Elroy Air flew the world’s first turbogenerator-hybrid electric vertical take-off and landing (hVTOL) aircraft on 12 November 12 at its test-flight facility in Byron, California—the Chaparral C1. The C1 is an autonomous hVTOL aircraft, with distributed electric propulsion and a turbogenerator-battery architecture.

Leveraging both its turbogenerator system and high-power batteries the C1 took off vertically, flew for 57 seconds, and landed successfully.

For vertical flight, distributed electric propulsion (DEP) using multiple redundant rotors enables robust and safe operations even in the case of motor failure—a key enabler for autonomy. However, today’s battery-electric eVTOL aircraft designed for Air Taxi and cargo operations are range-constrained due to the energy density limitations of available battery cells, and they must be operated in locations with substantial battery-charging infrastructure.

The combination of DEP and turbine-based electrical power generation yields a best-of-both-worlds option first suggested by NASA researchers in 2008. Turbogenerator-hybrid architecture addresses the limitations of all-electric systems by combining a gas turbine-driven generator with batteries, enabling long-range missions (a “must-have” for logistics) without requiring charging infrastructure, as well as safe redundant flight for autonomous operations.

To develop and bring the world’s first hVTOL air vehicle into flight test, the Elroy Air team overcame substantial technology challenges in electrical power management and structural vibration. Elroy Air’s engineering team is led by Zach Lovering, an aerospace engineer and eVTOL industry veteran who contributed to multiple aircraft development programs at Zee Aero (now Wisk), and subsequently led the pioneering Vahana eVTOL aircraft program at Acubed by Airbus.

Elroy Air’s Chaparral is in high demand from a number of leading partners in commercial, humanitarian, and defense logistics. Its vehicle backlog—reflected in LOIs and MOUs with a growing number of deposit-backed agreements—today exceeds $3 billion in future revenues. Since starting work with AFSOC (Air Force Special Operations Command) in 2019, the company now holds 3 active contracts with US Air Force (SBIR Phase II, SBIR Phase III, and TACFI). The Chaparral’s capabilities address an urgent operational need for logistics in contested environments where today’s alternative is dangerous resupply missions using expensive crewed aircraft, a demand reflected by its active partnerships with the Defense community.

AFWERX is excited to see the progress in hybrid electric powertrains for transformative vertical lift aircraft. Hybrid flight marks a key technical milestone for the industry to increase VTOL range and payload while validating the investment strategies of both AFWERX Prime and AFVentures TACFI program.

—Col. Elliott Leigh, AFWERX director and chief commercialization officer for the Department of the Air Force

AFWERX is the innovation arm of the DAF and a directorate within the Air Force Research Laboratory.

Chaparral and cargo pod

Chaparral is intended to be an autonomous eVTOL platform for middle-mile logistics, humanitarian aid shipping, and military resupply. The aircraft has eight propellers for vertical takeoff and landing, and four propellers for forward cruise. Chaparral is compatible with a range of cargo pods.