Ilyushin Il-86

The configuration issue


The configuration of heavy jet aircraft was a politically sensitive issue in the USSR. Aircraft designer Leonid Selyakov states this of the underwing-engine US-pioneered layout which gradually became standard for jet airliners :

"The configuration of the В-47, taken on strength by the US Air Force ... brought forth a veritable storm of critical opinions from [Soviet] aviation scientists.

Responsible TsAGI officials and industry leaders robustly called that aircraft 'utter nonsense' (similar opinions were expressed of the Boeing 747)."

Similar controversies were known in Western aeronautical circles but typified Soviet dogmatism which held that problems had immutable, "scientifically-correct" solutions.

Ilyushin therefore had to stress that it had first in the world used podded engines suspended from pylons beneath and ahead of the wing, on the experimental Ilyushin Il-22 four-engined jet bomber of 1946 (first use of this designation).

Having thus been presented the Il-86's ultimate configuration as indigenously Soviet, the bureau could at last show it in public in 1973, six years after publication of the aerobus specification and four years after the design assignment.

A modern six-window flightdeck followed, in place of the 18-to-20 window glazing of the Il-18, Il-62 and Il-76.

Powerplant issue

The main problem facing the Il-86 project was the lack of a suitable engine. It was never resolved.

By the close of the 1960s, the USA and the UK had turbofans with bypass ratios of 4 or 5 to 1. T

he first Soviet large turbofan, the Lotarev D-18T, did not appear before the mid-1980s.

The Soloviev D-30, originally intended for the Il-86, was the most advanced Soviet civil aeroengine.

It had a bypass ratio of 2.4 to 1 and aerodynamic clamshell thrust reversers. It failed to attain the required thrust, however: "only after the lapse of three years that were spent on preparing the advanced development project did it become clear that these engines would not provide the necessary take-off performance."

The less-advanced Kuznetsov NK-8 series engine, adopted on March 26, 1975, had a bypass ratio of 1.15 to 1 and drag-inducing grilles over its cascade thrust reversers.

Both these engines had high specific fuel consumptions and were noisy. Being ultimate developments of smaller engines, they could not offer growth to future Il-86s.

Automation issue


The appropriate/intermediate technology principles to which most Soviet airliners before the Il-86 had been designed meant that they had typically five-member flight crews.

The design and entry into service in 1972 of the Tu-154, an airliner built to high technology principles (more automation, less human input), showed that Soviet science lagged behind in the development of avionics which would remove the need for navigators and radio operators.

A programme of avionics development was mounted to enable the Il-86 to operate in most weathers with a three-member flight crew, matching Western technology of the time.


Manufacturing capacity issue


The shortage of manufacturing facilities for the Il-86 was a problem from the outset: "The rapid modernisation of the Soviet Air Force ... has left limited scope for the expansion of commercial production ... the lack of production capacity is being remedied partly by ... international cooperation."

This meant involving the Polish aircraft industry in the project.

Formal aerobus programme launch


In October 1967, the Soviet government approved a Ministry of Civil Aviation (Aeroflot) specification for an aerobus. This called for 350 seats and a range of 3,600 km (1,900 nmis) with a 40-tonne payload or 5,800 km/3,100 nmi with seats taken but no freight.

The airliner had to operate from smaller airports (classified as Klass "B" and "V" [Russian: класс "Б", "В"] or "Class B/C" by the Soviets) 2,600 m (8,500 ft) runways.
In the second half of the 1960s, OKB-240 (as the Ilyushin bureau was formally known) was restoring positions lost (with Yakovlev, in favour of Tupolev and Antonov) during the Khrushchev era and was well placed to secure design of the aerobus.

When the Soviet cabinet's defence industry committee promoted the Aeroflot specification on September 8, 1969 to a preliminary project, (Russian: аванпроект; transliterated: avanproyekt), it entrusted it to Ilyushin.

The bureau received specific operational requirements for the aerobus on February 22, 1970.

In developing the concept which had been agreed, Ilyushin faced four challenges: configuration (layout or "shape"), powerplant, automation (avionics) and manufacturing capacity.

Conceptual development


Ilyushin began work on the aerobus in late 1969, initially by assessing the development potential of existing aircraft. An enlarged Il-62 (the Il-62-250) would have had a 30-tonne payload, 259 seats and a 6.8 metre/22 ft longer fuselage: a virtual analogue of the Douglas DC-8 "Super Sixty" series.

Other proposed Il-62 modifications involved double-deck and "two fuselages side-by-side" developments.

There was also a project to "civilianise" the Il-76.


From March 1970 the bureau developed all-new designs under the Il-86 designation. Instead of the "appropriate technology" approach of the Il-62, these designs were to have powered controls, complex high-lift devices and advanced automation which would reduce the number of flightdeck crew.

An early avanproyekt was shown to the Soviet leadership at an exhibition of civil aviation innovations at Vnukovo-2 Airport near Moscow on May 17, 1971.

A scale model with the designation of "Il-86" showed the "self-loading" concept with integral boarding stairs, below-deck luggage stores, and below-deck midships galley.

It had a twin-aisle interior with nine-abreast seating in a "3-3-3" layout. Ilyushin considered it politic to make the interior wider than any planned airliner except the Boeing 747

The 6.08 m (19.9 ft) fuselage diameter was partly dictated by the need to provide standing room in the underfloor luggage compartments. It remained the second-widest airliner interior until the Airbus A380.


On this basis, on 9 March 1972, the bureau was asked to proceed with detailed design.

The difference between the 1971 model and the eventual Il-86 was in configuration: the model had looked like an Il-62.

At that time, the Central Aero and Hydrodynamics Institute (TsAGI) favoured the clean-winged, rear-engined, T-tailed configuration for airliners.

The BAC Three-Eleven[27] and BAC/CASA/MBB Europlane[28] projects had similar configurations.

Design, testing and certification


The design process at Ilyushin was managed by Sergey Ilyushin's successor as head of the bureau, Genrikh Novozhilov.

The timescale announced in 1973 envisaged first flight in 1976 and service entry in time for the Moscow Olympics in 1980.


The prototype flew at Khodynka airfield (where Ilyushin's experimental factory was) on December 22, 1976 (Soviet airliners often flew before the close of calendar years due to the requirements of Five-Year Plans). It was announced that the type had a patented electromagnetic pulse deicing system.

which used 500 times less energy than conventional deicers.

It is claimed that over 50 new technological processes were introduced into Soviet practice as a result of the Il-86 programme.

The initial test programme was flown by Ilyushin staff, ending two months ahead of schedule on October 20, 1978. Other sources claim that these tests were completed on 22 September 1978.

(According to a faster schedule announced at the time of the first flight, Ilyushin tests were to have ended in time for the 60th anniversary of the October Revolution on November 7, 1977.) In-house testing involved speeds up to Mach 0.93 and bank angles up to 11 degrees greater than specified.

Initial certification flying by pilots independent of Ilyushin ended on June 6, 1977. State acceptance trials began on April 24, 1979 and ended on December 24, 1980.

Certification by Gosaviaregistr SSSR [the USSR State Aviation Registry] was granted under certificate number 10-86.

The Il-86 entered Aeroflot service on 26 December the same year.

The service-entry deadline of summer 1980, announced by Minister of Civil Aviation Boris Bugayev in 1977 had passed, however, and the Il-86 missed the Moscow Olympics in the summer of 1980.


Overall development of the Il-86 occupied over a decade.

The length of this period was due to the sensitivity of the airliner's configuration, problems with its powerplant, prolonged avionics development and the low priority of civil as opposed to military aircraft.

In its earlier stages, the Il-86 programme was also held back by hopes of US airliner imports.

Certificating the Il-86 to the very demanding set of Soviet and Comecon standards called NLGS-2 also delayed progress; it was the first Soviet aircraft to undergo a full certification programme since certification was introduced in the USSR in 1967 and became mandatory five years later.

Manufacture


Production of the Il-86 began in 1976 and continued until 1994.

There was no prototype. The first two machines were handmade by Ilyushin at the bureau's own Moscow facility in 1976 and 1977.

One was used for flight testing and the other for static ground testing.
Beyond these initial examples, Ministry of Aircraft Manufacture ("MAP," "Minaviaprom") Factory 64 at Voronezh (today VASO) was tasked with building more than half of each Il-86 and performing final assembly.

Three aircraft were assembled at Voronezh by 1979.

The first (flown on October 25, 1977) was built largely by hand, subsequent machines making increasing use of production equipment.

These aircraft were used in certification and development flying before handover to Aeroflot.

Voronezh factory production engineers conducted a "redesign cycle" of over 50 areas, cutting some 1,500 kg (3,300 lb) of airframe weight.

Polish co-production


Capacity at Voronezh was insufficient and the Polish aircraft industry was involved in the Il-86 project from the start.

The arrangement involved significant technology transfer to Poland: PZL Amalgamation Mielec factory Director Jerzy Belczak said it involved “… a radical retooling of our enterprise” involving “over 50 new processes.”[60] Observers noted that "work on the Il-86 will bring Poland's ... WSK-Mielec to a new level of capability ... in the manufacturing processes involved with an aircraft of this size, including titanium structures, chemical milling and the machining of integral panels."


By the mid-1980s, PZL was planned to produce half of the Il-86, including the entire wing, and also to work on Il-86 developments (“Now we are preparing to manufacture units for the next model of the Il wide-body plane,” according to Belczak).

From May 1977, the Polish factory manufactured entire empennages including tailplanes and the fin, all control surfaces, high-lift devices and engine pylons for the Il-86, representing "about 16 per cent of these aircraft."[64] Amid labour and political unrest in Poland from 1980, the Voronezh factory retained wing manufacture.

Production totals

After certification in 1980, annual Il-86 outputs were: 1980, one; 1981, nil; 1982, 11; 1983, 12; 1984, 8; 1985, 9 (including the four for 8 ADON); 1986, 11; 1987, 10; 1988, 10; 1989, 9; 1990, 11 (including the three for export to China), 1991, 3.[65] Of the 106 examples built, one never flew (being used for static tests) and three were exported.

The Five-Year Plan in force when the USSR ceased to exist called for 40 more aircraft to be manufactured by 1994, but the manufacturing facility closed in early 1992.