EFW N - 20 The EFW N - 20 Aiguillon ( ) was Switzerland ' s first indigenous jet fighter aircraft . The Swiss Federal Aircraft Factory developed a design for a four - engined swept winged fighter following the end of the Second World War . During the test programme an unpowered glider was built and flown . A turbojet powered test aircraft , known as the Arbalète ( ) also flew . The N - 20 design was not produced , both the single Aiguillon and Arbalète airframes survive and are on public display at the Flieger - Flab - Museum , Dübendorf , the glider test aircraft was destroyed in an accident . Design and development . The aircraft was to be powered by four turbofan engines buried in the wings , with the bypass air feeding cold - air pipes each side of the engines , being routed through a combustion chamber where additional fuel could be burned as a form of reheat , or deflected though large slots on the upper and lower wings to act as aerodynamic flaps or thrust reversers . Two engines could be shut down in flight to increase range . It was planned that the N - 20 would carry its armament in a detachable weapons bay , capable of carrying large loads of cannons , rockets or bombs . It was initially planned that the aircraft ' s engines would be designed and built by the Swiss company Sulzer . The initial engine choice was a small turbojet , the Sulzer D45 with an output of 752 kp . but they abandoned this project in 1947 . Only two prototype D45 engines were built in 1948 . The first engine , D45 . 01 was used in a test rig between 1950 and 1951 and the second engine , D45 . 04 ( of limited airworthiness ) was used until 1955 in the test rig . The D45 . 04 is today also part of the Dübendorf museum N - 20 display The British Armstrong Siddeley Mamba turboprop was then chosen as the basis for the N - 20 ' s engines , with the propeller reduction gear replaced by a low pressure compressor . This powerplant was named Swiss Mamba SM - 1 , the conversion was carried out in 1948 by EFW , only six of these engines were built ( four were built into the N - 20 with two more as spare engines ) . A spare engine is today part of the Swiss Museum of Transport , at the Flieger - Flab - Museum Dübendorf . EFW N - 20 . 01 . Since Swiss industry still had no experience with the aircraft and aerodynamics of jet aircraft , several wind tunnel models were produced . In addition , a 3 / 5 scale wooden glider , the EFW N - 20 . 01 was built to allow testing of the novel wing shape , this flew on 17 April 1948 . The machine was equipped with a JATO solid rocket motor , with which she was able to start independently and reached the necessary altitude for tests . The nose gear came from a de Havilland Vampire , the main landing gear from a Messerschmitt Bf 109 both was electromechanical retractable . The boddy was made from wood and fabric cover . The N - 20 . 01 was destroyed in a landing accident on 1 July 1949 at Emmen AFB . EFW N - 20 . 02 Arbalète . The glider had successfully proven the design and was followed by a similar sized powered test aircraft , the EFW N - 20 . 02 " Arbalète " ( " Crossbow " ) , powered by four 0 . 98 kN ( 220 lbf ) Turboméca Piméné turbojets mounted above and below the wings . This aircraft flew on 16 November 1951 . It proved to have good manoeuvrability and reached a maximum speed of 750 km / h ( 466 mph ) . EFW N - 20 . 10 Aiguillon . The full scale aircraft was estimated to have a maximum speed of 1 , 095 km ( 680 mph ) , but the initial converted Mamba , the SM - 1 , which was test - flown under a de Havilland Mosquito in 1948 and was the first turbofan to fly , did not generate adequate thrust . Considerable further work was required for the definitive two - shaft SM - 5 engine , which was meant to generate 14 . 7 kN ( 3 , 300 lbf ) thrust . The prototype was completed in 1952 and , fitted with four SM - 1 engines , flew briefly during a taxi test on 8 April 1952 , but the development of the engine and the N - 20 aircraft was cancelled soon afterwards . EFW N - 20 . 20 Harpon . It was found out in various tests that the engines would not produce the desired output . So the project N - 20 . 20 was started . The aircraft was equal to the N - 20 . 10 , but had at each wing root one conventional engine , Rolls - Royce Avon or Armstrong Siddeley Sapphire . The wing was a little thinner and the main landing gear came a little closer to the fuselage , because now no engines required space inside the wing . The N 20 : 20 was never realized though some wind tunnel models were manufactured .