IMAC Scale Aerobatics

"To duplicate full scale aerobatics with miniature radio controlled aircraft
in a realistic manner that is challenging for the contestants
as well as interesting for the spectators."

What is IMAC?

In 1974 a group of about 100 RC pilots got together and thought it would be cool imitate IAC aerobatic competitions with their RC airplanes. Since most IAC planes at the time were bi-planes, this group called themselves the National Sport Biplane Association. The IAC thought this was a cool idea, so they embraced the group and the name changed to IMAC!

IMAC stands for International Miniature Aerobatic Club. It is a special interest group of the AMA. The purpose of its existence is summed up nicely in the "official objective" listed at the top of this page. By replicating full-scale aerobatics with radio controlled airplanes, IMAC truly is a miniature version of the International Aerobatic Club (IAC). It is sometimes called the "Mini-IAC".

Competition Format

There are five levels or "classes" of competition based upon your experience and skill level. The freestyle is an optional event that takes place after the other classes have finished competing. The freestyle event is where RC pilots show off their mind-blowing 3D routines!

Basic
Sportsman
Intermediate
Advanced
Unlimited
Optional Freestyle

Each class is given one or more series of known maneuvers to perform which is called a sequence. IMAC competitions usually require that the pilot fly an unknown sequence that is given to the pilot the day of the contest.

The difficulty of each maneuver of a sequence is given a K-Factor. The judges' score of each maneuver is multiplied by the K-Factor to obtain the final score. Perfecting more difficult maneuvers will land you higher scores! The K-factors of the required maneuvers increase as you move from Basic to Unlimited.

Aircraft Requirements

In order to be eligible to participate in IMAC Scale Aerobatic competitions, your aircraft must resemble a full scale aircraft capable of competing in an IAC contest. The rules state that the aircraft shall be judged for "likeness" at a distance of approximately 10 feet.

The wingspan of the airplane determines the "scale" it is. The fuselage width and height can't deviate more than 10% of scale. The rules also state that a realistic human pilot figure and a viewable instrument panel must be installed in the cockpit. The engine of the aircraft can not be louder than 96dBA.

Full-Scale vs. Scale Aerobatics

Although IMAC's goal is to replicate full scale aerobatics, there are some distinct differences that must be taken into account. The perspective of the pilot is obviously what really distinguishes the two. Since an RC pilot is stationary, it is easy to see when the RC airplane drifts off course due to the wind. For this reason, all of IMAC's maneuvers must be corrected for wind drift.

Since our radio controlled planes are much lighter than full-scale planes, the wind knocks them around a bit more. To compensate for this, IMAC deducts one point for every 10 degree deviation from a perfect maneuver where as the IAC deducts one point for ever 5 degrees.

RC planes aren't burdened by the physical limitations of a human pilot. This allows IMAC's higher class sequences to be a bit more aggressive with higher G maneuvers than what is typically seen in IAC competitions.

I had the honor of hearing Matt Chapman speak at the 2009 Toledo Show. He told an interesting story about his first IMAC contest. He described how other beginners were complaining that it wasn't fair that Matt Chapman was competing in the Basic Class. He found it amusing that those same pilots later apologized to him after watching his performance!

This proves that being one of the all time best Full-Scale Aerobatic pilots of all time doesn't really help you much when it comes to flying RC! There are a lot of similarities, but they are definitely two different animals...

International Scale Aerobatic Organizations

Although IMAC is a special interest group of the AMA, it is truly an international organization as RC pilots compete in IMAC competitions in many countries throughout the world. Below are just a few of the organizations across the globe that recognize and compete in IMAC competitions. If you know of more, please let me know so I can add it to the list!

Getting Started with Scale Aerobatics

You don't need a million dollar plane or top dollar equipment to get started learning Scale Aerobatics. The best way to get started is to dive in head first!

Download, print and study the AMA Rules for Radio Control Scale Aerobatics. Take your favorite sport model to the field and go at it! Practice, practice, and practice some more. When you think you are ready to compete, use the links above to find out where to sign up!