Complex sentence: In aeronautics spoilerons are flight control surfaces, specifically spoilers that can be used asymmetrically to achieve the effect of ailerons, i.e. to roll an aircraft by reducing the lift of one wing but unlike ailerons not increasing the lift of the other wing.
Split into simpler sentences: In aeronautics spoilerons are flight control surfaces, specifically spoilers that can be used asymmetrically to achieve the effect of ailerons. Spoilerons help to roll an aircraft by reducing the lift of one wing, but, unlike ailerons, not by increasing the lift of the other wing.