However , the new Minerva engines cost 50,000 BEF while the government could purchase war - surplus Hispano - Suiza engines from France for only 6,500 BEF .
The air force evaluated the type and judged it suitable .
The new Minerva engines cost 50,000 BEF while the government could purchase war - surplus Hispano - Suiza engines from France for only 6,500 BEF .
The air force evaluated the type and judged it suitable .