French Nieuport 17 C1 The Nieuport 17 C.1 (or Nieuport XVII C.1 in contemporary sources) was a French sesquiplane fighter designed and manufactured by the Nieuport company during World War I.
An improvement over the Nieuport 11, it was a little larger than earlier Nieuports and better adapted to the more powerful engine than the interim Nieuport 16.
Aside from early examples, it had the new Alkan-Hamy synchronization gear, permitting the use of a fuselage-mounted synchronised Vickers gun firing through the propeller disc.
At the time of its introduction in March 1916, the type's outstanding manoeuvrability and excellent rate of climb gave it a significant advantage over fighters on both sides and was described as "the best pursuit plane of the day".
It was used by many operators and entered service with every Allied power and copies were also operated by the Deutsche Luftstreitkräfte (German Air Service). Mass-produced by several French firms,
the Nieuport 17 and its derivatives were built under licence in Italy by Nieuport-Macchi and in Russia by Dux.
Unlicenced copies, notably the Siemens-Schuckert D.I and the Euler D.I, were produced in Germany.
The Nieuport 21 and 23 represented relatively minor alterations. Aerodynamic refinement led to the Clerget-powered 17bis. More powerful versions of the Le Rhône rotary engines with detail improvements resulted in the Nieuport 24, 24bis and 27.