Sabrewing Aircraft is working to keep the development of its Rhaegal family of autonomous eVTOL aircraft on track despite delays caused by restrictions associated with the Covid-19 pandemic. The California-based company has had to delay the start of flight testing for subscale versions of the aircraft due to quarantine rules in the San Francisco Bay Area and also around Edwards Air Force Base.
Meanwhile, Sabrewing hopes to start building the first full-size Rhaegal prototypes in September 2020, and Part 23 certification is now expected to be delayed until the first quarter of 2022. The company intends to get EASA approval first, followed by an FAA signoff.
In April, the U.S. Air Force awarded Sabrewing Aircraft the first contract under its new Agility Prime program to support the development of eVTOL aircraft for potential military applications. The $3.25 million contract was confirmed on April 21 under Agility Prime’s AFWERX Small Business Innovative Research Phase II project and will involve testing of Sabrewing’s Rhaegal-A prototype unmanned cargo aircraft.
On May 1, Sabrewing “rolled out” an early example of the Rhaegal-A as the finale to the Air Force’s week-long Agility Prime event. The company has also built a Rhaegal-B model as part of its wider program to develop a family of autonomous cargo-carrying aircraft for civil and military applications.
The Rhaegal-B is about twice the size of the -A model. Already in the works is a larger Wyvern model, which will be almost twice the size of the -B.
Sabrewing’s aircraft promise significantly greater payload and range than other eVTOL designs aimed at the air cargo sector. “Our cargo UAV can take off and land like a helicopter with a heavy payload, as well as fly farther, faster, and higher at a fraction of the cost of any other aircraft in its class,” commented company CEO Ed De Reyes.
The Rhaegal-B is designated as the program’s production aircraft, and it can carry standard industry Unit Load Devices used by existing air freight carriers. It can carry two LD-1 containers or four smaller LD-2 containers or two LD-3 containers.
The aircraft is expected to deliver a payload capacity of 5,400 pounds. Operating in eVTOL mode, it can fly in and out of locations without a runway on flights of up to 1,150 miles. If it operates as a conventional fixed-wing aircraft into an airport, the maximum payload it can carry increases to 10,000 pounds. The aircraft can fly at altitudes of up to 22,000 feet and at speeds of up to 230 mph.
The Agility Prime evaluation of the Rhaegal will test its detect-and-avoid capability, which is a key feature of autonomous operations, as well as confirm whether it can operate in an environment where GPS signals are jammed or unavailable. The trials will simulate operations with typical cargo payloads and also casualty evacuation missions.
According to De Reyes, the company hopes that the U.S. military will opt to buy a version of the Rhaegal-B to be operated under the name, the Aleut. It has been widely reported that the Aleut community of St. Paul Island in Alaska has agreed that Sabrewing can use the island as a flight test site, with a view to the community taking advantage of the aircraft in the future for vital supplies.
De Reyes described the Rhaegal as a semi-autonomous aircraft that can have its flight path adjusted by a remote ground station. However, due to its weight class and current certification requirements, it will be operated with a pilot on board.