boston future skyline
During the year 1930 there was clearly one engine which as on hype named as 'Ricardo' sleeve valve engine. Mirrlees the period introduced two Mirrleesengines represented this patent way of the valve engine. Well the previous had bore close to 5.5 inches and made a stroke of just about 6.5 inches and produced 20BHP each cylinder at rate of 900 r.p.m. one other had 17 inches bore and 21.5 inches stroke, giving 50BHP per cylinder with the rate of 200 r.p.m.