Small-Field Flying - 2011/02

88 MODEL AVIATION
of new materials with the old concept of a membrane-covered
framework.
The standard approach for a membrane-covered structure is to build
the framework from sticks. This involves gluing joints and learning the
tricks associated with assembling a set of stick frames. It is not hard to
do or to learn, but it does require an investment of time.
These days we see many, if not most, small models made from
sheets of thin, lightweight foam. Using sheet foam normally translates to
a drastic reduction in build time with equal or lighter flying weights than
those of comparable built-up, balsa-frame, membrane-covered aircraft.
Because sheet foam is becoming such a popular construction
material for micromodels, Gordon thought he could take it to a new
level. One reason for building a frame-based model rather than one
made from solid sheets of the construction material is lighter weight.
Even with lightweight sheets of foam,
removing a large portion would mean an
overall weight savings.
Gordon has been making foam
Paul Bradley | bradleyp@Small-Field Flying ix.netcom.com
Also included in this column:
• The Firefly from Robert
Dance
• Pat Tritle’s dual-mode Bird
Dog
• New kits from Bob Selman
• Another throttle-only model
by John Krouse
• The ParkZone Micro T-28
gets clear vision
• A 200-square-inch oldie from
Bob Aberle
Making foam skeletons without a laser
Gordon Johnson takes “stick-and-tissue” structural concepts to a new level. His Airbender
has a film-covered foam framework cut from sheet stock and a wing frame.
Robert Dance’s Firefly was featured as a Flying Models construction
article. The 14.5-ounce aircraft is covered with yellow silk and
trimmed in blue dope.
Although Pat Tritle designed the L-19 for rubber-powered FF, it
would make a great conversion to small-field RC using
components from the ParkZone Micro P-51 or HobbyZone
Champ.
Light is might. Since we are in the middle of the traditional
building season, I’ll lead off with construction ideas from Gordon
Johnson. He is from the Boston, Massachusetts, area and is fairly
well known within the indoor micromodel world.
Although Gordon builds airplanes that Joe Malinchak normally
covers in MA’s “Micro-Flying” column, he has developed some
construction methods that can be applied to slightly larger aircraft
that are flown indoors and outside—or small-field models.
For several years Gordon has worked with and developed
approaches for structures that have frames covered with a
membrane. You may ask what is so new about that; we have had
stick-and-tissue construction methods almost since the first model
airplane was built.
Where Gordon departs from long-established methods is in his mix
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February 2011 89
Below: John Krouse likes to fly
throttle-only small-field models.
This pusher spans 18 inches and
weighs 34 grams. Power is provided
by a Gary Jones 4:1 gear drive
turning a GWS 5 x 3 propeller,
energized by a single 130 mAh Li-
Poly cell.
Left: Shown at the KIEF event,
Bob Selman has several new
indoor/outdoor small-field flyer
kits. Check out these designs on
the BSD Micro RC Web site.
Keith Sparks, doing business as Park Flyer Plastics, has a great
clear canopy/pilot package for the ParkZone Micro T-28 and P-51.
Scale models with visible pilots are more impressive than those
without.
framework covered with light plastic film. The big change is that he
cuts the frames from foam sheets rather than assembling them from
foam strips. Cutting the frames from sheet eliminates most of the glue
joints and means that he doesn’t have to deal with slicing and fitting
strips.
Look at the photo that Gordon provided of his Airbender. You can
see the film-covered foam framework cut from sheet stock and a wing
frame.
Cutting such frames is easy with a sharp blade, straightedge, and
sharpened brass tubing. Gordon uses the brass tubing to cut the
corners of a frame area.
Once the corners are “drilled,” he simply cuts straight lines
between the holes and then drops out the material to be removed. It
does not take long for him to complete a frame.
When the frames are cut, you can apply some color and then apply
the covering material. The resulting structure is incredibly light and
surprisingly strong. As is the case with almost all aspects of building
model airplanes, the only limitation is your imagination.
The December 2010 Flying Models magazine featured two great
construction articles about airplanes that are perfect for small-field
flying. One of those was Robert Dance’s cool-looking Firefly.
Bob Aberle continues his quest for a 200-
square-inch old-timer event with this 1937 Ray
Heit Scram. The built-up, stick-style fuselage gives it character.
Bob powers his with a Lazertoyz 10-gram 1811-20 brushless
outrunner motor.
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90 MODEL AVIATION
I presented Robert’s lovely Piper Pacer in
the August 2010 column. He is
multitalented, which is evident in his Firefly
design. He provided a nice photo of it for me
to include here.
The 45-inch-span, 14.5-ounce aircraft is
covered with yellow silk and trimmed in
blue dope. Most electric-power modelers
choose brushless motors, but Robert’s
Firefly uses the tried-and-true brushed 6-volt
Speed 400.
Not long ago the mighty Speed 400 was
the dominant motor for electric-powered
small-field flyers. Although it is a bit old
school, the battery pack is a modern two-cell
Li-Poly of roughly 1350 mAh capacity. The
Firefly has captured my fancy.
DLE Gas Engines
$269.95
20cc
30cc
$319.00
Engines not shown
DLE 55cc $410.00
DLE 111cc $730.00
170cc $1049.00
Shop on-line or call to order
Contact us a 253-875-6890
Dealers Welcome
www.valleyviewrc.com
The other design in Flying Models that
caught my small-field eye was a nice 26-
inch-span L-19 Bird Dog by Pat Tritle. He
supplied me with a nice photo of it.
Although Pat designed the L-19 for
rubber-powered FF, it would make a great
conversion to small-field RC using
components from the ParkZone Micro P-51
or HobbyZone Champ. The FF Bird Dog
weighs 45 grams, or roughly 1.6 ounces. Its
weight as an RC model would probably be
close to 2 ounces.
Pat is selling laser-cut kits for the L-19
through Pat’s Custom Models. See the
“Sources” listing for contact information.
While I was at the KIEF (Keystone Indoor
Electric Fly) gathering in October, I had the
opportunity to examine and fly several new
models that Bob Selman is selling through
BSD Micro RC. An accompanying photo
shows the George Harris designs: a 20-inchspan
twin called the “LTX,” a 14-inch-span
Smith Miniplane, and an 18-inch-span
Ercoupe.
The twin uses two brushed motors with
the Gary Jones 4:1 gear drive, and the other
airplanes are intended for the small AP03
brushless motor. The models are in the 1.25-
to 1.75-ounce weight range. They work well
indoors or in small outdoor spaces.
Check out these designs on the BSD
Micro RC Web site. The address is in the
“Sources” listing.
Not long ago I shared with you a No-Cal
(profile) Hughes racer that John Krouse built.
The model was unique in that it used only
throttle control; no flight control surfaces
were active.
John built his airplane for indoor use.
Flying inside with no rudder control would
be challenging enough—there are no wind
gusts but there are walls—but John took the
throttle-only concept one step further. Enter
his outdoor pusher design with throttle-only
control.
The outside environment presents a major
challenge: wind. I would think that keeping a
throttle-only model upwind would be fun.
John’s design is up to that challenge. He
constructed it from balsa, and it uses a singlesurface
1/32-inch-thick cambered wing with
an 8%-thick airfoil.
The pusher has an 18-inch wingspan and
weighs 34 grams. Power is provided by a
Gary Jones 4:1 gear drive turning a GWS 5 x
3 propeller, energized by a single 130 mAh
Li-Poly cell. The receiver is a Plantraco 900
MHz unit that includes a built-in speed
control. The equipment is available from
BSD Micro RC.
You’ve devised another interesting
project, John.
ParkZone has provided us with some
fantastic small-field RTFs in recent years,
and they generally have opaque windshields
or canopies. The downside of that kind of
enclosure is that you can’t see the pilot.
This is especially troubling with models
such as the ParkZone Micro P-51 and T-28,
which have nice bubble-type canopies. I like
scale models with visible pilots.
Enter Keith Sparks, who is a well-known
scale modeler and the proprietor of Park
Flyer Plastics. He has developed aftermarket
clear canopies for the Micro P-51 and Micro
T-28. He also sells terrific pilot figures that
are sized to work with those models.
The photo that Keith provided of the T-28
dressed up with a clear canopy and pilot
figure is striking. If you would like to give
your ParkZone Micro P-51 or T-28 a plastic
greenhouse canopy, take a look at Keith’s
Web site. The address is in the “Sources”
listing.
During the past year or so, MA Technical
Editor Bob Aberle has been on a mission to
generate interest in an old-timer/vintage event
for reduced-size models. His idea is to fly
designs with 200 square inches of wing area.
To underscore Bob’s proposed event, he
has developed several sets of plans and
corresponding models. His latest is the Ray
Heit Scram from 1937.
The built-up, stick-style fuselage gives the
airplane character. Bob powers his with a
Lazertoyz 10-gram 1811-20 brushless
outrunner motor. Energy comes from a twocell,
800 mAh Li-Poly battery pack. The allup
flying weight is 7 ounces.
As is the case with Bob’s other 200-
square-inch old-timers, you can get plans for
the Scram from the RC Micro World online
magazine. That publication has been
undergoing some changes; one is that its
content is now free to everyone.
A subscription gets you all of the plans
featured on the site in a full-size digital
format. Contact information is in the
“Sources” listing.
The space meter tells me we have run out
for this issue. As always, I look forward to
hearing from you regarding your latest smallfield
modeling project. MA
Sources:
Flying Models
(973) 383-3355
www.flying-models.com
Pat’s Custom Models
(505) 296-4511
www.patscustom-models.com
BSD Micro RC
(417) 358-9521
www.bsdmicrorc.com
Park Flyer Plastics
(817) 233-1215
http://parkflyerplastics.com
RC Micro World
www.rcmicroworld.com
Paul Bradley
10201 Scarletoak Dr.
Independence KY 41051
www.parmodels.com
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