Warszawa 2012-06-26
Iliuszyn Ił-86.
The Il-86 is the first Soviet wide-body airliner. His story is unusual and tells a lot about the backstage industry of the Moscow state. Below, we will cite many facts that are currently (2012) suppressed or even hidden. However, the main reason why we became interested in this aircraft is the fact that the Polish Aviation Industry participated in the construction and development of this machine.
The beginnings of the program.
At the beginning of the 1960s, in the free world, turbojet aircraft were introduced to commercial aviation, which took about 200 passengers on board. The decision turned out to be right and following this lead, it was decided to introduce the next generation of commercial aircraft with a capacity of about 400 passengers into operation. This is how the Boeing B-747 was born, and then the Airbus A.300. In the USA they were called jumbo (colossus, landara), and in Western Europe airbuses. In accordance with the long-standing policy of the Kremlin, the CCCP decided to develop such an aerobus aircraft (aerobus). So, the propaganda motive came first.
Did the Kremlin really need a plane carrying 400 passengers? Well, most definitely. Aeroflot was then the largest company of its kind in the world. The following numbers testify to the dynamics of passenger transport; In the period 1971 - 1975, Aeroflot transported 433 million people, an average of 86,600,000 people/year. (At that time, the CCCP had five-year terms and their statistical yearbooks provided results for a period of 5 years.). Between 1976 and 1980, Aeroflot carried 500 million people, or 100 million a year. According to Kremlin materials, on December 29, 1976, Aeroflot carried its one hundred millionth passenger. In 1984, Aeroflot aircraft carried 600,000 people in just one day. So, in one year, they could transport 219 million people. What was the reason for this huge number of passengers? There was a poor railway network and an even worse road network. Few people owned private cars. And the state paid for the plane tickets. Most of the passengers were employees traveling to/from work in different parts of the CCCP. Companies paid for their flight.
The first project of a giant passenger plane was a transport version of the giant An-22. The design bureau OKB-153 led by Oleg Antonov developed a preliminary design of the aircraft, which could take 724 passengers on board. Passengers were to occupy the lower and upper decks. In 1969, the revised design of the aircraft was released, which took 605 people on board. 383 people on the upper deck. 223 people on the lower deck. However, the program has been suspended. The main reason was an outdated design that did not provide adequate performance.
Studio works.
Many logistical problems had to be solved before the constructors started designing new structures. Many Soviet airports and airports in other Comecon countries had airports with small stations. About low bandwidth. In the West, these problems were solved by building larger, more modern terminals. In the East, this was impossible due to the modest budgets. It was necessary to increase the capacity of stations without their special expansion. Luggage was the main problem. It was impossible to allow 400 people to check in their luggage for freight. Ideally, the passenger should have a suitcase with him at all times, just like on a train. It was described that the passenger arrives at the airport 5 minutes before departure. He buys a ticket. He gets on the plane. He puts his suitcase next to it and hangs his coat on the hanger. The problem, however, is that the passenger next to the seat or above it should have a shelf, and this would significantly increase the space for one person, which is not good in an airplane. Analyzes showed that in such a system, an airplane with a capacity of 400 people should extend the passenger cabin by 4 m, and for an airplane with a capacity of 350 people, by 3 m. The problem was solved for a long time. Ultimately, it was stated that the passenger would leave the suitcase on the lower deck himself. The procedure was called - baggage in the manual system.
After the construction of the first Il-86 aircraft, tests were carried out for boarding passengers in the baggage system in the manual system. It turned out that 350 people left their luggage on the lower deck and took their seats within 20-25 minutes. Partial chaos is brought under control by dividing passengers into three groups: red, yellow, blue, which enter via three gangways, three corridors and three stairs between decks. It's like getting on three different planes.
The seat occupancy time is important in a situation where the plane would fly through transit ports. The constructors estimated that the stay in such a port will not exceed 50 minutes, so it will not be longer than that of much smaller machines. However, this did not work, as discussed below.
If it turns out that the passenger has a larger baggage or several pieces of it, the suitcases are checked in and they will be placed in a container that will be loaded on board the aircraft. The plane was supposed to take 8 standard containers on board. There is also a traditional layout, where all luggage will go to containers. Then the plane will take 16 containers to the lower deck. However, at the port of destination, the traveler has to wait for the suitcases to be unloaded from the containers.
The layout, luggage with you, was supposed to eliminate problems with losing suitcases. It was hoped that the adage would lose its power; breakfast in Paris, dinner in New York, and suitcases in Tokyo. It was also hoped that ground personnel would have less work, so their number could be reduced.
These solutions were also to be associated with the possibility of selling tickets directly on board the aircraft. Then the plane would be a real air bus. However, this solution ended up in fantasy for various reasons.
Similar ideas - hand luggage - were considered in the West. Airbus studied this problem in the 1970s. Lockheed was working on similar solutions. As a result, entertainment lounges were arranged on the lower deck in L-1011 TriStar aircraft belonging to Pacific Southwest Airlines in 1973. Lockheed considered importing its aircraft into the CCCP. However, then the luggage on the lower deck would be arranged by the airport staff, not the passengers themselves, who would carry their suitcases under the plane.
The second serious problem was the low bearing capacity of the runway (RWY), DK and PPS. The directives were – Adapt the aircraft to the existing infrastructure. Therefore, the aircraft had to meet the standards for loading concrete and asphalt concrete surfaces. So it was a multi-leg and multi-wheel chassis. At the same time, the aircraft had to fit within certain dimensions.
Launching the Aerobus program.
When the Kremlin got acquainted with the study works, and at the same time received confirmation from Soviet intelligence about the far advanced work on the future Boeing B-747 aircraft, the CCCP Ministry of Civil Aviation, and in fact Aeroflot, approved the start of work on the Aerobus. It happened in October 1967. At the same time, the first WTT appeared. It must be remembered that the program was implemented in accordance with the only aviation regulations in force at the time, i.e. Soviet military regulations. The size of the aircraft was set at 350 passengers. The range was set at 3,600 km with a freight of 40,000 kg or 5,800 km without a freight. The aircraft had to operate from smaller airfields classified as Class B / C, with DS (RWY), with a length of 2,300 m - 2,600 m. Tu-154 or DC-9.
The requirements were sent to three design offices; Ilyushin (OKB-240), Tupolev and Antonov. On September 8, 1969, Ilyushin's office received an order to continue the work, which received a more detailed WTT on February 22, 1970. The office separated four themes from the program; configuration, powerplant, equipment and avionics, production capacity.
OKB-240.
When work on the Il-86 aircraft began, the head of the Bureau was still Sergei Vladimirovich Ilyushin (Сергей Владимирович Ильюшин), who, despite receiving the third title of Hero of Socialist Labor in 1974, was already a very elderly man. He died in 1977 in Moscow. Thus, the official head of the Bureau was actually Genrikh Novozhilov.
Ilyushin's office began work on the Aerobus aircraft by evaluating the development potential of existing aircraft. A project of an enlarged Il-62 aircraft, designated Il-62-250, was created. The plane was supposed to take on board a maximum of 259 passengers, total freight 30,000 kg. The fuselage was to be extended by 6.80 m. More futuristic ideas were also developed; Il-62 with a double deck and Il-62 with a double hull. There was also a project for a civilian Il-76 aircraft. However, at the end of 1969, work began on a completely new structure in the office, because the projects cited above were not prospective.
From March 1970, the project received the designation Il-86. The constructors were aware that in order to achieve the intended effect, they should first focus on two topics; super wing support systems (slots and flaps) and advanced automation (avionics). The latter could reduce the number of crew members.
In 1971, a passenger aircraft model marked Il-86 was presented. In addition to this, many other details are given; The prototype of the aircraft was supposed to take off in 1975. It was to carry a total of 380 people in three cabins (104 + 132 + 144 people).
Basic T-T Data; Span 48.33 m, length 58.5 m, height 15.70 m, airfoil area 320 square meters, hull diameter 6.08 m, gross weight 188,000 kg, freight weight 40,000 kg, cruising speed 950 km/h 10,000 m, range with a load of 40,000 kg 2,320 km, range with a load of 20,000 kg 3,250 km, drive unit four D-30 K engines with a thrust of 4 x 13,000 kG.
Looking at the model, it is not difficult to notice that it is a continuation of the line of the Il-62 aircraft. The layout remained unchanged. The wings are identical, only with a much larger area. The layout of the drive unit and the tail empennage have been left. The hull was significantly thickened. The chassis was expanded. An integral staircase leading to the lower deck of the aircraft was demonstrated. Since passengers were also to move around the lower deck, its height had to be such that an average-sized person could stand upright there. In a way, this forced the fuselage diameter of 6.08 m and the layout of the seats in the 3-3-3 row. Whether this was really the case, we do not know. However, many experts on the subject claim that the diameter of the fuselage was chosen politically, so that the interior was wider than all commercial machines of the time. This, however, failed, because the Boeing 747 was already bigger.
On March 9, 1972, the Kremlin ordered the continuation of the Il-86 project.
Intelligence activities.
In 1970 or 1971, a delegation from the CCCP Ministry of Civil Aviation visited the Boeing plants in Renton and Everett. The purpose of the three-day visit was to look at the B 747 aircraft, and the official, possible purchase of these machines.
Let us recall that the first half of the 1970s was marked by a détente in US-CCCP relations, the apogee of which was the joint Soyuz-Apollo space flight, and the end of the idyll was the Soviet aggression against Afghanistan. It is not true that the Russians wanted to buy the B 747. This was against their propaganda and the superiority of communism over capitalism. It was another plan of the Russian intelligence to obtain at least the plans of the plane.
In 1971, the next Paris Air Show was held. Here again, representatives of the OKB Iliushin's Office met Genrikh Novozhilov (the chief designer of the office) and Boeing Joe Sutter (the chief of engineers building the B 747). The gentlemen met at dinner and exchanged important information. Apparently, the Russian provided information on titanium technology, and the latter reciprocated with a sketch of the flexible structure of the wing drawn on a napkin.
The Soviet fairy tale of buying large passenger planes must have attracted other big manufacturers as well. On March 11, 1974, a Lockheed delegation arrived in Moscow offering the L-1011 TriStar. The Soviets expressed interest in 30 machines in the TriStar version with L-1011-385-250 and a license to produce them by the end of the century. They planned to build a new factory employing 80,000 people. Negotiations-fiction lasted until mid-1976. The story about the purchase of B 747 or L-1011 aircraft for Aeroflot was spread until 1980.
Much more important for the Soviet side were negotiations with General Electric regarding the purchase of 12 General Electric CF6-50 engines. We wrote about it below.
Powerplant configuration and engines.
The layout with the engines suspended on pylons under the wings is currently (2012) standard. This was not the case in the 50s/60s. In the US, a lot of controversy was caused by the layout of the B-47 bomber. In the CCCP, the configuration of heavy turbojet aircraft was a politically sensitive issue. The rulers in the Kremlin did not like arrangements resembling structures from the West. The constructors widely believed that such an approach to the matter was nonsense. The more so that the CAGI institute clearly indicated that with such a large fuselage, the arrangement of engines suspended under the wings is more advantageous. There was a long exchange of correspondence. But Ilyushin had his way. He proved that he was the creator of this system by developing the Il-22 bomber plane, which was true.
In this way, the Il-86 received engines suspended under the wings. The problem with the engines did not end there. The main problem of the Il-86 project was the lack of a suitable engine. Anyway, the problem is not completely solved.
As early as the 1960s, the US and UK had turbofan engines with a cold to hot ratio of 4-1 and even 5-1. In CCCP, the military continued to rely on single-flow engines, which had the advantage that their cross-section was smaller, so the frontal resistance was smaller, and this gave better acceleration to military machines. There was a big problem with turbofan engines for civil transport. The engines just weren't there.
The Soloviev D-30 engine was delegated for the Il-86 aircraft. The engine's bypass ratio is 2.54 and was equipped with fold-out thrust reversers. But the work on it dragged on. Relevant parameters could not be reached. The engine was used in the Ił-76 aircraft, and in the 80s they were used to power the Polish Ił-62 M and Tu-154 M with the designation D-30 KU with a thrust of 4 x 107.9 kN, 4 x 11 282 daN (4 x 11 500 kg). As we can see, the engine did not have a satisfactory thrust for the colossus Il-86. In addition, the engine is noisy and consumes a lot of fuel.
Lotarev D-18 engines were promising. It was the first Russian engine with a large degree - bypass. But here the Russian constructors encountered huge problems and the work progressed even more slowly. It seemed that the engine would never be fitted to any aircraft. The first launch of a prototype with satisfactory parameters took place only in 1982. The engines were used to drive the An-124 and An-225 transport giants.
The alternative was to buy engines in the free world. But that's another story and a humiliation for a communist country. Negotiations with General Electric regarding the purchase of 12 General Electric CF6-50 engines were important for the Russian side. The CF6 engine is basically a large family of engines used to power wide-body aircraft. Its first launch was in 1971. The engine at the beginning of the 70s was very modern and turned out to be a successful design.
But in 1978, the US Department of Commerce vetoed the export of 12 General Electric CF6-50 engines ordered by the CCCP for the planned long-range Il-86 (Il-86 D). The Department of Commerce's reasoning was logical. If the Russians want to build more than 100 Il-86 machines, they should order a minimum of 400 engines, not 12. Therefore, there is a reasonable suspicion that they want to copy the engines, as they have done more than once; Rolls-Royce Nene - Klimow WK-1, or even entire B-29 aircraft - Tu-4.
The Soviets also sought their luck in the UK, trying in 1976 to buy a few Rolls-Royce RB.211-22 engines. This engine was first launched in 1972. The British, however, did not sell these engines. After a few years, Deputy Minister Dondukov, deputy to Minister Alexander Gromyko, admitted that they intended to copy the engines and launch its production.
Of the turbofan engines, practically the only proven propulsion was the Nikolai Kuznetsov NK-8-4 engine with a thrust of 4 x 102.963 kN (4 x 10,610 kG). Total length 5.288 m, maximum diameter 1.442 m, total weight 2,350 kg. The bypass ratio of the engine was 1.15 - 1. The engine had a cascade thrust reverser. The engine was noisy and used a lot of fuel. The engine was used in the Il-62 and Tu-154 aircraft.
However, there was no other solution. On March 26, 1975, the Kuznetsov NK-8 engine in the NK-86 version with increased thrust was delegated to drive Il-86 aircraft. But work on the engine has been going on since 1973. The engine received an additional compression ratio and the operating temperature was raised. This allowed the thrust to increase to 1 x 127.50 kN, i.e. by 25.00 kN. A thrust of 1 x 150.00 kN would be satisfactory, but it was beyond the capabilities of this design. The first tests on the dynamometer were performed in July 1974. Of course, these engines powered later Il-86 aircraft from December 22, 1976. The engine was certified in April 1979. The production was undertaken by the KMPO plant. Engine life is estimated at 10,000 hours of operation with major overhauls every 4,000 hours.
Equipment and avionics.
Equipment and avionics are another problem that kept the Soviet authorities and designers awake at night. In the 70s, the typical crew of a Soviet machine consisted of 5 pilots, while at that time in the free world the crew consisted of 3 pilots, and since the 80s, 2 pilots. 5 people are; 1st pilot (captain), 2nd pilot, navigator, mechanic and radio operator (radio-operator). Only 3 pilots were provided for the Il-86 aircraft, adjusting their functions to the system in force in the West. The navigator and radio operator (radio operator) were eliminated. A mechanic was left to watch over all the plane's systems, especially the engines and fuel.
The problem was not the number of crew members, but modern systems and devices that would facilitate piloting. The Soviets could use a complete system procurement procedure, as was the case with the DC-3/Li-2 aircraft in 1930. But then the rulers in the Kremlin would downgrade the program and give it reserve status. The second way was to buy or steal individual devices. Soviet intelligence was good at it, and this path was pursued.
Continued in the next chapter.
Written by Karol Placha Hetman