Flying for Fun-2007/04

Frank Wyatt with a CL handle in his right
hand and the RC transmitter on his
stomach. See text for details.
Why are a CL bellcrank and RC servos and receiver in this view of the fuselage bottom?
The text supplies an explanation.
Also included in this column:
• RC/CL “switch-hitters”
• An ancient CL design
converted to RC electric
• Thoughts on the effects of
torque
• Jim Walker models
• New electric cells
THE RESPONSE TO my wondering in the December issue whether
or not anyone enjoyed my occasional efforts to describe unusual fullscale
prototypes elicited a huge response, all affirmative. The results
have been satisfying; I’m humbled and challenged by the kind words
sent by so many readers.
My sincere thanks to all who responded with words of
encouragement. I will do some more. Any nominees?
Since writing that column I have been fortunate to receive a much
better three-view of the Stearman-Hammond and the Cessna “Magic
Carpet.” If you would like a copy, send an SASE (#10 business-size
envelope) to me at 909 N. Maize Rd.,
Wichita KS 67212. I cannot send them via Email.
For some reason I insist on misspelling
“Ercoupe,” as Weldon Smith informs me. All
my adult life I’ve thought the name had an
“o” following the “r.” Not only that, but I’ve been mispronouncing it
as well. Thanks, Weldon.
Switch-hitter is a term that is normally used to describe a baseball
player who can bat right- or left-handed depending on which hand the
pitcher is using. Keeping with that theme I’m going to feature some
models that have been converted from RC to CL and CL to electricpowered
RC.
Frank Wyatt of Jacksonville, Florida, is flying ordinary ARF RC
Scale models as CL models. Not only that, but he is using an old
This Sportsman Aviation RC ARF has been converted to a CL Sport Scale model with
retracts, flaps, and throttle activated by radio control.
A Scientific Models Cyclone. Notice the Ohlsson & Rice decal on
the side and the wheels with wooden hubs.
A clear-doped and silked Tethered Trainer illustrates original
construction. This is unusual for a 1943 CL design.
Transparent covering on Ed Solenberg’s RC electric conversion of
a Tethered Trainer. Some structure lightening is evident.
Reproduction of 60-year-old ad for Scientific Models’ Cyclone—the
same model as the earlier Tethered Trainer. Note Walker patent.
transmitter/receiver and servos to operate the retracts, throttle, and
flaps on these models. It took me a few minutes to grasp what he was
doing, and then it occurred to me that you readers might find this
concept of interest.
A handful of advanced CL Scale modelers have been using
specialized, custom-built transmitters strapped to their belts to operate
functions in their world-class competition aircraft for several years.
However, Frank is flying sport CL using RC ARFs and old radio
equipment at a greatly reduced investment and with much less
complexity.
Frank uses an old camera strap clipped into a pair of eyebolts in
the transmitter’s case to hold his old transmitter onto his stomach.
That way he can move the appropriate sticks with his left hand while
flying with the CL handle in his right hand.
He leaves the transmitter antenna retracted, but range is not a
problem at 70 feet and old AM systems are fine. Does one need to get
a pin on a frequency board to fly CL? That depends on the facility.
Frank buys stock RC ARFs with built-in retracts and flaps, adds a
1/4 plywood plate for a 4-inch Brodak bellcrank, and runs .027
leadouts through tubing in the fuselage side and plywood wingtip
guides. The servos are straight stock units. This is not a use for RC
ARFs that one sees very often.
Frank sent along a video of the models flying, and they seem to
perform the same as any kit-built CL Scale models. Innovation and
inventiveness have been hallmarks of modelers throughout history,
and this application certainly meets the criteria.
I’m obligated to mention that the use of any device broadcasting a
radio-frequency signal is illegal for use in any AMA CL contest. This
concept would be lots of fun for sport flying.
What a novel use for RC ARFs and old radio-control equipment!
This just might catch on. It certainly would add a dimension of fun
to flying CL.
Let’s switch to the other side of the plate. How about ancient CL
designs flown via RC? Ed Solenberger of Santa Rosa, California, sent
photos and details of a wonderful conversion project that will ring
bells for some of us old-timers.
Ed resurrected the Tethered Trainer from a November 1943 Air
Trails and converted it to an electric-powered RC model. This sort of
thing has been done with Stanzel Sharks, and at one time Top Flite
kitted an RC version of George Aldrich’s immortal Nobler. That
conversion is novel because of the rarity and vintage of the prototype.
The Tethered Trainer, designed by Earl
Cayton, was something of a breakthrough
design in 1943, when CL designs were
hogged from extremely strong, heavy balsa
blocks. I presume that those earliest
published designs and kits were in many
ways influenced by the Walker Fireball,
which American Junior kitted just before
World War II.
The Fireball featured a machine-shaped,
solid-balsa fuselage divided down the
horizontal centerline to provide access to the
ignition system and batteries, which were
placed in a hollowed-out interior. The wings
were made from sheet balsa, top and
bottom, over ribs, and the tail feathers were
solid sheet.
The successes of Jim Walker’s design
probably led many other designers to
conclude that the way to go was sturdy and
therefore heavy models—sort of the rockon-
a-string concept. The Tethered Trainer
was a breakthrough in much lighter
structures and actually used techniques that
were familiar to FF designers and builders.
Notice the sheet-balsa fuselage sides,
former and stringer structure, and built-up
tail surfaces. The Tethered Trainer
demonstrated that a CL model did not need
to be built like a rock to fly well.
I remember being extremely attracted to
the design when the construction article
came out, but at the time I did not have a
suitable engine. In those days the cost of a
new engine was considerable compared to a
carryout boy’s income (35¢ an hour). Not
only that, but no new engines were even
available in 1943 because of wartime
shortages.
In 1946 Scientific Models picked up the
Cayton design and kitted it as the
“Cyclone.” I did build one and recall that it
was a great flier on an O&R .23 engine on
glow. Although the ad implies that the
Cyclone was suitable for a .60, it most
certainly would have been wild and terribly
nose-heavy with that power plant.
Ed lightened the design a bit and flies his
with an E-flite Park 370 Outrunner motor.
Batteries are three Li-Poly cells for 1080
Kv. The propeller is a 9 x 4.7 APC electric.
Covering is a low-heat film from Hobby
Lobby called “Polycover.” The overall
weight is a mere 12.5 ounces.
Full-size plans were available for many
of the designs published in Air Trails back
then from the magazine plans service for
25¢, as I recall. Plans for the Cyclone are
now available through the AMA Plans
Service as set 29252. Check the Web site
for an astonishing list of FF, CL, and even
old RC designs.
Although it was designed more than 60
years ago, the Tethered Trainer/Cyclone has
been converted into a terrific-flying electric
RC model—certainly not a use even
remotely considered when it was a new
design.
One can only wonder how this concept
might work with some of the other CL
designs of long ago. How about an electricpowered
RC Chief, Madman, Zilch, etc.?
Notice in the pictures of the CL models that
some are set up to fly counterclockwise and
others fly clockwise. What is that all about?
In the early days of CL flying, many kits
and magazine designs took advantage of the
tendency of a motor/propeller’s torque to
turn the model left, thus helping keep the
lines tight. We lived in fear of a CL model
losing line tension and consequently having
no control of it.
Many old CL fliers still prefer to fly
clockwise as a result. I think the
counterclockwise pattern was started when
we learned to fly inverted since upside
down the lines tended to stay tighter. For
left-handed pilots clockwise was also more
comfortable.
When 1/2A Proto racing was introduced
as an official AMA event for kids, Dale
Kirn made and sold left-hand (reverserotation)
crankshafts available for Cox Tee
Dee engines. These and a reverse-pitch
propeller helped kids, for whom the event
was designed, fly with tight lines even
though they flew the models
counterclockwise.
My left-handed son Bruce flew his CL
Scale entries clockwise, which always
caused a stir. Several times at the Nats
someone began yelling at us that we
were setting up on the wrong side of the
circle. His method helped keep his lines
tight, particularly on windy days.
As mentioned in previous columns,
all this pertains to two-line systems.
Stanzel Mono-Line, a single line that was
twisted for control, didn’t need tight
lines at all.
Those who fly RC models know their
aircraft tend to turn left on takeoff, and
most designs require right rudder early in
the takeoff run—particularly taildraggers.
The same thing is true with
Power FF, where the power pattern at
launch tends to go left.
That is a result of the torque of the
propeller’s counterclockwise rotation.
Torque compensation is also the reason
why many RC designs need right thrust
in the engine mount.
A-J Models is the American Junior
models name used on the Jim Walker
products. I am writing this just before
Christmas, but you won’t see it until
March. I wish I’d thought of mentioning
this item in the October issue, but I will
now.
Frank Macy (http://americanjunior
classics.com) has revived many of the
Jim Walker designs, including the classic
A-J Interceptor and Hornet, and has them
for sale. For those who don’t know or
have forgotten, the Interceptor was a
folding-wing, catapult-launched glider
and the Hornet was a wonderful-flying,
all-wood, rubber-powered model.
These models make wonderful gifts
for youngsters (of any age). Many of us
old guys learned much about trimming,
balancing, and enjoying model airplanes
with Interceptors. I’ve had a ball flying
mine, and the darn things still are
strongly attracted to trees even after 60
years. We and the trees have grown up
and out (with a pure white top in my
instance), but the fun remains.
Frank publishes a newsletter containing
all sorts of interesting photos and history.
Go to his Web site for a real treat.
Lithium-manganese, also referred to as
“123,” cells are being used in electricpowered
models. These are the lowercost
and safer units that are turning up in
Black & Decker, Skil, and other
manufacturers’ cordless tools.
The cells’ distributor currently
charges the toolmakers approximately $4
per cell, but for hobby use they are more
along the lines of $10 per cell. For some
good information and technical papers go
to www.fmadirect.com and follow the
link to 123 batteries.
Several advantages of these new cells
are more energy per ounce, they won’t
ignite if overcharged, and hopefully
lower cost.
I hope this column has shown you some
ways to fly for fun. MA