Gustave Delage joined Nieuport in January 1914 and gave the firm a family of sesquiplane scouts — aircraft with a full-size upper wing and a much narrower lower wing carried on a single spar. The layout was inspired by the pre-war “one-and-a-half wing” racers and offered two things a fighter pilot craved: a clean view below the aircraft, and low drag for a good climb.

O Nieuport 11 “Bebé” of 1915 proved the concept in combat, helping to break the Fokker Scourge. The Nieuport 17 that followed in 1916 was a refinement rather than a revolution: a slightly larger airframe, a more powerful Le Rhône rotary, rounded wingtips and a cleaner cowling, and provision for a proper synchronised gun. The result kept the Bebé’s agility while adding the speed and firepower the earlier machine lacked.

A conventional biplane has two wings of similar chord, braced together into a rigid box that resists twisting. Delage’s sesquiplane deliberately traded that box away: the lower wing was made narrow and hung on a single spar, braced to the upper wing by a distinctive V-strut. The pay-off was excellent downward visibility, light weight and low drag, all of which helped the climb and the turn.

The cost was torsional rigidity. With only one spar and no box structure, the lower wing could flex and twist under aerodynamic load. In gentle flying this was harmless, but it set a hard limit that the design never fully escaped — and which the next expander describes.

Early Nieuport scouts predated a reliable French gun-synchronising gear, so the RFC mounted a Lewis gun above the upper wing on the Foster mounting — a curved rail that let the pilot slide the gun back and down to swap the 47- or 97-round drum, and, usefully, to fire upward into the belly of an enemy aircraft. It was Albert Ball’s favoured trick.

As synchronisation matured, French Nieuport 17s standardised on a single synchronised Vickers firing through the propeller arc, a lighter and simpler installation. Some machines carried both. Either arrangement kept the armament on the aircraft’s centreline, so aiming meant pointing the whole fighter — the essence of the era’s dogfighting.

This is the caveat that any honest account of the Nieuport 17 has to include. Because the lower wing carried its loads on a single spar with no box to resist twisting, a prolonged or high-speed dive could let the wing flutter and twist. In the worst cases it failed — typically at the wing root or at the junction of the spar and the V-strut — and a failure there was usually fatal.

Pilots adapted by not holding steep dives, and the Royal Flying Corps ordered lower wings strengthened in 1917. The flaw was not unique to Nieuport: when the German designer Robert Thelen copied the sesquiplane layout for the Albatros D.III, it inherited exactly the same wing-shedding tendency. The lesson — that visibility and climb had been bought with structural margin — helped push front-line units toward the sturdier two-spar SPAD from 1917.

The 17 sat in the middle of a fast-evolving family. The Nieuport 21 was a lower-powered trainer/scout; the 17bis introduced a Clerget rotary and a slightly refined fuselage; the Nieuport 23 was near-identical to the 17 but differed in gun mounting and small fittings, so the two are often counted together. The later 24 e 27 brought rounded fuselages and further refinement before the whole sesquiplane line gave way to the SPAD.

Production was not confined to France. Macchi built Nieuport scouts under licence in Italy, and the Dux works produced them in Russia; Switzerland later built the type under licence as well. Because records are incomplete and the 17 and 23 share a production run, total-built figures in the literature vary widely — a point worth keeping in mind whenever a single number is quoted.

Per-aircraft procurement prices for the Nieuport 17 are not reliably recorded in surviving sources, and translating 1916 French war-contract francs into modern money is fraught — wartime inflation and the post-war collapse of the franc make any single figure misleading. We have therefore left the unit-cost row as “not reliably recorded.”

What can be said is about flying one today. Operating an airworthy WWI-type replica on a small rotary or radial — hangarage, insurance, fuel and castor oil, and the specialist maintenance a vintage engine needs — is commonly discussed in the vintage-aviation community in the region of a few thousand US dollars per flight hour. The ~$2,000–4,000/hour figure in the table is an unofficial estimate for a modern replica, not a historical cost, and is flagged as such.