strikerone,
1. What is a 2x2 plane?
This is the maximum length allowed for international competetion which is in meters or about 79 inches x 79 inched length and wingspan.

2. What are the major differences between pattern and IMAC?
Pattern and IMAC both fly routines called sequences. Pattern uses planes that are purpose built for the job. IMAC uses planes that are scale versions of full size aircraft. Small variations of outline are allowed and the color scheme is optional.

3. What is the AA in 3D/AA?
AA stands for Artistic Aerobatics which normally includes 3D manuvers. EFE is another name which stands for Expanded Flight Envelope and there are contests for this style of flying.

Welcome to RC. Your choice of the Mid-Star is one of the best as a second plane.

For more reading visit the pattern and IMAC sites:
http://www.nsrca.org/
http://www.mini-iac.com/

You didn't give a location. Let the members know where you are and you will be invited to visit a local club that you will give you additional information.

EXCAP232