01/31/2012. Remarks by Kees Kort: This is a depot of the Army Expeditionary Force (A.E.F.), probably for a flying school (training), as indicated by the uniforms of the men visible and the big numbers on the fuselage side which define the machine on a training field. Given the inventory of wings the depot was expecting many repairs owing to training mishaps.
The machine with the big number '72' on the fuselage side bears extra information in small numbers and letters: '15 M 80 HP'. The '15 M' indicates the metric wing surface, 15 sq.m (161.46 sq.ft), while the '80 HP' indicates gives the engine and its horse power, the 80 hp Le Rhône engine. With this extra information the machine can be exactly identified as a Nieuport 21 (factory designation) which was designated Nieuport XXI by the SFA (Service des Fabrications Aéronautiques, department of aircraft production). The US purchased a total of 197 Nieuport 21's to serve as fighter trainers, during 1917-1918.
The two Nieuport machines which come second and third (behind the Nieuport 21 at right) are Nieuport two-seat trainers which are developments of the much earlier Nieuport X (Nieuport used the Roman number system in the factory identification of that time). These two-seater trainers were in the Nieuport 80-series; the Nieuport 81, of which the A.E.F. in France bought 173 machines, while 244 machines were acquired of the Nieuport 83.
Although there is outwardly very little difference between the Nieuport 81 and 83, a decisive distinction is that the Nieuport 83 had struts for the wing connection that were mounted vertically in contrast to the other Nieuport trainers which had an outward cant. As the machine behind the Nieuport 21 has vertical wing to fuselage struts, this is a Nieuport 83, and the other is a Nieuport 81.