Radio Control Pylon Racing - 2006/08

“Rubber ducky” vs. whip antennae
Also included in this column:
• Pylon race at the “Basin”
• SuperT Radio Control
Products
• 2007 F3D World
Championships news
August 2006 135
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Radio Control Pylon Racing Kurt Bozarth
One of SuperT RC’s latest releases: the improved HurriKane Q-500. The HurriKane
includes a laser-cut fuselage and a fully composite or foam/balsa wing.
An example of the popular and successful Q-40 Polecat developed by Dan Kane and
Bruce De Chastel and offered by SuperT RC. The author custom-painted this one.
A “rubber ducky”-type antenna is
detachable and convenient to use, but does
it offer adequate range? Read the column for
answers and more details.
IF YOU HAVE been to a Pylon race
recently, you most likely saw several racers
using “rubber ducky”-type antennae
instead of the stock whip antennae on their
transmitters. These rubber duckys are
usually 12-18 inches long and are easily
detachable.
I use a rubber ducky antenna and favor
it over the stock whip antenna for one
reason: I don’t have to worry about my
antenna hitting my caller or another racer
while I’m doing pirouettes in the middle of
the pack.
I have heard numerous comments from
racers questioning the range of a rubber
ducky antenna. I have also heard a host of
opinions that were disguised as facts about
whether these short antennae were
adequate or not.
I have never experienced an issue I can
attribute to a lack of range associated with
a rubber ducky antenna, but I am not an
08sig5.QXD 6/23/06 12:59 PM Page 135expert in this area. Perhaps my recent poor
performance at Winterfest was caused by
my antenna, but I doubt it.
After only a few short minutes of
searching the Web, I was able to find an
article at www.berg.net addressing
rubber ducky-style antennae. The article
was written by Peter Berg in 2002 and is
based on informal field tests comparing
rubber ducky to whip antenna range.
Peter’s disclaimer states that although
measurements were made with calibrated
and sophisticated test equipment, they
were not made on a calibrated test range.
He believes the numbers to be accurate
and representative, but they should only
be considered approximates.
Peter Berg ran field tests using a
standard whip antenna and a (well-known
brand) rubber ducky antenna mounted on
equivalent Futaba transmitters using the
same radio frequency module. He wrote:
“Measurements were made using a
calibrated HP spectrum analyzer as the
calibrated receiver. The receiving
antenna was a 50 ohm resistor with no
directivity or gain (a ‘monopole’). The
distance between the transmitter and the
receiving antenna was about 60 feet.”
The first factor Peter discusses is
range. He found a 4- to 6-decibel (dB)
loss in received signal strength of the
rubber ducky antenna compared to that of
the factory-standard whip antenna.
“This was to be expected, and the
amount of margin built into today’s
receivers tolerates that, as long as we
remember that we are eating up safety
margin,” he wrote.
The next factor Peter discusses is
directivity.
“The ducky is much less directionsensitive
than the long whip,” he wrote.
Peter found that the best range for the
rubber ducky was when it was pointing
approximately 30˚ from the aircraft.
Pointing the rubber ducky antenna
approximately 60˚ from the aircraft was
acceptable with a small loss. Pointing the
rubber ducky 90˚ from the aircraft
produced a “measurable loss.” Point your
rubber ducky-style antenna at your
aircraft for the greatest signal strength.
The directivity characteristics of the
standard whip antenna are completely
opposite of those of the rubber ducky
antenna.
“The standard whip antenna helps
create the strongest overall signal
strength at the receiver antenna, but we
found the directivity to be much more
critical than that of the ducky,” wrote
Peter.
He found that the best angles in the
vertical and horizontal fields were 60˚-
90˚. This means the maximum radiation
of a standard whip antenna is out of the
sides of the antenna. The worst angle is
when the whip antenna was pointed
“approximately” at the receiving antenna.
Peter measured a sharp dip in received
signal strength of more than 25 dB.
“At this short of a distance
(approximately 60 feet), this would mean
a reduction in received signal strength of
more than 99.7%!” he wrote.
Do not point your standard whip
antenna at your aircraft; point it 60˚-90˚
away for the greatest signal strength.
Peter’s conclusion:
“Pointing a whip antenna at the
airplane is bad, and pointing a rubber
duck antenna at the airplane is good.
These measurements proved nothing
new. We have known for a long time that
the antenna patterns are as described
above.”
Racing at the Basin: The San Fernando
Valley Radio Control Flyers hosted a
Pylon race April 22-23, 2006, at the
Apollo XI field located in the Sepulveda
Basin in California. This race was part of
the Western Pylon Series and included
Sport Quickie (AMA event 424), Quickie
500 (AMA event 428), or Q-500, and
Quarter 40 (AMA event 422), or Q-40.
This annual event draws a large
crowd, with some of the best racers in the
country in attendance. And this year
several records were set!
Club President George Finch and the
Valley Radio Control Flyers did an
outstanding job of hosting the contest.
Twenty workers showed up each day
along with a group of Boy Scouts to run
the concession stand.
“Without the workers, there would be
no racing at the Basin!” said CD Barry
Leavengood.
The weather was cold (by California
standards!) and ideal for racing. Travis
Flynn set a record in Q-500 with a time
of 1:03.38, and Tanner Pacini set a Junior
Q-500 record with a time of 1:08.01.
Saturday’s winners were Gino
Delponte in Q-40, Travis Flynn in Q-500,
and Dan Coutier in Sport Quickie.
Sunday’s winners included Robert Holik
in Q-40, Travis Flynn again in Q-500,
and Jim Padelt in Sport Quickie.
Scott McAffee provided the following
interesting comments about the weekend.
“Just an observation on Travis’s
record: I watched the flight very closely
and Travis got no gifts from the
flagmen—his flight was clean and he
went around all the poles. I have watched
Travis fly for years, but this was the best
flight I have ever seen him put up. He
left no more than a tenth or two out on
the course.
“There was a period of about an hour
around lunchtime when the weather was
perfect for Quickies and they really felt
faster than normal. Most of us put up
personal best times in these heats.
“Gotta feel bad for Jimmy Allen and
Gary Schmidt who turned 1:04s and got
beat! Also for Fred who put up a heck of
a flight but could enjoy being the record
holder for only minutes.”
Evidently Fred Burgdorf set a record
in Q-500, only to have Travis Flynn beat
it moments later.
Dan Thordarson sent me the following
details about two new racers who
attended.
“Dan Courtier entered his first race
(AMA 424), finishing in first place on
Saturday with a fast time of 1:38. He
started practicing just a few months ago.
Sean Ekins entered his third (AMA 424)
race and finished second both days with
consistent times of roughly 1:38 as well.
Keep an eye on these two guys!”
SuperT RC: World class Pylon racers
Travis Flynn and Dan Kane have teamed
up to form SuperT Radio Control
Products. According to Dan, the business
was created to bring different Pylon
components together in one spot:
www.supertrc.com.
Dan Kane co-developed the popular
and successful Q-40 Polecat and felt that
it would be the logical choice for
SuperT’s first product. Travis expanded
their business plan by adding other
racing items such as flight stands and
flight boxes. Most recently they have
developed two new Q-500 models
utilizing tab-and-lock methods made
famous by Dave Norman and his Seeker
Q-500 design.
Dan has also updated his popular Q-
500 design—the HurriKane—with all the
latest improvements, including an NACA
66012 airfoil. Another SuperT design,
the Laser V, consists of a laser-cut
fuselage designed to accommodate Bruce
De Chastel’s composite Shotgun wing
and Bill Vargas’s foam-core and balsasheeted
Racer II wing.
RC Combat and Pylon junkie A.J.
Seaholm did an outstanding job of
designing SuperT’s Web site. One can
custom-order a Q-40 or Q-500 model in
less time than it takes Travis to fly 10
laps. Caution: You will not be able to
surf the Web site without feeling the
overwhelming need to order something.
2007 F3D World Championships: AMA
will host the 2007 F3D (FAI RC Pylon
Racing) World Championships at the
International Aeromodeling Center in
Muncie, Indiana, June 30-July 4.
Wayne Yeager has once again been
selected to serve as the event director. He
most recently served as the event director
for the 1995 F3D World Championships,
which was also held in Muncie.
If you have race results and topics you
would like to see presented in my
column, send them to me. If not, I will
have to resort to the obsolete technology
of mind-reading. I’ll be back again in
two months—now go practice. MA
136 MODEL AVIATION
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