The Avro 511 was designed as a fast scout for military use at a time (1913) when the role of aircraft in war was first emerging. It was a single-seat wood-and-canvas
biplane. The fuselage was of square cross-section and carried Avro's characteristic "comma"
rudder, with no fin. The wings were heavily staggered and had pronounced sweepback, both features intended to improve stability. They were not constructed with the usual span-length spars, but used a cellular approach. The
interplane struts were not the usual single-piece shaped rods, but built up multi-piece, wide chord structures covered in canvas. There were conventional midsection "N" type struts between the fuselage and the upper wing.
Ailerons were carried on both upper and lower wings. Most unusually for its time, the inboard lower wing featured landing
flaps, so the 511 landed at a sedate 35 mph (56 km/h). The single rotary
Gnome Monosoupape was neatly cowled, though this was later modified to improve cooling. Mainwheels were mounted on a single axle plus centre-skid undercarriage and there was a tailskid. Later in 1914 the 511 was modified with a new pair of wings with no sweepback and a V-form (cranked axle), skidless main undercarriage, becoming the Avro 514. ==Operational history==