RADIO CONTROL SOARING - 2003/09

THIS MONTH I will cover two exciting topics in the otherwise
quiet world of Radio Control (RC) gliders. First, Phil Barnes has
released an instructional video (really a two-DVD set) detailing
exactly how he makes vacuum-bagged wings. Phil is one of the
top three professional wing makers in our country, and he tells all
of his production secrets in this video.
Second, United States F3B team member Gavin Botha
unofficially set a world speed record during an April contest. I’ll
give you details about Gavin’s glider and the record run. The US
team is leaving for the World Championships the same week this
magazine will hit the mailboxes.
The new DVD set is Vacuum Bagging Made Easy: The
Production Methods of Phil Barnes. Vacuum-bagging (in the
context of RC gliders) is a process using a plastic bag and a
vacuum pump to compress composites onto foam cores while they
Mike Garton, 2733 NE 95th Ave., Ankeny IA 50021; E-mail: [email protected]
RADIO CONTROL SOARING
US F3B team member Gavin Botha and his SP-1. Note generous
tail moment. Wing loading is 11 ounces per square foot.
Gavin Botha and Darrell Zaballos designed the SP-1. Gavin
designed the airfoils using XFOIL software.
An aesthetically and aerodynamically beautiful planform was
created using CNC milled molds. Wing is two pieces.
This two-DVD set is big news to all who make composite wings.
Phil gives hundreds of tips in nearly five hours.
102 MODEL AVIATION
cure. The method allows people to make high-performance
fiberglass, Kevlar, and carbon wings at home.
Phil has been a full-time wing maker since 1996. He has
supplied most of the vacuum-bagged wings for Northeast
Sailplane Products (NSP) since that time. He makes wings for the
Pole Cat Aeroplane Works XP-3 and parts for the Mantis glider
series originally designed by Tom Kiesling.
The quality of Phil’s work is better than 99% of modelers can
achieve. He has developed production methods that allow him to
make an RC glider wing with three to five hours of labor; this can
include paint, joinery hardware, integrated hinges, and routed
servo wells.
The DVD is just short of five hours long. Phil makes an XP-3
discus-launch glider wing and an NSP Fusion three-meter wing
during the instruction. See the picture in this column showing the
chapter index on the back of the case.
As of my deadline, only Bill Haymaker is distributing the two-
DVD set. The original release was on DVD+RW format. I have
been encouraging Bill to invest a little in equipment and release it
on more common DVD and videotape formats. Hopefully the
more common formats will be available by the time you read this.
Bill’s addresses are at the end of the column. If the Web site
address goes bad by the time you read this, a search engine will
surely find it using the title of the video. The DVD set is $55 plus
$6 shipping and handling. The production quality is good.
I consider myself an experienced vacuum-bagger, but I learned
more than a dozen tricks. This set is a must-buy for anybody who
is considering vacuum-bagging. The methods you will learn are
priceless.
F3B is the contest format recognized by the world aviation
governing body (Fédération Aéronautique Internationale, or FAI)
for choosing an RC glider world champion. F3B includes three
tasks—distance, duration, and speed—in each contest round.
The F3B format has not been widely adopted in America. The
reason sport fliers cite is the initial investment in sailplanes and
This is the chapter index from Phil’s DVDs. If you scratch build,
the information in this set is priceless.
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Wingspan – 73 in.
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106 MODEL AVIATION
special F3B-legal winches. Contest
organizers lament the increased man
power required to run an F3B contest.
Even without widespread adoption,
F3B has long been the driving force
behind the improvement in our sport
gliders. Race-car research-anddevelopment
trickles down to production
cars, and the same is true with RC gliders.
F3B and now F3F (Slope Racing) are
driving the development higher in
performance glider structures and airfoils.
So even if F3B is not your cup of tea, you
should be glad it exists.
The following is from Buzz Averill,
who is chairman of the FAI Team
Selection Committee for RC Soaring.
“During the April 12-13 F3B contest in
Eloy AZ Gavin Botha flew a magnificent
12.72 second speed run. His slowest time
for the weekend (5 rounds) was 16.26
seconds. He also did very well in the
duration and distance events, winning the
contest over 4 time world champ Daryl
Perkins, fellow team mates Darrell
Zaballos, and Mike Lachowski. He also
beat former team member Gordon
Jennings who was flying very well.
Against that bunch of fliers the rest of us
were distant also-rans.
“Back to Gavin’s record speed run. It
seems there is no official F3B speed
category in the AMA records because the
AMA doesn’t keep records for FAI events.
Also the FAI will not recognize Gavin’s
record because the FAI stamp he had
ordered had not been received by April
12th and therefore wasn’t on his AMA
license at the time of the record flight.
“Because of these circumstances Gavin
cannot get official credit for what was a
magnificent flight that shattered the
existing record by at least 1.5 seconds.
“Furthermore, Gavin and Darrell
Zaballos have been developing the model
used for all of their flights at Eloy as well
as the record flight for at least 5 or 6 years.
The SP-1 they were both flying was out
launching and out running every other
model on the field. I am attaching a
summary of the development process they
have gone through to arrive where they are
now (a dominant position).”
I requested more info about the SP-1.
Gavin Botha responded.
“The SP-1 is the second F3B model
designed and manufactured by Gavin
Botha and Darrell Zaballos. Taking on a
project of this scope is best done with at
least one trusted partner. The SP-1 is the
evolution of the Y2K based on several
years of experimenting, investigating,
analyzing, and evaluating existing designs.
“Based on lessons learned at the 2001
World Championships in the Czech
Republic, it was clear that the design must
be suited for all types of launching
conditions. F3B events are flown from
dawn to dusk in all types of weather
conditions.
“The design must be capable of down
wind launching at 8:00 AM and making a
10 minute duration flight. The Y2K
excelled in the good conditions we
experience in Northern California, but
suffered in the down wind, light air
conditions in the Czech Republic.
“The SP-1 was designed to launch hard
and perform in the worst conditions.
Hundreds of hours were spent designing
an airfoil and planform combination that
would meet these objectives, yet still have
good speed ability.
“The airfoil transitions from root to tip,
in order to compensate for Reynolds
number effects. It is 9% thick at the root
and rapidly transitions to 8% at the tip.
The airfoil is designed to effectively use
full TE [trailing edge] camber, and is
reflexed for speed. The control surfaces
are a constant 21% of the chord.
“Based on the excellent distance
performance of the Icon, the wingspan was
set at a comparable 129 inches. Wing area
was determined by trading optimal wing
loadings for the distance task with launch
performance requirements. The final wing
area ended up 1045 sq. in., resulting in an
AR = 16.
Visit the MODEL AVIATION Digital Archives!
Featuring a searchable database of Model
Aviation issues and articles from 1975 to 2000.
This is by far one of the best
efforts AMA has made to
construct something that is for
every member.
—Marco Pinto
Peninsula Channel Commanders
San Francisco CA
“
”
Find it at www.modelaircraft.org. On the main page, click
on the “Members Only” section, log in with your last name
and AMA number, then click on the “Visit the Digital
Archive” image.
108 MODEL AVIATION
“Female wing and stabilizer molds
were CNC machined by Team Arianne.
The fuselage plug was hand carved by
Darrell Zaballos, and fiberglass molds
were pulled from the plug. The structural
requirements for this design proved
extremely challenging due to the high
loads and thin wing sections, with
extremely thin control surfaces. It is
critical that an F3B design be very stiff
in all aspects.
“The wing uses 1.5 mm Rohacell
skins sandwiched between carbon cloth
on a 45 degree bias. This provides
excellent torsional rigidity. The control
surfaces use dual carbon torque tubes to
provide torsional rigidity. Lots of High
Modulus carbon is used for the spar
caps, to create a wing that bends very
little under extreme launching
conditions.
“Darrell and I have been sharing
building techniques with Don Peters,
maker of the Icon, for quite some time,
and the SP-1 features several of Don’s
ideas, including the Icon style ballast
system. A 2-piece V-Tail is used
primarily to save weight and for
convenience. Overall flying weight is 81
ounces.
“The final result is a model that
performs better than expected. The SP-1
performs well in all conditions, and
excels in duration, distance, and speed.
After a steep structural learning curve
(otherwise known as flight failures), and
some fine-tuning, it was immediately
evident that we had a winning design that
helped Darrell and I each earn a position
on the US F3B team.
“The only problem now is building
enough models to be ready for the 2003
World Championships in Germany.”
I asked Gavin to give an account of the
record run.
“The Arizona contest is always a well
run event that is always a ton of fun. I
truly look forward to each year. The great
people, excellent flying site, as well as
record-breaking conditions definitely
make this one of my favorite contests.
“The entire 2003 US team competed as
a team in the Arizona contest. Having the
full support of a great team (Darrel
Zaballos, Daryl Perkins, Mike Lachowski,
Tom Kiesling, Mike Smith, and Team
Manager Jim Thomas) truly is a benefit
when time comes to fly.
“Launching conditions were in 45
degree cross winds, which required
hooking over into the wind, prior to
climbing and building tension. A
relatively good head wind allowed for
maximum tension on the monofilament
line. The line tension resulted in a terrific
zoom and a launch height of about 1000
feet.
“At that instant I realized that I had
great conditions and the potential for a
great run. These conditions were
confirmed during the start dive. The SP-1
continued to accelerate all the way
through the dive and well into the first leg.
“My caller, Darrel Zaballos, became an
important part of the run, instantly
recognizing that it was faster than usual,
and called for an early roll-up and turn. In
order to turn a fast time in speed you
must be rolled and well into the turn
before the turn horn sounds, ideally just
clipping the 150m airplane.
“I was fortunate enough to capitalize
on the good conditions and flew a clean
course with good energy management.
Three legs later as I flew through the
finish line, I knew I had a very fast run
on my hands, although I was not
prepared to hear that I had just turned a
12.73 second run. The feeling at that
moment was fantastic.
“I continued to play in the strong
thermal, fully ballasted after the run, as
my adrenalin levels dropped and the
reality of the run set in. I can’t wait to
go back to Arizona. Anyone interested
in trying F3B needs to attend this
contest.”
The F3B World Championships will
be held August 4-9 in Kirchheim,
Germany. There is more information
about the members of the US F3B team
on the Web site. The World
Championships Web site should contain
daily event coverage. Good luck, team
USA! MA
Sources:
Vacuum Bagging DVD:
Bill Haymaker
107 Schofield Dr.
East Berlin PA 17316
[email protected]
www.paonline.com/hayman/video.htm
US F3B team
www.usaf3b.com/
2003 World Championships
www.f3b-wm-2003.de/
$3495
+ $450 S/H
BMJR Model Products
Box 1210, Sharpes, FL 32959-1210 • 321-537-1159 www.BMJRModels.com
Rambler 30
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