it in any quantity. Much improved versions were introduced by Statax's German division in 1929, producing 42 hp in a new sleeve valve version known as the 29B. Greenwood and Raymond of San Francisco acquired the patent rights for the US, Canada, and Japan, and planned a 5-cylinder of 100 hp and a 9-cylinder of 350 hp. Michell In 1917 Anthony Michell obtained patents for his swashplate engine design. Its unique feature was the means of transferring the load from the pistons to the swashplate, achieved using tilting slipper pads sliding on a film of oil. Another innovation by Michell was his mathematical analysis of the mechanical design, including the mass and motion of the components, so that his engines were in perfect dynamic balance at all speeds. In 1920 Michell established the Crankless Engines Company in Fitzroy (Australia), and produced working prototypes of pumps, compressors, car engines and aero engines, all based on the same basic design. Engine designer Phil Irving worked for the Crankless Engine Company before his time at HRD. A number of companies obtained a manufacturing license for Michell’s design. The most successful of these was the British company Waller and Son, who produced gas boosters. The largest Michell crankless engine was the XB-4070, a diesel aircraft engine built for the United States Navy. Consisting of 18 pistons, it was rated at 2000 horsepower and weighed 2150 pounds. John O. Almen Experimental barrel engines for aircraft use were built and tested by American John O. Almen of Seattle, Washington in the early 1920s, and by the mid-1920s the water-cooled Almen A-4 (18 cylinders, two groups of nine each horizontally-opposed) had passed its United States Army Air Corps acceptance tests. However, it never entered production, reportedly due to limited funds and the Air Corps' growing emphasis on air-cooled radial engines. The A-4 had much smaller frontal area than water-cooled engines of comparable power output, and thereby offered better streamlining possibilities. It was rated at 425 horsepower (317 kW), and weighed only 749 pounds (340 kg), thus giving a power/weight ratio of better than 1:2, a considerable design achievement at the time. Heraclio Alfaro Heraclio Alfaro Fournier was a Spanish aviator who was knighted at the age of 18 by King Alfonso XIII of Spain for designing, building, and flying Spain's first airplane. He developed a barrel engine for aircraft use which was later produced by the Indian