locked into place with
a nut.
The Low Wing-B sketch shows fixed and
a removable guides. This removable guide
type can be employed when flexible leadouts
are used.
The High Wing and Biplane present a
unique set of problems in creating leadout
supports. The guide alongside the High
Wing sketch is formed from piano wire and
substantially mounted in the wing.
The length of the wire guide depends on
how far down in the model the bellcrank is
mounted. The lower the bellcrank mounting
in the fuselage, the longer the wire mount. It
is important that the leadouts are parallel
with the bottom of the wing, to provide
stable flight performance.
The Biplane leadout guide is generally
mounted between the outer wing struts, as
shown. Again, the guide placement should
be such that the leadouts (depending on
bellcrank location) are parallel with the
upper and lower wing, to avoid flight
problems. The guide can be made from
plywood or sheet metal and firmly fastened
to the wing struts.
I asked the question earlier in the column
about improving the appearance of Scale
models for static judging. With extra
planning and ingenuity during the building
process, it seems that the leadouts could be
hidden and the guide could be made
removable.
Models of World War II fighters and
bombers might lend themselves to that idea
through the use of removable wing panels in
which flexible leadout connections could be
hidden. High Wing and Biplane subjects are
additional candidates for removable guides
and hidden leadouts. A well-executed
removable panel in the side of the fuselage
might also be used to hide coiled flexible
leadouts.
The use of removable guides and hidden
leadouts are permitted, as stated in CL Scale
general rule 7.5; paragraph e states that
“Removable lead-out guides may be
employed. They may be removed for static
judging and reinstalled prior to flight.”
It might also be useful to review rule 7.5,
paragraph d, concerning permission to
remove and replace scale bombs, rockets,
etc. for static judging and flying.
Please send ideas, notice of upcoming CL
Scale events, contest reports, and especially
photos to me at the e-mail address at the top
of this column.
Contributions for this column have been
lean. I hope that since the flying season has
been in full swing and the National
Championships is over, many of you will
find the time to jot down a few words and
send a photo or two telling us about your
summer activities.
Remember that this column can be only
as active as you make it. I hope to be
hearing from you. MA
Sources:
Bill Boss
77-06 269th St.
New Hyde Park NY 11040
National Association of Scale Aeromodelers
www.nasascale.org
Edition: Model Aviation - 2010/12
Page Numbers: 154,155
Edition: Model Aviation - 2010/12
Page Numbers: 154,155
154 MODEL AVIATION
types are high wing,
low wing, midwing,
and biplane.
When installing
leadouts, we make
every effort to create
a straight line from
the bellcrank
through the leadouts
and from the flying
lines to the control
handle. Properly
supporting the
leadouts at or near
the wingtip of the
inboard wing will
ensure that the
airplane maintains
the proper flight
attitude and control.
If the leadouts
are not properly supported at, or near, the
inboard wingtip, the aircraft could yaw from
side to side or take on an undesirable flight
attitude and have poor control.
The accompanying sketch shows some
In the OctOber column I wrote about
the three-line control system and the
necessity of having a balanced setup to
provide maximum safety and good flight
performance. I also mentioned that the
control handle and bellcrank must
complement each other or be a
matched set, to obtain maximum
throw for proper engine throttle
control and prevent slack in the
flying lines.
This month I will continue with
control-system basics, concerning
leadouts, their installation, and their
means of support. I suspect that there
are many ways to install and support
leadouts, but for purposes of this
column I will cover the three or four
basic methods.
Some of what follows might be
useful to newcomers as well as some
of the old-timers. A review is good
for everybody.
What is the purpose of the
leadouts? How must they be installed
and supported to keep the model in
stable flight? What are the rules
governing the use of external
removable guides, so that an airplane
has a clean look during Scale static
judging?
Leadouts are a means of
connecting the flying lines to the
aircraft bellcrank, and the placement
of the leadouts depends on the type
of model you are building. Basic
Also included in this column:
• Contest reminder
Leadout installations
[[email protected]]
Control Line Scale Bill Boss
This shows a few ways that leadouts and leadout guides can be installed. Also shown are a
couple of methods to make leadout guides removable, for better static judging scores. Author
sketch.
Lou Wolgast’s Profile de Havilland D.H.88 Comet represents one
of three full-scale wood-framed racers that entered the Englandto-
Australia MacRobertson Air Race in 1934. The model is
powered by two .049 engines. Wolgast photo.
basic methods of installing leadouts. For
low-wing and midwing subjects, Low
Wing-A and Low Wing-B are representative
methods.
In the former, the bellcrank is located in
the core of the wing and the leadouts exit
the bottom of the wing. They are supported
near the bottom of the wingtip. This
technique would be used on a low-wing
Scale model when full cockpit details would
be installed.
Low Wing-B is for the fuselage-mounted
bellcrank, as in a sport model with which
there is little concern about cockpit detail. In
this configuration the leadouts are supported
with a guide on top of the wing.
The High Wing sketch shows the leadout
guide, made from formed piano wire, that is
attached to the bottom of the wing near the
wingtip. Leadouts on the Biplane are
supported with a plywood or sheet-metal
guide that is attached to the upper and lower
wing struts of the airplane.
I have described supporting the leadouts
with a guide located at the wingtip, but there
is an alternative for low-wing and midwing
12sig5x.QXD_00MSTRPG.QXD 10/22/10 9:07 AM Page 154
aircraft that many Scale modelers have used
successfully. In spite of a couple degrees of
dihedral, the leadouts can be concealed
inside the wing.
This method does away with the need for
exit holes in the bottom of the wing and a
guide at the wingtip. The concealment
technique certainly enhances the appearance
of the airplane for static judging.
Alongside the Low Wing-A and Low
Wing-B sketches I have shown possible
methods of making the leadout guides
removable. The former has an 8-32 screw
drilled with a small hole and a piece of thin
piano wire formed into a loop and soldered
into the screw. The screw is threaded into a
mount in the wing and locked into place with
a nut.
The Low Wing-B sketch shows fixed and
a removable guides. This removable guide
type can be employed when flexible leadouts
are used.
The High Wing and Biplane present a
unique set of problems in creating leadout
supports. The guide alongside the High
Wing sketch is formed from piano wire and
substantially mounted in the wing.
The length of the wire guide depends on
how far down in the model the bellcrank is
mounted. The lower the bellcrank mounting
in the fuselage, the longer the wire mount. It
is important that the leadouts are parallel
with the bottom of the wing, to provide
stable flight performance.
The Biplane leadout guide is generally
mounted between the outer wing struts, as
shown. Again, the guide placement should
be such that the leadouts (depending on
bellcrank location) are parallel with the
upper and lower wing, to avoid flight
problems. The guide can be made from
plywood or sheet metal and firmly fastened
to the wing struts.
I asked the question earlier in the column
about improving the appearance of Scale
models for static judging. With extra
planning and ingenuity during the building
process, it seems that the leadouts could be
hidden and the guide could be made
removable.
Models of World War II fighters and
bombers might lend themselves to that idea
through the use of removable wing panels in
which flexible leadout connections could be
hidden. High Wing and Biplane subjects are
additional candidates for removable guides
and hidden leadouts. A well-executed
removable panel in the side of the fuselage
might also be used to hide coiled flexible
leadouts.
The use of removable guides and hidden
leadouts are permitted, as stated in CL Scale
general rule 7.5; paragraph e states that
“Removable lead-out guides may be
employed. They may be removed for static
judging and reinstalled prior to flight.”
It might also be useful to review rule 7.5,
paragraph d, concerning permission to
remove and replace scale bombs, rockets,
etc. for static judging and flying.
Please send ideas, notice of upcoming CL
Scale events, contest reports, and especially
photos to me at the e-mail address at the top
of this column.
Contributions for this column have been
lean. I hope that since the flying season has
been in full swing and the National
Championships is over, many of you will
find the time to jot down a few words and
send a photo or two telling us about your
summer activities.
Remember that this column can be only
as active as you make it. I hope to be
hearing from you. MA
Sources:
Bill Boss
77-06 269th St.
New Hyde Park NY 11040
National Association of Scale Aeromodelers
www.nasascale.org
