The Nieuport 19 was a twin-engined aircraft that was ordered by the RNAS, but that was never delivered.
The Nieuport 19 appears to have been a variant on the twin-engine three-seat Nieuport 18, an obscure design of early 1916. The Nieuport 19 designation was officially allocated in a French list of 18 February 1916.
The Nieuport 19 was to be powered by twin 110hp Clerget engines, and probably carried a crew of two (compared to three on the Nieuport 18). The RNAS ordered at least three, giving them serial numbers, but these aircraft were never delivered. The same was true for another twenty two Nieuport twins ordered by the RNAS, none of which were ever delivered.
Engine: Two Clerget engines