Roberts Model 4-X By This four-cylinder, water-cooled engine was made by the Roberts Motor Co. of Sandusky, Ohio, around 1910. Roberts used secret alloys it called "Aerotite" and "Magnalium" to enhance performance and reduce weight. The motor, weighing 170 pounds and developing 50 hp, was used in some Benoist and American-owned Bleriot aircraft. It cost $1,500 by mail order when it was new. Click here to return to the Early Years Gallery.