Saffron reveals the Open Rotor, a motor breakdown for Airbus and Boeing in the future




“New Midsize Airplane” by 2025 (also known as ” MOM ” to “Middle of the Market” ), the A320 NEO++ “, more or less at the same time, or even ” New Short Range “, the successor of the best-selling A320 and B737 in the years 2030 : Saffron is on all fronts. Today the leader of this market within the framework of CFM International, the joint venture with General Electric, Safran shoot the lights out in terms of innovation with the inauguration, on Tuesday, on the air base of Istres (Bouches-du-Rhône), its new test bench demonstrators : one will be an engine in the classic architecture, the” UHBR ” (“Ultra-High Bypass Ratio” or, in French, at a very high rate of dilution”), which may be available by 2025, the other, the Open Rotor, which presents an architecture that is in total rupture with the current technologies, could see the day after 2030.

“With this test bed and the demonstrator, the european industry is adopting new ways remarkable in order to explore the propulsion of the future in the field of aeronautics. This test bench, unique in Europe, puts us in optimal conditions to test our new engines. We could not have dreamt of a better start for this bench test as the Open Rotor, ” said Philippe Petitcolin, ceo of Safran.

Breaking technology

Even if its entry into service potential, therefore, is not for tomorrow, it is, in fact, the Open Rotor that started the first turn to the bench because of the complexity of its technology.

“If we want to be ready in 2030, we must start now,” added Philippe Peticolin during a point-release.

Since last may, a demonstrator running on the test bench in the open air for the purpose of validating all operating parameters of this engine, called to bring in a fuel reduction of 15% compared to the latest engine, the Leap, which is already today the nec plus ultra of the engines of aircraft medium-haul. Put into service on the versions remotorisées of the A320 (as from 2016) and the 737 (from 2017), but also selected by the chinese manufacturer Comac for its device C919 aircraft, the engine Leap, the successor to the legendary CFM56 in bringing on this latest improvement in fuel consumption of 15%. For the anecdote, General Electric had tested the Open Rotor on an MD-80 in the 80’s but had not gone further.

Increase the dilution rate

As this is the case since the beginning of the history of the turbojet, this leap in terms of fuel consumption, passes through a marked increase in the dilution rate (which is the ratio between the flow of hot and cold air). In the case of the Open Rotor, it should be above 30 when it points to only 11 today for Leap and that it could go up to 16 in the case of a “UHBR”, with the possibility of going to the maximum, one day, up to 20.

However, since it is necessary to increase the size of the engine to reach dilution rate high, it is hardly conceivable to imagine the development of conventional engines are able to achieve dilution rates similar to those promised by the Open Rotor. They would be too big, too heavy, and impossible to place under the wings. Also, to increase the diameter of the blower and thus the rate of dilution, the Open Rotor has no fairing and is equipped with two propellers contrarotatives ” open “, allowing the plane to reach a speed virtually equivalent to that of a device equipped with a turbojet classic.

The appearance of the aircraft has not changed much in the last 50 years

Above all, with its 4 meters in diameter, the Open Rotor could not be placed under the wings, and will therefore be installed in height, to the rear of the plane. A revolution because, since the 1950s, the face of the jets has not changed much. If there had experiences of aircraft with one or more engines at the back (DC-10, Lockheed Tristar, Boeing 727 or MD-80), the majority of the jets (with the exception of the CRJ of Bombardier) are now built with two wings and engines below (the” tube and wings “). In fact, a technology such as the Open Rotor will result in a greater degree of integration between engine and aircraft manufacturers.

Read here : The Airbus will they be tomorrow, the same silhouette as the Boeing?

While the lack of fairing left to fear a level of noise to be significant, wind tunnel tests have shown that the acoustic level of the Open Rotor would be equivalent to that of the Leap, with even an opportunity to improve, it was argued in Saffron. With this demonstrator, the engine manufacturer habs is in advance compared to Rolls Royce, who is now working on this concept but without being at this stage.

That will make the manufacturers?

Remains to be seen if the manufacturers will come through, however, the not. Everything will depend on the evolution of the price of fuel in fifteen years and the evolution of environmental constraints, not to mention also the acceptability of the passengers to fly on propeller planes to be slightly slower than the Jets. Since the beginning of the research on the Open-Rotor Airbus has always shown an interest more important than Boeing. While Saffron team today the two closest competitors, the A320 and the B737, Philippe Petitcolin says that” a single manufacturer is enough” to launch the program. For him, “the first aircraft manufacturer who chooses this product will take away the song.” The decision is crucial for aircraft manufacturers. The aircraft short-and medium-haul flights account for around 70% of the market.

The challenge of the “Middle of the Market”

In all cases, Saffron plays on all of the tables and will be present on the new conventional engines. Called “UHBR”, this engine could be available by 2025, at the time of the commissioning of new devices. Not on the aircraft market short-and medium-haul flights, but on that of the ” Middle of the Market “, a market that lies between the top of the range of the A320 family and B737 (220 seats approximately) and large-holders of close to 270 seats, and more. A concept on which works primarily Boeing. This plane of 220-260 seats about could be put into service around 2025, according to Boeing. There is no doubt that Airbus will react. According to Reuters, Airbus plancherait especially on an A321 NE0++. The Open Rotor being in the longer term, Airbus has preferred to preferred the”UHBR” for a flight test demonstration should not take place before 2020-2021.

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