Complex sentence: They planned to use the German produced BMW 801 radial engine in order to eliminate the deficiencies with the Piaggio engine, but Reggiane could not satisfy the demand, and none were delivered.
Split into simpler sentences: They planned to use the German produced BMW 801 radial engine in order to eliminate the deficiencies with the Piaggio engine. However, Reggiane could not satisfy the demand, and none were delivered.