Designed by Louis Blériot and Raymond Saulnier (of Morane-Saulnier), the original Blériot XI was a light and sleek monoplane constructed of oak and poplar. The flying surfaces were covered with cloth. The aircraft's original configuration included a R.E.P. engine spinning a four blade metal propeller which proved to be unsatisfactory. Blériot decided to use a basically simple 25 horsepower Anzani 3 cylinder radial engine with much better results.