The future holds great promise for urban mobility. It’s a topic that comes up time and again in several sectors and includes not only transport within the same megalopolis, but also transport from one city, or metropolis, to another.
In Europe for instance, people will soon be able to travel from Milan to London in about two hours and from Paris to London in just less than an hour. Any vehicle that manages to reach certain speeds will have to do so by air and, in order to be future-proof, it will have to guarantee high efficiency in terms of consumption and emissions.
This is one of the main reasons why Clean Sky, the European Union’s platform for studying and developing solutions for the future of aviation, features RACER (Rapid And Cost-Effective Rotorcraft) by Airbus Helicopters as its flagship project.
The RACER is a technology demonstrator, a so-called hybrid aircraft. Its shape immediately resembles a helicopter, but it is also equipped with uniquely shaped wings that have two counter-rotating propellers (one in a clockwise direction and the other counter-clockwise) directed toward the tail. These wings have an eminently futuristic shape and are vaguely reminiscent of a Formula 1 wing.
“The RACER is 50 percent faster than a traditional helicopter, but has lower costs, and brings together several new technologies,” says Tomasz Krysinski, Head of Research and Innovation at Airbus Helicopters.
The RACER is an avant-garde project and that’s why it counts on allies with highly technological capabilities. As announced at the last Helitech in Amsterdam, the first goal has already been achieved, with the RACER passing the Preliminary Design Review (PDR).
“This is the phase of defining the design of an aircraft’s subsystems and components, marking the beginning of the detailed design and production phase,” Krysinski says. GE Aviation Integrated Systems based in Hamble, England is also teaming up with Avio Aero for the RACER. The titanium cradles are designed by the Engineering team in Hamble and are a critical component, connecting the wings to the lateral gearboxes,” he says.
Typically, a complex component such as the titanium cradle would be built by assembling several metallic parts together, which is not very cost or weight efficient.
“This is the first time we’ve ever designed such a complex cast component, that has led to a reduction in weight, part count and costs,” says Paul Mandry, Astral Programme Manager at GE Aviation Hamble. Paulo Mancilla, Director of GE Aerostructures P&L and Engineering at Hamble notes that “the combination of 3D printing and casting allows allow us to remarkably reduce costs and offer structures which perform better because they are lighter.”
The relationship established between Avio Aero and Airbus Helicopters is an unprecedented collaborative model in this field. The main rotor transmission was conceived and developed together by the Italian-French engineering teams.
“The transmission system of a helicopter is vital because all the motion is transferred from the main gearbox to all the rotors determining the performance and total propulsion,” said Alessandro Bordoni, Head of Helicopter Transmissions System Engineering, during the joint conference with Airbus.
“We are directly responsible for the design and production of the two lateral gearboxes that supply power to the propellers of the wings, and we are also responsible for the two accessory gearboxes that supply power and electricity on board, and for the main gearbox’s high-speed first reduction stage,” Bordoni says.
That’s not all, because thanks to the experience gained on the GE Catalyst program, the RACER will also have 3D printed components. Additive manufacturing is increasingly sought by Avio Aero engineers in order to guarantee the typical advantages of weight, speed and freedom of design, especially when it comes to new generation aircraft.
Gian Mario Bragallini, Avio Aero Third Parties NPI (New Product Introduction) Engineering Leader, just like Krysinski, underscore the importance of developing new materials.
“The gears that make up the transmissions for this aircraft have been designed to withstand very high temperatures and extreme physical stresses, with new super alloys which have never been used before and capable of performing even in the event of an extreme oil-off condition,” he says.
As Bragallini explains, these are the limit conditions an aircraft may find itself facing extreme operating conditions. In these cases, the oil (vital for the operation of engines and transmissions) may run out: the materials used by Avio Aero ensure that the RACER is able to complete the mission, facing high temperatures and ensuring to bring the people home safely.