Small Combat Drone Engines Begin Ground Tests

To help fulfill the U.S. Air Force’s need for collaborative combat aircraft (CCA)—next-generation “loyal wingman” drones that can collaborate with crewed military jets—major engine manufacturers have set their sights on a new class of small, affordable engines for uncrewed aircraft systems (UAS). Engine manufacturers highlighted their new CCA offerings last month during the Air, Space & Cyber Conference in National Harbor, Maryland. 

On September 22, Pratt & Whitney revealed plans to develop a portfolio of small turbofan engines with thrust ranging from 500 to 1,800 pounds. Two days later, the company announced that it had completed critical tests, confirming that the small turbofan engines—derived from commercial aircraft engines—can produce sufficient thrust for use on CCA platforms. 

“For unmanned applications, our commercial-off-the-shelf engines can offer an up to 20% increase in their qualified thrust capability,” said Jill Albertelli, president of Pratt & Whitney's military engines business. “This means that we can deliver increased performance from these production engines. Ultimately, this will allow for reduced cost and weight for multiple applications.”

GEK Engine Gains Altitude

Meanwhile, rival engine maker GE Aerospace is also testing a similar small engine that it has been developing in collaboration with Kratos Turbine Technologies, a division of Kratos Defense & Security Solutions, for the past two years. The partners’ first product, the expendable 800-pound-thrust GEK800, passed a critical design review earlier this year and is now undergoing ground tests.

In June, GE and Kratos formally launched a joint development program to produce small turbofan engines specifically suited for the next generation of “affordable” military drones and CCA. At the same time, they revealed plans to produce a larger, 1,500-pound-thrust engine dubbed the GEK1500, which is designed for reusable aircraft in uncrewed combat scenarios. Designed with scalability in mind, the GEK family delivers a ceiling thrust level of around 3,000 pounds. 

On September 23, GE announced that the GEK800 had begun altitude testing in a facility at Purdue University’s Maurice J. Zucrow Laboratories in West Lafayette, Indiana. Expected to wrap up before the end of the year, the altitude test campaign will focus on evaluating the engine’s performance in the 5,000- to 35,000-foot range, GE noted. 

“The GEK800 engine has performed well and exceeded our expectations in its ground testing to date,” said Mark Rettig, vice president of GE Aerospace’s Edison Works advanced programs division. “During altitude testing, we will collect data on the engine’s performance in a range of altitudes to assess its operability in simulated real-world conditions.”

Honeywell Introduces HON1600 

On September 22, Honeywell Aerospace Technologies entered the fray with the announcement of a small-thrust-class engine that it has also designed for UAS and CCA applications. According to Honeywell, the new HON1600 engine features a flexible and scalable architecture that can support both turbojet and turbofan variants in the 800- to 1,600-pound thrust range, and it can operate at altitudes up to 40,000 feet. 

"We’ve designed this engine to meet the new generation of CCA and UAS platforms that require unprecedented performance to keep pace with mission demands,” said Dave Marinick, president of engines and power systems at Honeywell Aerospace Technologies. “Our propulsion system is based on proven and tested technology in use today, plus the latest advancements in digital modeling and manufacturing, to enable a cost-effective and efficient solution for military operators.” 

In 2023, the Air Force announced its intention to procure 1,000 aircraft for the CCA program starting in the late 2020s as part of its Next Generation Air Dominance (NGAD) family of systems. 

For the first increment of the CCA program, the Air Force selected General Atomics and Anduril to compete in developing production-representative prototypes of relatively large UAS platforms under the CCA program. General Atomics began flying its prototype this summer, and Anduril aims to begin test flights later this month. The CCA program is expected to announce the second-increment contract awards in early 2026.