Borel Bo.11  The Borel Bo.11 was a French two-seat general purpose monoplane designed and built by Etablissements Borel. The Bo.11 was mid-wing monoplane from 1911 with wire-braced wings and lateral control by wing warping. It was powered by a Gnome rotary piston engine. The Bo.11 served with the Aéronautique Militaire at military air training schools and at a civil flying school at Buc. The aircraft could be fitted with twin floats.