Sid "Scroll" Mayeux has over 25 years of experience in aviation training, safety, and risk management in the military, civilian, airline, and general aviation sectors. He currently trains Boeing 777 pilots, and he built and is flying a Van's RV-7A.
Multiple engines complicate design, because not only must the airplane be able to maintain flight on one engine, but also the pilot must be able to control it. Lateral/directional stability issues are key;