Three channel flight used to be called REM or rudder, elevator, and motor. Back in the 60's it was known as Class II for competition. One of the best designs for Class II that I ever flown was a Stark Shark powered by an OS .61 engine. About the only manouver that it could not do was knife edge flight. It rolled a well as any design with ailerons, flew inverted with complete control including turns, looped both inside and outside, and did spins (though not flat spins). So flying with just REM is not that limited, just slightly different. I can remember at least eight designs that I have built and enjoyed, with plans to do another two or three before the glue drys in my bottle.