Marchetti MVT

The Marchetti MVT (Marchetti-Vickers-Terni) was an Italian fighter from the early interwar period
that was also known as SIAI S.50.
It was designed by Alessandro Marchetti and was a single seat all-metal biplane with the fuselage suspended between upper and lower wings with the after part serving as an airfoil. Its semi elliptical wings were very thin and used wing warping to allow lateral control and it had all-moving tail surfaces. It was powered by a single 220hp SPA 6a water cooled engine and was armed with two 0.303in Vickers machine guns.
It was built at Vickers-Terni factory in the Italian city of La Speziaand flew for the first time in the autumn of 1919 and in December of that same year it achieved the speed of 250km/h (155mph), which was a world speed record for the time but it wasn't declared official because there weren't any representatives of the Fédération Aéronautique Internationale (International Aeronautical Federation - the world governing institution for aeronautics of the time) present to certify the speed.
It was redesigned in 1920 to give it longer span wings and splayed interplane bracing struts, a new cabane structure and it was fitted with a more powerful 285hp SPA 62a engine. After that redesign it was tested in Guidonia (the Italian air force test centre) where it reached the speed of 275km/h (171mph).
Marchetti was hired by the Italian firm SIAI in 1922 as the chief engineer and it was renamed as the SIAI S.50, however, the MVT didn't match the minimum specs required by the Italian Regia Aeronautica for 1923 which specified that a fighter had to be powered by a 300hp Hispano-Suiza HS.42 but SIAI presented it for the contest anyway and it received a favourable impression from the Regia Aeronautica who adquired three airplanes for evaluation and had plans made to order 12 of them, although they were never ordered or constructed. It's also known that at least one of the three of those that were sold to the Regia Aeronautica was fitted with floats.
This airplane set the basis for the much succesful SIAI S.52 as it was based on this one.

Sources:
1. https://en.wikipedia.org/wiki/Marchetti_MVT
2. Salamander Books - The Complete Book of FIghters