F3A (or Precision Aerobatics or Pattern) flying is the discipline of performing a set sequence of maneuvers with a model aircraft. Pilots progress through a series of classes with increasing levels of maneuver difficulty, with the top class being “FAI”, a class flown around the world with the same sequences.
Pattern is arguably the most graceful of the R/C flying disciplines, as the overall flight is assessed based on precision (or geometry), smoothness and gracefulness, positioning (display), and size of maneuvers. The attraction is the pursuit of perfection – always pushing to achieve that perfect flight.
Flying pattern also allows the pilot develop a set of skills that transition well into jets, scale, IMAC and many other disciplines. You can usually tell a pattern flyer by how smoothly they fly even the most difficult to tame model.
An F3A model aircraft will have a fuselage length of no more than 2 meters, a wing span of 2 meters (78.74″) or less, and the weight must not exceed 5kg’s (11.02lbs). The model can be made out of any material, built-up or composite, as long as it meets these 3 restrictions. Currently you’ll see canalizers, biplanes, triplanes and any number of platforms that pilots believe will give them an edge.
Power systems are either an internal combustion engine, with no size or fuel limitations, or an electric motor powered by a battery not exceeding 42 volts (10 lipo cells). There is a 94 decibel limit (@ 3 meters) for all aircraft regardless of power system.
In Canada, at most competitions you will see five progressive classes. The introductory class is Sportsman, and it works through 5 levels to FAI.
Sportsman class is where the beginning elements of aerobatics are established. The sequence usually includes elementary maneuvers like straight flight, level turns, a loop, a roll and maybe a stall turn. These skills are the building blocks of all aerobatic flying, and with practice will help the pilot feel confident putting the plane where it needs to be. Sportsman also allows the pilot to “exit the box” after some maneuvers; this provides an opportunity to relax, adjust and correct before starting the next maneuver.
The next class, Intermediate, introduces multiple loops, multiple rolls, combinations of roll and loop fragments, and a full turnaround (no exiting the box) sequence. These skills build on what the pilot learned in the Sportsman class, and the Intermediate class also introduces the requirement of focus. There is no longer any free pass to exit the box; every maneuver is judged and has the potential to impact the next maneuver! Focus and planning start to become important in designing the entire flight.
As you move up to Advanced, the difficulty of the maneuvers increases again, the number of maneuvers in a flight increases, and the judging becomes significantly less lenient. By the time you reach Advanced, you’ve become proficient at getting the airplane to do what you want, roughly where you want, and are starting to really master your inverted rudder control. You’re also paying attention to your aircraft set up, as this has a significant effect on how a maneuver is flown and presents to the judges. Wind correction becomes critical to putting a solid flight together.
Masters is the highest of the development classes. Maneuvers now integrate rolls and loops at the same time. Often there is much more inverted flying in Masters. You can fly more complex maneuvers, but now you’re paying attention to finer details. Consistent radii, consistent speed of flight, roll rates, overall geometry within the box, precision centering, clean snaps and spin entries, and dozens of other details are now more important. At this point, you’re likely to be able to notice the different strengths and weaknesses of different pattern airframes you fly.
FAI is what many aspire to for a host of different reasons. The expectation at this level is perfection. The maneuvers are complex and challenging, you’re not going to get the benefit of the doubt from the judges, your equipment is going to be close to the leading edge, and the competition level is extremely high.
FAI has 2 sequences – P or “Preliminary” and F or “semi-Finals”. At the world championships, all pilots fly four rounds of the Preliminary sequence. The top half of those will fly the F sequence in the semi-finals, and the top 10 will fly F and an unknown sequence for the finals to determine the best precision aerobatics pilot in the world.
A few years ago, FAI flyers would only fly the P sequence at a local contest, and while this is still prevalent elsewhere in the world, as of late you’ll find both sequences being flown at local contests. The thinking is that flying the significantly more difficult F sequence makes for better pilots, and better pilots means we can field a stronger National team for the Worlds.
All maneuvers in the aerobatic schedules are judged relative to a point on the ground. Flights are performed directly in front of the judges in an aerobatic zone or “box”, which extends 60 degrees to the left and right of a center line, and at an elevation of no more than 60 degrees. Generally the model aircraft is required to be flown at 150 meters from the pilot, in a plane perpendicular to the center line. Each time the model aircraft crosses the center line, a particular maneuver of an aerobatic schedule has to be performed, involving components such as loops, rolls, lines, spins, snap rolls, stall turns, knife-edge, and combinations of these.
At the ends of the aerobatic box, the model aircraft is required to do turn-around maneuvers to enable it to reverse its direction of travel. Maneuvers, or parts of them, performed outside of the box are penalized by loss of points, proportional to the degree of infraction. The competitor must therefore compensate constantly for possible wind drift and other weather elements.
The competitor’s performance is assessed by a panel of judges who will award marks, independently from each other, between 0 and 10 for each maneuver. Each maneuver starts with a and points are deducted for each downgrade (error) flown. Points are subtracted for various types of defects observed by the judges, the severity of these defects, and the number of times these defects are observed. Please see the judging quick notes to get a sense of the downgrades.
Maneuvers are also assigned a difficulty factor (K-factor, which is a multiplier of each maneuver) depending on the complexity of the particular maneuver. The scores are multiplied by the K-factor, totalled for the flight, and then “normalized”. With the excellent scoring programs available today, the pilot will receive back a sheet showing the raw score on each maneuver, the flight total as a percentage of points available, and even a multi-round summary showing graphically which maneuvers need some focus! Normalizing the scores means the top score becomes 1000 point, and the other competitors are indexed to that score. So if you score a 940 on the round, this means that you’ve flown 94% as well as the top placing flyer in that round.
Most contests are six rounds, and your two lowest scoring rounds are dropped so that only 4 count in the final placings. Judging and scoring are areas that need to be dug into further for a greater understanding of how it works.
Hopefully this gives you a good taste of what pattern flying is about. Yes, we’re largely obsessive, bordering on insane for trying to perfect these skills, but once you’ve flown that “my best ever!” round, you’ll be one of us! And you’ll be a better pilot for it.