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Sabrewing has announced it will partner with Safran Helicopter Engines on the propulsion system for its hybrid-electric Rhaegal-B cargo drone.
The announcement, by Sabrewing CEO Ed De Reyes, came during the May 1 unveiling of the company’s Rhaegal-A prototype as part of the U.S. Air Force’s virtual launch event for Agility Prime. Sabrewing has received a $3.25 million Small Business Innovation Research (SBIR) Phase II contract from AFWERX through Agility Prime, the Air Force’s initiative to accelerate development of the commercial eVTOL industry.
De Reyes and Sabrewing chief technology officer Oliver Garrow conducted the livestreamed roll-out from their “Dragonworks” facility in Hayward, California (the Rhaegal aircraft being named after an Old English word for dragon). De Reyes explained that Rhaegal-A is “strictly a test vehicle to test the ability of our engineering models to scale correctly,” and will provide a “parallel development path” for the larger Rhaegal-B.
Yet Rhaegal-A is an impressive engineering achievement on its own. “Even though the Rhaegal-A is half the size of the Rhaegal-B, it can still carry a greater payload than any other VTOL UAV [unmanned aerial vehicle] on the market, up to one metric ton,” De Reyes pointed out.
The larger Rhaegal-B is targeting a VTOL payload of 5,400 pounds (2,450 kilograms), or as much as 10,000 lb. (4,500 kg) for operations in which the vehicle takes off and lands on runways like a conventional airplane.
Both models have “turbo-electric” drivetrains, in which turbine engines drive generators that supply electricity to four tilting, ducted fans. The Rhaegal-B will use two Safran 3 turboshaft engines generating 2.8 megawatts, De Reyes said. He later told eVTOL.com that Sabrewing has decided to replace the single engine currently installed on the Rhaegal-A with an Ardiden 3 prior to the vehicle’s first flight, giving it the advantage of an extra 600 horsepower.
“We use all the power that’s available, and don’t store any onboard the aircraft,” he explained during the virtual roll-out. “This provides higher efficiency and better fuel mileage, if you don’t have to carry heavy batteries or take up the weight that would normally be taken up by payload in this configuration.”
The company’s SBIR contract provides research and development funding for Rhaegal’s detect-and-avoid system, and its navigation solution for GPS-denied environments. De Reyes said the company will test this solution “both on the test bench and in the air,” in addition to demonstrating the aircraft’s ability to deliver cargo to remote locations and its potential to conduct casevac missions. The Rhaegal-B could evacuate as many as six casualties at a time, accompanied by two flight medics, he suggested.
“While Sabrewing has more than 65 orders for aircraft and letters of intent for another 250 more following type certification, Agility Prime is providing additional funding to make sure that our aircraft is the safest, most reliable aircraft that we can design and build,” De Reyes said. The company plans to use Edwards Air Force Base near Lancaster, California, for its initial flight testing, although the COVID-19 pandemic has delayed those plans somewhat.
“We were originally planning on doing [first flight] June 1, so about a month from today,” Reyes said. “But because of COVID and because of the quarantine here in California . . . we are going to have to wait for our space in line once the economy opens up and we’re able to travel.”