 Complete the following phrase:  Brabham briefly and unsuccessfully campaigned his own second hand Formula One Maserati 250F during 1956, but his season was saved by drives for Cooper in sports cars and Formula Two, the junior category to Formula One. At that time, almost all racing cars had their engines mounted at the front but Coopers were different, having the engine placed behind the driver, which improved their handling. In 1957, Brabham drove another mid-engined Cooper, again only fitted with a 2-litre engine, at the 