An innovative electric unmanned aerial vehicle (UAV) developed in a cooperative Airbus Group effort has entered a new phase of flight testing, validating the concept’s ability to takeoff, land and hover as a quadcopter, then fly with speeds of a fixed wing aircraft.
The Quadcruiser made the first transition last week from VTOL (vertical takeoff and landing) and hover modes to horizontal flight, validating its stability and controllability.
Quadcruiser is a joint effort of Airbus Group Innovations – the research and development arm managed
by the Airbus Group Corporate Technical Office, with the Airbus Defence and Space business unit. Also included in the project team is Steinbeis Flugzeug- und Leichtbau GmbH (SFL), which built the 10-kg.-class demonstrator aircraft displayed at ILA Berlin, and being used for the ongoing testing in Germany
The Quadcruiser’s VTOL and hover flight is achieved with the four vertically-oriented electric lift motors, enabling it to perform like the well-known quadcopter-type remotely-controlled vehicles. During transition to fixed-wing aircraft mode, Quadcruiser’s rear pusher propeller accelerates the aircraft until its wings provide sufficient lift. The lift motors are then stopped, and their propellers adjusted to a low-drag position. Before landing, Quadcruiser transitions back to the quadcopter mode using its four lift motors.
Confirming the transition to horizontal flight
In initial flight trials, Quadcruiser demonstrated its vertical takeoff and landing capability, as well as low-speed flight in hover mode. The next step, achieved this month at Grabenstetten Airfield, was the successful transition from hover to cruise flight mode.
“These flight tests validated the safe operation of the flight control system during transition phase, as expected,” said Dr. Juergen Steinwandel, Executive Expert in Airbus Group Innovations’ TCC 6 (Technical Capability Center 6 – Energy and Propulsion). The application of electric motors – which are powered on the current Quadcruiser demonstrator by an 18.5 volt battery – benefitted from the growing expertise in e-aircraft and their systems at the Airbus Group Corporate Technical Office and Airbus Group Innovations.
Mission versatility and operational independence
The VTOL and hover capability, in combination with efficient aerodynamic cruise flight, offers the ability for Quadcruiser to be operated on long-range missions, as well as in urban environments. These capabilities are of interest to both civil operators and military operators, including law enforcement, border patrol and fire brigades. An advantage is complete independence from launch and recovery systems such as catapults. This reduces the logistic footprint and provides safe, simplified operation during take-off and landing.
The proof-of-concept Quadcruiser demonstrator is capable of up to 50 minutes of horizontal flight in the fixed-wing aircraft mode. This demonstrator vehicle represents a baseline for incremental developments that would see increases in size, complexity, level of autonomy and cost. Larger Quadcruiser versions could become hybrid aircraft, with an internal combustion engine incorporated to recharge the electric batteries for longer-duration flights.