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What is the Engines ITD and what are the challenges?

The Engines ITD builds on the success of the Sustainable and Green Engine (SAGE) ITD of Clean Sky 1, working towards radical engine architectures and new engine technologies to power the aircraft of the future. All the activities under the Engines ITD in Clean Sky 2 have a common goal: to increase fuel and energy efficiencies of the engine and reduce environmental impact, regardless of whether the engine is powering a large airliner or just a small utility aircraft, meaning more thrust while burning less fuel and emitting less CO2, NOx and noise.

But what exactly is an engine?

The main function of an engine is to convert fuel - which is basically stored energy - into mechanical or propulsive power to overcome gravity and air resistance, allowing aircraft to take off and fly. But they are also essential for generating power for a long list of important features and functions, such as the cabin for the galleys, for the inflight entertainment systems, or in the cockpit for the navigation and communication systems. The power that is needed to actuate the many moving surfaces on the wings and empennage (the tail) to manoeuvre the aircraft in the right direction is also generated by the engines.

All of that is a colossal workload for the engines, which have to function efficiently for hundreds of hours between major inspections, maintenance and overhaul.

In turn, it's the skill of the designers, engineers and manufacturers of those engines that determine their efficiency and reliability, and the fuel consumption impacts the cost of the flight tickets. According to IATA‘s 2017 Annual Review, jet fuel share of airlines‘ cost stood at 19.2 percent in 2016. It‘s a substantial and unpredictable burden for airline planners. Furthermore, in February 2018, IATA set out an aim for ‘one billion passengers to fly on flights powered by a mix of jet fuel and sustainable aviation fuel (SAF) by 2025‘, an ‘aspiration identified on the tenth anniversary of the first flight to blend sustainable aviation fuel and ordinary jet fuel‘.

The challenge for the players in the Engines ITD Programme of Clean Sky 2 is to use the achievements gained in Clean Sky 1's SAGE Programme to advance aero-engine technologies to a state of eco-compliance and technological readiness that can be employed in a whole range of aircraft that will take to the skies in the 2025 to 2050 timeframe, delivering a combination of benefits which will result in more affordable air travel and cleaner skies.

That challenge requires unprecedented capacity for foresight, imagination and innovative thought, for the efficiencies required – as the planet's finite fuel resources become ever-precious – are almost unimaginable.



In Clean Sky 2, the Engines ITD is building on the success of Clean Sky 1's SAGE, gearing up to deliver its main objectives which are to deliver substantial improvements in engine technology. In particular, the following challenges will be addressed:

  • Developing full engine and major engine system solutions that can deliver a step change reduction in emissions.
  • Taking a step-by-step approach to progressing the technology’s maturity or "Technology Readiness Level" (TRL), utilising design studies and rig tests to explore and understand the technologies under development, their system interactions and the risks associated with their implementation. The ultimate goal of the project is to achieve TRL6.



Seven demonstrators are planned, catering to the full spectrum of aircraft in commercial operations – from 4-19 seater aircraft in the SAT category – to the largest wide-body aircraft:


Ultra High Propulsive Efficiency (UHPE) demonstrator addressing Short / Medium Range aircraft market, 2014-2023:

Safran Aircraft Engines will lead the design, development and ground tests of a propulsion system demonstrator to validate the low pressure modules and nacelle technology bricks necessary to enable an Ultra High By-pass Ratio engine.

Baseline configuration for the demonstrator is made of new low pressure modules and nacelle parts integrated around an existing or adapted HP core in order to form the required ground demonstrator with a bypass ratio anticipated within the range 15-20. WP2 is aimed to attain TRL 5-6 maturation by mid 2022 for a set of specific technologies dedicated to the Ultra High Propulsive Efficiency concept.


Business aviation / Short range regional Turboprop Demonstrator, 2015-2020:

Safran Helicopter Engines leads the design, development and ground testing of an Integrated Power Plant System (IPPS) dedicated to short range turboprop applications. The IPPS demonstrator is based on the thermal core of the ARDIDEN3 turboshaft engine. Safran Helicopter Engines will coordinate the development and integration of the various IPPS modules (Power and Accessory gearbox, Propeller, Air intake & Nacelle). In parallel, developments for gas turbine components will be conducted (compressor, combustion chamber and turbine).


Advanced Geared Engine Configuration (HPC and LPT technology demonstration), 2015-2020:

This will include Design, development and ground testing of a new demonstrator to validate key enablers to reduce CO2 emissions and noise as well as engine weight. Key elements are: improvement of efficiencies, reduction of parasitic energy flows, innovative lightweight and temperature resistant materials, low pressure turbine and exhaust noises reduction.


Very High Bypass Ratio (VHBR) Large Turbofan demonstrator, 2014-2021:

Design, development, construction, ground testing and flight testing of an engine to demonstrate key technologies on a scale suitable for large engines. An existing engine will provide the core gas generator used for the demonstrator. Key technologies included in this demonstrator will be: an integrated low-pressure system for a high power very-high bypass ratio engine (fan, compressor, gearbox, LP turbine, VAN), Engine core optimisation and integration, and optimised control systems.


Very High Bypass Ratio (VHBR) Middle of Market Turbofan technology, 2014-2021:

The VHBR project includes the development and demonstration of technologies in each area to deliver validated power plant systems matured for implementation in full engine systems. Research and demonstration will focus on assessing the behaviour of fans at low speeds, fan pressure ratios and structural technology, aerodynamic and structural design of low pressure turbines for high speed operation. Also included will be  Systems Integration of novel accessory and power gearboxes, optimised power plant integration, compressor efficiency, and control & electrical power system technology developments.


Light weight and efficient jet-fuel reciprocating engine

The Small Aero-Engine Demonstration projects related to SATs (Small Air Transports) will focus on small fixed-wing aircraft in the general aviation domain, with power-plant solutions ranging from piston/diesel engines to small turboprop engines. These technologies will bring new solutions to replace old gasoline leaded fuel pistons or small turbines for single and twin engine aircraft.
The scope includes the development of a new 6-cylinder engine and the optimisation of its installation in a 9/10-seat aircraft, as well as core engine technologies testing for power density improvement, or evolutions on equipments like turbochargers, propellers and control system.


More Advanced European Small TurbopROp (MAESTRO)

MAESTRO will address the development, manufacturing and testing of a new and improved engine for the SAT market for application to aircraft of up to 19 passenger seats. Specific technical goals will be to deliver the next generation turboprop by delivering major improvements in engine technologies that focus around fuel efficiency, the extension of service life between overhauls and the reduction of noise footprint.


Tomorrow’s challenge, today’s call to action

Rolls-Royce's Market Outlook for the period 2014-2023 sees a need, globally, for 27,000 new aircraft, requiring 55,000 engines, spanning large passenger aircraft, regional planes, and business jets. Safran Aircraft Engines‘ forecast is that more than 34,000 new aircraft will be delivered in the civil aviation market by 2032. It's a huge market opportunity for the EU aviation industry to maintain and extend its global leadership, but also a major challenge to deliver radical new engine architectures and advanced technologies which are much needed to continue the emissions reductions and to meet overall sustainability targets to comply with ACARE and Flightpath 2050 Goals.



The Clean Sky initiative is already focusing on fuel efficiencies - and ecological compliance. The new technologies being developed within the Clean Sky ecosystem get to the heart of the challenge – more intelligent use of scarce resources and less impact on the environment. As a result, the global air transport of the future will be ready to operate aircraft equipped with the latest, cleanest and most efficient engines, thanks to Clean Sky.


CS2 Members: List of Participation