October 2004 145
THIS MONTH I’LL take a close look at control horns. These items
are so inexpensive that they are taken for granted and often
overlooked. I like to make certain that all of my models’ components
are free of defects, tight, and well adjusted.
Back in the good old days, Combat model kits came with a
plywood control horn. The wire attachment pushrod system was just
that—music wire that had either a “Z” bend or a 90° bend that went
through a hole in the plywood.
With the 90° method, you had to put something on the end of the
wire to keep it in place. Some fliers used a wheel collar, others used a
soldered-on washer, and still another method was to use some sort of
wire keeper.
I must admit that my soldering skills were rather weak. I learned
this the hard way, while flying a model. After losing an airplane or
two because of soldering failures, you soon either work on bettering
your skills or find another method of attaching the pushrod to the
control horn.
The only times I actually used the plywood horns were on my first
two models: a Junior Ringmaster and then a Yak-9. I soon found that
the experienced modelers were using a good-quality aluminum horn
that featured bushing made by Dynamic Models—the same company
that produced the legendary Johnson Combat Special engines.
Those with excellent soldering skills would attach the music-wire
pushrod right to the bushing on the control horn. I always used a
wheel collar. The problem with that type of system was that you could
not adjust the elevator to a neutral position once you bent the wire.
The pushrod that came with VooDoo kits was stout and difficult to
bend accurately. If your bend was off, giving you too much down, you
could put an adjustment kink in the pushrod to shorten it a bit. If you
had too much up-elevator, you were out of luck.
Sometime in the 1970s, the RC people developed threaded,
adjustable quick links. Howard Rush may have been one of the first
modelers to show this system on his Nemesis design. He had also
used tall nylon control horns that gave the elevator system further
adjustability.
Using adjustable quick links and tall control horns with multiple
holes gave the model builder a wide range of adjustment for
equalizing the amount of up and down and the total amount of throw.
Then modelers could set up their airplanes so that when they gave full
up, the models would not stall out and still give them a tight turn.
They could also add elevator movement when flying on windy days.
There was a variation to the nylon-control-horn system that used a
bolt with a nylon fitting that had a hole for a quick link. Using a bolt
allowed you to fine-tune the elevator movement since you could
adjust the throw one thread at a time. The bolts were sturdy and did
not fail unless they took a direct hit from another model.
The nylon horns do, on occasion, fail because of age. Nylon can
get brittle and eventually break. This typically happens after an impact
with the ground. Excessive vibration on an old horn will sometimes
cause a failure. It is a good idea to check all of your control horns on
all of your models from time to time.
CONTROL LINE COMBAT
Rich von Lopez, 8334 Colegio Dr., Los Angeles CA 90045
The author uses each of these handles for different events. Electrical tape holds hinge pin in place on smaller elevator; other
hinge pin is built into model’s structure.
You can clearly see the aluminum reinforcement as well as the
recessed bolts on the top elevator.
10sig5.QXD 7/23/04 9:30 am Page 145
146 MODEL AVIATION
The control-horn/pushrod system that
most of the European modelers utilize is a soft
aluminum knitting-needle-material pushrod
and a nylon control horn. They make little
fittings that go around the pushrod and are
then screwed tight to the pushrod. The head of
the screw keeps the screw from falling off of
the control horn. I have included a photo that
clearly illustrates what I am referring to. I
replace these fittings with wheel collars and 4-
40 bolts.
I have had some of the European fittings
fail, causing models to crash. The failure was
of the brass material itself. To keep the fitting
light, it was thinly made; thus if there was a
bit too much tension on the bolt, it would
Gearboxes for Electric Motors
•For 550 and 400 motors
•Available in 2.5, 3.0 and 3.5:1 ratios
•Increased thrust and flight times
•Lightweight & durable housing and gears
•Use with folding or fixed blade props
•Great Value at $21.95 suggested retail
MASTER AIRSCREW
Windsor Propeller Company, Inc.
Ph. 916.631-8386 • www.masterairscrew.com
Electric Folding Propellers
(12” and 15”)
Electric Only Series
Propellers:
6” through 13”
• Proven
Winner!
split. Sometimes this occurred in flight. I have
learned the hard way once again.
This system allows the pilots to adjust the
handle by making changes to the amount of
elevator they employ. This is done because
most handles the Europeans use do not have
any sort of adjustment device. They rely on
lines that are perfectly cut to equal lengths and
leadouts that are also equal. When they do
miss the mark, a pushrod adjustment will take
care of the difference.
Some of the really keen modelers take care
to gain even milligrams of a weight advantage
in the area of control horns. They will grind
down the bolts used to attach the control horn
to the baseplate so that no extra threads extend
beyond the baseplate. Others have even
countersunk the control-horn base so that the
bolt heads are flush with the top of the base,
and still others utilize aluminum bolts to shave
off a gram or two. The point is that you need
to look carefully at how you do things to get
adjustability and light weight.
Most modelers still use balsa as elevator
material, including the Europeans. Most will
reinforce the area where the control-horn bolts
pass through. The airplanes you get from
George Cleveland’s GRS Models company
have aluminum tape wrapped around the
center of the elevator so that the control horn
and the hinge-attachment fitting bolts pass
through the covering, the aluminum layer on
top, the balsa and the aluminum layer on the
bottom, and the covering.
The models you could once get from
Tomas Mejzlik utilized a thin layer of what
appeared to be fiberglass cloth. I have had to
make replacement elevators from time to time.
I employ a slightly different method that has
worked for me for years.
I start with a balsa elevator that has been
shaped and thinned at the edges and the rear,
but not where the bolts will pass through. I
mark the areas where the bolts will pass
through and reinforce these places with nylon
material attached using thin cyanoacrylate. I
wrap the nylon material around the front of the
elevator and continue on the bottom of the
elevator. Then I cover the elevator with Fascal.
This is a solid way of reinforcing elevators that
provides light weight and strength.
The most common way to attach the
elevator to the model or the model boom is to
use prefabricated hinge fittings—a music-wire
pin that travels through a piece of brass tubing
that has been attached to the model. The wire
hinge pin can be bent in such a way that it
touches the front of the elevator and is kept in
place with electrical tape.
Being able to put the elevators on and take
them off is wonderful if you are traveling with
models or have to box them up and ship them
to another part of the country.
A variation of a hinge pin going through
brass tubing is to have a stationary pin that is
glued to the model. The elevator will pivot on
the hole of the prefabricated hinge fitting. This
saves a bit of weight and works great.
The Wakkerman type models require that
the elevator be sewn on. I have used this
method for years on all the models I have
scratch-built, but I do it a bit different from the
Europeans.
I use braided nylon fishing line, a carpet
needle, and three holes on the inboard side of
the elevator and the outboard side of the
elevator. At one time I used as many as eight
holes on each side of the elevator; that turned
out to be overkill as far as strength was
concerned, and it took considerably more time
to do.
The Wakkerman models have what looks
to be a monofilament type of material sewn
across the length of the elevator. It does not
appear to be glued in place. My method
requires that you use cyanoacrylate glue to
keep the hinge from moving.
Back to handles and adjustability. Most of us
grew up using E-Z Just handles that allowed
for errors in line making. We simply
lengthened or shortened the leads on the
handle to get neutral on the elevator.
Later we got some excellent-quality
handles from George Aldrich that adjusted and
secured the cable with a nut that could be
finger-tightened. Most recently we have
European handles with a device that allows
adjustment while flying. Earlier in this column
I mentioned the nonadjustable handles that
most of the Europeans use.
What you like will depend on what feels
good to you and the line spacing you want. I
have included a photograph of a variety of
handles I use that you might want to try for
yourself. MA
10sig5.QXD 7/23/04 9:30 am Page 146
Edition: Model Aviation - 2004/10
Page Numbers: 145,146
Edition: Model Aviation - 2004/10
Page Numbers: 145,146
October 2004 145
THIS MONTH I’LL take a close look at control horns. These items
are so inexpensive that they are taken for granted and often
overlooked. I like to make certain that all of my models’ components
are free of defects, tight, and well adjusted.
Back in the good old days, Combat model kits came with a
plywood control horn. The wire attachment pushrod system was just
that—music wire that had either a “Z” bend or a 90° bend that went
through a hole in the plywood.
With the 90° method, you had to put something on the end of the
wire to keep it in place. Some fliers used a wheel collar, others used a
soldered-on washer, and still another method was to use some sort of
wire keeper.
I must admit that my soldering skills were rather weak. I learned
this the hard way, while flying a model. After losing an airplane or
two because of soldering failures, you soon either work on bettering
your skills or find another method of attaching the pushrod to the
control horn.
The only times I actually used the plywood horns were on my first
two models: a Junior Ringmaster and then a Yak-9. I soon found that
the experienced modelers were using a good-quality aluminum horn
that featured bushing made by Dynamic Models—the same company
that produced the legendary Johnson Combat Special engines.
Those with excellent soldering skills would attach the music-wire
pushrod right to the bushing on the control horn. I always used a
wheel collar. The problem with that type of system was that you could
not adjust the elevator to a neutral position once you bent the wire.
The pushrod that came with VooDoo kits was stout and difficult to
bend accurately. If your bend was off, giving you too much down, you
could put an adjustment kink in the pushrod to shorten it a bit. If you
had too much up-elevator, you were out of luck.
Sometime in the 1970s, the RC people developed threaded,
adjustable quick links. Howard Rush may have been one of the first
modelers to show this system on his Nemesis design. He had also
used tall nylon control horns that gave the elevator system further
adjustability.
Using adjustable quick links and tall control horns with multiple
holes gave the model builder a wide range of adjustment for
equalizing the amount of up and down and the total amount of throw.
Then modelers could set up their airplanes so that when they gave full
up, the models would not stall out and still give them a tight turn.
They could also add elevator movement when flying on windy days.
There was a variation to the nylon-control-horn system that used a
bolt with a nylon fitting that had a hole for a quick link. Using a bolt
allowed you to fine-tune the elevator movement since you could
adjust the throw one thread at a time. The bolts were sturdy and did
not fail unless they took a direct hit from another model.
The nylon horns do, on occasion, fail because of age. Nylon can
get brittle and eventually break. This typically happens after an impact
with the ground. Excessive vibration on an old horn will sometimes
cause a failure. It is a good idea to check all of your control horns on
all of your models from time to time.
CONTROL LINE COMBAT
Rich von Lopez, 8334 Colegio Dr., Los Angeles CA 90045
The author uses each of these handles for different events. Electrical tape holds hinge pin in place on smaller elevator; other
hinge pin is built into model’s structure.
You can clearly see the aluminum reinforcement as well as the
recessed bolts on the top elevator.
10sig5.QXD 7/23/04 9:30 am Page 145
146 MODEL AVIATION
The control-horn/pushrod system that
most of the European modelers utilize is a soft
aluminum knitting-needle-material pushrod
and a nylon control horn. They make little
fittings that go around the pushrod and are
then screwed tight to the pushrod. The head of
the screw keeps the screw from falling off of
the control horn. I have included a photo that
clearly illustrates what I am referring to. I
replace these fittings with wheel collars and 4-
40 bolts.
I have had some of the European fittings
fail, causing models to crash. The failure was
of the brass material itself. To keep the fitting
light, it was thinly made; thus if there was a
bit too much tension on the bolt, it would
Gearboxes for Electric Motors
•For 550 and 400 motors
•Available in 2.5, 3.0 and 3.5:1 ratios
•Increased thrust and flight times
•Lightweight & durable housing and gears
•Use with folding or fixed blade props
•Great Value at $21.95 suggested retail
MASTER AIRSCREW
Windsor Propeller Company, Inc.
Ph. 916.631-8386 • www.masterairscrew.com
Electric Folding Propellers
(12” and 15”)
Electric Only Series
Propellers:
6” through 13”
• Proven
Winner!
split. Sometimes this occurred in flight. I have
learned the hard way once again.
This system allows the pilots to adjust the
handle by making changes to the amount of
elevator they employ. This is done because
most handles the Europeans use do not have
any sort of adjustment device. They rely on
lines that are perfectly cut to equal lengths and
leadouts that are also equal. When they do
miss the mark, a pushrod adjustment will take
care of the difference.
Some of the really keen modelers take care
to gain even milligrams of a weight advantage
in the area of control horns. They will grind
down the bolts used to attach the control horn
to the baseplate so that no extra threads extend
beyond the baseplate. Others have even
countersunk the control-horn base so that the
bolt heads are flush with the top of the base,
and still others utilize aluminum bolts to shave
off a gram or two. The point is that you need
to look carefully at how you do things to get
adjustability and light weight.
Most modelers still use balsa as elevator
material, including the Europeans. Most will
reinforce the area where the control-horn bolts
pass through. The airplanes you get from
George Cleveland’s GRS Models company
have aluminum tape wrapped around the
center of the elevator so that the control horn
and the hinge-attachment fitting bolts pass
through the covering, the aluminum layer on
top, the balsa and the aluminum layer on the
bottom, and the covering.
The models you could once get from
Tomas Mejzlik utilized a thin layer of what
appeared to be fiberglass cloth. I have had to
make replacement elevators from time to time.
I employ a slightly different method that has
worked for me for years.
I start with a balsa elevator that has been
shaped and thinned at the edges and the rear,
but not where the bolts will pass through. I
mark the areas where the bolts will pass
through and reinforce these places with nylon
material attached using thin cyanoacrylate. I
wrap the nylon material around the front of the
elevator and continue on the bottom of the
elevator. Then I cover the elevator with Fascal.
This is a solid way of reinforcing elevators that
provides light weight and strength.
The most common way to attach the
elevator to the model or the model boom is to
use prefabricated hinge fittings—a music-wire
pin that travels through a piece of brass tubing
that has been attached to the model. The wire
hinge pin can be bent in such a way that it
touches the front of the elevator and is kept in
place with electrical tape.
Being able to put the elevators on and take
them off is wonderful if you are traveling with
models or have to box them up and ship them
to another part of the country.
A variation of a hinge pin going through
brass tubing is to have a stationary pin that is
glued to the model. The elevator will pivot on
the hole of the prefabricated hinge fitting. This
saves a bit of weight and works great.
The Wakkerman type models require that
the elevator be sewn on. I have used this
method for years on all the models I have
scratch-built, but I do it a bit different from the
Europeans.
I use braided nylon fishing line, a carpet
needle, and three holes on the inboard side of
the elevator and the outboard side of the
elevator. At one time I used as many as eight
holes on each side of the elevator; that turned
out to be overkill as far as strength was
concerned, and it took considerably more time
to do.
The Wakkerman models have what looks
to be a monofilament type of material sewn
across the length of the elevator. It does not
appear to be glued in place. My method
requires that you use cyanoacrylate glue to
keep the hinge from moving.
Back to handles and adjustability. Most of us
grew up using E-Z Just handles that allowed
for errors in line making. We simply
lengthened or shortened the leads on the
handle to get neutral on the elevator.
Later we got some excellent-quality
handles from George Aldrich that adjusted and
secured the cable with a nut that could be
finger-tightened. Most recently we have
European handles with a device that allows
adjustment while flying. Earlier in this column
I mentioned the nonadjustable handles that
most of the Europeans use.
What you like will depend on what feels
good to you and the line spacing you want. I
have included a photograph of a variety of
handles I use that you might want to try for
yourself. MA
10sig5.QXD 7/23/04 9:30 am Page 146