CycloTech is preparing to test fly a demonstrator using its gyrorotor propulsion technology.
The Linz, Austria-based research and development company is developing a rotor unit for what it calls a “de-scaled” version of a potential four-seater air taxi it hopes to develop this decade.
At the time eVTOL.com spoke to Hans-Georg Kinsky, CycloTech CEO, in mid-September 2020, the initial rotor unit was being installed in the flight demonstrator.
Following assembly and static tests, a “final status test” will take place, before flight trials commence. It is hoped to conduct the first flight in Q4 2020, he said.
The Cyclogyro rotor is designed to offer direct control of the magnitude and direction of thrust, a stable transition to forward flight, high agility, and compact design.
CycloTech has tested nine different rotor prototypes of its system since 2016. Initial static bench tests for power and thrust of the current design iteration to be used in the flight demonstration were conducted in 2019, including trials in a wind tunnel at the University of Glasgow.
Initial flight testing will focus on the controllability of the four rotors on the demonstrator, before moving on to stability in the hover and the transition to forward flight. Tests at increased speeds in the forward flight mode are planned for 2021, Kinsky added.
According to CycloTech, the de-scaled flight demonstrator is 2.4 meters (7.8 feet) long and 1.9 meters (6.2 feet) wide. It has a maximum take-off weight of 82 kilograms (180 pounds), a cruise speed of 50 kilometers per hour (31 miles per hour), and an endurance of two to five minutes.
CycloTech wants to prove the viability of the Voith-Schneider-Propeller concept for the aviation industry and commercialize it. A Cyclogyro rotor consists of several blades rotating around a central axis joined by conrods to a freely rotating hub.
Kinsky explained to eVTOL.com that changing the pitch angle of the rotor blades during a revolution “accelerates the airflow through the rotor” hub, which means “it should be capable of flying in tougher conditions.”
He said CycloTech has tried different concepts for controlling airflow since 2016, but, “finally we found one that allows us to cope with the high forces going through the hub.”
Kinsky added, “You need to design your rotor to still be able to get control at the offset points. We have done many calculations and simulations for all the parts involved so we know more or less the force on every single part.”
The concept is based around four or more rotors laid out in a ring-shaped arrangement that enable thrust magnitude and direction to be controlled on every single rotor.
This, CycloTech says, “allows for precise positioning through rotation around all aircraft axes as well as for adaptation to varying circumstances such as crosswinds and gusts.”
Kinsky told eVTOL.com, “We have a system that delivers high performance [and] is reliable. We haven’t had any components break in the last four years. We’re really confident that once we have our rotor units tested, we’ll be able to control [the thrust].”
CycloTech plans to scale up its technology to what Kinsky called “high precision” small unmanned aerial vehicles undertaking cargo delivery and inspections of critical infrastructure such as oil/gas pipelines and wind turbines. This drone, which CycloTech is currently developing, will be able to withstand crosswinds up to 20 meters per second (65 feet per second), Kinsky added. A “mid-range” drone will follow in around 2023, and then potentially an eVTOL air taxi.
The air taxi would have a 2,200-kg (4,850-lb.) maximum take-off weight, carry a 400-kg (880-lb.) payload, and measure seven meters in length by five meters in width (respectively around 23 feet by 16 feet). It would be capable of having up to eight rotors, offer 40 minutes’ flight time and a 85-km (53-mile) range, and have 1,600 kilowatt power.
CycloTech is “looking for co-operation partners” to help advance its technology, Kinsky said, including moving forward from the concept design stage for the air taxi. The company has four granted and two pending patents on its technology and is currently in discussion on three others.
Kinsky added CycloTech is also talking to the Munich, Germany-based air taxi developer AutoFlightX about how its rotors might be used in the company’s design.
A further potential application is a compound helicopter; CycloTech has a patent for a design with two laterally placed Cyclogyro motors replacing the conventional tail rotor.