Ilyushin Il-86
The Ilyushin Il-86 is a retired short- to medium-range wide-body jet airliner that served as the USSR's first wide-bodied aircraft. Designed and tested by the Ilyushin design bureau in the 1970s, it was certified by the Soviet aircraft industry, manufactured and marketed by the USSR.
Developed during the rule of Leonid Brezhnev, the Il-86 was marked by the economic and technological stagnation of the era: it used engines more typical of the late 1960s, spent a decade in development, and failed to enter service in time for the Moscow Olympics, as was originally intended. The type was used by Aeroflot and successor post-Soviet airlines; only three of the total 106 constructed were exported.
At the beginning of 2012, only four Il-86s remained in service, all with the Russian Air Force. By the end of 2020 the number in active service was reduced to three.
Development
Background
In the mid-1960s, the United States and Western Europe planned airliners seating twice the then-maximum of some 200 passengers. They were known as airbuses at the time. The Soviet leadership wanted to match them with an aerobus. Alongside the propaganda motive, the USSR genuinely needed an aerobus. Aeroflot expected over 100 million passengers a year within a decadeFirst to respond was OKB-153, the bureau led by Oleg Antonov. It proposed a 724-seat version of the An-22 airlifter. The project was promoted until 1969, ultimately with a 605-passenger interior. It did not go ahead due to fears that it would be old-fashioned and because the Kiev-based bureau was close to the deposed Nikita Khrushchev.
Concept
Many airports had terminals too small for "aerobuses". In the West, the solution to this involved constructing greater airport capacity. By contrast, Soviet aviation research institutes addressed ways of increasing passenger throughput without the need for additional airport capacity.Many Soviet airports also had surfaces too weak for "aerobuses". The Soviet solution again favoured adapting aircraft to existing conditions, rather than reconstructing airports. The aerobus thus had to match the ground loadings of existing airliners. This called for complex multi-wheel landing gear.
The Soviet solution to the airport capacity issue involved passengers loading and unloading their own luggage into and from the aircraft. This was eventually called "the luggage at hand system". Soviet aviation journalist Kim Bakshmi described it thus: "One arrives five minutes prior to departure, buys oneself a ticket on board the aircraft, hangs one's coat next to the seat and places one's bag or suitcase nearby."
Taking suitcases into the cabin, as in trains, was studied, but necessitated a 3 m fuselage extension with a 350-seat capacity. To avoid this, passengers were to deposit their luggage in underfloor compartments as they entered the airliner.
Ideas similar to the "luggage at hand system" were briefly addressed in the West. Airbus studied such an arrangement in the mid-1970s. Lockheed implemented it into the L-1011 TriStar in 1973 at the request of Pacific Southwest Airlines and possibly also to suit potential Soviet buyers.
In October 1967, the Soviet government approved a Ministry of Civil Aviation specification for an aerobus. This called for 350 seats and a range of with a 40-tonne payload or with seats taken but no freight. The airliner had to operate from smaller airports runways.
In the second half of the 1960s, OKB-240 was restoring positions lost 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,, 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, powerplant, automation 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 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 6.07 m fuselage diameter was partly dictated by the need to provide standing room in the underfloor luggage compartments. The Il-86 had the second-widest fuselage of any airliner until the Boeing 777.
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 favoured the clean-winged, rear-engined, T-tailed configuration for airliners. The BAC Three-Eleven and BAC/CASA/MBB Europlane projects had similar configurations.
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 aviation scientists. Responsible TsAGI officials and industry leaders robustly called that aircraft 'utter nonsense'."
Similar controversies were known in Western aeronautical circles but this Soviet approach showed a typical streak of dogmatism which held that problems had immutable, "scientifically correct" solutions. However, not all Soviet aviation engineers were so fixed in their ideas, and the configuration issue figured in a meeting held discreetly in Paris in the late 1960s between Boeing engineers and some of their Soviet counterparts. This meeting had been approved at the highest levels of both governments because each side had something the other wanted very badly: the Soviets wanted to know exactly why Boeing had put the 747 engines in under-wing pods instead of at the rear of the fuselage, while Withington and the Boeing engineers had a long list of questions about the processing and use of titanium in airframes. According to Sutter's account, both sides left the meeting well satisfied with the exchange of information.
It seems that this meeting may have made a real difference to Soviet aircraft design, but Boeing's contribution could naturally not be acknowledged publicly by the Soviet side. Ilyushin therefore had to stress that it had been the first in the world to use podded engines suspended from pylons beneath and ahead of the wing, on the experimental Ilyushin Il-22 four-engined jet bomber of 1946. Having thus 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.
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 US and the UK had turbofans with bypass ratios of 4 or 5 to 1. The 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.
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, 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 weather with a three-member flight crew, matching Western technology of the time.
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.