The Kamov Ka-18 (NATO reporting name Hog) was a four-seat development of the Ka-15M; it retained the same engine, rotor, transmission and control systems and landing gear. The main changes were to the fuselage, which was stretched to make room for two passengers and a baggage compartment. The prototype was completed in 1956 and flight testing began early in 1957. A limited number of the Ka-18 were built for use as air ambulances and for forestry patrol, geological survey and agricultural work. Towards the end of 1960, the production aircraft were given a 275hp AI-14VF engine (VF stands for Vertolet Forsirovannie meaning helicopter with turbocharger) instead of the AI-14V, thus enabling the payload to be increased by about 100kg and the ceiling by 300-500m. The chord of the endplate finswas also enlarged.
The Ka-18 was evaluated but not adopted by the Soviet Air Force.
G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984
Stretched all-weather Ka-15; up to 4 seats or internal stretcher and doctor or two rear passengers; alternatively 200kg cargo. Nose no longer transparent; doors hinged at rear; 176 litres of fuel in floor tanks; extended rear fuselage and fins/rudders of much greater chord; whole aircraft cleaned up aerodynamically. Alcohol de-icing of blades and windscreen, exhaust heater muff feeds hot air on demand to cabin. First flown early 1957. State trials 1958, produced with blind-flying insts and option of 70-litre ferry tanks for AV-MF, VVS and Aeroflot. Uka-18 dual control, role equipment for survey and vineyard spraying. ASCC reporting name "Hog".
Bill Gunston "The Osprey's Encyclopedia of Russian Aircraft", 2000