Old-Timers-2007/12

158 MODEL AVIATION
An explanation of both the RC and FF 1/2A Texaco events
Old-Timers Bob Angel | [email protected]
Also included in this column:
• Problems solved by using 2.4
GHz radios
• 2.4 GHz safety issues
• Discus launch comes to OT
flying!
• The Omahawks check in
Hardy Robinson’s magnificent Taube won
the popular vote in a special “Flying
Concours” event during a SAM 26-
sponsored OT meet at Taft in 2006.
Eut Tileston’s modern-looking OT Lancer requires more construction effort than
most OT models but is well worth it. Tandy Walker photo.
The Omahawks club (Nebraska) has a contingent of OT flying enthusiasts. They are
not into heavy competition, but are strictly a fun-flying group.
1/2A TEXACO IS a good starting point for
any aspirant to Old-Time (OT) flying, but it
is also one of the most popular events
among seasoned fliers and contestants. It
began life as a Society of Antique Modelers
(SAM) RC special event and later graduated
to a basic event flown at each annual SAM
Championships.
At the 2006 SAM Champs 41 people
entered 1/2A Texaco. Although only 31 flew,
it was still the most popular among the 27
RC or 27 FF categories.
The FFers picked up on the 1/2A Texaco
event too and put their own spin on it, with
slightly different rules from those in RC. It’s
still a special event for FF, which means that
it’s often flown in local contests but may or
may not be flown at the SAM Champs.
The 1/2A Texaco event wasn’t offered for
FF at the 2006 SAM Champs. A couple
similar special categories—Nostalgia 1/2A
glow and Nostalgia 1/4A glow—were flown
instead.
The simplicity of the RC 1/2A Texaco
rules and of the aircraft themselves is mainly
responsible for the event’s popularity. A
Cox reed-valve .049 engine is required,
using an integral 5.1cc tank mount such as
that supplied on the Cox Texaco Jr. or Babe
Bee engine.
A two-channel (two-servo) radio is all
that is required to operate the elevator and
rudder controls. You simply fill the tank,
start, launch, and try for a 15-minute max
flight. The engine runs until the fuel is
exhausted, similar to the way most CL
models are flown. The best two of three
allowed flights are scored, and the winner is
usually determined by a flyoff if two or
more fliers max.
Aircraft allowed in RC 1/2A Texaco are
any pre-1943 powered designs, which can
be scaled to any size. Most are built in the
range of 288-350 square inches of wing
area, use 6- to 8-inch propellers, and use
5%- to 15%-nitro fuel. They are required to
weigh a minimum of 8 ounces per square
foot of planform wing area.
There are two basic approaches to flying
the event. The most prevalent is to use a
small, light model with the maximumallowable
8-inch-diameter propeller and
low-nitro fuel while shooting for a fourminute
or longer engine run. The engine
lugs with that much propeller, but it eats up
flight time toward that 15-minute max while
it climbs slowly to altitude.
The alternate approach (which I favor) is
to use a larger (and heavier) model, a 6-inch
propeller and higher-nitro fuel, and go for
maximum altitude during a two-and-one-
quarter- to three-minute engine run. The
smaller propeller allows for a higher rpm,
resulting in better fuel draw and steadier
running.
Cox reed-valve engines can be extremely
frustrating to operate and often suffer speed
changes and flameouts during the run.
Because of their small size they are much
less tolerant of any kind of dirt, especially in
the fuel supply.
Bill Schmidt recently wrote an excellent
article about 1/2A engine operation for SAM
Speaks. It can be summarized with “Be a
fanatic about filtering and maintaining clean
fuel.”
I prefer the old open-exhaust engines,
but they can hand you more cleanliness
problems than the newer two-slot exhaust
types. If you kick up the tiniest speck of dirt
on the piston side, you’re in trouble until it’s
gone.
Years ago I started wrapping a paper
towel around my engine, supposedly to keep
it clean between runs. Mistake! My wife
reminded me about the fibers in those paper
towels. Reliability returned when I
abandoned that practice.
It was a little embarrassing because I had
designed super-clean rooms for working on
Atlas and other missile hydraulic steering
actuators. When a speck of fiber or lint can
bind a large, high-pressure ram used for
steering an ICBM, what can you expect
from a little .049 engine?
The FF rules for 1/2A Texaco have at
least a couple variances from RC that more
closely follow the historical Texaco event
rules. The models are older, from the
Antique category of pre-1939 design. Flight
time is unlimited (no max). Also, FF has no
minimum weight requirement—which may
or may not follow the original Texaco rules
as flown during the 1930s.
Another difference between FF and RC
rules seems unusual. Slightly larger glow
engines of up to .051 displacement and
more modern and powerful rotary-valve
designs are allowed in FF. Also permitted is
15cc of fuel, or nearly three times the
allotment of the RC models. I haven’t spent
much time observing that particular event,
but it would seem to result in some fairly
long chases.
The old and the new are represented by an
OT RC airplane flown with a new spread
spectrum 2.4 GHz radio. I’ll try not to
duplicate the general news about spread
spectrum while I write about what the
technology has in store for the OT RC flier.
Early tests at my home flying field
indicate much-improved rejection of the
spark-ignition noise, which often causes
radio glitching. We had several models
develop ignition interference problems that
were becoming frustrating to solve.
Steve Remington bought one of the
Futaba FASST systems and replaced his
Futaba FM receiver in a Super Cykepowered
model. The new system cured the
problem, so he ordered a second receiver,
which immediately cured the same problem
in his Ohlsson & Rice-powered Playboy.
I became a copycat and followed Steve’s
lead. I usually follow the motto of “never
buy the Mark I model of anything”;
however, after chasing the interference
gremlin for several weeks, enough was
enough.
I replaced my Futaba FM receiver with a
FASST receiver. I chose the Futaba system
because it allowed me to keep the same
servos and its small size fit the space
allotment nicely. After getting the same
immediate cure of the glitches, I took it a
step further.
Most RC spark-ignition aircraft are
flown using a 10K-ohm resistor in the hightension
lead for radio-noise suppression.
After testing progressively smaller-capacity
resistors I’m flying the Anderson Spitfirepowered
model with a 1K-ohm resistor. I
wasn’t quite able to eliminate the resistor
completely.
A couple safety items popped up with the
2.4 GHz systems. We determined that on
our home field we’d follow AMA’s general
advice of requiring frequency-pin use with
the new radios, even though they are
supposed to be impervious to accepting or
producing interference between themselves
and other radios. That’s to keep us in the
frequency-control habit because for
sometime we’ll be using multiple systems,
some old and some new, for our varied fleet.
The second safety problem emerged
when one flier (who will remain anonymous
upon request) switched immediately from
flying his 2.4 GHz to another model using a
standard FM transmitter. His model took
off, and at roughly 100 feet out he yelled the
famous “I ain’t got it!” as the aircraft went
down.
As he walked out to retrieve and survey
the damage, he noticed that his FM antenna
was approximately the same length as the
2.4 GHz antenna. He had become so
immediately accustomed to the short
antenna that he forgot to extend the FM
antenna.
Discus launch will be finding its way into
OT FF Glider flying! The question arose of
whether or not discus launch would be
allowed at this year’s SAM Champs. FF
CD Gene Wallock sagely pronounced it
okay, citing precedence in allowing various
kinds of grips permitted on OT Gliders. He
also opined that it might save a few muscle
cramps and kinks in some aging arms.
However, there was also a cautionary
note about careful practice and maybe
keeping it down to a single revolution to
prevent the pilot from crashing.
Richard Behrens of the Omahawks club,
based in Omaha, Nebraska, sent a nice
letter and picture of its OT group. With a
limit of three pictures in the column I
won’t be able to include all the photos I
received, but as a reward for being one of
the first contributors I’ll acknowledge this
group.
Most, if not all, appear to be
distinguished and genuine old-timers—not
just 29-year-old “wanna-bes.” Richard
mentions that they have mostly stayed
away from SAM competition because of a
perceived complexity in the events and a
certain lack of experience with them. He
also mentioned a lack of experience with
ignition engines and gave some opinions
about rules to entice beginners.
I hope the 1/2A Texaco rules I outlined
this month might inspire the group
members to consider giving that event a
try. I’ll bet that if one or two 1/2As showed
up at the field, by next year they might
have enough participation to join one of
the annual 1/2A Texaco postal events.
Let’s meet here again in a couple of
months. MA