Good luck and fair winds to all of this year’s Nats
contestants. For those stuck at home like me, Jim
Quinn will again be providing daily NatsNews
updates this year. Someday I hope to make the trek to
Muncie, Indiana.
Competition
Those who compete in RC Aerobatics (Pattern) are
a rare breed. National Society of Radio Controlled
Aerobatics (NSRCA) members number only a few
hundred. Many understand our rarity. Some members,
including me, ask why they compete at all. It certainly isn't for the prize money. Why then?
RC Aerobatics readers have
corresponded that they are Pattern
enthusiasts, but choose not to compete.
Some fly Pattern airplanes; others do
not. If you are a Pattern enthusiast,
perhaps you can help me understand
why I compete by telling me why you
do not compete. Is it because of cost,
commitment, travel, or is it that you
simply don’t want to? I would like to
hear from you.
Help us all understand the other
side of Pattern flying—the enthusiast
who flies just for
fun. I look forward
to hearing from
you, and feel free
to share a picture
or two of your
favorite airplane.
Energy
Last year I sold
my Honda EU2000i generator in favor
of a deep-cycle battery. After selling
our travel trailer, I couldn’t justify
the size and weight of the generator.
Hondas have great resale value and I
got almost what I paid for it through a
craigslist posting.
Deep-cycle batteries are great for
everyday flying. They are small and
compact, but lack capacity for dry
camping during a contest weekend.
After investigating many alternatives,
I concluded contests are for flying, not
setting up solar arrays, wind generators,
or carrying more deep-cycle batteries.
A clever idea is to charge every
LiPo at home, take them all to the
contest, and use a battery charger with
regenerative discharge to keep a deepcycle
battery topped off. Pretty 21st
century if you ask me; watts are watts.
For convenience and independence,
it’s hard to beat a small generator and
power supply. I purchased an 800-watt
Honeywell generator for less than half
the price of a Honda EU1000i and my
calculations show it should be more
than enough to run an IOTA 55 power
supply all weekend.
Different Kinds of Boxes
Switching from glow- to electricpowered
airplanes has made me
rethink eld boxes several times. I’ll
never forget the looks on the faces of
my children the night I threw my old
fuel-soaked eld box into a camp re.
The kids roared as the ames grew tall,
displaying magical colors.
Being a frugal person, my rst
charge box was a converted $15
plastic toolbox. Its biggest shortcoming
was the externally mounted power
socket and fan. When set up on the
ground—as it often was at contests—
the fan sucked in dirt and I never felt
comfortable powering it up on dewladen
grass.
The next and current box was built
from a CD case, with the fans and
power socket mounted on top. When
the top is latched shut, there are no
external openings and dirt cannot get
inside.
The shortcoming of this box is
insects. The box has two lighted fans
(intake and exhaust) used to cool an
internally mounted IOTA 55 power
supply. With the aid of an IQ4 Smart
Controller, the IOTA is often left in
our dark garage charging a deep-cycle
( eld) battery.
Guess what. Insects are attracted to
the light of the fans and get sucked into
the box to their deaths. A charge box
full of dead insects is not a pretty sight.
The upside is an insect-free garage!
With the old eld box up in smoke,
I purchased another $15 toolbox to
replace it. I like having a eld box with
a lid. It keeps dirt out and sun off the
tools. The downside of this box is its
size. Being big enough to carry 20-inch
propellers or larger made it a lug to
carry to and from the car.
I later purchased a small toolbox for
everyday tools. Now, the big toolbox
stays in the car with “just-in-case” parts
and equipment.
At this point I thought I had
perfected my eld box setup, until
I attended a contest where quite a
few yards separated the pits from
the parking lot. Counting boxes—
transmitter box, battery box (small),
tool box, and charge box—represented
two trips from the car to the pits. This
didn’t count a sun shade, lawn chair, ice
chest, generator/deep-cycle battery, and
most importantly, an airplane. Valet
anybody?
One day it dawned on me that one
of the best attributes of the old (glow)
eld box was that it contained my
everyday tools and transmitter. A (on
sale) $25 Harbor Freight briefcase
now carries my everyday tools and
transmitter dirt free, thereby reducing
the box count by one.
For a quick after-work practice
session, I only need to take charged
batteries, transmitter briefcase, and an
airplane to the eld. Only two trips to
and from the car.
O.S. 1.60 Powerplant
More than a decade ago, Pattern
enthusiasts began using the O.S. 1.60
as a Pattern engine. Their efforts where
collectively quanti ed in 2006 by Jon
Lowe in the O.S. 160 Cookbook. The
cookbook, now dated, was the O.S.
1.60 de facto standard of its day.
During the same time the
“Cookbook” approach was being
developed, another distinctly different
approach was being established called
“Caveman.” The goal of Caveman was
to limit the number of components,
thereby reducing the risk of failure.
With help and encouragement
from others, Art Wagner has, for the
past 12 years, continued developing
the Caveman approach. Art was kind
enough to spend an afternoon talking
with me about the Caveman setup that
is in his beautifully executed, Mark
Hunt-designed Pentathlon Evo.
Components of the Caveman include
an O.S. 1.60, Hyde mount, Hatori
header, ES carbon pipe, and Tettra
bubbleless tank. That’s it—no pump,
regulator, or other maintenance items.
Cool Power Pro-Pattern 20% is the
fuel of choice. Economical and simple!
Working our way from the fuel source
and out through the exhaust, let’s take
a closer look.
A 14-ounce Tettra bubbleless tank
is mounted behind the firewall, with
the neck of the fuel tank protruding
through the firewall into the open
center of a Merle Hyde soft engine
mount. This arrangement minimizes
the length of the fuel tubing. Art
calculates that 14 ounces of fuel by
volume weighs 13 ounces. During FAI
competition, the Caveman consumes
roughly 7 to 8 ounces of fuel, thereby
minimizing the CG shift.
Art reports the CG shift of a
firewall-mounted fuel tank is not the
“big mountain” that people think it is.
His Evo doesn’t require any inflight
trim adjustments, even during practice
flights when the tank has been run
nearly dry. A simple header-mounted
pressure nipple provides tank pressure.
Mounting the engine at a slight cant
centers a wraparound Hatori header
in the pipe tunnel. To compensate
for engine right thrust, the tail of the
header is cut at an angle parallel to the
face of the center-mounted ES pipe.
The pipe length is not critical on
the Caveman setup. The header-topipe
gap is anywhere from 1/16 inch to
1/8 inch. Although expensive, Vitube
has been the longest-lasting coupler
material found to date. The edges of
the NMP pipe clamps are smoothed
to prevent abrasion and ensure the
assembly’s long life.
After breaking many headers,
Art discovered exhaust waves cause
longitudinal pipe movement leading
to the headers breaking. He developed
a mounting method to lock the pipe
longitudinally. To accommodate future
removal, a piece of carbon cloth is
added to the pipe where the mount
will contact it.
J-B Weld is then used to epoxy a
Dave Brown pipe mount to the ES
pipe. The resulting epoxy fillet locks
the pipe to the mount longitudinally.
The entire assembly is then attached to
the airframe using a Lord mount.
Art was specific that if a power loss
develops, it means there is a leak in the
system. When properly set up, pilots
can expect the Caveman to go many
flights without maintenance. Art plans
to build another Evo weighing less than
10 pounds and powered by an O.S.
Caveman 1.40.
I wish Art the best of luck in his
endeavor, and look forward to pictures
of his Caveman 1.40.
Sportsman of the Month
Picture contributions have tapered
off. It must be time for a change. How
about submissions for the world’s
greatest Pattern airplane of all time?
Just kidding!
I like receiving pictures from RC
Aerobatics readers. If you would like
to share a photo of an airplane, hauler,
or something else of interest to Pattern
enthusiasts, send it in. It would be great
to receive some pictures of the good
ole days of Pattern (hint, hint).
Flight complete.
