at decreasing cost, and almost universal for marine engines after 1880. It was not widely used in railway locomotives where it was often perceived as complicated and unsuitable for the harsh railway operating environment and limited space afforded by the loading gauge (particularly in Britain). Compounding was never common on British railways and not employed at all after 1930, but was used in a limited way in many other countries. The first successful attempt to fly a heavier-than-air fixed-wing aircraft solely on steam power occurred in 1933, when George and William Besler converted a Travel Air 2000 biplane to fly on a 150 hp angle-compound V-twin steam engine of their own design instead of the usual Curtiss OX-5 inline or radial aviation gasoline engine it would have normally used. Multiple-expansion engines It is a logical extension of the compound engine (described above) to split the expansion into yet more stages to increase efficiency. The result is the multiple-expansion engine. Such engines use either three or four expansion stages and are known as triple- and quadruple-expansion engines respectively. These engines use a series of double-acting cylinders of progressively increasing diameter and/or stroke and hence volume. These cylinders are designed to divide the work into three or four equal portions, one for each expansion stage. The adjacent image shows an animation of a triple-expansion engine. The steam travels through the engine from left to right. The valve chest for each of the cylinders is to the left of the corresponding cylinder. History Early work 1781 – Jonathan Hornblower, the grandson of one of Newcomen's engine erectors in Cornwall, patented a double-cylinder compound reciprocating beam engine in 1781. He was prevented from developing it further by James Watt, who claimed his own patents were infringed. 1797 - Richard Trevithick develops an effective high pressure steam engine. 1804 – Arthur Woolf develops the stationary Woolf high-pressure compound engine, patented in 1805. The Woolf engine lessened the increased magnitude of the continual heating and cooling of a single-expansion high pressure steam engine that leads to inefficiency. It also solved the problem that the contemporary cast iron cylinders could not handle it well. Double-expansion 1833 – Hercules (1829) was modified to use an extra low pressure cylinder, taken from Agrippina, with steam from her high-pressure cylinders. This modification was designed by Dutch engineer Gerhard Moritz Roentgen, making him the inventor of the naval compound steam engine.