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Nacelle cowl NExt generation Opening System

Periodic Reporting for period 1 - NNEOS (Nacelle cowl NExt generation Opening System)

Reporting period: 2019-10-01 to 2021-03-31

With the new UHBR engines, the design of cowls is moving towards a split concept, which divides the thrust reverser cowling system in two parts: external and internal cowls. The internal cowls bring new challenges to the cowl opening system, due to the highly constraint space allocation, high temperature and vibration environment.

NNEOS will develop an innovative nacelle cowl opening system based on electromechanical actuation that will allow complete accessibility to the engine and nacelle components and consequently will help to drastically improve maintainability of the whole system. The NNEOS concept will be compact, safe, reliable and easy to operate and will be able to withstand the harsh environmental conditions required.
In addition, NNEOS concept integrates dual functionality to both lock and release the cowls, which will bring significant progress beyond the state of the art, reducing the part count, the space and the weight of the equipment needed to operate the thrust reverser or the fan cowls.

Main objectives of the project:
-Improve safety and accessibility to engine zones for maintenance/reparation through the development of an
electromechanical actuator that integrates the functionalities of opening/closing the cowls as well as holding them at
the open position during maintenance task
-Optimize weight and dimensions with a design that favours the integration within the nacelle available space
envelope:
-At a system level, provide a potential reduction for the volume required for the equipment by 15%
-At a system level, the aim is to achieve a 10% weight reduction associated to the system and connections when
compared to the current systems being used.
-Contribute to the reduction of the development time of the future engine architectures by 10%, through the
optimisation of system integration for the power plant systems Provide a friendly design that is easy to use but ensures
a safe operation of the nacelles
-Bring the technology to TRL5.
During this first half of the project the following tasks have been completed:
- Specification definition in close collaboration between the topic manager
-Preliminary design is closed and presented to the topic manager
- Detail design has been started
- Test plan has been defined.
Temperature constraints are a significant challenge in the development of NNEOS equipment, which faces the challenge to withstand temperatures as high as 250 ºC without degradation of system performance and durability, as per the technical specification.

Whilst regular metallic materials do not present major problems with these temperatures, design for manufacturing considering changes in tolerance and mechanical properties with temperature can be challenging. Additionally, such environment may be specially threatening for electrical (motor) and electronic components as well as for mechanical elements that need to be greased for their correct operation and other piece of equipment. Several tasks have been carried out to evaluate the state of the art for the following components, and define the necessary additional developments to undertake within this project for the NNEOS equipment to be able to operate under said environment:

•Electrical Motor: electrical motors fitted for this kind of application are far from reaching these temperatures. Between the newest developments for harsh environments some equipment can be found that are able to cope with ambient temperatures in the range of 200 ºC - 240ºC , but no existing equipment fits the range of power and the totality of requirements specified. Therefore, a new motor specifically designed for this project will be designed.
•Electronics Components: current stat of the art technology for electronic components does not reach the temperature required. Thermal analysis carried out during T2.1 demonstrates that external cooling is necessary for control electronics to be integrated within the actuator.
•Study of variation of manufacturing tolerances and mechanical properties for metallic parts, bearings, sealings, lubrication solutions, electrical cabling and connectors, etc: a detail study for state of the art technology has been carried out in order to detect the best alternatives to be used and the necessary improvements to be included in the design.
First model of actuator