Jane's Encyclopedia of Aviation
MacDonald S-20 (USA)
Single-seat light sporting monoplane, plans for which are available to amateur constructors.
MacDonald S-20 homebuilt sporting aircraft (53 hp Volkswagen 1,500 cc modified motor car engine)
MacDonald S-20 homebuilt sporting aircraft (53 hp Volkswagen 1,500 cc modified motor car engine)
MacDonald S-20 homebuilt sporting aircraft (53 hp Volkswagen 1500 modified motor car engine)
Wikipedia