SNCAC NC . 150 The SNCAC NC . 150 ( also known as the Centre NC . 150 ) was a prototype French high - altitude bomber aircraft designed and flown just prior to the start of the Second World War . It was a twin - engined monoplane , with a third engine driving a supercharger . Although testing was promising , and orders were planned for a modified version as a back - up for the Lioré et Olivier LeO 45 and Amiot 354 bombers , the surrender of France in June 1940 ended development with only the single example being built . Design and development . When the nationalisation of the French aircraft industry resulted in the creation of the " Société Nationale de Constructions Aéronautiques du Centre " ( SNCAC ) from the merger of Farman Aviation Works and Hanriot in 1936 , the new company inherited Farman ' s experience in high - altitude research , and this research continued . In 1937 , it proposed a pressurised transatlantic mailplane derivative of the Farman F . 223 . 3 bomber , this being developed into the unpressurised NC . 223 . 4 transport , of which three were built for Air France . SNCAC continued work on high - altitude aircraft , proposing two pressurised bombers in 1938 . The first , the NC . 140 , was a four - engined bomber using the wings of the Farman F . 223 . 3 but was quickly abandoned in favour of the smaller , twin - engined NC . 150 . The NC . 150 was a mid - winged monoplane with a retractable tailwheel undercarriage which was designed to make maximum use of non - strategic materials such as wood . The wings were of mixed construction , with a metal centre - section , and wood outer wings that had metal spars , wooden ribs and plywood skinning . Similarly , the fuselage had wooden forward and aft fuselage section connecting to the metal centre section , while the twin tail was of wooden construction with plywood skinning . It was to be powered by two Hispano - Suiza 12Y V12 engines , with power being maintained at high altitudes by using a single three - stage supercharger driven by a separate Hispano - Suiza 12X engine mounted in the fuselage . SNCAC began work on two prototypes as a private venture in 1938 . These two prototypes were not to be fitted with cabin pressurisation , although this was planned for a third prototype . The French Air Ministry placed an order for the two prototypes on 24 April 1939 , with the second aircraft to carry full armament . The first prototype , designated NC . 150 . 01 , made its maiden flight from Toussus - le - Noble on 11 May 1939 . Meanwhile , the French Air Ministry had become worried about possible delays to the Lioré et Olivier LeO 45 and Amiot 354 twin - engined bombers which were planned to re - equip the medium bomber squadrons of the " Armée de l ' Air " caused by shortages of light alloys , and after successful testing in early 1940 , ordered a change of plans . Pressurisation was to be abandoned , and the unusual central supercharger with its dedicated engine ( known as the " " bi - tri " " concept ) was to be replaced by individually supercharged engines . Two production versions were planned , the NC . 152 , powered by Hispano - Suiza engines , and the NC . 153 , with imported American radial engines . Development was stopped , however , by France ' s surrender to Germany in June 1940 , both the second and third prototypes being abandoned before completion .