In the waning days of last year, tests of the PD-14, a Russian state-of-the-art aircraft engine, began aboard the Il-76LL flying laboratory. Specialists deemed the tests an "exceptionally important event". What makes this engine unique and why is it referred to as one of the most important Russian project in civil aviation in the last 30 years? Seven facts about the PD-14 shed light on this issue.
The PD-14 is a fifth-generation engine that combines the best traditions of the Russian aviation industry with the aviation standards of the 21st century. A turbojet engine is a sophisticated device requiring complex design solutions. For example, a single turbine blade (each cascade has about 70 blades) rotates at 12,000 rpm and is subject to a centrifugal force of 18 tons. To put this into perspective: the suspension of a London double-decker bus is subjected to the same force.
1. The first aircraft engine developed in Russia after the collapse of the USSR
The PD-14 project is a new page in the history of turbofan double-flow engines and represents a new Russian engineering design in the area of civil engine engineering in the last 29 years: the first flight of Il-76LL to test the PS-90A took place on December 26, 1986.
The PD-14 was created on the basis of a specially designed unique gas generator which combines three elements: a high performance compressor, a turbine, and a low emission combustion chamber. The unitized gas generator for the PD-14 makes it possible to create engines with thrust of 8 to 18 tons.
2. Baseline design for the engine family
The PD-14-based engine family will allow virtually all Russian airplanes to be equipped with modern power units: from the PD-7 for the short-haul Sukhoi Superjet 100 to the PD-18 which can be installed on the long haul Il-96. There are plans to develop a PD-10V helicopter engine based on the PD-14's gas generator in order to replace the D-136 engine on the world's largest helicopter, the Mi-26. The same engine can also be used on a Russian-Chinese heavy duty helicopter currently in development. Gas compressors and gas turbine power plants with a 8-16 megawatt capacity can be designed based on the PD-14.
3. 16 new technologies have been developed for the PD-14
The Central Institute of Aviation Motor Development (CIAM), Russia's leading research institute in the industry, and Aviadvigatel played a key part in the development of 16 critical technologies for the PD-14, including: monocrystal high-pressure turbine blades with an advanced cooling system operating at a gas temperature up to 2000°К; hollow wide chord titanium alloy fan blades, which made it possible to increase the efficiency of the fan cascade by 5% compared to the PS-90; a low-emission combustion chamber made of an intermetallic compound alloy; sound-absorbing structures from composite materials; ceramic coating on hot section parts; hollow blades for the low pressure turbine, and more.
4. 20 new materials were developed for the project
20 new materials were developed for the PD-14 in collaboration with the All-Russian Scientific Research Institute of Aviation Materials (VIAM). The use of composite materials, nacelles and wide hollow chord titanium fan blades considerably decreased the weight of the engine. The PD-14 offers some undeniable advantages: a 10-15% reduction of specific fuel consumption, a 15-20% reduction in the cost of the life cycle; a 14-17% reduction in the cost of engine operation compared to existing engines.
However, creating new materials is only half the battle: to use them in civil aircraft engines, they must be certified according to international standards. If not, the engine would only be allowed for use exclusively within Russia, no matter how good the engine may be. The rules here are very stringent since they concern people's safety. The same goes for engine production: the companies operating in this sector require certification according to the European Aeronautical Safety Agency's (EASA) standards. All together, this calls for an improvement in production standards. The development of the PD-14 was performed using new digital technology, which has allowed a seventh engine to be made using mass production technology, while previous pilot batches included up to 35 engines. All in all, the PD-14 project will keep over 10,000 highly qualified jobs in Russia.
5. Eco-friendly and quiet aircraft engine
Optimizing thermal cycle parameters, using a low-emission combustion chamber, and the engine's low specific fuel consumption made it possible to minimize hazardous emissions from the PD-14. The emission value obtained is 30-45% lower than set standards.
The PD-14 is a quiet engine. The engine's noise level was significantly lowered thanks to the simulation of units using a 3D-wind tunnel, increasing the bypass ratio to transition to a low-frequency range and using efficient last generation sound-attenuating systems. Noise values meet the International Civil Aviation Organization's standards with flying colors.
6. The first Russian 5th generation engine
Progress in aircraft engine production is characterized by several parameters, the main being the turbine inlet temperature. The transition to each new generation of turbojet engines (there are five generations altogether) is characterized by the increase of this temperature by 100 to 200 degrees.
To point, the temperature of 1st generation engines developed in late 1940s did not exceed 877°C. This temperature increased to 977°С in 2nd generation engines from the 1950s. 3rd generation engines (developed in the 1960s) reached 1176°C. 4th generation engines (made in the 1970-1980s) reached 1376°С. Turbine blades in the 5th generation engines, first produced in the West in the mid-1990s, operate at 1626°С. Currently, only 15% of engines in the world are 5th generation.
7. The technology behind PD-14 is a state secret
In addition to Russian companies, only companies in the USA, Great Britain and France possess the complete production cycle technology for producing turbojet engines. In other words, there are fewer countries that produce modern aircraft turbojet engines than there are that possess nuclear weapons or launch spacecrafts. For example, China's years-long efforts in this field have still not borne fruit. While the Chinese managed to quickly copy the Russian Su-27 fighter aircraft, they have not been able to copy its engine, the AL-31F. China still has to buy this already dated engine from Russia. For this reason, aircraft engine development technology is protected as top secret.