aircraft used for initial flight training by Yuri Gagarin (1st human in space) and Ken Rowe (No Kum-Sok, who defected from North Korea with a Mikoyan-Gurevich MiG-15 jet fighter during the Korean War). Later, as the need for conventional landing gear trainers abated, Yakovlev re-designed the Yak-18 with retractable tricycle landing gear and an Ivchenko AI-14RF radial engine of 224 kW (300 hp); this was designated the Yak-18A. The design proved exceptionally easy to build and maintain. There are an estimated 40 original Yak-18s in existence worldwide. Five are currently flyable in the US, three are flyable in Europe, and the Chinese Air Force has one flyable with several other airframes in storage. Approximately four other aircraft worldwide are currently being restored for flight. Many are found in major aviation museums worldwide including the National Air and Space Museum in the USA. The Nanchang CJ-6, produced in China, is sometimes quoted as a variant but is a completely different aircraft designed in China by Bushi Cheng and built by Nanchang Aircraft Company. Operational history The Yak-18 became the standard trainer for Air Force flying schools and DOSAAF, was in wide use in China, and in many other countries. Photographs showing Kim Jong-Un visiting a North Korean Air Force base in March 2014 suggest that the North Koreans may still maintain original Yak-18s or CJ-5s in a bombing role. Variants Yak-18 The original production version. Retractable main undercarriage, fixed tailwheel. Yak-18U This version was built in small numbers. It had retractable tricycle landing gear. Yak-18A Cleaned up version of the Yak-18U, powered by a 194 kW (260 hp) Ivchenko AI-14 FR engine. Built in large numbers. Yak-18P (NATO reporting name Mouse) Single-seat aerobatic aircraft for use by flying clubs. Adaptation of Yak-18 two-seat trainer. Yak-18PM Single-seat aerobatic aircraft with retractable tricycle landing gear. Yak-18PS Aerobatic aircraft with retractable main gear. Hongzhuan-501 (Red Craftsman) Probable original designation for early CJ-5 production aircraft. Nanchang CJ-5 The Yak-18 was built under licence in China as the CJ-5 for use by the PLAAF, PLANAF and civilian flying clubs; 379 CJ-5s had been built when production ended in 1958. Similar model designation The Yakovlev Yak-18T was developed as an Aeroflot training aircraft and also as a light passenger transport aircraft, with a cabin for one pilot and three passengers. It is not a variant of the Yak-18 as it has very little in common, and was