Morane-Saulnier I

The Morane-Saulnier I, AKA Morane-Saulnier MS.6, was a French fighter of the 1910s. It was basically a modified version of the Morane-Saulnier N.
Following the advice of Lord Trenchard, the Royal Flying Corps placed an order for a more powerful Morane-Saulnier N, so the firm Morane-Saulnier answered by fitting a 110hp Le-Rhône engine to a type N, creating that way the type I, even if externally it was identical to the type N, with the only difference that it was armed with a 0.303in Vickers Machine Gun.
Initially the Royal Flying Corp's order was for just one aircraft, but later, in March 1916 it was extended to thirteen.
However, just four aircrafts were delivered to the RFC in July 1916, having it flown in March of that year in RFC trials. No further production was ordered as the more advanced version, the Morane-Saulnier V proved to be better and more promising. However, the type I remained with the RFC, at the frontlines until October 1916 when they were replaced and sold to Russia, where they served with the Imperial Russian Air Service until the end of the war.

Sources:
1. https://en.wikipedia.org/wiki/Morane-Saulnier_I
2. Salamander Books - The Complete Book of Fighters