What LiquidPiston does

LiquidPiston, founded in 2003 and headquartered in Bloomfield, Connecticut, develops compact rotary internal combustion engines built on its patented High Efficiency Hybrid Cycle (HEHC) thermodynamic cycle. The company's X Engine is a non-Wankel rotary architecture featuring a 2-lobed oval rotor in a 3-sided housing with only a few moving parts, and is protected by 83 granted and pending patents worldwide. The product family spans the 70cc X-Mini spark-ignited engine (3-5 HP, 4-pound core), the 750cc X-Engine Diesel/X4 (40-70 HP, compression-ignition on diesel or JP-8), the 210cc XTS-210 supercharged two-stroke (25 HP), the LPI 10kW Genset (75% lighter and smaller than currently-fielded AMMPS generators), and the HEXEC hybrid-electric power system for eVTOL and UAS propulsion. The company claims up to 5x power density and 30% efficiency improvement over conventional engines, with multi-fuel capability including diesel, Jet A, JP-8, kerosene, gasoline, propane, and hydrogen.

The company's business model is anchored on U.S. defense R&D contracts, which total $65M cumulatively across the Army, Air Force, DARPA, and DEVCOM Army Research Laboratory. Forward monetization is expected to flow from technology licensing to engine manufacturers and systems integrators, custom engineering consulting, and direct sales of integrated power systems. Revenue diversification into industrial, commercial, marine, UAV, urban mobility, and automotive markets is planned but remains pre-commercial. The company has raised over $50M from investors across multiple rounds, including a $30M Reg A+ crowdfunding round in October 2023 and a $30K-$5M Reg CF round in April 2026.

Operationally, LiquidPiston employs 11-50 people and operates from a 20,000 sq ft facility (expanded from 12,000 sq ft in March 2023 with an adjacent 4,000 sq ft machining center) equipped with two dynamometer/test cells, instrumentation, and CNC machining. Leadership includes co-founders Dr. Alexander Shkolnik (CEO) and Dr. Nikolay Shkolnik, with Vincenzo Perrone joining as VP of Engineering in October 2025 and former GE CTO Mark Little joining the Board in June 2026 to support the transition from R&D to commercialization.

Name

LiquidPiston

Legal name

LiquidPiston, Incorporated

Website

https://liquidpiston.com

Company type

Private

Founded year

2003

Operating status

Operating

Headcount range

11–50 employees

Short description

LiquidPiston develops patented non-Wankel rotary combustion engines using its HEHC thermodynamic cycle, targeting U.S. defense and aerospace customers with compact, multi-fuel power systems ranging from 3 HP to 25 HP and a 10kW man-portable genset.

Ownership category

akta.pro rank

Product category

Rotary Engine Technology and Mobile Power Generation

NAICS

Engine, Turbine, and Power Transmission Equipment Manufacturing (3336), Other Engine Equipment Manufacturing (333618)

SIC

Engines & Turbines (3510), Aircraft Engines & Engine Parts (3724)

akta.pro primary industry

Internal Combustion Engine (ICE) Manufacturing (Gasoline/Diesel) (IMACAHAA)

akta.pro secondary industries

Engine Modules & Hot-Section Components (Compressors/Turbines/Combustors) (IMABADAJ), Diesel Engine Power Plants (Medium/High-Speed Reciprocating) (EUACACAB)

Keywords

• Rotary engine technology
• Hybrid power systems
• Military propulsion systems
• Thermodynamic cycle engines
• Portable power generation

Headquarters

HQ city

Bloomfield

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Technology or R&D, Personnel, Operations, Supply Chain, Marketing or Sales

Revenue model

1. Government R&D Contracts: LiquidPiston receives substantial government contracts from U.S. military branches (Army, Air Force) and DARPA for engine development programs. These include development contracts for compact rotary engines, hybrid power systems, and power generation solutions.
2. Crowdfunding Equity Raises: The company has raised capital through Regulation CF and Reg A equity offerings. Previously raised over $20M in Reg CF and Reg A equity offerings, including a $30M Reg A+ crowdfunding round in 2023.
3. Technology Licensing: LiquidPiston licenses its technology to partners, including engine developers and manufacturers looking to expand their product lines with compact, lightweight, quiet, low-vibration, powerful, fuel-efficient engines.
4. Engineering Consulting Services: The company offers technical engineering consulting services to custom design and develop application-specific engines for its partners and customers, including engine manufacturers and systems integrators.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels4 records

Core offering

LiquidPiston designs and develops compact, lightweight, high-efficiency rotary internal combustion engines based on its patented High Efficiency Hybrid Cycle (HEHC), ranging from a 70cc X-Mini spark-ignited engine to 40HP diesel X-Engine variants and a 25HP supercharged XTS-210, with a 10kW Genset product for mobile power. The company sells to U.S. military and aerospace customers under direct contracts, licenses its engine technology to OEM partners, and provides engineering consulting for application-specific engine development.

Product overview

LiquidPiston develops a portfolio of compact, powerful, quiet, low-vibration, multi-fuel capable rotary combustion engines scalable from 1HP to over 1000 HP. The core product family includes the X-Mini (70cc spark-ignited multi-fuel engine at 3-5 HP), X-Engine Diesel/X4 (750cc compression-ignition at 40 HP), XTS-210 (210cc supercharged two-stroke at 25 HP), and the LPI 10kW Genset. These products share the patented HEHC (High-Efficiency Hybrid Cycle) thermodynamic cycle and unique non-Wankel rotary 'X' engine architecture. The company focuses on military and aerospace markets while targeting industrial, commercial, marine, UAV, urban mobility, and automotive applications. All engines offer multi-fuel capability including heavy fuels (Diesel, Jet A, JP-8) and are optimized for hybrid-electric integration.

Differentiator

Problem solved

Functional benefit

Brands

• X Engine: LiquidPiston's core rotary engine platform that embodies the HEHC thermodynamic cycle, available in diesel and spark-ignited variants ranging from 3HP to 40HP.
• HEHC (High Efficiency Hybrid Cycle)
• XTS-210 Engine
• X-Mini
• X-Engine Diesel

Products and services

• X-Mini Spark-Ignited Multi-Fuel Engine A 70cc spark-ignited, multi-fuel rotary four-stroke engine prototype weighing approximately 4 pounds and producing 3.5 HP (net indicated) at 10,000 RPM, expected to reach 5 HP at up to 15,000 RPM at maturity. Features the patented HEHC thermodynamic cycle with only two primary moving parts (rotor and eccentric shaft), and is intended for small engine applications including UAVs, portable generators, hand-held power equipment, and other light-mobility use cases for development partners and systems integrators.
• X-Engine Diesel (X4) A compression-ignition rotary diesel engine family (X1, X2, X4) in 750cc/40HP configurations that demonstrates compression ignition of diesel or JP-8 heavy fuel, achieving net indicated efficiency of 33% at light-load with a water-cooled engine block for extended operation. Targeted at military power generation, heavy-fuel propulsion, and defense applications where multi-fuel operation and SWaP efficiency are critical, with engines in development for delivery to U.S. Army, Air Force, and DARPA programs.
• XTS-210 Engine A 25 horsepower, two-stroke, supercharged, liquid-cooled 210cc X-Engine variant that reduces size and weight by nearly 80% versus diesel engines with comparable power output. Heavy-fuel compatible (Diesel, Jet A, JP-8, kerosene) and multi-fuel capable, with a target brake specific fuel consumption under 350 g/kWh at maturity and 5x greater power density and specific power versus piston diesel engines. Optimized for hybrid-electric applications and mobile power generation.
• LPI 10kW Genset A 10 kilowatt generator set integrating the XTS-210 X-Engine into a man-portable package that is approximately 75% lighter and smaller than currently-fielded AMMPS generators and occupies about 9 cubic feet. Designed for military and commercial mobile power generation applications, including battlefield power, mobile command post auxiliary power, and forward operating base power. LiquidPiston began testing a 10kW generator prototype under the U.S. Army program.
• HEXE (Hybrid Electric X Engine) Power System A hybrid-electric power system combining LiquidPiston's rotary X Engine with electric propulsion, demonstrated for eVTOL and unmanned aerial system propulsion applications, offering up to 60% longer flight duration versus battery-only solutions and supporting quiet operating modes. The hybrid system has been successfully demonstrated running on hydrogen, validating zero-emission capability, and is the subject of a $35M U.S. Air Force contract for eVTOL and UAS propulsion development.
• Engineering Consulting and Custom Engine Development Services Technical engineering consulting services offered by LiquidPiston to custom design and develop application-specific engines for partners and customers, including engine manufacturers and systems integrators. These services pair with technology licensing arrangements to enable partners to integrate HEHC-based X Engine technology into their own product lines across industrial, commercial, marine, UAV, urban mobility, and automotive applications.

Quantifiable outcome

• 5x greater power density vs. piston diesel engines
• +6 more outcomes

Named customers5 records

Segments4 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Three partnerships are on record, tiered core and minor.

• Contact CorporationcoreOEM/ Whitelabel/ Licensing Partner · 10 October 2025Contact Corporation announced a lightweight telescopic mast trailer system with on-board power at AUSA, featuring twin 10kW liquid-fueled generators from LiquidPiston for enhanced military communications for the U.S. Department of War.
• Pinnacle EnginesminorStrategic or Co-development Partner · 27 March 2023LiquidPiston acquired physical assets and software licenses from Pinnacle Engines, a venture capital-backed engine development company based in California. Acquired items included engine dynamometer, testing equipment, tools, and software licenses.
• KoreConXminorOthersPartnership with KoreConX for investor management platform, enabling investors to access information, manage shares, and receive updates from LiquidPiston.

Scale indicators14 records

Recent moves7 records

Expansion highlights6 records

Direct peers

• Aixro: Aixro develops Wankel-type rotary engines specifically for UAVs and aerospace applications — the most direct technology and end-market peer to LiquidPiston's rotary X-Engine platform for unmanned aircraft propulsion.
• Orbital Corporation (now part of Danfoss Power Solutions): Orbital developed the O-200 and related rotary UAV engines before being acquired by Danfoss; directly comparable to LiquidPiston as a specialist rotary/UAV engine developer serving defense and aerospace customers.
• Pinnacle Engines: Venture-backed rotary/engine developer whose physical assets and software licenses LiquidPiston acquired in March 2023 — historically a direct peer in advanced engine development for similar applications.

Broad incumbents

• Honda: Honda has decades of Wankel rotary engine experience (e.g., RE92, NSU-derived heritage) and broad engine manufacturing; represents the legacy rotary-engine incumbent that LiquidPiston's non-Wankel architecture is positioned against.
• Mazda: Mazda is the most prominent Wankel/rotary-engine OEM (RX-7, RX-8, rotary range-extender prototypes) and a broad incumbent in rotary-engine commercialization that LiquidPiston must differentiate against.
• Cummins: Cummins is a leading diesel-engine and power-generation incumbent supplying military generators (e.g., AMMPS — the product LiquidPiston competes against); a broad incumbent with overlapping genset and defense-power offerings.
• Pratt & Whitney: Pratt & Whitney manufactures aircraft engines and propulsion systems for defense and aerospace — a broad incumbent whose small-engine and hybrid-propulsion efforts intersect with LiquidPiston's aerospace targets.
• Rolls-Royce: Rolls-Royce designs and manufactures aerospace engines and power systems, including hybrid-electric propulsion initiatives — relevant broad incumbent competing for similar defense and advanced-air-mobility programs.
• Honeywell Aerospace: Honeywell develops turbogenerators, APUs, and propulsion technologies for defense and aerospace — overlapping with LiquidPiston's auxiliary power and hybrid propulsion applications in the same customer set.

Emerging players

• AVID Aerospace: AVID Aerospace is an emerging player developing hybrid-electric propulsion and power systems for UAS and eVTOL — a partial-overlap emerging competitor targeting the same defense/UAV power-density niche as LiquidPiston.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• YouTubeyoutube.com/results?search_query=liquidpiston
• Facebookfacebook.com/liquidpiston
• LinkedInlinkedin.com/company/liquidpiston
• Instagraminstagram.com/liquidpiston
• Xx.com/LiquidPiston

Revenue estimate

Valuation estimate

Number of profiles

Profiles5 records

Funding overview

Funding rounds14 records

Investors2 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about LiquidPiston