Ambrosini SAI . 207 The Ambrosini SAI . 207 was a light fighter interceptor built entirely from wood and developed in Italy during World War II . Powered by a single 750 hp Isotta - Fraschini Delta the SAI . 207 enjoyed limited success during evaluation of the 12 pre - production aircraft . Development . The SAI . 207 was developed from the Ambrosini SAI . 7 racing and sporting monoplane after the light fighter concept had been proven with the Ambrosini SAI . 107 prototype . Steffanuti designed the aircraft to have a lightweight structure and light armament to allow lower - powered engines to be used , without unduly reducing performance . The first of three prototypes was completed and flown in the Autumn of 1940 as the sole SAI . 107 , which was a minimum change fighter development of the SAI . 7 , with identical dimensions , apart from length , at and the Isotta - Fraschini Gamma engine . Weighing only the Sai . 107 reached a speed of in trials held at the Guidonia research establishment and manoeuvrability proved to be excellent . The SAI . 107 was lost , along with pilot Arturo Ferrarin , in a crash on 18 July 1941 . Two more fighter prototypes were built as SAI . 207s , flying for the first time in the Spring of 1941 and 1942 . Design . The SAI . 207 was a single - seat , low - wing monoplane with a conventional tail - wheel undercarriage , developed from the Ambrosini SAI . 7 . Of wooden construction , giving a light structure , power was supplied by Isotta - Fraschini Delta R . C . 40 engine , cooling air entering the engine through a central intake . Armament consisted of two Breda - SAFAT machine gun s . In level flight the performance of this aircraft was impressive , achieving a speed of and over in a dive . The Ministero dell ' Aeronautica soon placed a production order for 2 , 000 machines , plus a pre - production batch of 12 aircraft for operational testing . After the mixed results of operational evaluation and the signing of the Armistice , no production aircraft were built . Operational history . Flight testing revealed some major shortcomings , most of which were not rectified before the Armistice in 1943 ; the low power and high wing loading resulted in poor climb performance ; the light structure prevented more powerful cannon from being used as the recoil forces overstressed the mounting structure ; the rear cylinders of the engine overheated during recovery from a dive ; the light structure also led to problems , with the second prototype wing exploding during a dive recovery due to internal pressure built up , caused by the lack of internal fairings in the undercarriage bays ; the wooden structure was also badly affected by rain or humidity . The pre - production batch of 12 aircraft served briefly with three squadrons . The first was 83rd " Squadriglia " , 18 " Gruppo " , 3 " Stormo " , led by Guglielmo Specker , one of the " Regia Aeronautica " s best known " aces " , at Cerveteri airfield , near Rome . The aircraft entered service in July 1943 , flying a number of combat missions against heavy Allied raids over the Italian capital , but without success . After one month , they were sent to Castiglione del Lago G . Eleuteri airfield ( at that time one of the main RA training airbases ) , where it was planned that 161 and 162nd " Squadriglia " would take the aircraft into service . Despite its speed , Italian pilots were not impressed by the type and its service in the summer of 1943 quickly ended . The aircraft of 83rd Squadriglia were returned to SAI - Ambrosini to be refurbished , but the Armistice made it impossible for them to return to their squadron .