DM121 Turbofan Engine Model: Metal vs. 3D Printed – Which One’s Right for Model Enthusiasts?

Hello everyone! I am a designer of TECHING.

When I was a kid, I always dreamed of taking apart a jet engine to see how the blades and turbines really moved. As I grew up, I started collecting various aviation models, but every time I looked at the turbofan engine models on the market, something felt off — the plastic felt flimsy, cheap to the touch, the details were rough, and the engines weren’t stable or realistic when running. They simply couldn’t satisfy someone who truly loves aviation and mechanics.

As a designer at TECHING, creating a turbofan model that could actually run has always been my goal. It needed to spin realistically, have high-quality materials and fine details, and still be affordable for regular hobbyists. Over the years, I had already designed a few models (DM119, DM135), which were well-received by fans. But one day, I received a letter from a 30-year-old fan. He loved our DM119, but said the price was intimidating. That made me reflect: could I design a turbofan model that everyone loves and can actually afford? That’s when I decided to make a dream come true for people like me — a running turbofan engine that lets you enjoy the beauty of mechanics while also being a collectible.

And so, the design for the DM121 officially began. After completing the design drawings, I first printed a prototype using a 3D printer. This not only saved a lot of cost but also helped me understand why people were so drawn to 3D-printed models.

I’ve seen plenty of 3D-printed models on the market, like the WS-15 and TR900. They’re similar in size to metal models and can run, too. But when you hold them in your hand, you immediately notice the difference: the feel and level of detail just don’t compare. Most 3D-printed models have 200–300 parts, while metal models often exceed 500. That’s the difference in mechanical depth and detail. And the price? 3D-printed models aren’t cheap either — a similar size can still cost several hundred dollars. If the price is comparable, why settle for a lightweight, visually pleasing plastic model instead of one with superior feel and detail?

Honestly, the first time I ran the 3D-printed DM121, I felt a small sense of accomplishment watching the blades slowly turn. I even painted it myself, trying to make it look more like a real engine. But after a few months, the shortcomings of plastic became obvious — too light, not sharp enough in detail, wobbly at high speeds, and not durable. It could spin, but it lacked that heavy, metallic feel and the sense of weight that makes a model worthy of being a collectible.

After testing the 3D-printed prototype, I moved on to making the metal molds. This is where the real satisfaction as a designer came in:

Full metal components: The metal model uses high-strength aluminum and zinc alloy, giving it a strong metallic shine, a solid cold weight, improved corrosion resistance, and mechanical strength.

More parts, more realistic details: Fan and exhaust casings were refined, a low-pressure compressor stage was added, and the mechanical structure became more precise. The high-pressure turbine was coated in realistic dark red to mimic the engine combustion chamber.

Enhanced operation: A throttle lever and power switch were added to make the running experience closer to a real jet engine.

Improved collectible value: Metal nameplates and industrial design elements make the model more display-worthy and collectible.

Despite how it looks, the production was far from easy. Machining the parts required extreme precision — even a slight deviation could jam the blades or gears. Being all-metal, the model is heavy, making stability at high speeds a real challenge. I also wanted it to have throttle and power controls like a real engine, while reproducing the complex internal structure. Metal surfaces scratch easily, and achieving the right visual effect was another challenge.

To overcome these issues, I repeatedly refined the molds, balanced the blades and bearings, designed a modular assembly, polished and coated key parts, and added the throttle and power controls. After a year of development, the all-metal DM121 ran smoothly, felt heavy and solid in the hand, and had highly detailed, realistic features. This process not only deepened my understanding of engine mechanics but also strengthened my resolve to produce high-quality, yet affordable, turbofan models.

Finally, the all-metal DM121 was complete. At 1/12 scale, it accurately reproduces the internal structure of a turbofan engine, with over 500 parts recreating most of the mechanical details. The built-in motor and rechargeable lithium battery make it spin smoothly with realistic sound. In hand, it has real weight and metallic luster — perfect for both play and display.

Completing this model reinforced my goal: to create more high-quality, detailed, yet affordable turbofan models, so anyone can experience the beauty of mechanics and realistic operation at home. To me, the DM121 metal version isn’t just a model — it’s a mechanical toy you can touch and operate, a collectible worth keeping, and a gift for every aviation and model enthusiast.