What is this “open rotor” reactor presented by Safran?

Recently, the French group Safran unveiled a new thruster whose promises do not leave anyone indifferent. And rightly so, the manufacturer promises to save aircraft about 20% fuel. This could therefore make it possible to save financially while at the same time limiting the impact on the environment a little more.

A vision for the future

Safran is a large French industrial and technological group active in the fields of aerospace, aerospace and defense. Within the CFM consortium, Safran is associated with GE Aviation. As explained The ride in an article dated June 16, 2021, these two companies presented a “open rotor” thruster design which could provide aircraft with the means to save 20% fuel. However, when this figure refers to the entire civil aviation sector, the promise is huge. It would indeed save for tens of billions of dollars worth of kerosenebut also to limit CO2 emissions, and thus the impact on the environment.

Moreover, the respective bow thruster is visibly part of the future. According to Safran, the latter would be completely hydrogen propulsion compatible. Today, several companies are working on hydrogen-powered aircraft projects, including Airbus and its “zero-emissions aircraft” that should see the light of day around 2035. Safran is also considering electric hybridization to increase the overall efficiency of the propellant.

propulsion open rotor
Credits: YouTube recording/Safran

A technology that is not new

In a 2019 publication, Safran’s R&D director explained all the details of what a real breakthrough in the sector of civil aviation. The stakeholder already underlined a huge financial saving and a significant reduction in CO2 emissions. The bow thruster, called CFM Rise, has a very different design than current turbojets. With “open rotor” we need to understand the end of formwork. The propellers – made of composite carbon – are in the open air, which increases their effective surface area. Behind the same propellers we find mobile fins whose mission is to regulate the airflow.

Despite the innovative nature of this project, you should know that open rotor technology is not new. Indeed, this had already been the subject of a operation in the 1970s. At the time, if the energy savings were substantial, the fuel price was still too low to ensure an economic interest. In addition, the technologies used did not yet offer the possibility of erasing the noise pollution of this type of configuration. In terms of sound, Safran promises a noise level comparable to that of current turbojets. And yet the diameter of the CFM Rise has a diameter twice as bigor about 4.50 m.

Particularly confident, Safran announces that research into this type of bow thruster should lead to a marketed around 2035. Meanwhile, current turbojets continue to make progress with the arrival of a latest generation. The most telling example is none other than General Electric’s GE9X, which is supposed to equip Boeing’s 777X aircraft.