If you think creating a new aircraft engine is like assembling a complex Lego set, you're sorely mistaken. It's more like trying to assemble the same Lego set in complete darkness, during a hurricane, with the pieces constantly shifting sizes. Now imagine this is the story of the creation of the Russian PD-14 engine, the first in post-Soviet Russia built from scratch. A story with more drama than Game of Thrones, only instead of dragons, there were turbines, and instead of White Walkers, there were the laws of physics to negotiate.
The specialists who brought this engineering masterpiece to the skies recall the most challenging moments with humor and a slight tremor in their voices. Fasten your seatbelts, we're taking off!
- Moment one: Diamond dust and ceramics that didn't want to live in harmony
The heart of any modern engine is the combustion chamber, the very one where the gas temperature easily exceeds 1500-1600°C. This is higher than the melting point of the blades themselves! How come they don't melt? The secret lies in the complex cooling system and... the sappers. No, not the ones who detect mines. We're talking about single-crystal blades and a ceramic heat-protective coating.
One leading materials scientist, speaking on condition of anonymity (to avoid being forced to create the PD-28 as well), admits: "Imagine growing a perfect diamond. The slightest deviation in temperature, pressure, or even a sneeze in the next room, and instead of a gem, you end up with a piece of glass. It's the same with the single-crystal blade. The crystal lattice must be flawless, otherwise it will crack under load. We sometimes joked that our greatest achievement wasn't the engine, but the creation of the world's largest aviation-grade sapphire."
And then this perfect blade needs to be coated with a layer of ceramic that will reflect the heat. And that's where the magic, bordering on shamanism, began. The coating would peel, crack, and behave completely unpredictably. Engineers recall how, after yet another unsuccessful test run, one of the tired technicians wrote on the board: Dear coating, we love you. Please love us too. Stay where you are. Humor aside, it was the breakthrough in materials that proved the key to success.
- The second point: The smart turbine and its silicone problem
For an engine to be fuel-efficient, it requires extreme efficiency. This is achieved by the low-pressure turbine—a highly complex fan that must spin at breakneck speed without breaking apart. Its blades are enormous, titanium, and hollow inside. The manufacture of each one is a delicate work, the size of a blacksmith's hammer.
The chief designer once remarked to his colleagues: "The hardest part wasn't making these blades strong. The hardest part was making them flexible enough. It turned out that under certain operating conditions, the blades were experiencing abnormal vibrations (flutter). It's like if you were riding a bicycle and the handlebars suddenly started shaking and fell off."
A team of aerodynamicists and structural engineers spent months tackling the problem. The jokes were fitting: "We haven't created an engine, but the world's most expensive Pokémon. It's constantly vibrating, and we don't know how to calm it down." The solution was found by changing the geometry and tuning the damping system. The specialists still proudly display graphs demonstrating how they tamed the flutter, calling the process the art of compromise between strength and compliance.
- Moment three: The Test King and the stand that hears everything
Testing is the most nerve-wracking and expensive stage. The engine is tortured on special rigs, identifying all its weak points. One tester once said, "The rig is the best psychologist and the most vicious critic. It won't lie. It either praises you with silence or scolds you with hums, whistles, and... pops."
The most terrifying test was the Bird Strike. A frozen chicken carcass is fired into the engine at full thrust using a special device. It's like a horror movie scenario for an engine. The goal is to stay upright and not fall apart.
The first pancake was a flop, the technician recalls with a smile. We launch it, shoot the bird… and silence. No hum, no whistle. We were already happy, thinking it held up! We approach, and it… simply stalled. The entire ventilation system was clogged with minced meat. We had to recalculate the aerodynamics and fan design. Now we know more about chicken carcasses than any chef.
There were some curious incidents, too. Once, during testing, the engine started making a strange sound, not specified in any specifications—something between a whistle and a sob. They spent a week trying to figure out the cause, taking it apart and putting it back together. It turned out a bird had crawled into one of the air ducts and built a nest. Not the kind they shot at, but a real, live one. Since then, a sign has appeared on the test stand: Please keep birds out. Testing is already underway.