Russia Pursues Development Of New Military Transport Aircraft
While inspecting the renovation of an Antonov An-124-100 super-heavy transport aircraft with Military Transport Aviation Commander Lt. Gen. Vladimir Benediktov and United Aircraft Corp. (UAC) head Yuri Slyusar, Shoigu asked whether the Soviet-era 50,000-lb.-thrust-class Progress D-18T turbofan used on the four-engine aircraft will power the “hundred” aircraft. Two variants are being considered, Benediktov replied: a modernized D-18T and a new engine.
A new auxiliary transport—the Ilyushin Il-212 with a payload of 17 tons—is being considered
The Il-76MD-90A will remain the basic Russian military aircraft workhorse for the coming decades
What this “hundred” is became clearer on Nov. 4, when Ulyanovsk Oblast Gov. Aleksey Russkikh said on Russian military-affiliated Zvezda TV that the Aviastar plant will produce new Ilyushin Il-100s designed to carry 100 metric tons of cargo. “We are starting to construct a new production hall for it,” he said. The Ulyanovsk plant currently produces the 60-metric-ton-capable Il-76MD-90A and refurbishes and modernizes An-124-100s.
In May 2022, UAC-Ilyushin employees filed a patent in Russia for the design of a “super-heavy military transport aircraft,” with the Russian defense ministry as the owner, indicating that it is the result of work ordered and paid for by the government. There is no proof that the patent shows the Il-100, but it is very likely that aircraft; its authors confirm it as an Ilyushin design.
The configuration is typical of heavy transport aircraft: a four-engine, high-wing monoplane with a T-tail. The hold is accessed via an upward-hinging fuselage nose and a standard rear-door ramp. The main landing gear consists of two eight-wheel bogies, and the front gear has four wheels side by side.
Before the launch of the current Il-100 project, there were many proposals in Russia for a new super-heavy military transport aircraft, starting with the Il-106 project (with which the Il-100 has much in common) developed in 1987-92 as an equivalent to the Boeing C-17. Later concepts included resuming production of the improved An-124-100, as well as the massive Slon (Elephant) concept of an enlarged An-124-100 with a cargo capacity of 180 metric tons.
The choice of engines for the Il-100 is a bit confusing. During the conversation in Ulyanovsk, in a video released by the defense ministry, Benediktov talked about modernized D-18T engines or “new PD engines,” and Yuri Slyusar added the numerical designations: “24, 26.” However, the press release from UAC reads differently, describing “either a modernized D-18T or PD-35.”
In the Russian system, the numerical suffix in an engine designation refers to the thrust class in metric tons. A PD-35, for example, refers to an engine with about 35 metric tons (77,000 lb.) of thrust, similar to a Rolls-Royce Trent 1000 or General Electric GEnx-1B.
Despite appearances, there is no great contradiction here. The name PD-35 also refers to a new family of giant turbofan engines for transport and passenger aircraft; “PD” comes from Prospektivny Dvigatel, or “future engine.” The base PD-35 variant is expected to have a takeoff thrust of 35 metric tons and will be the first Russian aircraft engine of its size.
Using the gas generator of the PD-35, the Russians intend to make smaller engines. The PD-24 and PD-28 were mentioned in previous presentations. Alexander Inozemtsev, general designer of PD-35 manufacturer UEC-Aviadvigatel, says that upscaling the gas generator by 15% could enable a thrust of 50 metric tons, if required.
A Moscow Aviation Institute scientific paper from 2017 considers a twin-engine transport aircraft with a payload of 100 metric tons. According to the paper, a twin-engine aircraft would require engines with 42 metric tons of thrust. Such an engine could be a hypothetical PD-42, a further development of the PD-35, but the implementation of such a variant is much less likely.
Initially, the PD-35 engine was intended for the Chinese-Russian Comac-UAC CR929 widebody airliner, and the 35-metric-ton version was planned as the first one. Then Russia invaded Ukraine in 2022, prompting Western sanctions. Due to the impact of the sanctions, UAC dropped out of the CR929 program in August 2023. Therefore, the lower-thrust engine—one of the PD-24s or PD-26s mentioned by Slyusar—will likely be the first modification created.
By 2022, the PD-35 was high among Russia’s priorities. In December 2021, Prime Minister Mikhail Mishustin announced the allocation of an additional 44.6 billion rubles ($494.5 million at today’s exchange rate) for the PD-35 program, with total investment in the project of 224 billion rubles. The United Engine Corp. (UEC) announced that the first tests of the PD-35 engine core took place in October 2023 and promised tests of the demonstrator of the entire engine would start in early 2024.
However, the sanctions also cut off Russian airlines from purchases and support for Airbus and Boeing airliners. To compensate, the Russian government has ordered industry to produce 270 Irkut MC-21, 142 Sukhoi Superjet and 115 Tupolev Tu-214 airliners by 2030. For Russia, these are very large numbers. In November 2023, Inozemtsev said previous plans to make PD-35s by 2027-28 are slipping by a couple of years, as funds have been redistributed to increase production of the PD-8, PD-14 and PS-90A engines needed for the aircraft.
Another engine option for the Il-100 mentioned by Benediktov—a modernized D-18T—also is not easy. The D-18T was created in the early 1980s specifically for the An-124-100 by Ivchenko Progress and was produced by the Motor Sich plant, both located in Zaporizhzhia, Ukraine. It was the only plant that repaired these engines. After Russia annexed Crimea in 2014, Kyiv banned the supply of military equipment to Russia. However, Motor Sich—whose owner was Vyacheslav Boguslayev, a Russophile—continued to overhaul engines for Russian An-124-100s for several years through intermediaries.
Finally in 2016, the Ural Civil Aviation Plant (UZGA) in Yekaterinburg, Russia, began D-18T overhauls. Now UEC says it has started production of many components of the D-18T and is able to do so with the modernized engine in Russia as well.
During his visit to Ulyanovsk, Shoigu announced that the number of operational 120-metric-ton-payload An-124-100s in the Russian Aerospace Forces will be doubled by 2025. The service officially has 26 of this type, but only about a dozen are operational; the rest have been standing in the airfields of Seshcha air base and Ulyanovsk for many years, waiting for repairs. Previously, the overhauls were carried out at a rate of one aircraft per year.
Benediktov said in Ulyanovsk that a three-year contract for 60 D-18T engines for the An-124-100 is underway, undoubtedly referring to engine repairs for the nonoperational aircraft. Sixty engines means the return to service of 15 aircraft, roughly doubling the number in service by 2025.
The reason for such a radical ramp-up of An-124-100 overhauls is, of course, the war in Ukraine, during which demand for transport aviation has increased drastically. Look to data from a Russian Air Force Il-76MD airlifter that crashed during takeoff from Gissar air base near Dushanbe, Tajikistan, on Oct. 19. The accident documentation states that during its first 40 years of operation, until 2021, the aircraft performed 3,173 cycles, or 6-7 flights per month. Meanwhile, between a repair in May 2021 and the crash in October, it performed 1,058 cycles, or about 35 per month—five times more than before the invasion.
Meanwhile, the light auxiliary transport category also has seen a complete change of plans. The troubled Il-112V turboprop project—intended to have a maximum payload of 6 metric tons—had been developed for years but was abandoned after the fatal crash of the prototype. Its structural weight turned out to be much heavier than assumed, while the Klimov TV7-117ST turboprops—the most powerful turboprops available in Russia—turned out to be too weak. After the first flight on March 30, 2019, the aircraft was returned for two years to the production hall to be reworked. On Aug. 17, 2021, the only flying Il-112V’s engine caught fire, causing the aircraft to crash, killing the crew of three.
Now the Il-212 is to be built instead. According to a well-informed source in the Russian aviation industry, there is no defense ministry contract for this aircraft yet, but it is being seriously considered. During the visit to Ulyanovsk, Shoigu described a light transport aircraft “that should replace the An-72 and An-26,” undoubtedly referring to the Il-212 project. “We have found a solution,” he said. “Now we need to set deadlines for how quickly we can implement this solution.”
Russian officials say the Il-212 will be a deep modification of the Il-112. At the same time, a source at UAC reports that the Il-212 is to be powered by two PD-8 turbofans, with a maximum payload of 17 metric tons. It is difficult to reconcile these two assertions.
The UEC-Saturn PD-8 engine, with a thrust of 8 metric tons, is a new Russian project to replace two imported engines: the French-Russian PowerJet SaM146 engine for the Sukhoi SSJ-New (Superjet) regional passenger aircraft and the Ukrainian Progress D-436TP engine for the Beriev Be-200 amphibious aircraft.
Until recently, Ilyushin led the project to develop an Il-276 medium transport aircraft with a 20-metric-ton cargo capacity, called “half of the Il-76” because it had two PS-90A engines rather than four and a cargo hold of half the length. The same project was previously called the Il-214, or Medium Transport Aircraft, in the version planned jointly with India. Since the launch of the Il-212 project, the Il-276 has lost its raison d’etre.
In the middle, between the Il-212 at 17 metric tons of cargo and the Il-100 at 100 metric tons, will remain the Il-76; there will be no new project in this class. The decision for the Il-76 to remain the primary military transport aircraft in Russia for decades to come was made on Dec. 20, 2006, when Moscow adopted a resolution to start producing it in Ulyanovsk. This was not a resumption of production, however, but meant starting almost completely from scratch, because the Soviet-era Il-76s were produced at a plant in Tashkent, Uzbekistan.
The new Russian version is designated the Il-76MD-90A; the “-90A” comes from the PS-90A engine. In addition to the engines, the wing and most of the equipment are new as well.
The decisive factor in the launch of Il-76 production was the relatively low price of the entire program, including the infrastructure prepared over decades for the airlifter in the form of repair bases, training facilities and personnel. As a “force multiplier,” the new Il-76 platform will be used for tanker, airborne command post and other special aircraft derivatives, the lack of which is bothersome for Russia.
Production of the Il-76MD-90A in Russia is ramping up slowly. By December 2023, the Ulyanovsk plant had delivered 18 new aircraft to the military. A flow production line was launched in 2021, which is expected to accelerate the production rate to 18 aircraft per year in 2025.
The Il-76MD-90A, with a lifting capacity of 60 metric tons, meets the basic needs of the Russian Air Force, but it has one drawback: a narrow cargo hold that is only 3.4 m (11.2 ft.) wide. It still fits the equipment of the Russian Airborne Forces—whose new equipment has been designed for years with the Il-76’s capabilities in mind—but poses problems for other services. According to Russian media, about 35% of the current equipment of a mechanized division does not fit into the Il-76. All large military transport aircraft in the world created after the Il-76 have much wider cargo decks. The future Il-100, for example, will have a cargo hold approximately 5.8 m wide.