v1.0.0 / 01 mar 10 / greg goebel / public domain
* Following the introduction of reliable and effective turboprop engines in the 1950s, the Soviet Union decided to develop a twin-turboprop short-haul airliner, which emerged as the Antonov "An-24". The An-24 proved very successful, leading to several derivatives, including the "An-26" cargolifter; the specialized "An-30" survey platform; and the near-unique "An-32", a cargolifter designed specifically for "hot & high" operations. This document gives a history and description of the An-24 family.
* In the early 1950s, the primary Soviet civil airliners were the twin-piston Ilyushin Il-12 and its improved successor, the Il-14. The introduction of turboprop propulsion led to work from late 1957 on a successor at the experimental design bureau (OKB in its Russian acronym) run by Oleg K. Antonov. Specifications for the new short-haul airliner included the ability to operate off rough airstrips and in extremes of temperature and environment. Initially, passenger capacity was set at 32 or 40 seats, but during the design phase the capacity was raised to 44 seats. That change delayed initial flight of the first of two prototypes of the "An-24" to 20 December 1959. Incidentally, first flights of Soviet aircraft had a distinct tendency to take place in late December, it seems in reflection of end-of-year deadlines.
Trials working out well, following the construction of five preproduction machines deliveries of the production "An-24" or "An-24A" to Aeroflot, the Soviet state airline, began in 1962 -- though for various reasons the workup to actual service was delayed somewhat as well, the first scheduled passenger flights beginning in September 1963. The aircraft were built at a state factory in Kiev. NATO assigned the An-24 the somewhat eccentric codename of "Coke".
* The An-24 was comparable to and definitely reminiscent of the popular contemporary Dutch Fokker F-27 twin turboliner. Like the F-27, the An-24 was a twin-turboprop short-haul airliner with a high straight wing, tricycle landing gear, and a conventional tail assembly. It was built of aircraft aluminum, using advanced chemical milling techniques that permitted better control over the thickness of skin panels. The aircraft was designed in modular subassemblies to ease manufacturing.
The An-24 was powered by twin Ivchenko AI-24 turboprops, driving four-bladed constant-speed reversible props. Early production aircraft had AI-24 Series I engines providing 1,790 kW (2,400 EHP) takeoff power each, while later machines went to AI-24 Series II engines with 1,900 kW (2,550 EHP) each. Each engine nacelle included a fire extinguishing system that could be set to an automatic operation mode. A TG-16M auxiliary power unit (APU) turbine was fitted in the left engine nacelle to provide ground power.
The two-spar wing was straight, featuring double slotted flaps inboard of the engines, double slotted flaps outboard of the engines, and ailerons outboard on the wings. The wings had a slight anhedral droop outboard of the engines. The tail arrangement was conventional, with the tailplanes featuring a noticeable dihedral. There was a large forward tailfin fillet and a ventral fin, with the ventral fin added after prototype trials revealed yaw instability. Flight surfaces, as well as the engine inlets, used a deicing system based on hot engine bleed air driven from the engines. In contrast, the windshield and props were electrically deiced.
The landing gear was hydraulically actuated. All three gear assemblies had twin wheels, with the nose gear retracting backward and each main gear assembly retracting forward into an engine nacelle. The nose gear was fully steerable. Tire pressure could be adjusted from the cockpit for different airfield conditions. The An-24A lacked the nose glazing common to Soviet airliners of the period, with the nose instead containing RPSN-2AN Emblema (Emblem) weather radar. The avionics suite also included radios, navaids, an instrument landing system, and an autopilot.
The An-24 had been designed for were three crew -- pilot, copilot, and navigator -- but the traditionalism of customers like Aeroflot won out, with a flight engineer and radio operator added. Of course, the An-24 was pressurized and climate-controlled. There was a single door on the left rear with a folding two-section "airstair"; in service, 50 passengers were seated four-across, though lower density configurations were possible. There was also an emergency exit on each side of the fuselage; a baggage compartment fore and aft, with a large cargo door forward on the right that slid in and upward to open, and a smaller service door to the rear on the right; plus toilet, coat closet, and galley in the rear.
VIP versions of the An-24A, designated as "An-24 Salon", were built as well, with luxury interiors for high government and military officials. These machines were operated by the VVS (Voyenno Vozdushniye Sily / Red Air Force) in civil-like color schemes.
* The An-24 was followed in production by the "An-24B", with the initial prototype -- converted from a production An-24A -- performing its initial flight on 16 November 1965. It went into production at the Kiev factory and another state factory at Ulan-Ude in Siberia. The main drive behind development of the An-24B was to alter the design to make it easier to build and to modify as per customer requirement. For example, some customers wanted additional range, so the An-24B could be built with additional fuel tankage in the center wing section.
The only real external recognition feature of the An-24B from the outset was an additional window on each side of the fuselage, though to confuse matters some An-24As would be modified with added windows, too. After early production, An-24Bs were built with single slotted flaps inboard, replacing the original double slotted flaps, which were hard to build. The new single flaps were longer than the double flaps, in effect increasing the chord of the wings inboard of the engines. In addition, later An-24B production featured twin fixed ventral fins instead of one as a means of improving yaw stability.
While the size of the passenger compartment wasn't changed, accommodations were rearranged to permit a maximum of 52 passengers -- though it made for a cramped and uncomfortable ride, 48 passengers in a single-class configuration being more liveable. A partition could be installed in one of two positions in the passenger compartment for multi-class operation. Some niceties were added as well; believe or not, the original An-24 didn't have overhead baggage racks, and the addition of this feature to the An-24B eliminated the need for passengers to check their small baggage.
All the passenger seats could be removed for cargo operations, with the An-24B able to handle up to 5.4 tonnes (5.95 tons) of cargo. It was also possible to arrange the An-24B for mixed passenger-cargo ("combi") operation, with cargo forward, near the big front loading door, and seats aft. The two sections were separated by the installable partition, giving an option of either 38 or 20 seats. How useful the An-24B was as a cargo hauler is ambiguous: although fairly large items could be loaded using the big forward cargo door, the An-24B didn't have built-in facilities like an overhead winch on a rail for handling cargo. Of course, VIP configurations were flown as well, typically with 20 or 28 seats and multiple compartments, with various luxuries.
* After producing enough An-24s and An-24Bs for domestic use and ensuring the machine was well-validated, in 1962 the Kiev plant began to produce an export version, the "An-24V". Export machines were not built at the Ulan-Ude plant. There is some confusion between the An-24V and An-24B in Western sources, partly because their designations are very similar in Cyrillic, partly because there wasn't much difference between them. As was typical of Soviet export aircraft, the An-24V was built to two standards: a "standard A" for Warsaw Pact nations that was almost identical to the An-24B, and a "standard B" for everyone else that had less sophisticated avionics. Whatever the standard, the precise avionics fit actually varied according to customer, with some Western avionics provided for locales where it was needed -- for example, aircraft going into airports in the West needed to use Western instrument landing system kit.
* There had been consideration of a military transport version of the An-24 from early on. Several concepts were drawn up, with one design featuring a tail cargo door and loading ramp, but the decision was made to fly a prototype of a minimum-change military variant of the An-24A, designated the "An-24T". The third An-24 prototype was modified to become the prototype of the An-24T, with flight tests of the militarized machine beginning in September 1961. Trials in 1962 revealed that the VVS actually didn't think a minimum-change derivative of the An-24A was all that useful, with the An-24T prototype seen as lacking range, payload capacity, cargo handling gear, and a ventral hatch for cargo transfer and parachute drops.
The An-24T prototype ended up back in civil service, but the Antonov OKB took the criticisms to heart, and in 1965 converted an An-24A to an "An-24T Mark II" AKA "An-34" configuration. Extra fuel tanks were installed to increase range, while uprated AI-24T engines with 2,100 kW (2,820 EHP) takeoff power each provided greater payload capability. A cargo-loading hatch was installed in the belly of the cargo hold, the hatch featuring double doors that opened inward, while cargo-handling gear was fitted.
The belly hatch was hardly an optimum solution for cargo loading issues, since the low belly clearance restricted the height of cargoes that could be loaded through the hatch. However, the VVS found the machine satisfactory and the An-24T -- no "Mark II" in the service designation, since the Mark I had never reached operational service -- went into production at a state factory in Irkutsk, with initial deliveries in 1966 and formal introduction to service in 1967. An "An-24TV" variant was built for the export market, again in two levels of configuration. Very few An-24T/TVs were ever used by civil services.
* The production An-24T clearly differed from the An-24 airliners in that the An-24T only had a few windows on each side, and no doors at the rear of the fuselage. The An-24T also differed from the airliners in that it was fitted with a prominent astrodome for the navigator behind the cockpit, and a spine running from the tailfin fillet up to midwing. Like the An-24B, the An-24T had twin ventral fins. Very early An-24T production had the double slotted inboard flaps, but most were built with the big single-piece flaps.
The belly cargo hatch had a length of about 2.72 meters (8 feet 11 inches)
and width varying from 1.25 to 1.4 meters (4 feet 1 inches to 4 feet 7
inches); in production machines, the two doors opened fore and aft. The
hatch had been slightly longer and narrower in the prototype, with doors that
opened to the sides. There was a powered winch above the hatch -- plus a
conveyor system built into the floor, powered by chain drive, for freight
handling and parachute dropping. The floor was made of aluminum sheeting
backed by plastic foam for light weight. There were 42 tip-up seats along
the sides for paratroopers; up to 24 stretchers and a seat for a medical
attendant could be fitted for the medical transport mission.
ANTONOV AN-24T:
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spec metric english
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wingspan 29.2 meters 95 feet 10 inches
wing area 72.46 sq_meters 780 sq_feet
length 23.53 meters 77 feet 2 inches
height 8.32 meters 27 feet 4 inches
empty weight 14,970 kilograms 33,000 pounds
MTO weight 19,800 kilograms 43,650 pounds
cruise speed 450 KPH 280 MPH / 245 KT
service ceiling 8,400 meters 18,520 feet
range (max fuel) 3,000 kilometers 1,865 MI / 1,620 NMI
range (max payload) 640 kilometers 400 MI / 345 NMI
_____________________ _________________ _______________________
The An-24T was fitted with PSBN-3N Emblema radar, an enhanced version of the
PSBN-2N fitted to the An-24A/B that provided improved ground mapping
capabilities. Of course other militarized avionics was fitted as well. The
An-24T actually had a night-capable bombsight system to permit precise
airdropping of cargoes. In fact, as per VVS policy at the time, the An-24T
could actually be used as a bomber in a pinch, carrying ordnance on two racks
that could be installed on each side of the lower fuselage. Somewhat more
practically, the external racks could be used to carry paradropped radio
beacons and other parachutable packages that didn't go boom.
* The An-24T proved satisfactory in service, but its takeoff performance under "hot & high" (hot weather / high altitude) conditions left something to be desired. In cold weather conditions, the flight surface deicing system, driving by engine bleed air, drew off too much excess power, with the result that it couldn't be used on takeoffs. In addition, the TG-16M APU didn't always provide as much power as needed.
There turned out to be a straightforward solution to the problem. Earlier in the decade, the Tumanskiy engine OKB had developed a compact turbojet, the "RU19-300", for a jet trainer that didn't enter production. Instead of simply discarding the engine, Tumanskiy engineers redesigned it into a combination APU/booster engine, the "RU19A-300", with a thrust of 2.16 kN (220 kgp / 485 lbf). The left engine nacelle of the An-24T was redesigned to accommodate the RU19A-300 instead of the TG-16M, with the resulting new An-24 version designated the "An-24RT" -- where the "R" effectively stood for "reaction", indicating the jet booster.
The RU19A-300 fit proved all that was hoped for, providing adequate boost power under difficult takeoff conditions, plenty of airflow for the deicing system, and plenty of power for ground operation. In fact, the booster engine was so clearly useful that the decision was made to produce An-24B airliners with the booster engine as well, resulting in the "An-24RV", which gradually replaced the An-24B on the production line. The An-24RV was built in both regular airliner and salon VIP configurations, and used by Aeroflot and civil air services of Soviet-friendly states.
* Roughly 1,100 An-24s of all variants were built up to end of production in 1978. The An-24 was a fine "flying truck", able to carry large loads; it was also comfortable and economical to operate, while the RU19A-300 booster engine installed on the An-24RT/RV provided plenty of power for mission equipment. As a result, there were plenty of special mission variants of the An-24:
The An-24LP was intended to complement the smaller biplane An-2 in the fire-fighting role. The An-24LP was faster and could get more fire-fighters to the scene of a blaze than an An-2. The Soviets had used the big Mi-6 "Hook" helicopter for hauling fire-fighters, but the An-24LP was faster and cheaper. The An-24LP also had a water tank to allow it to be used as a "water bomber", but despite the fact that the An-2 could only carry a quarter as much water, it was better for the job. That was because the An-2 could land on almost any nearby stretch of open and firm land, while the An-24LP had to operate from something resembling a proper airfield.
Other An-24s were employed in small or single quantities as calibration aircraft for electronic air navigation or landing aid systems; meteorological research; propulsion system testbeds, including one that tested eight-bladed low-noise propellers; and avionics testbeds, including an "An-24T Troyanda" with oversized "cheek" fairings containing experimental antisubmarine warfare (ASW) gear.
There was some investigation from the mid-1960s on a derivative of the An-24 powered by four Ivchenko AI-25 small turbofans, each mounted on a pylon extending under and forward of the wing. This variant was to be designated the "An-50", but the authorities thought the Yakovlev Yak-40 trijet, also powered by the AI-50, was a better bet, and the An-50 remained a paper project.
* In 1966, the Red Chinese government negotiated the manufacture of the An-24, with the plant in Xian flying the first "Y7", as the type was known in China, in late 1970 -- this machine being effectively an An-24RV. Unfortunately, the upheaval of the Cultural Revolution threw further development of the Y7 off track, with the type only finally entering service in the mid-1980s. Most were delivered to the Chinese military, though some were fitted out as airliners and flown by the Civil Aviation Administration of China (CAAC). China and the USSR were not on good terms during this time and the Y7s were built outside of license.
In the mid-1980s, a stock Y7 was refitted with winglets, Westernized avionics, and a new interior as the prototype of a "Y7-100", mostly for the export market. A freighter version, the "Y7-100C", was also developed. A version of the Y7-100 with derated engines, intended to improve engine life, was introduced as the "Y7-200", but it was underpowered and was only built in small numbers, if any production machines were built at all.
The Chinese were never all that enthusiastic about the An-24, with only 62 Y7s and about 50 Y7-100s built to the turn of the century. However, Xian continues to improve the Y7 series with help from Russian and Western organizations. Prototypes were flown in the mid-1990s of the improved "Y7-200A" and "Y7-200B" with Pratt & Whitney Canada PW127C turboprops, four-blade Hamilton Standard propellers, a redesigned cabin, and a slight fuselage stretch permitting carriage of up to 60 passengers.
They were followed by the "MA-60", with uprated PW127J turboprops and seating reduced to 56 to improve passenger comfort. Orders have been coming in for the MA-60, with Xian stating that the organization expects to sell hundreds of them. There have also been proposals for a maritime patrol aircraft derivative, the "MA-60MPA", with a search radar in the nose and underwing stores pylons, but it doesn't appear a prototype was ever flown.
* As noted, early on in the An-24 program there had been talk of developing a cargolifter derivative with a tail loading ramp, but the decision was made to instead produce the somewhat improvised An-24T, with its belly hatch. In the mid-1960s, the Antonov OKB perceived that the Red military seemed more receptive to an optimized cargolifter, and so OKB engineers pulled the old concept plans for an An-24 with a rear loading ramp out of the files, polished up the idea, and pitched it to the authorities.
The key to the offering was a slick new rear loading ramp design that could either be hinged down for "drive-in" loading, or slid under the floor of the cargo hold for loading from a truck tailgate or airdrops of cargo. When closed, the ramp formed a tight seal, permitting pressurization of the cargo hold. OKB engineers built a tidy 1/12th scale model to show how the ramp worked. On inspecting the model, the authorities were impressed and promptly gave the go-ahead for development of the "An-26" in March 1968. First flight of the initial An-26 prototype was on 21 May 1969.
Installation of the loading ramp of course meant substantial redesign of the An-24's rear fuselage. The new rear fuselage was 26 centimeters (10.5 inches) longer; of course the ventral fins of the An-24 went away, but they were replaced by strakes flanking the base of the cargo hatch. The strakes not only provided directional stability, but also compensated for turbulence caused by the new rear fuselage scheme that would have otherwise led to increased drag. The tailfin was increased in area, though not in height, while the span of the tailplanes was increased as well.
There was a desire not to fiddle much with the design of the rest of the An-26 relative to the An-24 to ensure parts commonality, but some changes were made forward, most significantly fit of an observation dome on the left side of the fuselage behind the cockpit, with the optical bombsight fitted there on a swinging mount. The changes to the An-26 resulted in increased weight, so the wings were reinforced and the An-26 was fitted with uprated AI-24VT engines providing 2,100 kW (2,820 EHP), driving improved four-bladed propellers. The RU19A-300 APU/booster was also fitted.
A second An-26 prototype followed later in 1969, with both machines making a visit to the Paris Air Show that year and making a good impression on visitors. NATO assigned the type the codename "Curl". The initial production example was rolled out of the Kiev factory at the end of August, with full series production beginning in 1970. About 1,400 An-26s would be built to end of production in 1986, with about 40% of the total going to the Soviet military, and the rest split evenly between Soviet civil aviation and export users.
* The An-26, as described above, was very much like an An-24 except for the tail section and some changes like the side observation dome. It could easily be confused with an An-24 at first glance, though the strakes on the side of the rear fuselage were an easy giveaway on a second.
The cargo bay had an overhead hoist on a rail for cargo loading. Vehicles could drive up the tail ramp to get on board; if they weren't self-propelled, there was a pulley at the head of the cargo bay to allow them to be pulled on board by an external tractor. Not all had a floor conveyor system, that being reserved for machines intended for paradropping supplies. There were tip-up seats along the walls for troops. While early An-26 production featured the PSBN-3N radar, later production has the more advanced Groza-26 radar. Later production also featured the intake for the RU19A-300 APU/booster moved from the right side of the engine nacelle to the bottom.
* Although the An-26 was meant primarily for military use, a prototype of a
civilianized "An-26B" cargolifter was rebuilt from a stock An-26 in 1976.
The experiment going well, the An-26B went into service in the early 1980s,
with 116 built up to end of production in 1985.
ANTONOV AN-26B:
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spec metric english
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wingspan 29.2 meters 95 feet 10 inches
wing area 74.98 sq_meters 807.1 sq_feet
length 23.8 meters 78 feet 1 inch
height 8.575 meters 28 feet 2 inches
empty weight 15,400 kilograms 33,950 pounds
MTO weight 24,400 kilograms 53,790 pounds
cruise speed 440 KPH 275 MPH / 235 KT
service ceiling 7,500 meters 24,600 feet
range (max fuel) 2,550 kilometers 1,585 MI / 1,375 NMI
range (max load) 1,100 kilometers 685 MI / 595 NMI
_____________________ _________________ _______________________
The An-26B differed from the military An-26 by being fitted with civilianized
avionics; deleting the side observation bubble and replacing it with a
fairing; and deleting the tip-up paratrooper seats, with two seats installed
for cargo handling crew. The overhead traveling winch was retained, and as
with the An-26, some An-26Bs had a rolling conveyor system. These machines
were mainly intended for hauling standardized cargo pallets. They had
separate climate-control systems for the cockpit and the cargo bay, allowing
the cargo bay to be chilled for hauling perishable goods.
* As with the An-24, a number of specialized variants of the An-26 were flown:
An-26s were also converted for missions such as weather research, with the type being used for air survey duties and avionics trials as well. Since the fall of the USSR, there has also been a push to refurbish old An-26s to commercial configurations, including at least one modified as a VIP transport and, somewhat more practically, with at least ten converted to the "An-24-100" convertible freight / passenger liner or "combi" configuration. In the mid-1990s, at least one An-26 was converted to the "An-26D" long-range configuration by being fitted with a large conformal external tank on each side of the fuselage.
The Chinese obtained a number of An-26s and reverse-engineered the variant, developing their own copy, the Xian "Y7H". Initial flight of a prototype was in 1988, with the Y7H going into service with the Chinese military in 1992. The Y7H has apparently only been built in small numbers, a few dozen in all, including "Y7H-500" civilianized machines and "Y7H-300" export machines.
* From 1966, the Antonov organization performed work on a specialized aerial mapping variant of the An-24, originally designated the "An-24FK", with initial flight of a prototype on 21 August 1967. It featured a redesigned forward fuselage, with a raised cockpit to improve visibility and a bomber-style glazed nose for the navigator, plus a set of cameras mounted in the belly. The variant was accepted for series manufacture, with the first production "An-30", as it had been redesignated, being rolled out in 1971. One was displayed at the Paris Air Show in 1975, with the type then being assigned the NATO codename "Clank".
The production An-30 featured AI-24VT engines as per the An-26, with each engine providing 2,100 kW (2,820 EHP), and was fitted with the RU19A-300 APU/booster. Various configurations of daylight and infrared cameras could be carried, shooting out windows in the belly of the aircraft that were covered by sliding doors when the cameras were not in use, with the doors protecting the windows from being cracked by rocks tossed up during takeoff or landing. Two operator workstations were fitted for controlling the photographic systems, as well as comfy seats for crew not busy at the moment, plus a food locker. The prototype had a full set of windows as per the An-24, but most of the side windows were deleted in the An-32. The oversized forward right cargo loading door was retained, however.
Access to the new glazed nose, nicknamed the "veranda", was through a cramped
crawlspace. The glazed nose meant the elimination of radar, though a small
Doppler groundspeed radar was fitted. The lack of a true radar was later
seen as regrettable, and so some An-30s were fitted with a Groza-M30 radar in
a fairing under the nose, with the rear of the fairing being part of the nose
landing gear doors. In most other respects, the An-30 was similar to the
An-24 and could even be fitted with the external stores racks, though it
never was in practice.
ANTONOV AN-30:
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spec metric english
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wingspan 29.2 meters 95 feet 10 inches
wing area 74.98 sq_meters 807.1 sq_feet
length 24.26 meters 79 feet 7 inches
height 8.32 meters 27 feet 4 inches
empty weight 15,590 kilograms 34,370 pounds
MTO weight 23,000 kilograms 50,700 pounds
cruise speed 430 KPH 265 MPH / 230 KT
service ceiling 8,300 meters 18,300 feet
range 2,630 kilometers 1,635 MI / 1,420 NMI
_____________________ _________________ _______________________
* A total of 65 An-30s was built for Aeroflot, with six more built for other
Soviet civil organizations and 18 built for export. China was the biggest
export user, obtaining at least seven machines. Other users included
Afghanistan, Bulgaria, Czechoslovakia, Mongolia, Romania, Vietnam, and
reportedly a few African countries.
26 "An-30Bs" were built for the VVS, differing primarily from the civil An-30 in military avionics fit, including chaff-flare dispensers for self-defense. A handful of An-30Bs were used in the Afghan conflict to complement mainline military reconnaissance assets. Some military An-30Bs featured special reconnaissance equipment fits, including SLAR, TV cameras, and infrared line scanners, and there were also a few cases of civil An-30s being fitted with advanced gear surveillance for survey purposes. There were a number of specialized variants as well:
After the fall of the USSR, two An-30s were even converted into 20-seat "An-30-100" VIP transports -- a role in which the specialized features of the An-30 were absolutely irrelevant. This puzzling exercise was apparently performed simply because they were handy airframes that would otherwise have been mothballed or scrapped. A handful of An-30s were also used for test, trials, and research purposes, though details are scarce.
* In the mid-1970s, the Indian military issued a requirement for a new medium cargo aircraft. The An-26 generally fit the bill, but it lacked the needed performance, particularly under the "hot & high" conditions presented by the mountains of India's northern borders. However, Antonov OKB engineers felt that they could provide a solution by re-engining the An-26 with Ivchenko AI-20D turboprops, providing a whopping 3,865 kW (5,180 EHP) each -- 85% more than the AI-24VT engines used on the An-26. Power was not going to a problem with the new powerplants, and so the Indians were intrigued with the "An-32", as the proposal was designated.
An early-production An-26 was converted as the An-32 prototype, performing its first flight on 9 July 1976. The prototype was displayed at the Paris Air Show in 1977, with NATO assigning the type the codename "Cline". Two preproduction prototypes followed, with the An-32 going into production at the Kiev factory in 1980. The initial idea had been for Hindustan Aeronautics Limited (HAL) to license-build the An-32 in India, but that scheme fell through.
* The An-32 featured the AI-20D turboprops mounted in nacelles that placed the engines above the wings, not forward of them as with the An-26. This was partly because the AI-20Ds were substantially bigger, affecting the aircraft center of gravity, and partly because they used wider-span four-bladed props -- increased from 4.5 meters (14 feet 9 inches) in diameter to 4.7 meters (15 feet 5 inches) in diameter -- leading to a ground clearance problem. The increase in engine power and the repositioning of the engines of course had a series of "follow-on" effects that demanded a few other changes in the aircraft design:
In addition, although the An-26 used single-piece inboard flaps instead of the double slotted flaps originally used on the An-24, the An-32 was intended for "hot & high" operation and so the fit of triple slotted flaps was seen as worthwhile. While the exhausts of the engines on the An-32 prototype had been initially positioned at midwing, they were later extended to behind the wing trailing edge, with production machines retaining this configuration. It is unclear why this change was made, but at the very least extending the exhausts eliminated the nasty streak of soot on the wing behind the engines on the early prototype configuration. The prototype also initially featured a fixed slat on the bottom leading edge of the tailplanes that was supposed to help de-icing by altering airflow, but the decision was made that it was more bother than it was worth and hot-air deicing was reinstated.
Improved avionics were fitted; the additional thrust provided by the
RU19A-1900 APU/booster was no longer a matter of importance, so the An-32
reverted to the TG-16 APU. Cargo-handling gear was like that of the AN-26,
and the side observation dome with bombsight was retained as well, as was the
capability of carrying external cargoes.
ANTONOV AN-32:
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spec metric english
_____________________ _________________ _______________________
wingspan 29.2 meters 95 feet 10 inches
wing area 74.98 sq_meters 807.1 sq_feet
length 23.78 meters 78 feet
height 8.75 meters 28 feet 9 inches
empty weight 16,800 kilograms 37,040 pounds
MTO weight 27,000 kilograms 59,525 pounds
cruise speed 470 KPH 290 MPH / 255 KT
service ceiling 9,500 meters 31,170 feet
range (max fuel) 2,500 kilometers 1,555 MI / 1,350 NMI
range (max load) 2,000 kilometers 1,245 MI / 1,070 NMI
_____________________ _________________ _______________________
* The high-mounted engines of the An-32 gave the aircraft a distinctly
"muscular" look, which was not deceiving: everybody who operated it was
impressed by how much power it had, even under a full load and "hot & high"
operating conditions. In 1985, to no surprise an An-32 set over a dozen
altitude and performance records in its class. The An-32 was also, as was
the case with the best Soviet gear, very rugged and reliable.
A total of 214 was built for export up to 1994, with India being the biggest user at 123 aircraft, the first Indian An-32 being delivered in the summer of 1984. Afghanistan being the second-biggest at 49 aircraft. There was about a dozen or so more users, including Angola, Bangladesh, Colombia, Croatia, Ethiopia, Mexico, Nicaragua, Panama, Peru, Saudi Arabia, Tunisia, Swaziland, and possibly a few others. Users with high mountain terrain like Peru found the An-32 particularly useful. Two of the Mexican An-32s were apparently fitted with a quick-change equipment suite by the Heli-Dyne company of the US for operation in the maritime patrol role.
The Soviet military had no particular interest in the unique capabilities of the An-32 until the very last days of the USSR, finally ordering a batch of almost 50 for special operations. Some of these machines were built with downrated AI-20M engines providing 3,170 kW (4,250 EHP), the maximum power of the AI-20D being seen as less attractive than extending engine life and lowering fuel consumption. The production of these machines overlapped the collapse of the Soviet Union and they never went into Russian service, instead being sold off on the export market.
However, from the late 1980s about three dozen civilianized "An-32A" machines -- very much like the baseline An-32 but with civil avionics -- were built for domestic civil organizations. They were followed in the mid-1990s by the "An-32B", which featured general small refinements, with about 40 built, mostly for domestic use -- though a few ended up in North Korean hands by a sneaky roundabout process. The Antonov organization has also designed a further improved "An-32B-100" cargolifter and "An-32V-200" tactical transport, with various updates such as fuselage reinforcements, new engines, and modernized avionics, it appears mostly for the export market. It is unclear how many of these improved An-32 variants have been built.
There have been a few special conversions of the An-32. In the early 1990s, two were converted as demonstrators for an "An-32P" fire-fighting configuration, featuring a large tank for fire retardant mounted externally on each side of the lower fuselage, but though there was polite interest, nobody bought off on the concept. A few An-32 testbeds, including one to evaluate new eight-bladed "propfan" propellers, have been flown, and proposals have been offered for special variants such as a maritime patrol configuration. The An-32 does seem to have a future, there being no other medium transport in the world so well suited to "hot & high" operating conditions.
* The following list summarizes the major variants of the An-24 family:
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An-24 Initial civil airliner variant AKA "An-24A".
An-24B An-24 with general improvements like 1-piece flaps.
An-24V An-24B for export.
An-24T Military cargolift variant with belly loading hatch.
An-24VT An-24T cargolifter for export.
An-24RT An-24T cargolifter with APU/booster unit.
An-24RV An-24B airliner with APU/booster unit.
An-26 An-24B-derived military cargolifter with tail ramp.
An-26B Civilianized An-26.
An-30 Survey platform based on An-24B for civil & export use.
An-30B Militarized An-30.
An-32 An-26B with more powerful engines for "hot & high" use.
An-32A Civilianized An-32.
Y7 Chinese An-24 production.
Y7H Chinese An-26 production.
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* There's only really one source for this document: ANTONOV'S TURBOPROP TWINS by Yefim Gordon, Dmitriy Komissarov, and Sergey Komissarov (Midland Publishing, 2003). Older Western sources tend to be very unreliable in their descriptions of Soviet-Russian aircraft.
* Revision history:
v1.0.0 / 01 mar 10 / gvg
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