Radio Control Slope Soaring - 2011/02

114 MODEL AVIATION
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Radio Control Slope Soaring Dave Garwood
Cularis flight report
Also included in this column:
• Panel lines and weathering
• Training tip
Above: This Multiplex Cularis ARF fitted as
a sailplane only turns and burns over Cape
Cod Bay. It can handle light 5 mph winds
with a competent pilot. Jim Harrigan
photo.
The 102-inch-span foam Multiplex Cularis is nimble in a good breeze. It can carry more
weight for penetration into winds exceeding 20 mph. Harrigan photo.
Dave details the underside of the Marty Hill P-40 Warhawk wing
using Sanford Sharpie Fine and Ultra Fine markers. The green
tracing templates, flexible plastic rulers, and three-view drawing
on the bench are important resources.
With the wing-panel lining finished (wing in the background), Dave
adds panel lines and fabric sag markings to the P-40 fuselage and
empennage.
In the August 2010 column I
reported on my search for an RTF or ARF
slope sailplane, and I decided to try a
Multiplex Cularis “servos installed”
version. The Cularis “RR,” or receiverready,
came with an impressive amount of
prefabrication, requiring only gluing on the
wingtips and rudder, connecting the rudder
control link, installing a receiver, and
balancing the airframe.
The Cularis flew fine in hand-toss
testing and did well in gentle winch
launches. I had an inquiry from a member
of the Harbor Soaring Society regarding
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February 2011 115
The Marty Hill P-40 Warhawk fuselage is detailed with base paint, panel lines, and cutvinyl
markings. When it’s finished, Dave will add clear spray sealant.
The P-40 with airbrush weathering in addition to all the detail described above. The
transformation is dramatic and well worth the small effort.
the strength of the wing-joiner system and
its suitability for winch launching.
I agree with his concern; the Cularis
wing-joiner system, which consists of
plastic tubes sliding into plastic tubes, does
not appear to be designed or built for
vigorous winch launching. This model is
designed to be an electric-powered
sailplane, which does not need a wingjoiner
system that is strong enough to
withstand a contest winch launch.
Nevertheless, my Cularis did take a few
gentle-on-the-pedal winch launches and
flew fairly well in the thermal regime as
long as I kept up the speed. It does not like
to be flown slowly and will signal its
protest with a gentle tip stall or a fairly
dramatic forward stall. Keep the airspeed
up and all will be okay.
In September I flew the Cularis on the
slope during two days—once in light- and
once in medium-lift conditions. I launched
in 5-7 mph winds on a 100-foot dune,
thinking that the long wingspan would
handle the light lift. It did, until it came
time for a turn, and then the tip stalls of the
inside-the-turn wing began.
However, the Cularis recovers well
from a tip stall and quickly resumes flying,
but in very light lift I had to cross-control
(opposite aileron to hold the inside wing up
through the turn, and steer with the rudder)
to make turns. Once I got that routine
down, the Cularis became pleasant to fly,
making scores of gentle, close-in, silent
passes without complaint.
Later in the week I launched the model
into 20 mph winds on a 65-foot hill, and it
came into its own. It became truly fun to
fly.
I had wondered if it was carrying
enough weight in the sailplane version to
fly well, given the stalling problems I had
experienced when flying it slowly. I
thought that with no motor and battery pack
onboard, I was flying it below its design
weight and that maybe I should add weight,
especially to help it penetrate stiffer winds.
But the winds came up before I added
ballast, and penetration in 20 mph was no
problem. The Cularis flew great in the
breezy conditions, with controls that were
responsive enough and fast enough to give
a thrilling flight.
Whether or not you like the looks of the
model is an individual aesthetic judgment,
but I find its appearance attractive. I’ve
added it to the list of sailplanes I like to
keep ready for spontaneous Slope Soaring
trips.
In the October 2010 column I featured a
Marty Hill P-40 Warhawk finished up
through painting and markings. This month
I’ll cover two more finishing techniques:
panel lining and airbrush weathering. Both
look harder than they are, you can improve
on both with practice, and both add visual
appeal to a scale PSS (Power Slope
Soaring) model.
Full-scale aircraft tend to collect dirt in
the joints between panels, and that is what
makes their panel lines visible.
Aeromodelers’ drawn-on panel lines
represent the dirt in the cracks, add scale
realism, and are visually pleasing.
I added panel lines to my Warhawk
using three-view drawings from the book
Curtiss P-40 in Action, from Squadron, as
a guide. Another rich source of detailed
drawings is Bob’s Aircraft
Documentation.
My most commonly used panel-linedrawing
pen is a Sanford Sharpie Ultra
Fine Point Permanent Marker, available at
stationery supply stores. For bolder lines I
use a Sanford Fine Point Sharpie. The
lines it makes are waterproof, and the ink
does not run under the ruler or template,
preventing smears.
Top Flite makes a Panel Line Pen (part
TOP02510). Staedtler makes a series of
Pigment Liners in a range of widths, which
I have also used successfully.
To guide the marker I use flexible
plastic rulers and flexible plastic drafting
templates including circle templates, home
furniture layout templates, and a
computer-system flowchart layout
template. A set of flexible French curves
can also be useful. Sometimes I also use
1/8-inch vinyl masking tape to lay guides
for curves.
Holding the template in a fixed position
on the model is fundamental in getting a
clean line. That is easy to do by hand on
short lines if the airplane is secure on the
bench—perhaps on a folded towel and
held in place with sandbags or other
weights. For long lines it’s useful to
temporarily tape the ruler or template to
the aircraft.
Making a line or shape on one side and
immediately drawing its mirror image on
the other wing or other side of the fuselage
helps speed up the work. Once I’ve
decided the position of a line and laid it
out with a scale or via mental
measurements, going directly to the other
side saves me from recalculating positions
after an entire wing is completed.
Drawing on a painted surface will clog
the Sharpie, but you can clear it by wiping
the marker on scrap paper. I’ve gotten into
the habit of wiping the pen tip before
drawing each line. Small errors with the
marking pen can be corrected with alcohol
on a paper towel or by carefully scraping
with a sharp hobby-knife point.
On a model that has a dark finish, an
alternative method of making lightcolored
panel lines is to spray the aircraft
with a silver-paint undercoat and then
apply the final color coat. When all paint
is dry, scratch through the final coat to let
the silver panel lines show through.
Dirt from the atmosphere in addition to
leaking oil, engine exhaust, and gun
smoke leave distinctive patterns on fullscale
airplanes. They don’t stay factoryfresh
in appearance for long when
assigned to a combat squadron. We can
02sig4.QXD_00MSTRPG.QXD 12/20/10 8:15 AM Page 115
simulate weathering with an airbrush,
making use of its wonderful ability to
precisely apply small amounts of paint.
The general idea is to add a hint of
slightly darker color to areas of an aircraft
where dirt would tend to collect. For a dark
model, weathering paint might be slightly
lighter gray.
Carl Maas and Brian Laird, model
finishing and detailing masters, taught me to
do this using a handheld card as a mask
while airbrushing. The card is held along
the panel line, and the weathering paint is
sprayed over the card. Frisket mask works
great for more complicated shapes.
Jan Carstanjen, a fellow scale builder,
contributed a great tip. Use a Post-It note
(or more than one) to temporarily mask
against the airbrush. This gives you fine
control, to get the paint where you want it.
On the Russian winter-scheme Warhawk
I used dark-gray paint, thinned 50%, for the
weathering effect on panel lines and on the
fabric sags of the ailerons and elevators.
Other modelers use flat-black paint thinned
75% or more.
A light touch on the airbrush gives the
best result with any choice of paint color.
Subtlety and restraint pays off.
The following is more from Jan
Carstanjen.
“On the rudder, place a Post-It note on
the panel line and use light pastel chalk
above the line, reverse and use a slightly
darker color below line. Makes ribs in
fabric covering stand out better.”
The last step in a panel line and
weathering finish is an overall clear coat. I
typically use Testors Dull-Cote in rattle
cans, and I generally mask off the canopy
markings because I want them to stay shiny.
Don’t be too hard on yourself for little
slips in markings or too-heavy application
of the airbrush. It’s the overall impression
that counts and modelers who work at a
moderate skill level can noticeably improve
the appearance of their aircraft with these
techniques.
Few sport fliers would notice if you used
a Mustang panel-line pattern on your
Spitfire, but everyone can tell the difference
between an airplane with panel lines and an
airplane without.
Training Tip: If you have to help a new
slope flier launch, you might have to help
him or her land the model. When a new
person comes to the slope, most of us want
him or her to succeed and to enjoy the
experience, and we don’t mind helping as
much as we can.
We might check the radio setup for a
delta-wing aircraft or double-check control
surfaces for correct and free movement. An
experienced slope pilot might launch for a
newbie and stand close for a few minutes
to make sure that the flight is going
smoothly. With any luck, the new flier’s
model performs well and he or she is
wearing a huge grin.
Let’s say that the experienced pilot
launches his or her sailplane and turns his
or her attention to flying. Later, and at an
unexpected moment, the new flier calls
“Help!” and loses his or her model in the
rotor behind the hill before anyone else can
react. The new person may or may not
have seen where it went down.
That happened at our Lake Ontario,
New York, flying site, and a pack of pilots
spent a half-hour searching for the
sailplane in the long grass and bushes. That
was time away from flying.
Next time, to save flying time, we’ll
assign one experienced pilot to be attentive
and available to assist the new flier with
his or her first slope landing. This might
include instruction and demonstration
covering landing pattern, rotor avoidance,
and turbulence handling—and to have
more eyes on the model as it returns to
earth. MA
Sources:
Multiplex
(858) 748-6948
www.multiplexusa.com
Squadron
(877) 414-0434
www.squadron.com
Bob’s Aircraft Documentation
(714) 979-8058
www.bobsairdoc.com
Airliners.Net
www.airliners.net
League of Silent Flight
www.silentflight.org
116 MODEL AVIATION
BMJR Model Products
• NFFS One-Design
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• Design by Carl Goldberg
scaled to 84%
• Wingspan 42 in.
• Wing Area 265 sq. in.
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321-537-1159 • www.BMJRModels.com
$5325
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02sig4.QXD_00MSTRPG.QXD 12/20/10 8:15 AM Page 116