Free Flight Sport-2011/09

September 2011 123
Also included in this column:
• Howard Littman offers finishing tips
• Tandy Walker’s J-3 Cub
• Doug Beardsworth’s Spitfire
• Bill Schmidt builds the aircraft
[[email protected]]
Free Flight Sport Gene Smith
Frank Rowsome’s Messerschmitt Bf 109
THE MESSERSCHMITT Bf 109 has been
one of my favorite airplanes since, well,
forever. I think a part of it has to do with the
plethora of cool paint schemes available
from the airplane’s service in Europe, Africa,
and Russia.
Frank Rowsome also likes the appearance
of the 109. He especially liked the scheme of
the Bf 109 Emil that was on the Flying Aces
Club (FAC) Nats T-shirt in 2004. That
particular Emil fought in the Battle of Britain
and it had no swastika.
Although Frank is an experienced
builder, the Emil was his first effort at a
Jumbo model. As we often find with first
efforts, it turned into a learning experience.
The nose kept collapsing on landing so he
had to sheet the nose section.
A Jumbo has a wingspan greater than 36
inches. To make the model easier to
transport, Frank elected to use plug-in wings.
He mounted a 1/8-inch carbon-fiber tube
through the fuselage. The carbon fiber slides
into aluminum tubes epoxied to the main
spar in each wing. Alignment dowels near
the wing TE and small rare-earth magnets
are used to keep the wings seated properly.
Frank found that the slightest knock will
cause dislocation of the alignment dowel and
subsequent crash damage on landing. Rather
than using an alignment dowel, I like to add
a second set of spars in the first two wing
bays roughly ¾ the chord from the LE. This
second set of spars is used for another tube in
a tube fixture to secure the wing. This, in
conjunction with the super magnet, allows
the wing to stay in place during flight but
still pop off in hard landings or for storage.
Frank wanted the rudder to be adjustable
so he hinged it at the scale location for looks,
but discovered that produced a hopelessly
over-sensitive adjustment. Rudder offsets
almost too small to see produce death spirals,
often resulting in significant damage to the
model.
I experienced the same problem with my
Regianne 2005. I had to glue the rudder in
place to get the model to perform
consistently. I have started building an
adjustable trim tab into the rudder. That
allows trim adjustments without the extreme
sensitivity.
While doing repairs, Frank discovered
that Midwest Products Aero-Gloss dope
releases the adhesion of UHU glue sticks
even after years of drying time.
The Bf 109’s wing attachment problems
produced one of the best scale reenactment
crashes Frank has ever seen. In Round 1 of
the World War II mass launch at Ingleside,
Maryland, last November, it had a gentle,
glancing mid-air with Stew Meyers’ little
F6F Hellcat. The Bf 109’s wing dislocated,
producing a realistic shoot-down spin!
Stew’s Hellcat went on to win the event.
One thing that does work on the model is
its dethermalizer (DT). Since the horizontal
stabilizer is mounted up on the vertical
stabilizer with struts down to the fuselage, it
is challenging to rig a DT. Frank solved the
Above: The author uses two sets of
telescoping aluminum tubes and a pair
of super magnets to align and secure
removable wings.
Left: Sunlight illuminates Frank
Rowsome’s Bf 109 as he prepares it for
an early morning sortie. Farrell photo.
Below: Doug Beardsworth created this beautiful Spitfire from
plans from Flying Scale Models of WWII. Beardsworth photo.
09sig4.QXD_00MSTRPG.QXD 7/22/11 11:52 AM Page 123
124 MODEL AVIATION
III for structure and UHU purple glue stick
for tissue since 2004. Elmer’s permanent
glue stick works also, but he doesn’t think it
works as well as the UHU.
If you are in a hurry, Titebond cures in
roughly 20 seconds in the microwave, but
don’t use pins—no metal in the microwave!
Some people apply tissue with glue stick
over bare balsa. However, Howard prefers
using Varathane Diamond Wood Finish,
water-based, satin, clear, thinned 50/50 with
water as a sanding sealer on the balsa before
covering. It seems to work as well as dope,
meets the new safety and emission
standards, and has no odor. When you cover
with wet tissue, the Varathane keeps the
water from soaking into the balsa, and it
sands to a glassy finish that takes wet
covering especially well.
After prepping the balsa with Varathane
Diamond finish, Howard has been covering
wet with a variety of tissues. They include
problem by hinging the elevators at the scale
location. There is an arm attached to the
elevator shaft that swings within the vertical
stab. A #2-56 nylon set screw on the end of
the arm is used to adjust the elevator trim.
Fishing line fed through aluminum
tubing furnishes both the trip and reset
tension on the DT arm, so the elevators pop
up when the timer trips. In that
configuration, the end of the arm and the set
screw are accessible for adjustment in the
cutout at the bottom of the fuselage for the
tail wheel—all scale! Frank figured the odds
must have been ten to one against the
system working at all—not to mention
working reliably—but it does! Thanks for
sharing your experiences, Frank.
Howard Littman, moderator of the
Guillow’s Challenge group on Yahoo,
shared some tips about glue and finish
techniques. He has been using Titebond II or
Bill Schmidt built this model of his favorite airplane, the F2G-1
Super Corsair, by enlarging and modifying the Comet Corsair
plan. Schmidt photo.
The classic lines of the Aeronca Champion are reproduced in this
beauty by Bill Schmidt. Schmidt photo.
Tandy Walker built everyman’s airplane,
the Piper J-3 Cub, as his first FAC FF Scale
model. Walker photo.
standard Guillow’s tissue (takes a light
touch), Esaki tissue (beautiful but short
working time), Easy Built tissue (again,
takes a light touch, but good variety of
colors), and silkspan (just fun to use wet).
To finish the tissue, he has been using
Krylon Crystal Clear #1305 instead of dope
and it works quite well except for the lack of
water resistance (no seaplanes!). He has
experimented with Future acrylic floor
finish and a similar product made by
Armstrong, but primarily uses the Krylon.
Tandy Walker, longtime Society of
Antique Modelers (SAM) flier, selected the
Herr Engineering 35.5-inch-span Piper J-3
Cub kit HRR302 for an FAC Scale project.
Mike Midkiff helped with the project and
suggested several changes such as reducing
the wing dihedral and raising the location of
the rubber motor peg at the back of the
fuselage to change thrust line.
09sig4.QXD_00MSTRPG.QXD 7/22/11 11:53 AM Page 124
The model’s finished weight, without
the rubber motor, is 79 grams. The power
train is six loops of 1/8 rubber turning a
Peck 9.5-inch propeller. Mike helped
Tandy with the test flights. After adding
some nose weight and a rudder tab, they
were able to get in some great flights.
Doug Beardsworth’s Spitfire was built
from the Flying Scale Models of WWII
plans book, now out of print. Doug said it
was a fun build, but with a fairly
complicated paint scheme. He used the
plasticized nitrate/Floquil blend finish that
he has described in previous columns.
In the past he has used frisket paper to
mask areas for airbrushing. Frisket paper
is a clear, flexible plastic with a mild
adhesive on one side. It comes on a slick
paper backing, similar to labels, and can
be found in stores that handle artist
supplies. Although it does work well, it is
hard to see because of its transparency.
On his next project, Doug is going to
try this tip from Orv Olm. Spray a sheet of
domestic tissue with two or three coats of
Krylon Crystal Clear. Cut your masks out
of that tissue and attach them to the model
with 3M Products Scotch Repositionable
Glue Stick (Post-It Note glue). It makes
nice, clean lines when airbrushing, peels
off with no paint pull, and is easier to
handle than airbrush frisket.
The 18½-inch-span model’s empty
weight is 25.2 grams. Doug moved the
peg location forward, and used a Stott
spool at the rear of the motor. The hookto-
peg distance of 5½ inches handles a
15% motor without any bunching. He has
also flown it with 20-25% motors for FAC
Scale events without a problem. The
motor cross section is two loops of 3/32
Tan Supersport rubber.
The Spitfire was a challenge to trim for
flying, but when Doug finally got it going
it was very satisfying! After trying to fly it
left in power and glide, he changed it to
fly right under the initial power burst,
followed by lazy left-hand circles when in
the low-power cruise portion followed by
a glide to the right.
Doug isn’t sure it is trimmed out the
best it can be, but at least now he can get
it to go fairly consistently. The one thing
it demands is a fairly strong upward righthand
bank at launch. Doug finds that if he
launches with the wings level, the model
burns off the power burst without a tight
climbing right-hand spiral.
Walt Farrell told him that if an aircraft
is really sensitive and demands certain
launch angles, it may not be optimally
trimmed. That has been my experience as
well.
For a model that could “use a little
more trimming,” the Spitfire has acquitted
itself well. At its first competition last
October, it took second in World War II
Combat and third in FAC Scale!
Bill Schmidt is probably best known for his
great-flying, well-designed, rubber-powered
civil aircraft, eight of which have been
kitted by Dare Hobby. It might surprise you
to know that his favorite aircraft is the F2G-
1 Super Corsair.
This 28-cylinder, 3,000 hp brute has
always been the airplane to Bill. He
enlarged the 50¢ Comet plans of the F4U-1
Birdcage Corsair by 111% and modified the
outlines to create the F2G-1. MA
Sources:
Midwest Products
(800) 348-3497
www.midwestproducts.com
UHU
(800) 341-4674
www.saunders-usa.com/uhu
Guillow’s Challenge Group
http://goo.gl/vf6W8
Titebond
(800) 669-4583
www.titebond.com
Varathane
(877) 385-8155
www.rustoleum.com
Krylon
(800) 457-9566
www.krylon.com
Herr Engineering Corp.
(800) 247-5008
http://goo.gl/CElUW
Dare Design and Engineering
(800) 578-3273
www.darehobby.com