Astro’s Elroy Blasts Off
The exclusive story of the origins and progress of the PassengerDrone

By Kenneth I. Swartz
Vertiflite Nov/Dec 2018

Astro Aerospace holds the distinction of being one of a handful of electric aircraft developers in the world to have successfully flown a piloted electric vertical takeoff and landing (eVTOL) aircraft. (More details on Astro and links to more resources are available at www.eVTOL.news/passenger-drone.)

Although the Texas-based company is new to the aerospace business, in March 2018 it completed the strategic acquisition of all rights to PassengerDrone. The aircraft first came to international attention with the team’s YouTube video release on July 16, 2017, which revealed that the 16-rotor eVTOL aircraft had made successful autonomous flights, followed by an actual passenger flight that September.

Astro Aerospace was founded by Bruce Bent, a Canadian technology investor and the chief financial officer of Matthews Southwest, a large Dallas area-based private real-estate development company with major projects in the US, Canada, the UK and Dubai in the United Arab Emirates.

In late March 2018, the prototype PassengerDrone was shipped from Europe to North America to begin a new life as the Astro “AA360,” though that name was replaced with “Elroy” in September 2018.

With the tagline “Flight Made Easy,” Astro’s goal is to “make self-flying unmanned and manned vehicles available to anyone, at any time, from anywhere, and to turn this new and exciting aircraft into a mainstream mode of transportation.”

In the Beginning

PassengerDrone was the brainchild of Boyan Zhelev and Ivaylo Nikolov, two Bulgaria-born electronics and software experts who spent many years working on security solutions before turning their attention to the development of drones in 2004.

“At that time, only a couple of companies and teams were developing multi-rotor aircraft … [and our] initial development target was a completely autonomous system mainly for surveillance applications. Our team soon realized that there were no existing, ready-to-use electronics modules or software solutions for such applications, so we started developing these from scratch,” recalled Zhelev.

The partners began “designing and building the necessary electronics modules and hardware, and developing the advanced software algorithms. Then after three years of efforts, our multi-rotor prototypes began performing completely autonomous flights in 2007.”

These efforts led to a successful business partnership with some industry-leading German companies in the emerging consumer drone market, as well as work developing military applications that utilized the team’s know-how in advanced motor control and radio communications.

Work on a manned eVTOL aircraft began in 2015, with the goal of “developing a passenger drone aircraft that is intuitive to fly, even for an inexperienced pilot, and that can be operated completely autonomously,” recalled Zhelev. “Our aim was developing flight control systems which can assist human operators or pilots in handling flying, with ease — much like the challenging development of automobile autopilots, but adding a third dimension.”

The next three years were spent “developing a completely new system architecture to provide this desired ease of flight, with a strong focus on safety, redundancy, flight performance, ergonomics and transportability.”

The first tests with scale models began in late 2015 and the milestone first unmanned flight of the two-seat PassengerDrone took place near Sofia, Bulgaria, on April 25, 2017.

“The unmanned flight tests immediately confirmed the predicted aircraft performance and proved [the validity] of thousands of simulation hours of flight control systems tests … and our numerous scale model test flights,” said Zhelev.

The developers spent the next five months performing intensive testing with different simulated payload weights, simulated engine failures and different control modes.

Then on Sept. 16, Zhelev had the delight of enjoying “the flying carpet feeling in our first manned flight,” covering a distance of 2–3 miles (3–5 km) in a circular pattern. The aircraft was designed for a top speed of 45 mph (72 km/h) and a maximum payload of 270 lb (122 kg).

The program was wrapped in secrecy until a press release on Sept. 29, when PassengerDrone was officially launched and photos and YouTube videos released that attracted widespread international attention.

However, the identity of the eVTOL developers and the location of the test flights remained in mystery for another year until the author was granted exclusive access in late September to write this story for Vertiflite. (Some news stories erroneously reported that the aircraft was being flown in Switzerland or California.)

The Elroy 1.0, shown here with Rob Paterson, is now at Paterson Composites adjacent to Toronto’s Pearson Airport. The company will be fabricating the cockpit, airframe and propeller blades for Elroy 2.0 and Orbit 1.0. (Photo by the author)

Prototype Design

From the beginning, the flight control system of the aircraft was designed to support advanced autonomous, unmanned and manned flight in the controlled airspace of the future, not just basic flight maneuvers.

The prototype aircraft utilized the stylish all-composite tandem seat cockpit of Niki Rotor Aviation’s Kallithea and Lightning gyroplanes. Founded in 2011 by Nikolay Nikolov, the Bulgarian gyroplane manufacturer is a local success story and based in Pravec, approximately 37 miles (60 km) from the capital, Sofia.

The Niki cockpit was extensively modified to become an eVTOL aircraft with the installation of a digital instrument panel with a user-friendly interface and a touch flight control, fly-by-wire joystick, and a battery compartment behind the cockpit where the Rotax motor would usually go.

The configuration of the distributed electric propulsion system was determined through many simulations and a thorough structural analysis, said Zhelev. The design provides the required flight performance and redundancy, and the compact footprint means the eVTOL can easily fit in an automobile garage or be transported by road.

Prior to its first flight in April 2017, the PassengerDrone had skids. (Astro photos)

The demonstrator fuselage was from the tandem-seat Bulgarian Niki gyroplane.

The aircraft is powered by 16 brushless DC electric motors mounted along two parallel composite tubes above and outboard of the cockpit. The motors are positioned in upward- and downward-facing pairs with support tubes attached to the airframe by a four-arm hub behind the cockpit where the original gyroplane rotor mast would normally be. According to the designers, their in-house-developed adaptive flight control algorithm keeps the aircraft stable in most weather conditions, with hardly any vibration.

The aircraft is also equipped with a remote LTE (4G) telemetry and control capability that can send flight information in real time and use situational awareness, ADS-B display of local air traffic, real-time weather radar and immersive 3D terrain data while in flight (with the joystick available as an override).

With the exception of the main power cables, there are no other wires in the entire aircraft. From the connection between the control joystick, main control CPU, engine controllers and the navigation screens, everything is communicated by light using a fiber-optic control system. This was designed to ensure safety and reliability, reduce weight and reduce the risk of electromagnetic interference.

Sale & Acquisition

After PassengerDrone made its first manned flight, the Bulgarian founders offered the program for sale to an investor who had the financial resources to carry the eVTOL program forward and into production.

By the time the aircraft had flown, there was already a lot of media buzz about eVTOL and urban air mobility, but few companies had flown an aircraft. According to the Vertical Flight Society’s eVTOL. news website, there were about 36 known eVTOL aircraft at the time and only three — Volocopter, Ehang and Kitty Hawk — had publicly revealed manned flights by then.

In March 2018, Astro Aerospace (then known as CPSM, Inc., a publicly traded company) bought the assets of InFly Technology of Bulgaria, which had earlier been acquired by Confida Aerospace Ltd.

That’s when Astro hired founders Boyan Zhelev as its chief product officer and Ivaylo Nikolov as its head of research and development (R&D).

Over a 14-year period, the founders had developed a deep understanding of unmanned aircraft systems (UAS) architecture including navigation and advanced flight control algorithms, and sensorless control of permanent magnet synchronous motors as they migrated to more powerful embedded platforms.

Astro officially announced the acquisition of PassengerDrone on May 9, 2018, and revealed a leading drone expert, Paul F. Beard, CEO of uAvionix, had joined the new company’s board of directors. uAvionix develops small, lightweight, economical ADS-B transceivers, transponders, and GPS receivers for manned and unmanned aircraft.

New Partners

Immediately after the purchase, Bent went looking for a composite manufacturer in Canada that could help develop Astro’s next generation of aircraft.

That’s when he discovered Paterson Composites Inc. (PCI) of Toronto, which recently moved into a new 29,000 ft² (2,700 m²) facility adjacent to Lester B. Pearson International Airport (YYZ), Canada’s busiest airport.

In fact, that’s where Astro took delivery of two crates containing the prototype PassengerDrone that were air freighted from Sofia, Bulgaria, in late March.

Rob Paterson and his business partners (who have a history with the Canadian Olympic sailing team and the 2010 America’s Cup yacht races) first started making high performance, lightweight competitive catamaran sailboats in 2005 out of carbon fiber and epoxy.

About six years ago, PCI decided to branch out into other markets, such as aerospace, defense, automotive, medical and mining, and obtained its ISO 9001, AS9100 and Canadian Controlled Goods Program credentials.

Around this time, Paterson met the Aerovelo team led by Todd Reichert and Cameron Robertson in Toronto, who were competing to win the (then) AHS Sikorsky Prize with the Atlas human-powered helicopter.

The rear fuselage of the demonstrator terminates with a cavity where the gyroplane motor and propeller normally are. (Photo by the author)
The first manned flight of the then-PassengerDrone was on Sept. 16, 2017 with Boyan Zhelev. (Astro video image)
After the Aerovelo team won the AHS competition, it started designing an aerodynamic bicycle to compete in the annual World Human Powered Speed Challenge, and “we helped out with the frame construction and the fairings of the Eta bicycle,” said Paterson. (See “From Aerovelo to Kitty Hawk,” Vertiflite, Nov/Dec 2017, for more on the Aerovelo story.)

PCI used its new computer numerical control (CNC) router to machine the blue Styrofoam block that the Aerovelo team wrapped in carbon fiber to create the bicycle frame; it also produced Eta’s distinctive lightweight bullet-shaped external fairings.

In 2015, Aerovelo succeeded in its goal with its Eta speed bike of setting a world speed record, and then incremented the record four times, most recently with an astounding 89.59 mph (144.17 km/h).

Paterson subsequently built a composite replica of the bicycle for display at Google’s headquarters (since Google co-founder Larry Page hired much of the Aerovelo team to work at his Kitty Hawk eVTOL company) and his work with Aerovelo helped secure new aerospace projects, including a contract with Aurora Flight Sciences to build composite components for one of its aircraft.

In June 2018, Astro added even more depth to its team with the addition of Kasaero GmbH of Stuttgart, Germany, which is now working alongside Paterson Composites to develop the next generation of Astro aircraft.

Shown here at Markham Airport in Ontario, the Elroy’s cockpit doors open like gull wings. (Astro photo by Michael White)
The Elroy made three unmanned flights at Markham Airport near Toronto, culminating on Sept. 19 in a four-and-a-half minute flight making figure-eights. (Astro photo by Michael White)
Kasaero is an aviation R&D company specializing in lightweight design, composite technology and certification. Since its founding in 2008, Kasaero has been involved in innovative electric aviation projects including the NASA Green Flight Challenge entrant, e-Genius, and Solar Flight’s unique solar-powered two-seater, the Sunseeker Duo. Kasaero also built up the composite prototype production for the Dornier Seastar amphibious aircraft by Diamond Aircraft in Canada. Bent said the company’s combined experience in aircraft certification, engineering, problem solving and manufacturing are a valuable addition to the team.

First Canadian Test Flight

In September 2018, Transport Canada granted Astro a Special Flight Operations Certificate (SFOC) to allow flight tests of a UAS in Canadian airspace.

That’s when Astro announced the aircraft had been renamed “Elroy” (furthering the Jetson’s theme of the company name).

Elroy conducted three unmanned flight tests at Markham Airport northeast of Toronto, culminating on Sept. 19 in a four-and-a-half minute flight, reaching heights of over 60 ft (18 m) and speeds of over 30 mph (50 km/h) while flying a figure eight pattern.

“To see Elroy fly so smoothly and efficiently validates all of our efforts and continues to move us forward as a leader in the eVTOL space,” said Bent.

The recently upgraded avionics and flight control system was subjected to a number of maneuvers and the vehicle remained exceptionally stable, even during a couple of unexpected wind gusts. The test flights provided valuable system data that will help move the program forward.

New Aircraft for New Markets

The team is now developing two new all-composite aircraft for cargo and passenger use — Orbit 1.0 and Elroy 2.0 — that should begin test flights near Toronto in the spring.

While Elroy 1.0 features tandem seating, Elroy 2.0 will be stylishly designed with a wider cabin to accommodate side-by-side seating and a raised lift system to provide greater clearance, said Paterson, who will be helping Astro construct the aircraft including the cockpit, airframe and propeller blades.

Astro sees a wide range of market applications for its passenger and cargo aircraft including urban air mobility, search and rescue, package delivery, movement of people and cargo around large properties or farms, and even agricultural spraying.

“What you can do with this platform is only really limited by your imagination,” said Paterson.

Astro is reluctant to share any details regarding the power output of its electric engines or the energy density of the batteries, but revealed that a hybrid-electric aircraft is part of its development plans and future models will be equipped with a ballistic parachute system for enhanced safety.

In October, the core development team consisted of about a dozen people, half of whom are engineers. “We have an excellent working relationship, and everyone has their own area of expertise,” said Paterson. “We are looking to grow our team
and are looking to hire more people in the near future.”

About the Author

Ken Swartz runs aerospace marketing communications agency Aeromedia Communications in Toronto, Canada. He specializes in contract public relations, freelance writing, and social media marketing for the aviation and aerospace industry. He has reported on the helicopter industry for 40 years. In 2010, he received the Helicopter Association International’s “Communicator of the Year” award. He can be reached at kennethswartz@me.com.

The Astro Aerospace Elroy became public as the PassengerDrone in Summer 2017 with photos of its autonomous flights in Bulgaria. (Astro photo)

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