You need MORE than 1:1 thrust/weight ratio. In the upper classes of IMAC, there are maneuvers that require upline snaps (kills your energy and speed) and you must continue on an upline from there. 1.5:1 thrust ratio would be a minimum IMO. Picture a 24 pound airplane going straight up. Now do one positive snap. You just lost a LOT of energy. Now accelerate vertically and do a couple aileron rolls. Keep going up. That takes a LOT of power.

In the lower classes, you don't need that much power. 1:1 ratio is enough.

You don't NEED a 33% or 35% plane to get into IMAC. But, even though the money seams like a lot, you will spend 3X that much buying a 28%, then a 30% and finally moving into the 35%. The cost difference between a 28% (50cc) and a 35% (100cc) is about $1000-$1500 more. If you get into IMAC, you'll end up with a 35% eventually, so just do it now. You can buy a nice used 35% for around $2500. I have more than that in a 30% plane. Good deals can be had on used airplanes, if you can wait or spend some time hunting for the right one.


I think krayzc-RCU was asking:
Are you wanting to compete in official IMAC competitions? Or do you just want to dink around at the field and fly those types of maneuvers without actually entering a contest?

Thats 2 different planes. Or, same plane, but with different HP and thrust. Obviously, the contest plane will have a lot more thrust to pull off the big maneuvers. If you're just going to dink around at the field, you don't need that much HP, because nobody is judging you or deducting points if you can't pull off that big maneuver.