The Nieuport 17bis designation was initially used by Nieuport for a Nieuport 11 variant that had been retrofitted with the wings and side fairings from a Nieuport 17, however this type was not produced in any numbers and the designation was reused. The Nieuport 17bis was the first of the vee strut scouts to feature a fully streamlined fuselage, with longitudinal stringers to fair out the shape. Other than the changes to the fuselage, minimal alterations were made, and unlike the later
24, 24bis and
27, the flying surfaces remained the same as used on the 17, as was much of the internal structure. Unlike the 17, or any of the other Vee strutters, it had the
Vickers Machine Gun offset to the port (left) side of the centerline. Due to shortages of
Le Rhône rotaries, they were fitted with the
Clerget 9B rotary instead of the lighter
Le Rhône 9J used in most of the other Nieuport single seat scouts. A few examples were fitted with the lower powered
Clerget 9Z. As a result of the Clerget's slightly greater diameter, the cowling was ballooned out slightly to provide clearance. Climb rates varied, and in the first test the 17bis outclimbed the Triplane by a significant margin, however in the second test the times to altitude were identical between the two types. Adding a
Lewis machine gun to the Vickers reduced the climb rate, and increased the time it took to climb to by 2 minutes. Initial reports were impressive, but the Clerget engines lost power quickly between overhauls, and the problem was worse with the British built engines. Many pilots tried to have French-built engines in their aircraft. Some aircraft were also delivered to units with incorrect propellers, which also hampered performance. It combined the flying surfaces including the tail of the 23 with the fuselage of the 24bis, and was fitted with other Nieuport 23 parts, such as an earlier form of cowling. Aside from the lack of a plywood leading edge to the wing, the key identifying feature was the rake of the forward cabane struts connecting the top wing to the fuselage. On the 17, 17bis, 21, 23 and 23bis, the cabane struts were angled forward from the fuselage, while on the 24, 24bis, 25 and 27, they were angled aft. Both the 17bis and the 23bis used the square ailerons, rather than the rounded ailerons used on production versions of the later types. ==Operational history==