González Gil - Pazó GP - 1 The González Gil - Pazó GP - 1 was a single engine , two seat open cockpit training aircraft , built in Spain in the 1930s to compete for a government contract . Declared the winner , production was curtailed by the Spanish Civil War . Two cabin variants , the González Gil - Pazó GP - 2 and GP - 4 , were also built . Design and development . The first aircraft produced from the collaboration between Arturo González Gil y Santibañez and José Pazó was the Gil - Pazó No . 1 . It was , like all of their aircraft , a low wing cantilever monoplane . It was built of wood and metal with plywood skinning , seated two and had an unfaired conventional undercarriage . Reportedly similar to a Miles Hawk , it was powered by an ADC Cirrus engine . Almost no specifications are known , apart from a loaded weight of 778 kg ( 1715 lb ) . It first flew in June 1932 and was last recorded at Cuatro Vientos , Madrid in July 1936 . In 1934 the Director General de Aeronáutica issued a specification for a two seat trainer and Gil - Pazó ' s response was the GP - 1 . This " supremely elegant " aircraft , with two open cockpits and a trousered undercarriage was reportedly somewhat like the Miles Hawk Major in appearance . Its wings , of semi - elliptic plan , had a wooden structure and a stressed plywood skin . Flaps were fitted . The fuselage was a steel tube structure , fabric covered at the rear with dural skinning forward . For its first flight in June 1934 it was powered by the same Cirrus engine as the No . 1 but this was replaced by a 145 kW ( 195 hp ) Walter Junior inverted in - line engine for the trainer contract competition . The competitive trials , against the Loring X , the Hispano HS - 34 and the Adaro 1 . E . 7 , assessed the Gil - Pazó GP - 1 as the clear winner , so in 1936 González Gil and Pazó received an order for 100 aircraft . These were to be built by AISA , the Talleres Loring factory at Carabanchel Alto , Madrid . None of these had been completed by July 1936 at the start of the Spanish civil war , and with rebel forces approaching Madrid in October , AISA retreated to Alicante . About forty GP - 1s were built here during the war in a collaboration with Hispano - Suiza . In 1935 - 6 the open cockpit GP - 1 was developed into two cabin types , the González Gil - Pazó GP - 2 and GP - 4 . Both had raised rear fuselages faired into the cabin tops . The GP - 2 was powered by a 97 kW ( 130 hp ) de Havilland Gipsy Major engine and had two seats in tandem . Only one two - seater was built . A second GP - 2 was built as a single seater with one , rather than two , cabin side windows each side . The GP - 4 was powered by a 97 kW ( 130 hp ) Walter Major engine and carried four people . Only one GP - 4 was constructed . Operational history . Two notable flights were made before the Civil War . In January 1936 Ramón Torres and Carlos Coll set a record with their flight from Barcelona to Agadir , Morocco in the two seat GP - 2 . The single seat GP - 2 was flown by Lorenzo Richi in March 1936 from Madrid to Bata in what was then Spanish Guinea at an average speed of 187 km / h ( 116 mph ) . About thirty of the forty GP - 1s built at Alicante were captured by the Nationalist forces , given military serials and incorporated into Grupo 30 . After the war at least twelve of these were given Spanish civil registrations ; one remained on the register until 1961 . One GP - 2 and the sole GP - 4 were also on the Spanish civil register until about 1960 . The GP - 4 had been flown into Nationalist hands by Pazó in September 1936 , where it was used for liaison and transport duties .