In a quiet lab, something extraordinary is happening. With a silent laser and nearly 750 pounds of metallic powder, Boom Supersonic is building the heart of a jet engine. It’s not in a factory with forges and foundries, but inside a box roughly the size of a small refrigerator. It’s additive manufacturing.
3D printing is changing the design and testing of jet engines
Additive manufacturing, more commonly known as 3D printing, is changing how Boom designs, builds, and tests Symphony™, the engine that will power Overture, its supersonic airliner.
While the aerospace industry has recently embraced 3D printing, Boom was an early adopter, dating back to the development of XB-1, the company’s supersonic demonstrator aircraft.
Now, with the Symphony engine program underway, Boom is doubling down on this advanced technology, not just for speed and cost savings but also to fundamentally rethink how complex systems are brought to life.
We sat down with Ruslan Pshichenko, who leads Boom’s additive manufacturing efforts, to talk about Symphony, sprint cores, metallics, and the subtle magic of turning powder into power.
Q: How is Boom integrating additive manufacturing into Symphony’s development?
We’re using additive manufacturing to rapidly prototype metallic components in the heart of sprint core, our test article for Symphony. Sprint core includes the most complex and critical part of any jet engine. By isolating this section, we can test Symphony’s thermal and structural behavior at relevant pressures and temperatures, without building the entire engine up front. Additive manufacturing allows us to produce key parts for sprint core faster and more efficiently than traditional methods.
Q: What is a sprint core, exactly?
Sprint core is Symphony’s core section, built as a stand-alone test article. It includes the high-pressure compressor, the combustor, and the high-pressure turbine (essentially the engine’s “hot” section).
By testing just the core, we can gather data on combustion, thermal loads, and rotating machinery without building the whole engine. This staged development approach helps us iterate faster and manage technical risk.
Q: What engine parts are you printing for Symphony?
We’re printing 193 parts in total. All are functional components essential for the sprint core to produce thrust. These include some of the most advanced and heat-stressed parts in the engine:
- High-Pressure Turbine (HPT) Blades: These blades spin at extremely high speeds, extracting energy from the hot gases exiting the combustor to power the forward part of the engine.
- High-Pressure Turbine (HPT) Vanes: These vanes don’t rotate. Instead, they guide airflow onto the turbine blades at the right angle, improving efficiency and preventing damage.
- Turbine Center Frame (TCF) Vanes: These vanes help straighten airflow between turbine stages and contribute to the engine’s structural integrity.
- Blade Outer Air Seals (BOAS): These seals surround the tips of the blades and help maintain pressure by preventing air leakage, which is crucial for engine performance and fuel efficiency.
While these additively-manufactured components won’t fly on the final Symphony engine, they are fully operational and critical to validating the core architecture. On Symphony, these parts will be replaced by ones made from more traditional manufacturing methods.
Q: Is 3D printing new to Boom?
Not at all. We began using additive manufacturing in 2017 while building XB-1. In fact, close to 150 of its non-structural parts were printed using thermoplastics.
Most of XB-1’s 3D-printed components were printed in ULTEM™ 9085 CG, a flame-retardant, high-performance thermoplastic with excellent heat resistance and high strength-to-weight ratio. For these non-critical parts, we partnered early with Stratasys, an industry leader in additive manufacturing, and used three of their FDM (fused deposition modeling) printers: the Stratasys F900, 450mc, and F370, for most of the XB-1 build. (Explore how Boom used 3D printing during XB-1’s development here.)
XB-1 had 21 3D-printed titanium parts, some of which were developed by VELO3D. Titanium is ideal for high-temperature areas, especially near the engines, because it offers superior thermal tolerance in relation to its weight. While other metals offer better thermal tolerance than titanium, they are much heavier. (Read more about XB-1’s titanium parts here.)
That early experience helped us build internal expertise in additive manufacturing, which we’re now scaling up for Symphony.
Q: What printer is Boom using for Symphony?
We’ve selected the EOS M 400-4, a high-performance metal 3D printer known for its reliability and build volume. The M400-4 also features 4 lasers that work simultaneously to speed up production, which differentiates it from other printers. EOS has over 30 years of experience in metal additive manufacturing and is trusted across aerospace, making it the right choice for us.
Its build volume of 400mm x 400mm x 400mm (15.7 x 15.7 x 15.7 inches) allows us to produce more parts per run, which helps reduce machine time and costs.
Q: What makes printing metallics challenging?
A lot, actually. Unlike plastic 3D printing, working with metal powders requires deep process control and iteration. Each step is essential to ensuring the parts can withstand extreme temperatures, pressures, and vibrations inside a jet engine core.
Here are a few of the biggest challenges:
Support Strategies:
When printing, each part must be securely attached to the build plate using support structures. Poor support strategies can cause parts to warp, shift, or even fail mid-build, especially when printing complex shapes like turbine blades and vanes. We often conduct “de-risk” prints to validate our setup before committing to a full production run. Support strategy is a delicate balance between enough support for a part to successfully print, but not too much so that it becomes extremely challenging to remove the support post print.
Depowdering:
Once a print finishes, the parts are encased in unused metal powder. We use specialized equipment (like a Solukon SFM-AT800-S depowdering system) that uses vibration and rotation to remove powder from tight internal channels. This is especially critical for HPT blades, which often feature complex internal cooling passages.
Before and After Depowdering
Post-Processing & Inspection:
After depowdering, parts go through several post-processing steps:
- HIP (Hot Isostatic Pressing): Applies heat and pressure to seal internal voids.
- Heat Treatment: Stabilizes the microstructure which results in increased part strength.
- Dimensional Inspection, X-ray, and CT Scanning confirm that parts meet strict tolerances and are free of defects.
Detooling:
Support structures are made from the same material as the part, usually a superalloy, so removing them is a slow, careful process. Depending on the complexity, it often involves machining, EDM (electrical discharge machining), or manual work.
Q: What metal alloy do you use to print engine parts?
We’re using Haynes® 282®, a gamma-prime strengthened, wrought nickel-based superalloy specifically engineered for high-temperature structural applications in aerospace and industrial gas turbines. Haynes 282 offers excellent creep strength, weldability, and thermal stability at lower temperatures, making it ideal for turbine blades and vanes in sprint core.
Developing superalloys like this is its own field of material science. It involves precise control of chemical composition, microstructure, and heat treatment cycles to balance strength and fatigue life. Once validated, the alloy is scaled up, tested for manufacturability, and certified for use in its intended applications.
Q: How does additive manufacturing help you accelerate Symphony’s timeline?
It comes down to speed, flexibility, and iteration. 3D printing dramatically shortens lead times and enables faster design changes than traditional casting or forging. For a program like Symphony, we can try new ideas, test them, and implement changes far quicker than conventional methods allow.
Additive manufacturing, combined with other in-house AI and digital design tools, allows Boom to shave years off the traditional engine development cycle.
Q: Will any 3D-printed parts fly on Symphony once it enters service?
Eventually, yes, but not yet. The parts we’re printing for sprint core are intended for testing, not flight. However, we’re closely monitoring how the aerospace industry moves toward FAA-certified 3D-printed engine parts.
Q: Are 3D-printed engine parts currently flying on commercial aircraft?
Yes, but they’re mostly limited to non-rotating components. For example:
- GE LEAP Engines include 3D-printed fuel nozzles. Over 100,000 are already in service on Boeing 737 MAX and Airbus A320neo aircraft.
- GE Catalyst Engines contain more than 300 3D-printed parts, including combustors, heat exchangers, and structural frames.
Using 3D-printed rotating parts like HPT blades is still in early development across the industry, primarily due to certification hurdles and fatigue resistance concerns. That’s why sprint core is so valuable: it lets us validate these parts in a real-world engine environment before we move to production.
Q: Does the FAA regulate 3D-printed parts?
The FAA treats additive manufacturing as a special process, similar to welding or casting. There’s no separate category for “3D-printed parts,” but rigorous standards for qualification and inspection exist. One of the key guidance documents is AC 33.15-3, which outlines how Powder Bed Fusion (PBF) parts should be designed, tested, and certified for aircraft engines.
Any flight-critical part, especially rotating components, must undergo extensive material, durability, endurance, and structural validation before it can be approved for use.
Q: Will you use additive manufacturing beyond sprint core?
Absolutely. We’re already exploring 3D printing for various support and cooling systems, such as:
- Rakes for pressure and temperature measurements
- Impingement plates and tubes that help cool the engine internals
Because these parts often have complex geometries and experience less stress than turbine components, they’re perfect candidates for additive manufacturing.
Printing the future, safely
At Boom, additive manufacturing isn’t just a tool. It’s a mindset. It’s about moving fast, testing often, never compromising safety, and refusing to accept that aerospace innovation has to move slowly. As we continue developing Symphony, additive manufacturing will remain a key tool: accelerating iteration, reducing costs, and unlocking new possibilities in engine development.
This is the first in a series of blogs exploring how new and emerging technologies are shaping the future of supersonic flight. Stay tuned for more from the team behind Overture and Symphony.
