HERMEUS

AJ Piplica and his co-founders, all former aerospace engineers at Generation Orbit and SpaceX, founded Hermeus in Atlanta in 2018 with a bold thesis: hypersonic flight is achievable with existing materials and engineering if you rethink the engine architecture. Their Chimera engine is a turbine-based combined cycle (TBCC) engine that operates as a turbine at low speeds and transitions to a ramjet at hypersonic speeds — all in one unit.

The US Air Force awarded Hermeus contracts to explore hypersonic applications.

Hermeus is building hypersonic aircraft — planes that fly at Mach 5+ (5x the speed of sound, roughly 3,800 mph). The eventual goal: New York to London in 90 minutes instead of 7 hours.

The company started with a defense focus — developing hypersonic drone technology for the US Air Force. Revenue comes from government contracts and R&D funding.

Hermeus has successfully test-fired its Chimera engine, which combines a turbine and ramjet into a single unit.

Chimera Engine (turbine-based combined cycle hypersonic engine), Quarterhorse (unmanned hypersonic testbed), Darkhorse (autonomous hypersonic drone)

Start with defense (hypersonic drones for the Air Force), then transition to commercial hypersonic passenger travel. The military applications fund R&D and prove the technology.

Commercial aviation — flying passengers at Mach 5 — is the long-term vision but is likely a decade or more away. Sam Altman (OpenAI CEO) personally invested, signaling that AI will play a role in managing hypersonic flight systems.

The physics are brutal. Flying at Mach 5 generates extreme heat — the aircraft's skin reaches over 1,000 degrees Fahrenheit.

Materials, cooling systems, and structural integrity at those speeds are engineering problems that decades of government research have not fully solved. Hermeus also needs to prove the Chimera engine can operate reliably over thousands of hours, not just test firings.

Khosla Ventures, Sam Altman (personal), Bling Capital, US Air Force