W.Green, G.Swanborough The Complete Book of Fighters
NIEUPORT (LORRAINE-DIETRICH) France
The rotary engine having reached its development limit by late 1917, Gustave Delage turned his attention to stationary engines, and, on 23 October 1917, it was reported that a Nieuport fighter with a Lorraine-Dietrich water-cooled eight-cylinder Vee engine was under test. Fitted with either a 240 hp Lorraine-Dietrich 8Bb or 275 hp 8Bd, this was a somewhat ungainly aircraft, with a large gap and an aft-positioned cockpit. Forward view was impaired by large fairings over the engine cylinder blocks with the radiator mounted between them. Although this prototype was undergoing what were described as "acceptance tests” at Villacoublay, it was evidently discarded in favour of a similarly-powered, but more refined, prototype which, according to one report, was to be ready at the end of January 1918. This differed markedly from its predecessor, having equi-span sweptback wings of increased area, horn-balanced ailerons on both upper and lower mainplanes, a larger vertical tail and the radiator repositioned in the wing centre section. It is reasonably certain that the engine was the 275 hp 8Bd and flight testing was reported to be continuing late in April 1918. Previously, in February, time to 6,560 ft (2 000 m) had been recorded as 5.66 min and to 13,125 ft (4 000 m) as 16.5 min. An early estimate of maximum speed with a Lorraine-Dietrich engine of 220 hp was 137 mph (220 km/h) at 13,125 ft (4 000 m). The following data for weights are estimated.
Empty weight, 1,179 lb (535 kg).
Loaded weight, 1,874 lb (850 kg).
Wing area, 226.5 sq ft (21,00 m2).
NIEUPORT (HISPANO-SUIZA) France
Produced in parallel with the second Lorraine-Dietrich-engined prototype, a virtually identical airframe was fitted with one of the first 300 hp Hispano-Suiza eight-cylinder water-cooled engines and was reported to be in course of testing on 1 May 1918. As the prototype was fitted with two 7,7-mm Vickers machine guns it was obviously not merely a test vehicle for the HS 8Fb engine which it was intended to install in the Nie 29 and the prototype of which was nearing completion. Much was expected of the Nie 29 at that time, and it would have been logical for the Nieuport company to have abandoned its first 300 hp Hispano-Suiza-engined fighter in order to concentrate on the more advanced and refined monocoque-type fighter. That is as may be, but development of the former would seem to have been discontinued by the time that the Nie 29 entered flight test. The following data are based on manufacturer’s estimates.
Max speed, 143 mph (230 km/h) at 13,125 ft (4 000 m).
Time to 13,125 ft (4 000 m), 10 min.
Endurance, 2.5 hrs.
Empty weight, 1,323 lb (600 kg).
Loaded weight, 2,094 lb (950 kg).
Wing area, 226.05 sqft (21,00 m2).