thumb|the dkw&nbsp;rt&nbsp;125 of 1950 the rt&nbsp;125 is a german two-stroke motorcycle made by dkw in zschopau in the 1930s, ifa and mz in the 1950s and early 1960s, and dkw in ingolstadt in the 1950s and 1960s. "rt" stands for "reichstyp" or "national model". in the 1930s dkw pioneered the schnÃ¼rle two-stroke loop scavenging process to dispense with the use of a deflector piston and improve efficiency of the combustion chamber. dkw also developed a highly efficient arrangement of transfer ports. these two features were included in the rt&nbsp;125 to great commercial advantage. competitor companies such as adler and twn copied the adoption of flat-topped pistons and strove to develop equally transfer port arrangements without infringing dkw's patent. ==copies and variants== copies of the rt&nbsp;125 were built by at least eight different entities in at least six countries. ===royal enfield wd/re===  thumb|royal enfield wd/re "flying flea" in 1938, after the german government discovered that rs stokvis en zonen, the dutch importer of dkw motorcycles, had jewish directors, they forced dkw to remove their franchise from the company. the rt&nbsp;100, a smaller version of the rt&nbsp;125, had been popular in the netherlands, and rs stokvis en zonen commissioned royal enfield to make a motorcycle just like the rt&nbsp;100. the resulting motorcycle, the royal enfield re, copied the frame and front suspension of the rt&nbsp;100, but its engine did not use schnÃ¼rle loop scavenging because royal enfield did not know about the system. the engine size was increased to 125&nbsp;cc to improve the power output. few were made before production stopped in october 1939, when royal enfield converted its factory to war production. after a demonstration of the capability of the dkw rt&nbsp;100, the war department ordered a military version of the re, designated the wd/re, for use with airborne troops. this version, nicknamed the "flying flea" featured rigid forks and folding footrests and controls, including handlebars.{{citation needed|date=august
Motorcycles_introduced_in_the_1930s