Pattern is another name for Precision Aerobatics. It come in two flavors:
AMA style pattern
(National Society of Radio Controlled Aerobatics) and IMAC
(International Miniature Aerobatic Club).
There are several differences between the two types. IMAC rules require scale-like aircraft and AMA pattern requires a plane specifically made to fly RC aerobatic maneuvers.
Different maneuver sequences are used in each style. AMA style pattern has been around for many years, while IMAC is somewhat newer.
AMA pattern is divided into 5 classes, based on the skill level of the pilot. The first four are called Sportsman, Intermediate, Advanced, and Masters. These are technically the AMA classes. The 5th is the class used for international
competition and is called FAI F3A. Each progressively higher class contains additional, as well as more complex, maneuvers. Pilots progress through the classes based on their performances in AMA sanctioned contests. There is also the opportunity to move to a higher class voluntarily.
IMAC is based on the IAC full scale aerobatic pattern. IMAC is divided into 5 classes, based on the skill level of the pilot. The five are called Basic, Sportsman, Intermediate,
Advanced, and Unlimited. The unlimited class is used for international competition and is devoted to the perfection of world class IAC type maneuvers. Each progressively higher
class contains additional, as well as more complex, maneuvers. Pilots progress through the classes based on their performances in AMA/IMAC sanctioned contests. There is also the opportunity to move to a higher class voluntarily.
- What kind of plane do I need to fly aerobatics?
Almost any low-wing or mid-wing plane can be used to fly the Basic (IMAC) or Sportsman (NSRCA) maneuvers. The major additional requirements are that the plane be adequately powered. That means that it must be able to do a reasonably sized loop without loosing all of it's airspeed. The Ultra Sport and Utter Chaos are good candidates when powered by strong 60-sized engines. Low wing 40-size planes, such as the Global Avenger, are a second alternative,
especially when powered by some of the more recent and powerful .46 engines. Another excellent choice is any one of the many "Ugly
Stik" variations. The reduced (or zero) dihedral in the wings
of these planes reduces the rolling tendencies caused by the rudder
being above on high wing planes. Some of the older 60-size pattern
ships, such as the Escape, XLT, LA-1 and Summit are also excellent
1st or 2nd pattern ship. But they are NOT required.
Most seasoned pattern pilots are currently flying 1/3 scale or larger (IMAC)
or 1.20 4-cycle powered (NSRCA) planes. These are large, highly sophisticated and
specialized models, specifically designed to perform pattern maneuvers as effortlessly
as possible. However, these models are very expensive, quite complicated, and are
NOT required in the lower classes, Basic (IMAC)
or Sportsman (NSRCA). Apply the K.I.S.S. principle to your first foray
into aerobatics -- Keep It Simple, Stupid! Save the complexity to
later on when you're hopelessly hooked like the rest of us. You and your wallet will
both be better able to handle it then.
- What do I do first?
The first thing you need to do is get your hands of a copy of the AMA Competition
Regulations, often simply called the "Rule Book". You can get a copy free
from the AMA if you mail the carrier your AMA card was attached to, and send it to the AMA.
This book lists all of the rules concerning aircraft size and power requirements,
maneuver descriptions, and last but not least the judges guide. The judges guide describes
how the maneuvers are to be performed, and how they are to be
downgraded. This is absolutely one of the most important parts of the rule
book, although it is often the least read.
Find someone in your area who flies pattern to help "fill in the blanks" that
are bound to exist after reading the Competition Regulations. Hopefully, he will lead you
to ask the right questions and then provide the right answers.
- How do I learn to do the maneuvers?
The best way to learn the maneuvers is from someone who already knows how to do
them correctly. That's right, how to do them correctly. Many non-competition fliers fly
what they think are the maneuvers, but which DO NOT adhere to the maneuver descriptions
in the Competition Regulations. The only thing worse than not learning the maneuvers is
to learn them incorrectly.
A good caller or aerobatic's coach is an invaluable asset to your flying.
(A caller is a person who stands with the pilot and dictates each maneuver prior
to the maneuvers execution.) He will help you learn the maneuvers correctly.
If he's good, he'll frustrate you continually and gripe at you during and after every flight.
He'll expect absolute perfection from you and then tell you exactly where you've gone wrong
when you think a maneuver is perfect. He'll also help you figure out how to correct your
errors.
- What are the maneuver elements?
Every maneuver is made up of one or more of the following basic elements:
Lines, Rolls, Loops, Stall Turns, Spins, and Snaps. Every maneuver starts and ends
with a STRAIGHT LINE. This makes having a well-trimmed airplane extremely important.
- Terminology
Let's get some terms defined so we're all on the same page:
- ATTITUDE: The angle of the fuselage of the airplane relative to it's track.
The fuselage will not be oriented parallel to the flight path if there is any cross wind. This is normal, and is called "crabbing" into the wind.
- TRACK: The trajectory or flight path of the center of gravity of the aircraft over the ground. This is the path being judged.