Antonov An-2 Colt

text by Raul Colon

When the An-2 utility biplane took to the air for the first time in August 1947, nobody could have predicted that the aircraft will go on to become one of the most prolific aircraft of all time. At the end of its impressive production run, nearly 18,000 units were built. Most of them in the Soviet Union, but some units were built, under license agreements, in China and Poland. In China alone, 1,000 examples were built between 1957 and 1970. Beside the Soviet Union; Egypt, North Korea, China and Poland were the primarily users of the An-2 aircraft. When assigned by the Soviet Ministry of Defence for the development and production of a replacement for the multi-tasked Po-2 aircraft, the Antonov Design Bureau, selected a biplane configuration for the new plane mainly to provide it with a market advantage during short take-off operations as well as better low speed capabilities. The selection of such an antiquated configuration, especially in the advent of the jet age, caused some members of the Ministry of Defence to question Antonov’s overall design capability, but the success of the An-2 promptly silenced those voices. The selection of the biplane configuration was reached after carefully examining the requirements of the new aircraft. Low speed manoeuvrability was the primarily requirement for the An-2 operational profile. The An-2 was designed to be used as a multi-task aircraft capable of providing the Soviet Union’s Air Force with a reliable, compact aircraft capable of sustaining heavy battlefield damage while remaining air capable.

The original An-2, NATO codename, “Colt”; design evolved around the light alloy stressed airframe. Only the tail plane and the aircraft’s control surfaces were covered in fabric. The Colt was fitted with an oversize cockpit providing the two men crew with an excellent field of view. The aircraft was also fitted with a 1’0” window overhang on each side of the cockpit. The Colt’s center of gravity, caused by the narrowing of the wing chords, required that the aircraft to be fitted with a larger than usual tail plane. The Colt, known as the “Little Anna” in Eastern Europe, was able to carry up to two tons in its internal cargo bay. Due to problems associated with the An-2’s heavy tail plane, the cargo bay was placed in the forward-mid section of the aircraft. No cargo stored in the tail end of the plane for this reason. A large, upward-hinged door was installed on the portside of the fuselage for cargo loading. Inside the cargo door was an inward-opening door used for passenger loading. Up to twelve passengers were able to fit in the aircraft. An extended nose cone housed one Shvestsov ASh-621R nine cylinder, air-cooled radial engine capable of generating 1,000hp. An 11’-10” V509a propeller with four scimitars like blades was original installed on the Colt. Later versions were fitted with an 11’-0” four straight blade configuration. The An-2 was manned by a two men crew. A pilot and a flight engineer seated side-by-side.

The Colt was fitted with a fixed undercarriage plus a tail wheel structure. Several An-2s were modified to use skis or float configuration. Although the aircraft was originally designed for military utility duties, the Colt was primarily use as a multi purposed agricultural aircraft. The Colt entered front line service with the Soviet air force in the summer of 1948. It immediately became the force’s primay utility aircraft. The Soviet owned airliner Aeroflot was the other main user of the Colt. Over the years there were several versions of the “Little Anna”, one of them, the Fedya, was use as a spotter aircraft by the Soviet Army. The Fedya or An-2F was fitted with a new rear fuselage section for tactical observations. A .5” machine gun was installed as a defensive weapon. The other main version of the Colt was the An-2ZA Atmosphere research Airplane. The 2ZA had a heated compartment installed on the middle of the airframe for scientific experimentation. The 2ZA was fitted with a turbocharger in its engine in order to augment it operational ceiling from 14,415’ to 31,170’.

Later on in its production run, a turboprop version of the Colt arrived. Designated the An-3, the new Colt was not as successful as the An-2 and never replaced the original version. The whole An-3 programme was abandoned shortly after the first unit was completed. Since late 1959, the PZL-Mielec in Poland was the main production facility for the Colt. When the Cold War ended, Russia took hold of the largest operational An-2 fleet in the world. Today, the Russian Air Force uses around three hundred Colts in various agricultural and transport duties; thus making the An-2 one of the longest service aircraft of all time.