146 M ODEL AVIATION
COngrAtUlAtIOns! Junior team
member Austin Gunder of Red Lion PA won
F1J at the Junior World Championships, held
in August in the Czech Republic.
Austin maxed out, then maxed the fiveminute
flyoff round, besting the secondplace
finisher by almost two minutes.
In F1B, David Ellis of Guilford CT also
reached the flyoff, scoring 217 seconds—
only 22 seconds from first place.
Congratulations to the entire team for an
outstanding effort. Thanks also to team
manager George Batiuk, for all his hard
work in developing the Junior program.
Symposium 2000: Each year the National
Free Flight Society (NFFS) publishes a
collection of articles to promote and
encourage the investigation, discussion, and
documentation of technical and theoretical
aspects of Free Flight (FF).
The 2000 Symposium—the 34th edition—
delivers all that and more. The range of essays
in this issue would have been hard to imagine
when the first Symposium was produced
during Lyndon Johnson’s administration.
Perhaps the best illustration is “Atomic
Powered Free Flight” by Orville Olm.
Accompanied by a full-page woodcut by
Ross Jahnke, which shows a Rubber model
circling above a cooling tower, this paper
describes how small amounts of radiation
can improve the energy release from rubber
strip by more than 5%.
An article by Evgeny Verbitsky and
Doug Galbreath describes the latest version
of Evgeny’s geared F1C engine. He has
been working on this intermittently since
1963—even longer than the Symposiums
have been around.
The 4:1 gearing allows the use of a
much-larger-diameter propeller (315mm
diameter, 300mm pitch) at a slower speed,
for improved efficiency. Propeller rpm is
roughly 7,250 on the ground and 8,000 in
the air. Corresponding engine rpms are
29,000 static and 32,000 in the air.
Doug’s radar-gun evaluation showed that
the geared model attained a maximum speed
of 77 mph by approximately three seconds
into the climb, compared to a conventional
model’s 65 mph at the three-second mark.
The conventional model continues to
accelerate, peaking at roughly 77 mph (113
feet per second) at the five-second cutoff.
Peter King’s “The Effect of Airfoil
Geometry on Lift and Drag Coefficients”
investigates how reducing an airfoil’s
camber and thickness affects performance.
In addition to all the math, Peter mercifully
includes some easy-to-use graphs to show
how changing the parameters of an airfoil
can affect climb height and total duration.
The results were surprising; thinner isn’t
always better.
As a counterpoint to the theory, George
Batiuk offers an excellent series of tips on
organizing a Federation Aeronautique
Internationale (FAI) contest.
It shows the amount of work required
beforehand to make a contest happen
effortlessly. This should be required reading
for all Contest Directors.
Hermann Andresen contributed a
practical, in-depth piece about digital scales.
Since a scale is almost a necessity for FF
building, this is a must-read for all modelers.
For more-traditional weighing, Art
Loneergan’s “Ratio-Beam Balances” shows
how to make a simple, yet accurate beam
balance.
Several thought-provoking pieces
addressed the future of FF, including Mike
Woodhouse’s “The End of History?” and
Rex Hinson’s “What Are the Real Flying
Site Issues?”. Both articles merit careful
reading and additional discussion.
Louis Joyner, 4221 Old Leeds Rd., Birmingham AL 35213
FREE FLIGHT DURATION
Junior World Champ Austin Gunder at 2000 Nats. He was topplacing
American at 2000 Junior Champs in Czech Republic.
Junior David Ellis was third in Wakefield at Junior World Champs.
Shown here at last year’s Max Men Annual at Lost Hills CA.
One of my favorite articles was about
an event I’ve never flown in, and quite
frankly had little interest in. Rudolf
Hobinger and Aram Schlosberg’s piece
on the development of Rudolf’s
Carbonator F1K CO2 design traces the
design and construction of a highperformance
F1K model.
F1K models have a minimum weight
of 75 grams, a maximum projected
surface area of 12 dm2—approximately
186 square inches—and a maximum tank
volume of 3 cm3.
An F1K contest is flown in five rounds
with 120-second maxes. The max stays the
same for the flyoff, but the motor is required
to run for one minute on the ground before
launch. The static motor run goes up to two
minutes before launch for the second flyoff,
and so on.
In essence, the model is a powered glider
with a very long-running motor.
This article is particularly intriguing
because it shows the complete process of
developing a high-performance model—
from evaluating the rules, to developing the
design, to optimizing the construction.
A good bit of time was spent writing
computer programs to design the propeller.
One of the interesting outcomes is the
model’s one-blade molded prop with folding
counterweight. Calculations show a
theoretical advantage of as much as 8% over
a conventional two-blade prop for F1K.
Construction follows the latest trends,
but with some twists—including an
incredibly thin (1.5%) stabilizer.
I hope future Symposiums will follow
this example of exploring all the aspects of a
particular design; it is very useful to learn
the “why” and the “how.”
As in previous Symposiums, this one
featured the Ten Models of the Year winners,
including Bunt Bone by Don Zink and Vasily
Beschasny (F1A); PC-31 by Paul Crowley
(F1B); Diamonds by Dave Sugden (F1C);
Odyssey by Michael Achterberg, Faust
Parker, and Bob Johannes (F1J); Marie by
John Kamla (P-30); Obsession by Robert
Lipori (Mulvihill); Bandit by Bill Lynch
(F1J); Ploite 800 by Joe Mekina and Norman
D. Poti (large Power); and Sweep Up by Stan
Buddenbohm (Indoor Catapult Glider).
Special awards went to Alex Andriukov for
his variable-pitch propeller hub for F1B, and to
Rod Mogle for his electronic timer for F1C.
Free Flight Hall of Fame inductees
for 2000 include California Indoor flier
Cezar Banks (six silver and one bronze
medal in eight consecutive F1D World
Championships); Ian Kaynes, editor of
the British newsletter Free Flight News
and longtime chairman of the Free Flight
Subcommittee of the CIAM (the
international aeromodeling governing
body); and Thomas Koster, the
innovative Dane who won the Wakefield
Cup in 1965 at the age of 18, the Power
World Champs in 1977, and the Glider
title in 1979, proxy-flying for fellow
Dane Per Grunnet.
Order your copy of the 2000 Symposium
from NFFS Publications, c/o Robert
McLinden, 3903 W. Temple Pl., Denver CO
80236. The cost is $25 for NFFS members
Don Zink’s Bunt Bone was selected as one
of the Ten Models of the Year. Column lists
other models recognized by the NFFS.
January 2001 147
4 1/2''
7/8''
84 3/4''
5 3/4''
1 1/4''
21 3/8'' 20 5/8''
2 5/8''
3 5/8''
22 3/8''
29''
ROHACELL
D-BOX
CORE
45° CARBON
D-BOX
ROHACELL
CORE
UNI-DIRECTIONAL
CARBON CAPS
5 - 8 mm ROD ø
UNI-DIRECTIONAL
CARBON TRAILING EDGE
1/8'' SQ
LEADING EDGE
6 mm ø CARBON
FIBER TUBE
One of the Bunt Bone’s interesting features is the Rohacell foam-filled D-box. These
models are produced by Vasily Beschasny in Ukraine.
