Preparing the future
Safran Nacelles' high-tech industrial expertise enables the company to meet the environmental and economic objectives required by the market, by preparing the integrated propulsion of tomorrow: lighter, quieter, smarter, more electric and easier to maintain.
Thanks to its expertise on all the nacelle components (Air inlet, fan cowls, thrust reverser, exhaust system and EBU), Safran Nacelles devotes its R&T budget to research in innovative solutions in :
- acoustics to reduce aircraft noise,
- the application of new materials to reduce weight for greater fuel efficiency,
- manufacturing processes to reduce costs and increase production quality,
- the implementation of increasingly electric nacelles for both weight savings and reliability.
Safran Nacelles has developed an innovative luminous marking solution which revolutionizes aircraft visibility. It offers a unique way of promoting a company's identity, providing both an advertising medium and space for artistic expression. The patented Illuminate the sky by Safran Nacelles solution allows a luminous message (identification, advertising, logos, etc.) to be displayed anywhere on the aircraft fairing (engine nacelle, fuselage, tail…).
An innovative concept
The electroluminescent marking solution is based on a multi-layer system which is as thin as a sticker. It is powered by the aircraft's electrical power system, can be easily modifiable. It can be easily changed by another marking and be reprogrammable for a new animation of what it is displayed. It includes a control system to activate or deactivate it. It provides exceptional visibility both day and night, in particular in poor visibility conditions (half-light, night, rain, fog, etc.). This innovative solution highlights airline logos and liveries, as well as promoting the air transport sector's growing number of joint marketing campaigns and event affiliations.The electroluminescent marking also is scalable to private jets, enabling owners to personalize their aircraft with artistic designs. The sky's the only limit for this solution.
A new concept based on Safran Nacelles expertise
In flight and on the ground, the electroluminescent marking benefits from all the technical expertise acquired by Safran Nacelles, aeronautic leader in the design, development, production and maintenance of engine nacelles.
Full-scale demonstrators for integrated propulsion systems
The new technologies are being validated through such Safran Nacelles full-scale demonstrator programs as NAIAD and PANACHE.
NAIAD (NAcelle Innovative and Acoustic Demonstrator) features an all-composite laminar flow air inlet, advanced acoustic treatment on interior surfaces, and nacelle components produced with new manufacturing processes such as thermoplastic forming.
Also benefitting from Safran Nacelles' expertise is the PANACHE (Pylon And Nacelle Advanced Configuration for High Efficiency) nacelle demonstrator of the Nexcelle joint venture. 2013 Safran Innovation Grand Prize, its key features are a one-piece composite O-Duct that replaces the two-piece "D" doors on a traditional thrust reverser, along with new thrust reverser kinematics in which the entire O-Duct moves aft ward to the reverse thrust position, thereby eliminating the need for drag links in the secondary flow-path.
Acoustics & composites
Safran Nacelles' research has focused on composite materials to limit noise pollution, reduce weight and satisfy fuel consumption requirements. Airports around the world now set their own noise limits, forcing aircraft manufacturers and their suppliers to innovate continuously in reducing noise levels during take-off and landing.
Composite materials offer the possibility of reducing the weight, improving providing affective acoustic protection and reinforcing the structures on which they are used and permit effective acoustic treatment; this is why they are so important for aircraft nacelles.
Contributing to the A380's low operating noise level is Safran Nacelles' use of advanced acoustic treatment in the engine nacelle, while the company has applied an increased percentage of composites and metallic alloys to lower the nacelle's overall weight.
Safran Nacelles also masters the RTM (Resin Transfer Molding) process and 3D RTM process. Molding is carried out in a vacuum which offers numerous manufacturing advantages while giving rise to high-strength products. The RTM process is used on the Airbus A320neo and Falcon 7X/8X nacelle systems.
Acoustic technologies have been developed as well for engine nozzles, with the focus on metallics – notably titanium alloys, which allow the development of parts embodying an acceptable compromise between weight and operating temperature. The expertise developed by Safran Nacelles in this field is unrivalled in Europe.
The production of nozzles requires mastery of the forming of perforated metal sheets and brazing of honeycomb structures on these metal sheets in order to manufacture acoustic panels (A380 nozzle). Titanium, a material that requires a lot of care during implementation, was selected because it is light and offers good mechanical characteristics at high temperature (650°C max.). A centre of Excellence, or multi-disciplinary plateau specialized in the cutting-edge technologies, has been set up in Le Havre
Electric nacelle systems
Electric Thrust Reverser Actuation System
The ETRAS® (Electric Thrust Reverser Actuation System) replaces the former generation of thrust reverser hydraulically-controlled systems and offers the following advantages: simplified design, reduced weight, simplified maintenance and the elimination of corrosive hydraulic liquids.
The Airbus A380 is the first aircraft in the world to benefit from the advantages of an electric thrust reverser actuation system. The configuration of its thrust reversers - a two-piece composite D-duct - is one of the two configurations which currently benefit from an electrical actuation system, the second one being the nacelle one-piece O-duct thrust reverser on the Comac C919 whose propulsion system is currently being jointly developed at Nexcelle (a joint venture owned 50/50 by Safran Nacelles & GE) and CFM International, as a single, fully-integrated assembly.
Variable Fan Nozzle (VFN) System)
The purpose of this system is to fulfil the variation of section of the nacelle fan nozzle by modifying the exit section of the nozzle during the different aircraft flight phases, the fuel consumption of future ultra high By-pass ratio engines will be improved.
The electrical actuation system contributes to the VFN reliability and position accuracy, while improving maintenance aspect and physical and functional integration to the propulsion system.
Electrical Nacelle Anti Ice (ENAI)
The purpose of this system is to prevent the accretion of ice on the Nacelle air inlet lip. The technology used is the electrical power dissipation across some resistive heaters set underneath the inlet lip.
The standard air inlet anti icing technology is pneumatic. The principle is to pick up and convey hot air from the Engine to the cavity underneath the inlet lip to prevent the accretion of ice.
With the ENAI system, a power generator feeds the resistive heaters. This system is also thermally compati-ble with air inlets made out of Composite material, which is not the case for pneumatic anti icing systems.
Being the only piece in motion within a hot environment, the thrust reverser is the most complex aerostructure component existing. Among the innovating architectures that respond to the thrust reverser challenge, some are Safran Nacelles patents: the door thrust reverser (1981); the PERT thrust reverser (1997)...
There are different types of thrust reverser, each one corresponding to the way in which the engine primary flow and bypass air are redirected. The primary flow (15% of the engine air flow) is a hot air flow as it is the air taken into the compressor and expelled by the nozzle after combustion whereas the bypass air (85% of the engine air flow) is a cold air flow which travels between the engine and the interior of the nacelle.
The main types of thrust reverser are:
- two-door thrust reversers
- pivoting four-door thrust reversers
- cascade thrust reversers
Cascade thrust reversers
The cascade thrust reverser is the most classic one: the rear part of the nacelle comprises a cowling which slides away to reveal cascades coupled with blocking panels which are deployed to block the engine's direct exhaust exit and thus deviate the flow through the cascades so as to create a thrust reversal.
Two-door thrust reversers
While most of the thrust reversers only act on the engine bypass air, the two-door thrust reverser also acts on the primary flow. Consequently it is usually used on mixed turbofan engines of medium power and is located at the rear of the fuselage where its two doors can move into the interior of the nacelle so as to completely block the nozzle and redirect the air flow to the front of the engine with deflector spoilers.
Pivoting four-door thrust reversers
This type of thrust reverser can be used on all types of engine. Its doors form part of the nacelle in the closed position permitting the flow of the engine bypass air while in the open position the rear part of the door blocks the air flow and redirects the bypass air to the front part which equipped with a deflector spoiler creates the "reverse" effect required for the counter thrust.
Thrust reversers patented by Safran Nacelles
Various thrust reversers designed and patented by Safran Nacelles equip aircraft the world over.
On the regional jet and business jet market, Safran Nacelles has notably developed new two-door thrust reverser concepts which allow operating costs to be reduced: the PERT® (Planar Exit Rear Target) and Butterfly thrust reversers.
The PERT®thrust reverser
The patented PERT®(Planar Exit Rear Target) thrust reverser is a proven model with two doors that serve as the engine's exhaust exit during flight, and are deployed on landing for the engine reverse thrust function.
This design has the advantage of combining efficiency, optimization and weight.
The Butterfly thrust reverser
The Butterfly thrust reverser is a hybrid between the four-doors and two-doors concepts.
Its advantages are simplicity and lightness combined with aerodynamic efficiency.
This concept was patented in 1995.
Safran Nacelles unceasingly searches for and implements solutions to improve the aerodynamic performance of its nacelles. This consists firstly, in reducing drag in flight, by, for example, minimizing the surface defects at the interfaces between the various parts (step and gaps). The thrust reverser is continuously worked on in order to find ever more high-performance concepts. The aim is to reverse the flow from the engine in the most effective way possible without affecting the aerodynamics of the aircraft and the operation of the engine.