The Future of Advanced Air Mobility

The Rhaegal is a family of autonomous cargo aircraft being developed by Sabrewing Aircraft. The aircraft can operate in vertical takeoff and landing mode, or in conventional fixed-wing mode (or CTOL, for conventional takeoff and landing).

Since beginning development of an initial RG-1 model, the company has built the Rhaegal-A prototype and also a larger Rhaegal-B that is about twice the size. Beyond that, it intends to develop the even larger Wyvern model,  which will be almost twice the size of the -B. According to Sabrewing, the aircraft will offer around twice the payload when taking off and landing from a runway than when in VTOL mode (so up to 5,ooo pounds for the -A and up to 10,000 pounds for the -B).

The initial Rhaegal RG-1 prototype was powered by a single Rolls-Royce M250 turbine engine running on Jet-A that drives a generator that provides electrical power to 4 motor/fan drives, one at each corner, and batteries. However, Sabrewing says it decided to seek a new engine after realizing that Rolls-Royce would not be able to supply sufficient numbers of the M250. In January 2020, it launched a request for information to find a new engine and opted to use three of Safran's Ardiden turboshaft engines, which the French company developed for helicopters. 

The cargo bay is accessed through the nose and it can carry standard cargo pallets or bulk cargo using a convertible roller floor. Automatic collapsible wings are being suggested to ease ground operations, transport and storage. A camera, a lidar, a radar, and a forward-looking infrared detector (for landing at night) will assist flight control / detect-and-avoid alongside GPS and ADS-B feeds.

The Rhaegal aircraft are being built at the company's base in Camarillo, north of Los Angeles. 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.

Sabrewing is understood to have previously flown a one-eighth scale prototype for the Rhaegal-A. Range for both types is expected to be up to around 1,115 miles.

On April 21, 2020, Sabrewing announced that it had become the first company to win a contract under the U.S. Air Force's Agility Prime program to support eVTOL aircraft development. It has a $3.25 million AFWERX Small Business Innovative Research Phase II contract to support testing of a prototype designated as the Rhaegal-A. This was rolled out live online during the Agility Prime kick-off event on May 1, 2020. The company intends to develop a military version of the aircraft, designated the Aleut, and has not yet chosen the engine for this model. Sabrewing also plans to build an even larger Wyvern aircraft, which will be almost twice as big as the -B model. However, it will not start work on designing the Wyvern until regulators have issued appropriate regulations for the certification of this class of aircraft.

Planned flight testing was delayed by quarantines and other restrictions related to the Covid-19 pandemic and, as of July 2020, no date had been set for this work to begin. The company said it plans to start building the first full prototypes of the Rhaegal aircraft in September 2020, subject to Covid restrictions being lifted in California. Construction of the first full production aircraft had been due to be completed by January 2021, but this seemed likely to be delayed as well.

For civil applications, Sabrewing expects to be able to complete Part 23 type certification by the European Aviation Safety Agency in the first quarter of 2022, with FAA to follow later that year. 

Timeline

type certification granted

Sabrewing expects to certify the Rhaegal aircraft under Part 23 rules.

Projected

type certification granted

Sabrewing expects to certify the Rhaegal aircraft under Part 23 rules.

On April 6, the U.S. Air Force awarded Sabrewing a $3.2 million contract under its Agility Prime program to support flight trials and development work for potential military use of the Rhaegal aircraft. 

Outlook

Our objective assessment of this program’s probable success.

FutureFlight assesses the probability of success for a new aircraft program by considering the following criteria:

  • Total investment funds available in proportion to the anticipated cost of getting an aircraft certified and in service
  • A company’s in-house capability (in terms of numbers of engineers, technical staff, and customer support teams)
  • The past experience of the company and its senior leadership in developing aircraft
  • The caliber and past experience of key program partners
  • Whether key aircraft systems have been selected and are available for use
  • Whether the preliminary design review has been completed
  • Whether the design for the full-scale prototype has been completed
  • Whether the type certification process has been formally initiated with an appropriate regulator
  • Whether the company has achieved a first flight with a full-scale prototype
  • The number of hours logged in a flight test program
  • Whether type certification has been achieved
  • The number of orders and commitment received for the aircraft
  • Whether the company has adequate facilities to begin series production of the aircraft
Our Methodology

Cargo aircraft are less complex to design, build, certificate and operate than passenger aircraft so this project in theory has a head start although presumably a passenger version could come later. Also it is sensible to go for hybrid using a reliable turbine and electric/electric backup first.

It faces the usual challenges with regulations not existing yet for unmanned commercial aircraft sharing airspace with general/commercial aviation. These are in the early stages of development, however.

The award of a contract to support testing of the Rhaegal-A prototype under the U.S. Air Force's Agility Prime program suggests that Sabrewing may benefit from further Pentagon support.

Rhaegal Models

Rhaegal-B Specifications

local vtol Lift + Cruise

Performance

  • Passenger Capacity
  • Range
    1,150 mi
  • Cruise Speed
    230 mph
  • Powerplant Type
    ducted fan
  • Power Source
    hybrid_fe
  • Endurance
    n/a
  • Max Altitude
    22,000 ft
  • Takeoff Distance
    n/a
  • Landing Distance
    n/a
  • Empty Weight
    2,399 lb
  • MGTOW
    13,765 lb
  • Payload Weight
    10,000 lb

Dimensions

  • Length
    48 ft
  • Width
    n/a
  • Height
    15 ft
  • Wingspan
    56 ft

The Rhaegal-B is designated as the production model for the Rhaegal family of hybrid electric cargo aircraft, and it is also referred to as the Cargo UAV. It offers improved performance and higher payload compared with the original RH-1 model. Sabrewing is developing the aircraft to be able to operate both in vertical and conventional takeoff mode.

Power for the hybrid-electric aircraft, comes from three Safran Ardiden turboshaft engines, generating maxium takeoff thrust of 1,890 hp and maximum continuous thrust of 1,160 hp. The company is targetting service entry for 2022.

The fuselage will have a internal cargo volume o 570 cubic feet and be to hold one standard LD-1 cargo container, two LD-2s and one LD-3.

Key Personnel

Ed De Reyes, chairman and CEO of Sabrewing
Ed De Reyes

Chief Executive Officer (CEO)