Radio Control Pylon Racing - 2006/08
"Rubber ducky" vs. whip antennae
By Kurt Bozarth <[email protected]>
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 duckies 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, and I have heard a host of opinions disguised as facts about whether these short antennae are adequate. I have never experienced an issue I can attribute to a lack of range with a rubber ducky antenna, but I am not an expert in this area. Perhaps my recent poor performance at Winterfest was caused by my antenna, but I doubt it.
After a few minutes of searching the Web, I found an article at www.berg.net by Peter Berg (2002) addressing rubber ducky–style antennae. The article 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.
Field tests and findings (Peter Berg)
Peter 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.”
Key findings:
- Range: Peter found a 4–6 dB loss in received signal strength for the rubber ducky compared to the factory-standard whip. “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.
- Directivity (rubber ducky): The ducky is much less direction-sensitive than the long whip. Peter found the best range when the rubber ducky was pointing approximately 30° from the aircraft. Pointing it about 60° from the aircraft was acceptable with a small loss; pointing it 90° from the aircraft produced a measurable loss. Point your rubber ducky–style antenna at your aircraft for the greatest signal strength.
- Directivity (standard whip): The directivity pattern of the standard whip is essentially the opposite of the rubber ducky. The standard whip produces the strongest overall signal at the receiver when its maximum radiation is out to the sides of the antenna (best angles 60°–90°). The worst angles are when the whip is pointed approximately at the receiving antenna. Peter measured a sharp dip in received signal strength of more than 25 dB in those cases. “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.
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.”
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Racing at the Basin
The San Fernando Valley Radio Control Flyers hosted a pylon race April 22–23, 2006, at the Apollo XI field in the Sepulveda Basin, California. This race was part of the Western Pylon Series and included:
- Sport Quickie (AMA event 424)
- Quickie 500 (AMA event 428)
- Q-500
- Quarter 40 (AMA event 422), or Q-40
This annual event draws a large crowd, with some of the best racers in the country attending. Several records were set this year. 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 Q-500 record with a time of 1:03.38, and Tanner Pacini set a Junior Q-500 record with a time of 1:08.01.
Winners:
- Saturday: Gino Delponte (Q-40), Travis Flynn (Q-500), Dan Courtier (Sport Quickie)
- Sunday: Robert Holik (Q-40), Travis Flynn (Q-500), Jim Padelt (Sport Quickie)
Scott McAffee commented on 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 winds were perfect for Quickies and they really felt faster than normal. Most of us put up our personal best runs 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 Q-500 record, only to have Travis Flynn beat it moments later.
Dan Thordarson sent details about two new racers:
- Dan Courtier entered his first race (AMA 424), finishing first on Saturday with a fast time of 1:38. He started practicing just a few months ago.
- Sean Elkins entered his third AMA 424 race and finished second both days with consistent times of roughly 1:38. Keep an eye on these two guys!
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SuperT RC
World-class pylon racers Travis Flynn and Dan Kane have teamed up to form SuperT Radio Control Products: www.supertcrc.com. The business was created to bring different pylon components together in one spot.
Dan Kane co-developed the successful Q-40 Polecat and chose it as SuperT’s first product. Travis expanded the business plan by adding other racing items such as flight stands and flight boxes. They have developed two new Q-500 models using tab-and-lock methods popularized by Dave Norman’s 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, is a laser-cut fuselage designed to accommodate Bruce De Chastel’s composite Shotgun wing and Bill Vargas’s foam-core, balsa-sheathed Racer II wing.
RC combat and pylon enthusiast A.J. Seaholm designed SuperT’s website. 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 likely feel the overwhelming need to order something.
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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 been selected to serve as the event director. He most recently served as event director for the 1995 F3D World Championships, which was also held in Muncie.
If you have race results or 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
Transcribed from original scans by AI. Minor OCR errors may remain.
