The PD-8 was created for the same class of aircraft that the SaM146 previously powered, but simple copying of the French-Russian engine did not satisfy the designers.
Instead, in Rybinsk and Perm, the front part of the prospective power plant was redesigned, scaling up the technological groundwork and philosophy of the much larger flagship PD-14.
1228 mm and 24 blades
The PD-8 is equipped with a fan with a diameter of 1228 mm and 24 wide-chord titanium blades. Behind the fan operate 3 stages of low-pressure compressor and 7 stages of high-pressure compressor. The engine's bypass ratio is 4.4, and the overall pressure ratio is 28.
However, the PD-8 cannot be described as a scaled-down copy of the PD-14 fan. The older engine, with a diameter of 1900 mm, used hollow wide-chord titanium blade technology, which allowed for a reduction in the mass of the large rotating element.
The PD-8 has significantly smaller dimensions, so the blade design is different – they are solid, wide-chord. However, during the development of the Russian engine, the experience gained on the PD-14 in calculating strength, aerodynamics, and blade behavior in various modes was used.
This is a fundamental difference. The PD-8 inherited not literally the blade design of the PD-14, but the technological and computational groundwork of the PD family.
A wide blade is more important than a beautiful profile
A wide-chord blade allows aerodynamic and impact loads to be distributed over a larger blade area. For a fan, this is especially important when a foreign object enters: the load is not concentrated on a small part of the profile, and the structure maintains the necessary rigidity.
At the same time, the developers faced another challenge – not to turn the fan into an overly heavy flywheel. The greater the mass of the rotating assembly, the higher the loads on the shaft, bearings, and supports during acceleration and mode changes.
Therefore, the PD-8 achieved its own balance between diameter, number of blades, their mass, and strength.
And here the numbers clearly show the scale of the design. The fan has a diameter of only 1.228 m, and the entire engine assembly with the nacelle weighs about 2300 kg. The maximum takeoff thrust reaches 8056 kgf.
PD-8 tested not by calculations, but by blade destruction
The most illustrative test took place in December 2025. ODK engineers brought the warmed-up engine to takeoff mode, after which they destroyed one of the fan blades using a pyrotechnic charge.
The objective of the test is extremely specific: a detached blade must not penetrate the engine casing. In real flight, this is necessary to maintain the integrity of the aircraft structure and the possibility of a safe landing.
The PD-8 passed the test: fragments of the destroyed blade did not penetrate the fan casing. ODK specifically names debris containment as one of the main points of the certification basis.
This test much better demonstrates the real capabilities of the design than comparing the appearance of the blades. The engine was deliberately brought to a critical scenario and a rotor element was destroyed at takeoff mode – the casing had to contain it inside.