IMAC: As posted above, involves scale aerobatics. Pilots fly in one of 5 classes and perform pre-prescribed sequence of manuevers and are given a score of 0-10 on each. They may also fly a previously unknown sequence of manuevers and are likewise given a score of 0-10 for each. Prizes given in each class. Top 4 classes require that the model be a replica of full scale aerobatic plane and there is no minimum size requirement (most are 70"-120" span). Bottom line is that IMAC is an aerobatics competition.

http://www.mini-iac.com

IMAA: Not a competition. People who have a similar interest in flying large scale models in a non-competitive atmosphere get together at weekend meets and "sport fly". Planes must be at least 80" in span (monoplane) and 60" span (bi-plane).

http://www.fly-imaa.org



Just to confuse you- most all of the planes you see at an IMAC event meet the minimum size requirements for an IMAA meet and you will see many of these IMAC planes flown at IMAA events.