Heavy aircraft engines have long been a separate race of technologies. They determine the fuel efficiency of long-haul aircraft, noise levels, service life, and operating costs.
The American GE9X is currently considered the most technologically advanced engine in its class, while the Russian PD-35 is an attempt to restore Russia's own school of heavy civil engine building. "Pervy Tekhnichesky" compared the two power plants and identified the winner.
Thrust and Engine Class
The GE9X for the Boeing 777X develops thrust up to 47,000 kgf, making it the most powerful civil aircraft engine in the world.
The PD-35 is designed in the class of about 35,000 kgf – for Russian wide-body aircraft and prospective transport platforms.
But high thrust alone does not automatically mean "victory." The GE9X was created for the significantly heavier Boeing 777X, while the PD-35 belongs to a different weight segment. Here, it is more correct to speak not of superiority, but of different tasks and design philosophies, so we call it a draw.
Technologies and Materials
The GE9X features a composite fan with a diameter of 3.4 m, ceramic matrix composites in the hot section, and a bypass ratio of about 10:1. It is one of the most complex engines ever built for civil aviation.
The PD-35 uses PD-14 family technologies – single-crystal turbine blades, modern heat-resistant alloys, a digital control system, and wide-chord titanium fan blades.
However, in terms of the depth of implementation of composites and ceramic materials, the American school still maintains an advantage, we give a point to the GE9X.
Efficiency
The main trump card of the GE9X is its record fuel efficiency. Due to its enormous bypass ratio (10:1) and ultra-high pressure in the compressor, its specific fuel consumption at cruise mode is about 0.49–0.52 kg/kgf·h (approximately 10% more efficient than its predecessor GE90-115B).
For the PD-35, a cruising specific fuel consumption of 0.51–0.53 kg/kgf·h is declared. This is a huge step forward for our aviation: the indicator will be approximately 10–15% lower than that of PS-90A family engines (about 0.595 kg/kgf·h), and on par with the best Western counterparts like the GEnx.
But for now, the characteristics of the PD-35 remain theoretical, as there has been no serial operation yet. Here, the American engine wins not only with numbers but also with a colossal amount of real accumulated hours on test aircraft.
Program Readiness
The GE9X has already undergone a huge cycle of tests and flies on the Boeing 777X. However, the aircraft itself is still facing protracted certification, so it is too early to talk about full-scale mass operation.
The PD-35 is at an earlier stage. For Russian industry, this is primarily a demonstration of the ability to create engines of this class domestically.
In fact, Russia is returning to the segment of heavy civil engines for the first time in decades, we call it a draw.
Sovereignty and Strategic Importance
The main value of the PD-35 is not an attempt to "overtake America," but technological independence. Only a few countries in the world are capable of creating heavy aircraft engines of this level.
The GE9X is the pinnacle of a mature global engine-building school. The PD-35 is an attempt to re-enter this exclusive club, we give the victory to our engine.
Final score – 2:1 in favor of GE9X.
The American engine remains the leader in materials, readiness level, and confirmed efficiency. But Russia has once again returned to the club of heavy engine creators.
This is a full-fledged modern project that should return Russia's own heavy engine for large aviation.