Free Flight Sport - 2010/05

124 MODEL AVIATION
[[email protected]]
Free Flight Sport Gene Smith
Also included in this column:
• Chris Holford’s Ebenezer Hurricane
• George White’s P-39
• Hobby-store Towline
• Super Talon and Sunnanvind
• Covering with tissue tutorial
Mike Isermann’s Brown Racer
Mike Isermann modeled the retractable-gear, 18-inch-span version
of the Brown Racer for the FAC Greve mass-launch event.
Chris Holford, a British modeler,
created this realistic-flying Ebenezer
version of the Hurricane. Holford
photo.
Almost condemned to the trash, George White’s P-39 turned out
to fly great after a bit of work on the airfoil. White photo.
Towline flying has caught on with the Thermal Thumbers of Metro
Atlanta. David Mills holds not only his Super Talon, but also Dohrm
Crawford’s Sunnanvind. Mills photo.
MIKE ISERMANN’S LATEST mount for the Flying Aces
Club (FAC) Greve races is the Brown Racer. It spans 18 inches,
weighs 21.5 grams, and sports a 7-inch carved propeller. Those
are the numbers you like to see for a good-performing model.
I always liked the looks of the Brown Racer but shied away
from it because it was most commonly shown with fixed
landing gear—a definite handicap for duration. However, I
found out that the Brown Racer did compete one year with
retractable landing gear.
There was trouble with the retractable gear system, and it
was converted back to a conventional undercarriage the next
year. For FAC competition, though, a retractable-gear version
such as Mike’s is the way to go.
Chris Holford is one of many British FF modelers who enjoys
Ebenezer models: simple profile designs that use small engines.
Although Chris’s Hurricane is a bit larger than the average
Ebenezer airplane, it’s a great representation of the type.
The Hurricane spans 36 inches. Chris arrived at that size by
scaling the plans to use the largest size of paper his printer
could handle, which was 13 x 19 inches.
The model weighs 18 ounces. Chris knows it could have
been lighter, but he covered the tail twice to hide his
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One of the most popular Dime Scale models is the Beech
Staggerwing. This large group at the 2009 FAC Non-Nats seems to
agree. Grabski photo.
Patrick Murray proudly holds his Avenger, which won the WWII
Combat mass launch at the 2009 FAC Non-Nats. Grabski photo.
experiments with printing! The extra weight in the tail made
him add a fair amount of lead to the nose to get a reasonable
balance point.
Chris built in 2° of right thrust, but he might add more
because he had to put a small tab under the left wing to keep it
up. During initial flights, the Hurricane flew in a big left-hand
circle under power and the glide was almost straight.
The airplane’s PAW .55 uses a 7 x 3 Graupner propeller. The
little 1/2cc diesel has to be set to give nearly full power, and the
rate of climb is not so great. However, the Hurricane was able
to rise-off-ground (ROG) after a long run on short, level grass.
That had to be a sight!
Chris chose to model the Hurricane wheels down, because he
thought that would keep the CG low. And it’s great to see an FF
model ROG! Then just imagine it is on final approach!
The aircraft was constructed from light balsa and covered
with printed paper (not tissue). Chris finds that this makes a
rugged model. Two thin coats of nitrate dope completed the job,
and that is okay to use with diesel fuel.
He was unhappy with the printing on the “silver” paper,
because it tended to smudge with handling. Chris has tried
printing the panel lines and other markings on plain white paper
and then dusting them with silver paint from a rattle can. This
looks promising so far.
The wheels are balsa with thin plywood discs on either side
at the hub. The tires are made from an elastic tubular support
bandage dyed gray.
George White spent more time than he would have liked
rebuilding his Golden Age Models P-39 kit to get the wings set
the way he wanted them. He took the model to the field for
testing and, much to his astonishment, it flew beautifully off the
board.
George did a little fine-tuning, with only two half-turn
adjustments to the GizmoGeezer adjustable nose button. The P-
39 flew so well that he would have lost it had it not been
equipped with a DT.
The model is a bit on the heavy side, at 48 grams. George
attributes the extra weight to too much paint and the addition of
planking to fair in the fuselage below the wing.
He used the Neelmeyer 10% airfoil rather than the thick,
symmetrical airfoil shown on the kit plans. George believes that
the airfoil—plus the high-pitch Jason’s Deli-cup propeller
blades—are the secret of the model flying so well.
George got so tired of the rebuild that he nearly trashed the
model. Now he is glad he didn’t! He is experimenting with a
15% motor made from four strands of 3/16-inch rubber for the
limited-motor-weight mass-launch event.
While at Geneseo, New York, for the FAC Non-Nats last year,
Paul Grabski and George White set up next to Patrick Murray.
Paul and George were very impressed with the workmanship of
all the models that Pat flew.
Part of the secret to his airplanes is the fact that he owns a
CAD design company that specializes in fire-protection design, so
he has computer skills and graphics software.
Pat’s Stinson Gullwing has Pepsi markings matching those of
an aircraft that was flown in the 1930s. All of the markings are
computer-generated.
Pat can not only build models, but he can also fly them. He
won the World War II mass launch with his Grumman TBF
Avenger—quite an accomplishment flying against the more
streamlined in-line-engine fighters.
Foam Towline Glider: I mentioned Bill Kuhl’s Web site several
years ago, and it’s time to mention it again. It’s an excellent
resource for FF beginners and sport fliers.
The project that attracted my attention was the large foam
Towline Glider. You have probably seen the cheap gliders that are
sold in hobby and toy stores. Bill modified one of those with a
rudder tab and offset towhook, which made the model a simple
Towliner.
I tried the same thing with a similar glider, with mixed results.
My problems began when I discovered that the fuselage halves
had been sloppily assembled, resulting in a difference in
incidence between the two wings. That took cutting and shimming
to correct. The nose was longer than needed for reliable towing,
so I shortened it and added ballast to the nose to adjust the CG.
There was also inadequate dihedral. The wings were too weak
to survive a tow in any but the lightest wind, so I strengthened
them with nylon-reinforced packing tape. Flight tests await the
addition of tip dihedral and better weather.
David Mills built his Super Talon Towline Glider from Don
DeLoach’s kit. David slightly modified the kit by adding geodetic
ribs for bracing in the wing and stabilizer. The wing is now as
stiff as a board. David reduced the stabilizer area from 16% to
14% so that stabilizer incidence could be increased to aid
stability.
David noticed that his Super Talon rights itself quickly in
turbulence. He suspected at first that the fin might be too small
but has had no problem with Dutch roll.
He initially used a rubber band wing-mounting system but
returned to Don’s original concept of adding a platform under the
wing TE that allows incidence shims to be added. Each wing
panel is secured with a shearable 4-40 nylon bolt—a system that
works really well.
David hasn’t decided whether or not this large and light of a
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Glider has a real advantage in Classic
Towline, but he does know that the Super
Talon looks and flies great. It’s like
cranking up a Super D. All action on the
field stops when you tow up this beauty.
Don sold out of his original run of short
kits for the Super Talon, but he is taking
preorders for another kit run in May or
June of this year. The price is $150 plus
postage.
The Super Talon kit includes
everything but covering, timer, and
straight balsa. It has plans, four carbon
wing spars, tapered carbon tailboom, and
16 sheets of laser-cut parts.
Don also sells laser-cut ribs for his
Polecat P-30 (plans are $7 and a rib set is
$8) and a short kit for his Yak-3 ($15).
The Yak plans are available from Flying
Models magazine.
Dohrm Crawford decided to take the
Towline plunge with a Swedish design: the
Sunnanvind Old-Time glider. The plans
are in Swedish, which led to all sorts of
machinations to figure it out accurately.
Dohrm is planning to fly the
Sunnanvind at this year’s SAM (Society of
Antique Modelers) Champs at Muncie,
Indiana.
If you want to see an excellent tutorial
about covering a model with tissue, go to
the Guillow’s Web site, click on the
message board link in the middle of the
page, and open the “Building another
Messerschmitt” thread. The text and
pictures tell the story exceedingly well.
Thermals! MA
Sources:
GizmoGeezer
(306) 955-1620
www.gizmogeezer.com
Bill Kuhl’s Web site:
www.hbci.com/~bkuhl/Dart.htm
Guillow’s
(781) 245-5255
www.guillow.com
Don DeLoach short kits:
[email protected]
Thermal Thumbers of Metro Atlanta
www.thermalthumbers.com
National Free Flight Society
www.freeflight.org