Small-Field Flying - 2009/08

IN THE JUNE column, I had the opportunity to share with you a
departure project from Pat Tritle. Normally known for his excellent
small-field scale models, he ventured into the world of converting
vintage rubber-powered airplanes to RC.
The model was a nice RC electric-powered Midwest Jabberwock.
The fact that Pat is a longtime FF builder as well as a prolific RC Scale
designer, I think he placed his foot on the proverbial slippery slope.
After experiencing the joys of flying his Jabberwock, Pat decided that
he needed another vintage rubber-powered airplane conversion.
This time he applied his design skills to the project and developed a
55-inch-span version of the venerable Comet Sparky that Ed Lidgard
designed. It is one of those designs that anyone who has been in the
hobby for a while and has enjoyed the world of FF at one time or
another might have felt the need to build.
The Sparky has lovely lines. Pat’s version is approximately double
the size of the original and retains all of the eye appeal. The photo that
Pat provided lets us see the model in all its glory.
The converted aircraft is powered by a Suppo 2208-13 outrunner
motor that turns a GWS 9 x 5 propeller using a two-cell, 1600 mAh Li-
Poly pack. Controls include rudder, elevator, and throttle. At a flying
weight of 14.2 ounces, the Tritle Sparky is a relaxed flyer—perfect for
small-field venues.
Pat is offering Sparky kits, and they are available now. They
include all of the laser-cut parts, full-size plans, and a custom-made
spinner that gives the model part of its special look. Please see the
source information at the end of the column for contact information.
Although Pat Tritle has shown us his vintage rubber-powered FF
conversion, he is still producing new scale designs aimed at the smallfield-
flying devotee. His recent designs have been at the larger end of
the spectrum.
Recognizing that transporting bigger models to the flying field and
other factors can be issues for some of us, his latest offering is what I
consider the “sweet spot size” for small fields. That is, airplanes with
wingspans of approximately 40 inches.
Look at the photo of Pat’s new 40-inch-span J-3 Cub. He has
developed Cubs in other sizes and, at first blush, his latest version
might look like a simple rescaled version of an existing design. I have
spent numerous hours developing a design and can tell you that
changing a model’s size involves much more work than simply telling
the computer to change a drawing size by a given percentage value.
By the time you accommodate changed wood sizes, structural
changes to reflect the new size, power installation, and related factors,
you have a new creation. Pat’s medium-size Cub is the same way; it’s
a new design. It is extremely nice and a great fit for those of us who fly
in venues that are at the smaller end of the field-size range.
The Cub has a flying weight of 7.2 ounces. With a wing area of 230
square inches, the loading is only 4.5 ounces per square foot. Power
turning an 8 x 6 propeller.
Energy is provided by a two-cell, 430
mAh Li-Poly pack. Rudder, elevator, and
throttle controls are employed, and the model
gets 20-minute flights. Oh yeah; the plug-in
wings make transporting the Cub easy.
Pat reports that the airplane’s flying
qualities are excellent. The controls are
responsive but not twitchy. It’s great for
flying sites where you have to maneuver in a
fairly tight box.
If you want one of these 40-inch Cubs, Pat
has kits available. They include the full-size
plans, all laser-cut parts, and great Keith
Sparks-produced vacuum-formed
cowl/engine cylinders. Pat’s contact
information is at the end of the column.
Our hobby is constantly changing. It seems
that there is something new almost every
month—especially in the world of micro RC.
What was once reserved for the dedicated
specialist has become available to anyone
with an interest. This means that anyone with
a desire to experience diminutive models can
venture into this fascinating world.
However, the wide range of options makes
it daunting for someone who is just getting
started. Heck, it can be daunting for those of
us who have been involved in micro-flying for
a while. Fortunately, Bob Aberle has released
a great reference on the subject.
The World of Indoor/Micro Radio
Controlled Model Aircraft is a CD laid out in
traditional book format. There are several
benefits to having such a reference in this
format. It keeps the cost down, and the
content is searchable. You can plug in a
subject of interest, and the computer will find
all the instances in the book. That beats
flipping through the pages of a traditional
paper book.
You will find 138 excellent photos and
comprehensive coverage of the world of
micro RC in Bob’s 118-page book on CD. At
$13, which includes shipping, you can’t go
wrong. To get your copy, visit John Worth’s
Cloud 9 RC Micro World Web site.
RTF and Innovation: Not long ago, I shared some thoughts about
members of our small-field-flying community using equipment
supplied with ParkZone micro RTFs in their models. The ParkZone
brick microreceiver package is terrific, but it’s not the only resource
for the innovative micro-airplane builder.
I received correspondence from Ron Bartley of Canada regarding
his employing the gear from a Megatech C.C. Flyer. He was not
completely happy with the way that model performed, so he built his
own airframe. This was Ron’s first venture into the world of smaller
RC aircraft.
The Megatech system is somewhat limited in functions, compared
to the ParkZone brick radio package. It offers only throttle and
nonproportional rudder control.
Given the C.C. Flyer gear’s limited capabilities, Ron selected a
design from the era in which bang-bang rudder-only control was the
norm. He chose the wonderful Bob Coon-designed Guided Mite that
appeared in the April 1958 Flying Models. With a wingspan of 21
inches, the Guided Mite was perfect for the Megatech gear.
In addition to the radio, Ron also used the motor and a five-cell,
180 mAh NiMH battery pack. The model’s final weight was 4.5
ounces, and it gives nice five-minute flights. Ron is justifiably
happy with his first venture into the world of “micro” RC—especially
since he could use the gear from his C.C. Flyer.
Ron sent photos, so you can fully appreciate his excellent work. If
August 2009 93
Sam Will has a slick method of retaining the wheels on his Pat Tritle
44
you have Internet access and would like a
copy of the original Guided Mite construction
article, visit the Web address listed in the
“Sources” section.
An Old Problem With a Nice Solution: One
of the major benefits of writing this column is
the wonderful correspondence I receive from
readers. The pen pals—perhaps that should be
e-mail pals—I have been able to enjoy are a
bonus.
One such friend is Sam Will of Arizona.
We were recently comparing notes regarding
our respective builds of Pat Tritle’s 44-inch
Tiger Moth, and Sam mentioned a neat way
for retaining the wheels.
Since the Tiger Moth is a scale model,
Sam wanted to keep with that spirit in doing
the wheel retention, but not necessarily a scale
representation of the full-scale airplane. The
system he came up with involves slipping a
piece of brass tubing over the bent piano-wire
axle. Brass bushing is held in place with thin
CA.
The brass tubing extends out just past the
width of the chosen wheel. A small hole is
drilled in the end of the tubing. The wheel is
placed on the brass bushed axle, and a
homemade cotter pin is inserted. The cotter
pin gives the wheel retainer a scale feel and is
easy to remove, in case Sam wants to service
the wheel.
I often have to bush the axle for the
wheels I select, and this straightforward
retention system is perfect when a bushed
axle is being used. Thanks for the great idea,
Sam.
This brings us to the conclusion of this
installment. I love hearing from you, so don’t
be bashful about sending an e-mail or a letter
via postal mail. My contact information is in
the source listing. MA
Sources:
Pat’s Custom Models
(505) 296-4511
www.patscustom-models.com
John Worth’s Cloud 9 RC Micro World
www.cloud9rc.com
1958 Guided Mite construction article:
www.parmodels.com/GM_Article.pdf
Paul Bradley
10201 Scarletoak Dr.
Independence KY 41051