2023 FAI World Championships For Pylon Racing Model Aircraft

A Recap of This Year’s Event

By Paul Gibeault [email protected] | Photos courtesy of the author

As seen in the November 2023 issue of Model Aviation.

Since airplanes have existed, competitions have been held in air racing of all classes. Pylon Racing, in a closed circuit around pylons, is based on racing with full-scale, manned aircraft, the most famous being the Reno Air Races.

Back row (L-R): Paul Gibeault, assistant team manager; Matt Fehling, F3D caller; Bruce Brown, F3E pilot; Trey Witte, F3E pilot; Otto Dieffenbach, F3E pilot; and William Naemura, team manager. Kneeling (LR): Randy Bridge, F3D pilot; Leo Nordell, F3D pilot; Gino Del Ponte, F3D pilot; and AJ Hemken, F3D pilot.

The F3D (glow-powered) and F3E (electric-powered) model classes are recognized as world championship classes by the FAI. It is in no way a kind of scaled Reno-style, full-scale racing. These classes have been developed to bring the highest level of aerodynamic design, aircraft construction, powerplant, and propeller design to suit the specific needs of the circuit. Of course, the highest level of piloting airplanes around the course is essential to record fast times.

It must be noted that this FAI course size is different from any AMA class, so FAI pilots/callers must have the ability to adapt and fine-tune their timing accordingly.

This is Randy Bridge’s prized F3D competition propeller collection. When going into unfamiliar territory, you just can’t have too much ammunition!

This is an Australian-designed, left-handed, sawtooth, singleblade propeller with a 133mm pitch. It pivots to reduce stress points in order to run a thinner-blade, sawtooth leading edge for spanwise flow straightening. It works well in nice, warm weather but is not as well in bad weather.

This champion Czech F3E model incorporates a blower motor up front and an extractor motor in back to cool down the model’s electrical system after each race.

Competitors

The pilots present at this world championships have qualified to represent their country. There was a maximum of three Senior pilots, one Junior pilot, and one female pilot per country.

The pilot flying the model is accompanied by a caller for safety reasons. The caller holds and launches the model during the start and gives the pilot verbal information during the race and landing.

Teams from 12 countries competed this year. The attendance was perhaps slightly lower than other world championships, but the FAI racing committee decided to hold back-to-back world championships to get back on the international schedule that was interrupted because of COVID-19.

The Course

The course is triangular with two 180-meter long sides and a short side of 40 meters. One lap has a geometrical length of 400 meters, but in practice, the distance flown will be longer because the models fly with a turning radius of 15 to 25 meters around the course. The course is marked by three pylons, each with a height of 5 meters. In each race, three models will simultaneously fly 10 laps.

It is up to the pilot to fly as tight of a course as possible around the pylons without cutting inside of them. In this case, a penalty is applied: a 10% time increase for one pylon cut. When two pylon cuts are made, the flight is terminated and given a 200-second (points) result. This is approximately three times the number of seconds of a normal race time.

Gold-medal F3D team member AJ Hemken, from Prosper TX, looks confident going into the championship round.

The USA F3E Team (L-R): Bruce Brown, Trey Witte, and Otto Dieffenbach.

Veteran F3D pilot Bobo Sato (L) and his caller, Hiroshi "Rock Star" Nakamura (R), representing Japan.

AMA racing classes are all on the basis of "first past the post wins," whereas FAI racing is all scored on time. A racer can therefore be third across the finish line but win the race by posting the lowest heat time.

During the initial rounds, an error was pointed out by the British team, which found that the electronic timing system started all lanes at the same time instead of 1 second apart, as what is required. Those taking off in lanes two and three had their scores subsequently readjusted (improved).

Twelve judges kept track of the models, keeping time and giving penalties when pylons were cut. The judges on the farthest pylon also gave light signals to the competitors to inform them that the pylon had been passed.

All kinds of time is lost flying too far past the critical, farthest pylon, and the best teams are the ones that fly this pylon tight without cutting, which is an art form in itself to do consistently. The fastest pilots have developed a technique after turn one to maintain nearly knife-edge flight for the rest of the race. This eliminates a lot of drag from constant aileron input; however, this isn’t the case for full knife-edge flight, which produces more fuselage drag. It’s a very fine balancing act indeed, and it’s a sight to behold when watching the top racers.

The Models, Engines, and Propellers

The models are specified in the rules in terms of minimal wing area, minimum fuselage dimensions, engine-size capacity, minimum weight, and other features. Outside of these specifications, the design of the model is completely free and many of the competitors fly models of their own design.

These days, nearly all of the components of Pylon Racing models are made from high-tech materials, such as carbon fiber, and some are made in CAD/CAM-manufactured molds. Because the turns are made at 35-plus Gs, the models need to be made to the highest precision and strength standards, while at the lowest possible weight.

The rules of the F3D class prescribe piston-type engines that turn a propeller directly. In practice, only two-stroke engines run on FAI fuel (no nitro) and are fitted with muffled, tuned exhaust pipes. The tuned pipes give a great increase of power to the engines. These engines, with a capacity of 6.6cc, deliver approximately 4.5 hp at 32,000 to 34,000 rpm. The airspeeds of these models range from 330 to 360 kph (205 to 223 mph).

Currently, the only two commercially available engines in use are the venerable MB Profi, manufactured in Ukraine and assembled in Holland, and the DKT engine, manufactured in Italy. Both are extremely potent in the right hands. The most common tuned pipe is offered from Paulo Pompana out of Italy.

The battery power of the electric motors in the F3E class is limited by a "watt limiter." Competition 1,000-watt limiters are supplied to the competitors. There is a wide variety of speeds and propeller sizes, where the participant tries to achieve the highest possible efficiency at the highest possible speed.

It’s a tough balancing act between going fast and gliding the last lap of the race or going the whole 10 laps at a slower speed. A perfect race is one where the limiter shuts off the motor just as the pilot crosses the finish line on lap 10. Ideally, you want to expend every one of those electrons available in your battery—but not too soon! Some competitors use a battery heater, which allows for a higher voltage output (more power) but less total duration. Top Czech competitors use a twin-blower, electric cooling motor attached to the nose of their models after each race.

Father and son world champions, Gunnar and Emil Broberg (Sweden), pose with former world champion Randy Bridge (US).

Prizes were awarded at the banquet: Team USA, gold; Team Sweden, silver; and Team Czech Republic, bronze.

The propellers in both classes need to be very thin but also strong, and they are molded in carbon fiber. They have tip speeds in the supersonic region, and therefore need very special airfoils to be effective.

Although this F3E racing class is very specific and can only be flown by expert aeromodelers, all components can basically be purchased on the world market. A large number of pilots also develop their own models, engines, and propellers. Outstanding pilot vision is required because at 330 kph, these tiny fuselage models are just plain hard to see—for competitors and judges alike.

The single-blade F3E propellers are loud—loud enough to attract the attention of the local police when they were flown before 9 a.m. by one eager team! Conversely, the gear-reduced, large-diameter propellers are very quiet.

The Competition

Competitors in F3D are given 60 seconds to start and adjust their engines. The race is between three models and begins at the start/finish line, where the models take off from the ground. The F3E models are javelin hand-launched on a 10-second countdown. The race is completed after all models have completed 10 laps.

The number of laps flown and the race time for each competitor are recorded on an electronic timing system. Each pilot flew 12 rounds during this championship and the winner was the one who had accumulated the lowest score in seconds. The three worst scores were deleted. These deleted scores caused dramatic changes in individual placings throughout the competition.

Flying Site

This year’s competition took place at Drachten Airfield in the northern part of the Netherlands. Drachten is a nice little city. The field and all amenities were a roughly 6-minute drive from our nearby hotel. The airport was closed to full-scale activity for the duration of the event.

The Real Racing

I attended as the assistant team manager for the 2023 US Pylon Racing team. What am I doing here? Well, with Team Canada taking a pass, I was asked by US Team Manager Will Naemura to come and help out. The US had one of the largest teams, with three F3D pilots (6.5cc gas power), three F3E pilots (electric power), and one Junior F3D pilot. It’s a big job to look after two different teams (gas and electric) at the same contest.

Tuesday, Day One

The opening ceremony took place at 9 a.m. on Tuesday, outside in the pouring rain. Fortunately, the speeches were kept short! The only guy with proper footwear was Matt Fehling, from Florida, who wore flip-flops (he’s familiar with rain squalls). The weather report was grim, with intermittent rain the whole week.

I called for F3E pilot Otto Dieffenbach and we were the only electric fliers to get in flights on Monday. Otto is a full-scale pilot and a master of reading the rain fronts. He established our presence by getting in five test flights in between the rain, hail, and lightning. We had the F3E course to ourselves because no one else ventured out into the wet, blustery conditions.

Sportsmanship is what it’s all about. Individual F3D winners (L-R): Randy Bridge and Matt Fehling (silver); Gunnar and Emil Broberg (gold); AJ Hemken and Gino Del Ponte (bronze).

F3D Team Awards: Team USA, gold; Team Sweden, silver; Team Czech Republic, bronze.

Official practice started Tuesday, but it was delayed by rain. It briefly abated and the Japanese team went out first. At 11 a.m., a pounding rain squall occurred. It was hard to even hear each other inside of the big tent.

The teams out testing returned like drowned rats—poor guys, ugh!—yet we persisted because the show must go on.

Wednesday, Day Two

With all of the rain, only two rounds of F3E and one round of F3D were flown, and we were behind schedule. Our F3D team was very well poised with first, second, third, fourth, and sixth place.

Even so, many were not happy with their times. They would have been happy with world-record times, I guess. They made lots of daily engine run-ups.

In F3E, although Trey Witte and Bruce Brown were getting in times, they weren’t satisfied. Otto was having a hard time with a double cut, and then he ran out of battery on lap 9 for a "did not finish." This was not at all where he expected to be.

Others did worse, with a South African pilot crashing past Pylon One in F3E and former world champions posting some scores in the 200s.

Thursday, Day Three

With better weather on Thursday, there was a flurry of activity. The organizers were pushing hard to get in the maximum number of rounds possible.

Still, the word champions’ "gremlins" were lurking everywhere, with top fliers (and many others) losing flights with technical and flying difficulties that didn’t show up in practice.

Otto’s third flight, although slow, was a clean, 10-lap race with just enough battery for 10-1/4 laps. Bruce flew a nice, clean race and Trey registered his first cut. Otto squeaked in the last flight of F3E in round five and ran back to the main tent as the rain came down. All of those poor F3D models waiting outside on deck were getting soaked.

As of 3 p.m., we had five rounds of F3E and four rounds of F3D done. Everyone was queuing up at the lunch counter for hot soup, which was just the ticket. The rain squall was brief, and on we went. The wind was noticeably stronger toward the end, and it was giving the pilots trouble with both flying and landing. Leonas and Andreas Kaiser, from Germany, each lost an F3D model.

Daniel Arapakis, from Australia, lost an F3D model, a Swedish model was lost, and I believe there is still one South African F3E fuselage missing in action in the trees. An errant F3D model smoked the start line scoreboard on landing, rendering it inoperative. Although this caused some problems, the organizers carried on.

Friday, Day Four

Friday morning turned out bright and sunny, with a repaired start-line scoreboard in place. We were all happy to get racing.

A midair collision in F3D wiped out World Champion Emil Broberg, who now had two 200 scores. Randy Bridge suffered a most unfortunate loss when he pulled out of his race early and shut down. He ran out of glide momentum and, upon landing on the runway, hit Swedish caller Taru Hintikka. I’m led to believe that Taru is okay because her pit box took most of the blow, but Randy’s model was damaged and out of action. Randy was quite shaken by the incident. It seemed to be an unfortunate case of being in the wrong place at the wrong time.

In a surprise turn of events, Oliver Witt, from Great Britain, was in first place in F3D at the end of Friday, and the British team was elated. The decision had been made to cancel the super finals because of the weather constraints. We called it a day after 12 rounds of each class, allowing everyone to discard their three worst scores from the average.

F3E Individual awards (L-R): Christoph Meier (Germany), silver; Jan Sedlacek (Czech Republic), gold; and Tjarko van Empel (Netherlands), bronze.

F3E Team awards (L-R): Team Australia, silver; Team Netherlands, gold; Team Germany, bronze.

Saturday, Day Five: Judgement Day

Only one round of F3E, followed by the last two rounds of F3D, were left. In F3E, last year’s world champion, Czech pilot Jan Sedlacek, kept his grasp of first place with a healthy 6.19-second lead over Christoph Meier of Germany (second place) and Tjarko van Empel of the Netherlands (third place).

In the team standings, the Netherlands was first, showing a great lead of 22.52 seconds ahead of the Australian team, with Germany in third place. Our American team was in fifth place. Newcomer Otto learned a lot and certainly has the capability to move up in the standings with continued work.

F3D on Saturday was a barn burner. Young Leo Nordell, the US Junior, had engine problems, among others, that put him in second place next to German Junior competitor Leonas. When 16-year-old Leo did not have technical problems, he was right in the game with the Senior competitors. I look forward to seeing great things from Leo if he keeps it up.

Team USA F3D came through in the crunch, with everyone pulling together and posting some of their best times. Not only did these fast times improve their averages, but they also allowed them to discard their three worst times.

When the smoke cleared, reigning world champion from Sweden, Emil, emerged as champion, edging out record-holder Randy by a scant 2.15 seconds over 12 rounds. Gino Del Ponte was in third place by .01 of a second. AJ Hemken was in fourth by 3.22 seconds, and Oliver, from Great Britain, was 3.34 seconds down from AJ. This was extremely close racing!

Oliver lost his grip on first place by scoring two 200s, thus losing his lead. Of note, young Emil came within .3 seconds of breaking Randy’s world record in his best heat—certainly a deserving world champion! He used his DKT engines to great effect.

On the combined team standing, Team USA F3D won gold with a healthy 87 seconds over Team Sweden (second place), while the Czech Republic team came in third.

After being silver medalists twice in the previous world championships, Randy, with caller Matt, Gino, and AJ have demonstrated great breath as a team. It wasn’t an easy win in the harsh, wet conditions, and I’m sure they all looked forward to catching up on lost sleep!

It was impressive to see them collectively struggle though engine issues, airframe breakages, and trim problems, yet they relentlessly stayed the course until they achieved their goal of gold. Well done!

The 2025 Pylon Racing World Championships are slated to be held in England. The management and members of the 2023 F3D/F3A World Championship team would like to thank AMA and all of our corporate sponsors and supporters. Without their support, this wouldn’t be possible.

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