preset depth. Production and spread After the Austrian government decided to invest in the invention, Whitehead started the first torpedo factory in Rijeka. In 1870, he improved the devices to travel up to approximately at a speed of up to , and by 1881 the factory was exporting torpedoes to ten other countries. The torpedo was powered by compressed air and had an explosive charge of gun-cotton. Whitehead went on to develop more efficient devices, demonstrating torpedoes capable of in 1876, in 1886, and, finally, in 1890. Royal Navy (RN) representatives visited Rijeka for a demonstration in late 1869, and in 1870 a batch of torpedoes was ordered. In 1871, the British Admiralty paid Whitehead £15,000 for certain of his developments and production started at the Royal Laboratories in Woolwich the following year. In 1893, RN torpedo production was transferred to the Royal Gun Factory. The British later established a Torpedo Experimental Establishment at and a production facility at the Royal Naval Torpedo Factory, Greenock, in 1910. These are now closed. Whitehead opened a new factory near Portland Harbour, England, in 1890, which continued making torpedoes until the end of World War II. Because orders from the RN were not as large as expected, torpedoes were mostly exported. A series of devices was produced at Rijeka, with diameters from upward. The largest Whitehead torpedo was in diameter and long, made of polished steel or phosphor bronze, with a gun-cotton warhead. It was propelled by a three-cylinder Brotherhood radial engine, using compressed air at around and driving two contra-rotating propellers, and was designed to self-regulate its course and depth as far as possible. By 1881, nearly 1,500 torpedoes had been produced. Whitehead also opened a factory at St Tropez in 1890 that exported torpedoes to Brazil, The Netherlands, Turkey, and Greece. Whitehead purchased rights to the gyroscope of Ludwig Obry in 1888 but it was not sufficiently accurate, so in 1890 he purchased a better design to improve control of his designs, which came to be called the "Devil's Device". The firm of L. Schwartzkopff in Germany also produced torpedoes and exported them to Russia, Japan, and Spain. In 1885, Britain ordered a batch of 50 as torpedo production at home and Rijeka could not meet demand. By World War I, Whitehead's torpedo remained a worldwide success, and his company was able to maintain a monopoly on torpedo production. By that