The Antonov An-2

In the late 1940s, the Soviet Union introduced a new aircraft, the Antonov "An-2". It was a big, clumsy looking biplane intended for utility and cropdusting roles, and led to laughs in the West at Soviet backwardness. The An-2 had the last laugh, since it proved an immensely useful aircraft, was built in huge quantities, and is still in intensive service all over the world. This document provides a history and description of the An-2.

The Antonov An-2 Origins

During World War II, the Soviet Union made extremely good use of the little Polikarpov Po-2 biplane, which was at heart a trainer but was pressed into a wide range of other roles, including liaison aircraft, light attack aircraft, cropduster, and air ambulance. The Po-2 might not have seemed like much, but it did a superb job, and after the war, it would be replaced by a bigger and better successor.

Aircraft designer Oleg Konstantinovich Antonov had started out in the mid-1920s building gliders, becoming the USSR's most prominent glider builder. He spent World War II working as first deputy to Alexander Yakovlev in his aircraft OKB (experimental design bureau). In 1940, before the Nazi invasion of June 1941, Antonov had considered the design of a utility aircraft, using as a conceptual basis the Bedunkovich SKh-1 (Selzkokhozyaistvennyi 1 / Agricultural Economy 1"), a utility biplane with a radial engine and fixed landing gear that never entered series production.

Antonov's original design, designated simply "Aircraft Number 4", was much like a scaled-up SKh-1, but it seemed too old-fashioned and slow, and the authorities rejected the design in 1941. Once war came, Antonov had other things to worry about, but he didn't forget about his biplane design. In 1944, he came forward with a revised big biplane design, which incorporated features from the OKA-38 Aist (Stork) -- a copy of the German Fiesler Fi-156 Storch short takeoff and landing (STOL) light utility aircraft. The Soviets had built two Aists during the cynical "friendship of convenience" between the USSR and Nazi Germany, and Antonov had worked on them.

Once again, there was little interest, but Antonov really thought that his big STOL utility biplane was something the Soviet Union needed. It would help improve agricultural productivity through crop-dusting, and would be useful for transport in Siberia and other primitive regions of the USSR. With the end of the war in 1945, Yakovlev let Antonov go to the OKB branch facility in Novosibirsk, beyond the Urals in western Siberia, to pursue the utility biplane concept.

The authorities still weren't interested, but in early 1946 Antonov sent a detail design document for the proposed aircraft back to Yakovlev, who passed it up the chain of command along with a note that the aircraft should be built. Yakovlev was highly influential and the authorities finally took notice, authorizing in March 1946 the construction of two prototypes of the "izdeliye (product) T" (transportnii / transport) -- though only one prototype would actually be built. At the end of May, Antonov was given authority over his own design bureau, OKB-153.

At the end of July, the project goals were clarified, specifying the izdeliye T as a replacement for the Po-2, tailored to meet the needs of the Soviet Ministry of Agriculture & Forestry. Some sources claim this specification got the project rolling; actually, the project got rolling and led to the specification.

Antonov wanted to use the 750 kW (1,000 HP) Arkady Shvetsov ASh-62IR engine, a nine-cylinder air-cooled radial, but the ASh-62IR was in heavy demand for the Li-2 transport, a Soviet copy of the American Douglas DC-3 / C-47 Dakota. As a result, the authorities wanted him to use the smaller ASh-21 radial with a 520 kW (700 HP), specifying that he build separate prototypes with the different engines. Antonov protested at length, since he felt that the ASh-21 simply couldn't do the job, and that the duplication of effort on prototypes would delay the schedule. The authorities finally caved in, but still insisted that the design be able to use either engine.

By early 1947 a full-scale mockup was ready, with the type having been given the designation of "SKh-1", recycling the designation of the unproduced prewar Bedunkovich machine. The initial prototype was rolled out in the summer of 1947; development had been hastened by use of "off the shelf" components, such as the main wheels from the Ilyushin Il-2 Shturmovik ground-support aircraft and the tailwheel of the Tupolev Tu-2 bomber.

The prototype was fitted with the ASh-21 engine for ground trials, but was then refitted with the ASh-62IR engine for its first flight on 31 August 1947, with test pilot P.N. Volodin at the controls. The ASh-21 engine was refitted during the trials to determine whether it was adequate -- and it obviously wasn't, justifying Antonov's protests. The aircraft itself was clearly sound, with few tweaks required during trials and one test pilot praising its handling by saying that "the machine is stable during turns, easy to fly and a lot like the Po-2. In the event of a forced landing, this aircraft can put down on dirt roads and in small clearings without any risk."

The consensus was that anyone who could fly, could fly the SKh-1. Volodin flew the prototype from Novosibirsk to Moscow in October 1947 for state acceptance trials. The original plan had been to transport it by rail, but the flight was seen as an effective way to promote the aircraft. State trials went well, with flights even made with General Ivan P. Mazuruk, an aviation celebrity for his daring prewar polar flights and holder of the prestigious Hero of the Soviet Union medal.

During one flight, General Mazuruk wanted to land at the Moscow-Vnukovo Airport, but was refused landing permission by air traffic controllers. He shrugged and simply put the machine down on the grass runway shoulder. The airport director, a colonel, came out in a fury -- to suddenly become very agreeable, switching immediately from stormclouds to sunshine, when he realized who he was dealing with.

By the summer of 1948, the SKh-1 was in field trials in the Ukraine and elsewhere, demonstrating its massive superiority over the little Po-2. However, Antonov still had to deal with threats to his baby. With the Cold War getting chillier, Soviet production of weapon systems was going full steam, leaving little manufacturing capability left over for a more or less civil aircraft. Fortunately, Nikita Sergeyevich Kruschev, Communist Party general secretary of the Ukraine and later Soviet premier, had been impressed by the SKh-1 and encouraged his superiors in Moscow to put it into production.

In August 1948, formal approval of the production of the type was granted, with State Factory Number 473 in Kiev assigned to do the work. The aircraft was given the production designation of "An-2". However, it was still not time for Antonov and his design team to break out the champagne, since Factory 473 was a fairly small plant that hadn't ever built an aircraft before; it was more or less all that could be spared. Setting up the tooling for building an aircraft was bound to be time-consuming, and production forecasts were definitely on the low side. Antonov sent a team of engineers from Novosibirsk to Kiev to try to keep the project on track.

The first production "An-2T" utility transport performed its initial flight on 6 September 1949, with a preproduction batch of four machines delivered for evaluation in May 1950. Shortly after that, the Antonov OKB was relocated to Kiev. The group had never been more than a small and isolated component of the rest of the Novosibirsk facility, meaning there was nothing to keep the staff there when all the manufacturing was taking place in Kiev.

Things certainly might have seemed to be on track by that time, but late in 1952 the word came down that An-2 production would have to cease, with the Kiev factory reassigned to the manufacture of fuselages for the new Ilyushin Il-28 jet bomber. Antonov might well have despaired, but in March 1953 Soviet dictator Josef Stalin died of a stroke, with a wide number of changes in the way things were done following. One change, implemented as early as April 1953, was to restore An-2 production to Factory 473. It is a certain interesting commentary on the real world to see the haphazard way things actually get done, even in a rigidly planned economy.

The usefulness of the type was finally appreciated by both the military and Aeroflot, the state airline, with Antonov and his design team receiving a state prize in 1955. Factory 473 would build a total of 3,164 An-2s up to the end of production there in 1963. That was by no means the end of the matter. In 1965, State Factory Number 464 in Dolgoprudnii began production of the modified "An-2M" agricultural variant, building 506 into 1971.

The bulk of production was actually outside of the USSR. In the late 1950s, manufacture of the An-2 was assigned to the PZL Mielec plant in Poland, the initial ten machines being made from knockdown kits provided by the Kiev factory, the first making its maiden flight on 23 October 1963. At first, the Poles were not were not enthusiastic about building the big, plain biplane, but they soon found out the type was in great demand. Production would continue full bore into the late 1980s, to then start a decline as more modern types were introduced. The last Polish An-2s were delivered in 2002, after manufacture of 11,915 machines from the PZL Mielec plant.

Some sources claim that a small batch of An-2s were built in East Germany, but though the East Germans did modify some the An-2s provided to them, they never built any themselves. The only other foreign manufacturer of the type was the People's Republic of China, which initiated a project to build the aircraft at a state factory in Nanchang in 1956, the first Chinese-built An-2 performing its initial flight on 7 December 1957. The Chinese originally called the type the "Fongshou 2 (Harvester 2)". Full production began in 1958. Manufacturing was later switched to Harbin and then to Shijiazhuang, with the type redesignated "Yushiji 5 (Y-5 / Transport 5)". The Chinese also found the big biplane very useful and built at least a thousand, with production apparently continuing to the present at a low rate.

The An-2 was given the nickname of "Kukhuruznik", meaning "corn eater", which was a general term for a crop-duster; the same term was used for the Po-2, but the nickname would become distinctly associated with the An-2. Once the West became familiar with the An-2, it was assigned the NATO codename of "Colt", though possibly it might have been more appropriate to name it after the big "Clydesdale" dray horse. There was some snickering at the big, homely looking biplane outside of the USSR, since it seemed to reinforce the stereotype that the Soviets were crude and rustic. The reality was that the An-2 would prove to be a superlative aircraft for its intended roles.

It was certainly not regarded as any beauty queen, but it was so useful, sturdy, and docile that few had anything but affection for it. It could take off and land on a postage stamp and was, as mentioned, very easy to fly, though not noted for a blazing rate of climb. It also tended to be tailheavy; it wasn't wise to place loads too far back in the cargo compartment.

The Antonov An-2 described

The initial production An-2T utility transport version of the An-2 makes a reasonable baseline for description of the family. The An-2T is a fairly big and bulky machine as single-engine piston aircraft go, with a ASh-62IR radial engine, a greenhouse style canopy, biplane wings, and fixed taildragger landing gear. There are porthole windows on both sides, and an upward-opening cargo door with an inset inward-opening passenger door on the left rear of the aircraft.

Although consideration was given to building the An-2 with steel tubing and fabric, the final decision was to use riveted aircraft aluminum construction with some fabric skinning. The fuselage is all metal; the flight surfaces have aluminum framework, with the two-spar wing skinned with aluminum back to the front spar and covered with fabric elsewhere.

The original tailfin had an elliptical "guitar pick" form factor, but a "squared off" tailfin was introduced on the An-2M; it was the only major An-2 variant with this feature. The tail surfaces are fabric covered, as are all the flight control surfaces. All flight control surfaces are manually activated.

The Shvetsov ASh-62R engine is a nine-cylinder single-row aircooled radial, which some sources claim is based on the US Wright Cyclone engine. There is a carburetor intake on top of the engine cowling, an oil cooler below the cowling, and an exhaust on the right side. Kiev-built An-2s used the V-509A four-bladed wooden variable-pitch propeller, with curved blades and a diameter of 3.6 meters (11 feet 10 inches). Most Polish production used the AV-2 four-bladed wooden variable-pitch propeller, with straight, shorter, broader blades and a diameter of 3.35 meters (10 feet 12 inches).

The main landing gear uses pneumatic shock absorbers; agricultural versions have long-stroke shock absorbers to soak up the occasional hit against the ground. The tailwheel castors. Ground steering is by differential braking; the brakes are pneumatic and this is apparently something of a wheezy, comical-sounding process. Skis can optionally fitted for winter operations.

The cockpit features dual yoke-type controls, and the extensiveness of the canopy glazing really does give the impression of being a greenhouse, providing excellent visibility in the forward hemisphere. The glazing panels are flat to prevent visual distortion, and the canopy is bulged out to the sides to permit a downward view, a feature referred to as the "balcony" and a handy thing for trying to land on short fields, or crop-dusting. Avionics includes an automatic direction finder, a navigation beacon receiver, a radar altimeter, and radios.

The cockpit is separated from the cargo area by a bulkhead, optionally fitted with a double door. Along with the pilot and copilot, originally a seat could be fitted for a flight engineer, though later production did not require the third crewman. The original cargo door had dimensions of 1.53 by 1.45 meters (60 x 57 inches), but this was later expanded to 1.65 x 1.67 meters (65 x 66 inches). There is a fixed step on the bottom of the fuselage under the inset passenger door. The floor is reinforced, and there are tie-downs along the sides of the cargo bay, with screw-in sockets in the floor for inserting more tie-downs.

At first, all An-2s were delivered in overall olive drab coloring. Later, many Aeroflot machines were given snappier civil colors -- light greys or beiges, with blue detailing. With An-2s now in wide service all over the world in military, civil, and private hands, some have been given wild or outlandish paint jobs -- famous Japanese animator Hayao Miyazaki sent a bright-red An-2 on a tour of Japan to promote a movie about aviators. One was even, for some bizarre reason, given pre-WWII US Navy colors, including stars with red "meatballs" in the center.

Antonov An-2 Variants and the Antonov An-3

Along with the An-2T utility transport, other major An-2 variants included:

• An-2TP (transportno-passazhirskii / transport-passenger): A convertible cargo carrier and short-range airliner, basically an An-2T with fold-up seats added along the sides of the cargo bay. There were 10 seats in Kiev production, expanded to 12 in Polish production.
• An-2TD (transportno-desahntnii / cargo-paratroop): A cargo / parachute variant, much like the An-2TP but with a parachute static line and a light / audio alarm to indicate when to jump.
• An-2P (passazhirskii / passenger): A pure civil airliner version of the An-2, with 10 forward facing seats arranged in rows of 1 + 2, plus soundproofing, heating, and various comforts. Polish production had 12 or 14 seats.
• An-2PD (pasazersky dispozycjyny / executive passenger): Designation sometimes given to Polish executive / VIP transport variants.
• An-2SKh: Agricultural variant, fitted with a granular chemical hopper the cargo bay and a spreader under the fuselage. A special loader machine was used to top off the hopper through two top hatches. This kit could be exchanged with a liquid chemical system, with the chemical tank in the fuselage and the sprayers under the wings. The tank was filled through a port in the side. A few An-2SKh cropdusters were modified to dispense poisoned grain in an attempt to kill off an infestation of gophers in Kazakhstan. The Poles built the An-2SKh as the "An-2R" (rolniczy / agricultural).
• An-2S (sanitarnii / medical): Military / civil air ambulance, essentially an An-2T with mounts for three stretchers on each side of the cargo bay, plus provisions for medical supplies and kit, drinking water, and so on.
• An-2M (modifitseerovanii / modification): Improved agricultural variant, featuring the "square" tail, single-pilot operation, new chemical storage kit, and other refinements. The revised chemical storage scheme prevented the crew from getting into the machine from the main door, and so the windows were designed to hinge up to allow them to get in using a ladder -- a scheme that was obviously hazardous and unsurprisingly said to be unpopular. At least one was modified as an air ambulance.

In 1950, the Antonov OKB began work on a floatplane version of the An-2T, which emerged as the "An-4" or "An-2V" (vodnii / water-based). Initial flight was on 31 July 1951. The An-2V also featured waterproofing seals in strategic locations, a power winch, and a reversible propeller. Beaching gear could be used to haul the machine onto dry land. At least one was fitted with crop dusting gear like that of the An-2SKh for forestry purposes. The Poles built this variant under the designations of "An-2M" (morski / marine, duplicating the designation of the improved Soviet cropduster version) or "An-2W" (wodnozsamolot / seaplane).

Details of Chinese production are a bit unclear, but it appears the An-2T utility transport was built as the "Y-5A"; the An-2SKh agricultural aircraft was built as the "Y-5B"; the An-2TD cargo / paratroop aircraft was built as the "Y-5C"; and the An-2PD executive transport was built as the "Y-5K".

These were not necessarily perfect equivalents to Soviet machines. In particular, the Y-5C featured modified wingtips with three little finlets sticking out of the end of each tip, the finlets being arranged in tandem but at slightly different angles to the horizontal. The Chinese claim the finlets improved climb rate and cruise economy.

There were a number of experimental fire-bomber conversions of An-2s, fitted with water or retardant tanks and sprayers. One screwball conversion used a scheme in which the aircraft carried three dispensers containing 120 glass ampoules of retardant each, with the ampoules scattered over the fire area; the concept was found to be ineffective. The only An-2 fire-bombers to see any real use were ten An-2Vs fitted with floats that could store water. These machines were designated "An-2LP" (lesopozharnii / forest fire fighter).

The "An-6" featured a TK-19 turbocharger for improved high-altitude performance and was built in limited numbers. The "An-6 Meteo" or "An-ZA" (zondirovshchik atmosfery / atmospheric sampling) was built for high-altitude atmospheric research, and featured a second heated cockpit forward of the tailfin for a research technician. It did not enter production, the rear cockpit apparently having serious effects on handling, but six An-6s without the rear cockpit were built for weather studies and designated "An-2V" (vysotnii / high altitude), recycling the floatplane designation.

One of the more drastic variations was the "An-2F / Fedya", where "F" was a series code, AKA the "An-2NAK" (nochoy artilleriskii korrektirovshchik / night artillery spotter). This was a battlefield observation machine, evaluated in 1948:1950. The entire rear fuselage was replaced with a new rear fuselage, featuring a twin-fin tail, an all-around "greenhouse" center section, and a gun turret on top just behind the wing for top protection, with various armament options tested. It also had a forward-firing cannon, could carry a light bombload, and featured combat armor. Only two were built, the decision being that helicopters were better suited to the battlefield observation job.

Arguably the most drastic variant of all was the Polish "Lala-1" testbed for the turbofan-powered PZL M-15 agricultural plane. An An-2 was modified by chopping off most of the fuselage aft of the wing; installing an extended tailwheel under the end of the fuselage; fitting a tube frame with a twin-fin tail to the end of the aircraft; and putting the turbofan in the end of the fuselage, with an oversized intake on the right side.

There have been a number of schemes for extensively modifying An-2 to operate as "wing in ground effect (WIG)" or "surface skimmer" craft, with an oversized wing to allow them to efficiently skim over the wavetops at high speed on the cushion of air set up at high speeds. A demonstrator (with wheeled landing gear, not floats), was displayed at the 2003 Moscow Air Show; it was unclear if this was actually a flying machine or just a mockup.

A by-no-means complete list of other interesting subvariants and mods includes:

• A number of An-2 were built or converted for photographic mapping, featuring cameras and camera ports; and for geophysical studies, with a magnetometer system, some of these aircraft being designated "An-2Geo" or "An-2G".
• An-2s were modified for Arctic and Antarctic work, being fitted with ski landing gear, a generator engine, a gasoline heater, accommodations for a radio operator and a navigator, and an anchor system to keep the aircraft from being blown off the ice in a storm. These aircraft were painted bright orange to make them observable if they went down into the snow.
• An An-2TD was fitted with triple tandem wheels on the main gear and a skid attached to the tailwheel for soft-field operation. It worked okay for its intended purpose, but ground handling was troublesome and the scheme was not adopted for service. More successfully, oversized mainwheels or "superwheels" were developed to allow the An-2 to operate on soft ground, but they were rarely used in practice.
• The East Germans converted seven An-2SKh cropdusters into passenger airliners featuring large square windows; ironically, it seems these machines were later returned to the cropduster role. The Cubans similarly converted at least one An-2SKh to an airliner, with large oval windows.
• The Poles experimented with an An-2 fitted out as an attack aircraft, capable of carrying an unguided rocket pod under each wing and a bomb of up to 250 kilograms (550 pounds) mass under the centerline. The windows were modified to allow light automatic weapons through ports; limiters were installed to block firing into the aircraft wings or tail. The scheme was not adopted for service.
• A few An-2s were used in the search and rescue role, carrying appropriate gear and fitted with a hatch under the tail to allow dropping survival kit. Other specialized conversions included a drone boat controller for the Red Navy, communications relay aircraft, and East German signals intelligence platforms.

Formal interest in a turboprop version of the An-2 began to arise in the early 1970s. The Antonov OKB came up with what amounted to an almost completely clean-up redesigned follow-on to the An-2 called the "An-3", but on consideration it seemed like overkill and it wasn't built.

Soviet engineering tended toward the pragmatic and generally followed the rule of not trying to fix what wasn't broken. Focus shifted to simply converting the An-2 to a turboprop configuration, though the An-3 designation was retained for the conversions.

An An-2SKh was fitted with the Glushenkov TVD-20 turboprop providing 1,065 kW (1,430 EHP), driving a three-bladed reversible propeller. A new door was fitted to the forward fuselage to allow the crew to get in and out when cropdusting gear was installed, eliminating the awkward crew-entry scheme of the An-2M. Cockpit improvements were also provided, particularly an air conditioner, which was something of a necessity during hot summers when the cockpit turned into a sweatbox.

Initial flight was in 1979, but work on the project was protracted, with state trials finally completed in 1991. Various refinements were considered for a "production" An-3, such as a larger squared-off rudder fitted to the existing An-2 tailfin, and simplified window glazing. The plan by that time was to convert most of the An-2 fleet to An-3 standards, but with the fall of the USSR the exercise went on hold. The project was revived in the late 1990s, with an "An-3T" utility transport demonstrated at airshows, and it appears that conversions are now being performed, if at a slow rate.

The Antonov organization is now considering an An-2 with a Klimov VK-1500 turboprop, providing 1,120 ekW (1,500 EHP) and driving a six-bladed composite propeller. In addition, a number of Chinese Y-5s have apparently been fitted with Pratt & Whitney Canada PT6A turboprop engines.

The Antonov An-2 In Service

The An-2 is in service all around the world, with An-2 flying now or at one time in all the states of Eastern Europe and China, plus Afghanistan, Angola, Benin, Bolivia, Botswana, Brazil, Cambodia, Chad, Colombia, Cuba, Djibouti, Egypt, Ethiopia, France, Greece, Grenada, Guinea, India, Iraq, Laos, Lesotho, Mali, Mexico, Mongolia, Mozambique, Nepal, the Netherlands, Nicaragua, North Korea, Peru, South Africa, Sudan, Tunisia, Turkey, Venezuela, Vietnam, Yemen, and Zambia. A rising number of An-2 retired from official service have been picked up by private pilots.

An-2s have seen considerable combat action. Soviet forces used them heavily in utility roles at all times, and as battlefield spotters during the Hungarian invasion of 1956 and the Afghan War of the 1980s. Apparently some An-2s were used to dump riot gases on Chinese forces during border squabbles in the late 1960s.

The North Vietnamese used the type in their war with the Americans, employing it to haul cargos, sometimes into South Vietnam, and on occasion as an improvised attack aircraft. US records suggest the An-2 was not well-suited to the strike role, since mentions of encounters with armed An-2s usually state they were shot down. Vietnamese An-2s were used in later conflicts as spotters and utility aircraft. An-2s have been used by North Korea to insert spies and saboteurs into South Korea. An-2s have played roles in the wars of the Balkan and Soviet successions.

However, the An-2's major accomplishments have been peaceful, with the type proving an outstanding utility and passenger transport, agricultural aircraft, bush aircraft, and jack-of-all trades. In July 1997, to celebrate the golden anniversary of the An-2, WSK Mielec sponsored a round-the-world flight in an An-2 piloted by Woldemar Miszkurka. It was a leisurely trip, taking three months. Somewhat sadly, there was some bureaucratic tangle and the flight path of the commemorative trip did not include Russia.

Footnote: The Antonov An-14 & Antonov An-28

The An-2 wasn't the only small utility transport developed by the Antonov OKB. In 1957, the organization began the design of a twin-engine light cargolifter / transport with a focus on short takeoff / rough field operation, easy handling, and simple maintenance. Initial flight of the first of two prototypes was on 15 March 1958. Development was protracted, with the "An-14" finally entering service in 1965. It was named the "Pchelka (Baby Bee)", and also given the unflattering NATO codename of "Clod".

The An-14 featured a high, wide-span wing with twin Ivchenko AI-14RF nine-cylinder radial piston engines, a twin fin tail, and fixed tricycle landing gear with single wheels on all assemblies. Each wing featured double slotted flaps and a leading-edge slat, and a brace running from the mainwheel stub wing to midwing. There were clamshell doors on the rear for cargo loading. The aircraft was designed for single-pilot operation; typical payloads included eight passengers, or up to 720 kilograms (1,590 pounds) of cargo.

The An-14 could be fitted with ski or float landing gear, and could be rigged up as a cropduster with a 1,000 liter (264 US gallon) chemical tank. There was also an air ambulance variant, with accommodations for six litters and a medical attendant; a dual-control trainer variant; an executive aircraft variant, with luxury accommodations for five passengers; and a geophysical photo-survey variant.

The An-14 was not in the same class as the An-2, being smaller, with less payload and range. It was somewhat more comparable to the popular American Beech Model 18, though the two aircraft had very different configurations. The Pchelka was said to be sturdy, but what sort of reputation it had is unclear. Only about 300 were built to end of production in the mid-1970s -- not a bad quantity in itself, but a pittance compared to production for the An-2. The main users were Aeroflot and the Red Air Force. Some were obtained by East Germany, Bulgaria, and Guinea.

In 1967, the Soviets announced that a turboprop derivative of the An-14 was in development, with the machine given the original designation of "An-14M". Initial flight of the first prototype was in September 1969, but development of this machine was protracted as well, with the type undergoing major redesign and not introduced into service until 1984 as the "An-28". It was given the NATO codename of "Cash".

The overall configuration of the An-28 was like that of the An-14 -- high and wide-span wing, twin tail, fixed tricycle landing gear -- but it was powered by twin Glushenkov TVD-10V turboprops providing 715 kW (960 SHP) each, and featured a fuselage stretch, plus general cleanup of the design. Cabin volume was doubled and passenger capacity was raised to 17; maximum cargo capacity was two tonnes (2.2 tons). The An-28 featured an interesting scheme in which spoilers on one wing are deployed automatically to help with the failure of an engine on the other wing. The cabin included a hoist for cargo handling. Manufacture of the An-28, including the engines, was farmed out to PZL in Poland.

The An-28 has a certain broad resemblance to the de Havilland Canada Twin Otter, though the Antonov machine is somewhat bigger and of course has a twin tail. Total production numbers are unclear, though 1,200 were planned at one time, with most for Aeroflot and the Red Air Force, plus some for Polish service.

PZL Mielec built specialized variants of the An-28:

• The "An-28RM Bryza 1RM" search and rescue machine features search radar in a belly radome, Doppler navigation radar, plus a Global Positioning System receiver, and is fitted for carriage of casualty litters as well as an air-dropped life raft.
• The "An-28TD Bryza 1TD" is an airdrop transport, with the clamshell rear doors replaced by a single door that slides underneath the cabin floor to open.

PZL Mielec has also promoted a Westernized version of the An-28, the "M-28 Skytruck", with 820 kW (1,100 SHP) Pratt & Whitney Canada PT6A-65B turboprops driving five-bladed Hartzell propellers and Bendix-King avionics. A single prototype was converted from a stock An-28 and the type is in production, with some export sales. A stretched "super Skytruck" was in the works at last notice.

Author: Greg Goebel