---
title: "US Army Tests Drone with 3D-Printed Heavy-Fuel Hybrid Engine"
description: "The U.S. Army, through DEVCOM, has demonstrated an experimental UAV featuring a 3D-printed heavy-fuel hybrid rotary engine and a 400-volt electrical subsystem for vertical takeoff and landing."
date: 2026-11-03T08:36:09.605Z
lang: en
url: https://xab.info/en/posts/us-army-tests-drone-3d-hybrid-engine
tags: [us-army, drone, 3d-printing, hybrid-engine, devcom, vtol, military-technology]
author: "Alexander Buran"
publisher: "XAB.info"
---

# US Army Tests Drone with 3D-Printed Heavy-Fuel Hybrid Engine

![U.S. Army experimental drone with hybrid engine during field testing](https://xab.info/media/2026/11/03/armiya-ssha-bespilotnik-3d-dvigatel-gibridnaya-sistemya/armiya-ssha-bespilotnik-3d-dvigatel-gibridnaya-sistemya-1.webp)

## Key Points

- U.S. Army DEVCOM developed a hybrid power plant for UAVs: a heavy-fuel rotary engine + a 400-volt electrical system
- Engine components are 3D-printed; computational fluid dynamics modeling improved heavy-fuel combustion
- The system is designed for vertical takeoff and landing in complex environments, increasing range and payload
- The drone will be transferred to military partners for joint experiments

The U.S. Army Combat Capabilities Development Command (DEVCOM) has announced successful tests of an experimental unmanned aerial vehicle equipped with a power plant manufactured using additive manufacturing technologies. As reported citing an official U.S. Army statement, researchers have developed an advanced heavy-fuel rotary engine as part of a new research program aimed at overcoming key limitations of modern UAVs regarding range, payload capacity, and autonomy.

### Hybrid Architecture: Rotary Engine and 400-Volt System

According to the U.S. Army, the new power plant is a series-hybrid system in which a heavy-fuel rotary engine is integrated with a 400-volt electrical subsystem. This configuration, developers state, is designed to support vertical takeoff and landing (VTOL) operations in challenging environments. The engine-generator included in the unit converts the mechanical energy of the rotary engine into electrical energy, allowing power to be flexibly distributed between traction circuits and onboard consumers.

### Computational Fluid Dynamics and 3D Printing as Key Tools

Program manager Chol-Bum Kweon explained that to solve the challenges of efficient heavy-fuel combustion in the rotary engine, researchers applied advanced computational fluid dynamics modeling. As a result, the fuel spray and vaporization system was improved, and compressed air and fuel vapor leaks were minimized—factors that traditionally reduced the efficiency of such units. Using 3D printing to manufacture power plant components allowed for complex geometric shapes of channels and chambers unattainable with traditional machining methods, directly impacting the engine's aerodynamic performance.

### Program Goals: Autonomy, Altitude, and Payload

«The program addresses critical power and propulsion problems, which should allow drones to fly longer and faster, operate at higher altitudes, carry larger payloads, and perform in extreme environments,» Kweon stated. Transitioning to heavy fuel, unlike light aviation gasolines, expands logistical capabilities: such fuels are easier to store and transport in field conditions, and their energy density is higher. This is especially relevant for tactical UAVs that must operate disconnected from baseline infrastructure.

### Technology Transfer to Military Partners

The U.S. Army statement notes that the new drone will be provided to military partners for further experiments and joint developments. This indicates Washington's intention to extend the program's results beyond internal testing and involve allies in refining the platform. Published footage shows the gray UAV fuselage marked with «U.S. ARMY» and the DEVCOM logo, mounted on a green metal frame in a field setting; the upper cowling is removed, exposing a complex bundle of piping, wiring harnesses, and rotary engine components typical of prototypes at the ground-testing stage.

### Context: Technology Race in the Strike and Reconnaissance UAV Segment

The development of hybrid propulsion systems for drones has become a priority direction for several militaries against the backdrop of active drone use in modern conflicts. Increasing flight duration and payload capacity directly expands the tactical operating radius of UAVs and allows them to carry heavier payloads—from reconnaissance systems to strike munitions. The DEVCOM program fits into the broader context of U.S. Army efforts to create a new generation of tactical unmanned systems capable of operating in environments where traditional aviation and ground vehicles are limited in use.

## Fact-Check & Sources

- [В армии США появился гибридный дрон с напечатанным на 3D-принтере двигателем (фото)](https://www.rbc.ua/ukr/news/armiyi-ssha-z-yavivsya-gibridniy-dron-nadrukovanim-1793694757.html) - Primary source: a retelling of an official U.S. Army statement. Contains a quote from the program manager, a description of the hybrid architecture, and plans for partner transfer. The photo confirms the U.S. ARMY / DEVCOM markings and engine design.

## FAQ

### What is a series-hybrid system in the context of this UAV?

It is an architecture where the heavy-fuel rotary engine acts as a generator, producing electricity for a 400-volt system, which in turn powers the traction electric motors. The engine is not directly connected to the propellers, allowing its operating mode to be optimized.

### Why was heavy fuel chosen instead of aviation gasoline?

Heavy fuel has higher energy density and is easier to store and handle logistically in field conditions, enhancing UAV autonomy and reducing reliance on specialized refueling systems.

### What is the role of 3D printing in creating the engine?

Additive manufacturing allowed the production of complex geometry elements—channels, combustion chambers, injector parts—that are difficult or impossible to make using traditional machining, improving aerodynamics and thermal performance.

### Who will receive the drone after testing?

According to the U.S. Army statement, the new UAV will be provided to military partners for further experimentation and joint development, though specific recipient countries were not named in the available release.