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Hermeus

APrivateFounded 2018πŸ‡ΊπŸ‡ΈEl Segundo, California
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CEO

AJ Piplica

Overview

Hermeus is a defense aviation company focused on rapidly designing, building, and flight-testing high-Mach and hypersonic aircraft for national-security missions. Its Quarterhorse program is progressing through a series of unmanned demonstrators to unlock high-speed flight, while the Chimera engine architecture underpins Darkhorse, the reusable hypersonic UAS Hermeus aims to field for defense customers.

Main Products

Quarterhorse

Quarterhorse

In Flight Testing

An iterative program of unmanned, remotely piloted test aircraft designed to unlock high-speed flight one step at a time. Hermeus says the Quarterhorse program spans four aircraft, each purpose-built to validate a specific technical challenge and feed the next build.

Mk 1 flew at Edwards AFB in May 2025. Mk 2.1, roughly F-16-sized and powered by a Pratt & Whitney F100, flew in February 2026 and later received an FAA experimental airworthiness certificate for its ongoing supersonic campaign.

Program Vehicles4
Mk 2.1 EnginePratt & Whitney F100
Current Test ObjectiveSupersonic flight
Successful First Flights2 (Mk 1 and Mk 2.1)
Darkhorse

Darkhorse

In Development

A multi-mission reusable hypersonic uncrewed aerial system (UAS) designed for defense and national security missions including ISR and strike in contested environments. Powered by the Chimera II TBCC engine.

Darkhorse remains the defense product Hermeus is building toward as Quarterhorse expands the validated flight envelope and Chimera II matures around the Pratt & Whitney F100 core.

Target SpeedMach 5 (~3,300 mph)
EngineChimera II TBCC (P&W F100 + ramjet)
Aircraft TypeReusable hypersonic UAS

Halcyon

Conceptual

A planned Mach 5 commercial hypersonic airliner that would carry approximately 20 passengers at 90,000+ feet altitude, cutting transatlantic flight times from 7 hours to 90 minutes. Represents Hermeus's long-term commercial vision.

Still a long-term aspiration rather than a near-term program. Hermeus is currently prioritizing defense aircraft, Quarterhorse flight testing, and propulsion maturation.

Target SpeedMach 5 (~3,300 mph)
Passenger Capacity~20
Range~4,600 miles
Example RouteNYC β†’ London in 90 minutes

What's Next

Quarterhorse Mk 2 supersonic flight campaign

Quarterhorse Mk 2.1 is now in an FAA-cleared flight-test campaign at Spaceport America, with Hermeus explicitly targeting supersonic flight as the next milestone.

2026

Expand to a fleet of three F-16-scale aircraft

Hermeus says the new financing will let it scale to a fleet of three F-16-scale aircraft, accelerate toward Mach 3, and begin customer payload integration rather than iterating one aircraft at a time.

2026-2027

El Segundo prototyping expansion and Atlanta production ramp

The company has said it is growing its prototyping footprint with a new headquarters in El Segundo while the Atlanta facility shifts toward production, a sign that hardware throughput and manufacturability are becoming central execution priorities.

2026

HEAT engine test facility completion

The Hypersonic Engine Assembly and Test facility at Cecil Airport remains an important infrastructure milestone for higher-throughput F100 and Chimera engine testing as Hermeus pushes deeper into the high-Mach regime.

2026-2027

Operations & Revenue

StatusDevelopment Stage

Actively flight-testing Quarterhorse with two successful first flights completed and a supersonic campaign underway for Mk 2.1. Hermeus says it is moving from prototyping toward mission-ready high-Mach platforms, expanding prototyping in El Segundo while shifting the Atlanta site toward production.

Revenue Streams

U.S. Government Contracts

Hermeus' near-term business is centered on U.S. government and national-security work while it matures Quarterhorse, Darkhorse, and its propulsion stack.

Darkhorse Military UAS (future)

Potential future program revenue from Darkhorse, a reusable hypersonic unmanned aircraft for defense and national-security missions. Technology is being de-risked through Quarterhorse and Chimera II development.

Halcyon Commercial Airliner (future)

Long-term passenger-aircraft opportunity built around the same high-speed technology stack. It remains secondary to the company's defense aircraft roadmap.

Key Metrics

Employees

~300

Est. Annual Revenue

Pre-revenue (government contracts only)

Total Capital Raised

>$500M

Post-Money Valuation

$1B

Employees

~300

Quarterhorse First Flights

2

Timeline

2026Quarterhorse Mk 2.1 first flight

The F-16-sized Quarterhorse Mk 2.1 completes its maiden flight at Spaceport America, giving Hermeus its second successful first flight in less than a year and opening a supersonic flight-test campaign.

2026FAA clears Quarterhorse Mk 2.1 flight campaign

The FAA grants Quarterhorse Mk 2.1 a Special Airworthiness Certificate in the experimental category, allowing Hermeus to continue progressively higher-altitude and higher-speed testing toward supersonic flight.

2026$350M Series C and new El Segundo HQ

Hermeus closes a $350M Series C financing that brings total capital raised to over $500M and says it will expand its prototyping footprint with a new headquarters in El Segundo while shifting the Atlanta site toward production.

2025Quarterhorse Mk 1 first flight

The Quarterhorse Mk 1 completes its maiden flight at Edwards Air Force Base, marking Hermeus's first successful flight test.

2022$100M Series B and ABMS selection

Hermeus raises $100M led by Sam Altman with Founders Fund and In-Q-Tel. The company is selected for the USAF Advanced Battle Management System (ABMS) contract with a $950M ceiling.

2022Chimera turbojet-to-ramjet transition achieved

The Chimera turboramjet engine successfully transitions from turbojet to ramjet mode during testing at the Notre Dame Turbomachinery Lab, a critical milestone for Mach 5 propulsion.

2021NASA Space Act Agreement

Hermeus signs a Space Act Agreement with NASA for collaborative research on high-speed aircraft technologies.

2021$60M USAF Quarterhorse contract

The U.S. Air Force awards Hermeus a $60M contract to build and fly three Quarterhorse prototype aircraft and develop reusable hypersonic propulsion technology.

2020Chimera engine prototype demonstrated

Hermeus demonstrates a subscale Chimera engine prototype, validating the turbojet-to-ramjet transition concept that is core to its Mach 5 propulsion strategy.

2020First USAF contract

The U.S. Air Force awards Hermeus a $1.5M SBIR Phase II contract to study a Mach 5 aircraft concept for Presidential and Executive Airlift.

2018Founded

AJ Piplica, Glenn Case, Mike Smayda, and Skyler Shuford found Hermeus in Atlanta, Georgia, with the mission of radically accelerating air travel through hypersonic flight.

Funding

RoundDateAmountInvestorsSource
Seed2019UndisclosedKhosla Ventures
Series A2020$16MCanaan Partners, Khosla Ventures, Bling Capital
Series B2022$100MSam Altman, Founders Fund, In-Q-Tel, Khosla Ventures, Canaan Partners
Series C2026$350MKhosla Ventures-led; continued backing from Canaan Partners, Founders Fund, RTX Ventures, Bling Capital, and In-Q-Tel, plus new investors including Cox Enterprises/Socium Ventures and Destiny Tech100; financing also includes debt capital from Silicon Valley Bank, Pinegrove Venture Partners, Hercules Capital, and Trinity Capital
USAF Contract2021$60MU.S. Air Force