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LORD OPEN-ROTOR S2 Report Summary

Project ID: 338539
Funded under: FP7-JTI
Country: Switzerland

Final Report Summary - LORD OPEN-ROTOR S2 (LORD Engine Mounting System for the SAGE2 Open-Rotor demonstrator)

Executive Summary:
The goals of this project, for LORD, was to create an engine mount system capable of mounting the open rotor engine demonstrator. As such, the primary objectives of this project were:
1. Mount the SAGE2 open rotor engine demonstrator to the test stand.
2. Evaluate innovative noise control means within the mounting system.
3. Assess certification challenges as they may pertain to the engine mounting system.
4. Effectively transfer engine mounting design knowledge from the US technical centre to the European based technology group

LORD successfully deliver the Engine Mount System to the Topic Manager in October 2016, before the end of the project and in time for the assembly operation of the entire engine by the Topic Manager.
This system has been entirely design, build and test through LORD European engineering team, which benefit the many years of Experience of LORD Corporation in designing and developing aircraft engine attach and isolation system. The technology used for the system includes elastomeric components at the pylon interfaces, this technology provides the necessary compliance for the engine to operate efficiently, and reduce the vibration transmission from to the pylon.
Topic Manager global engine dynamic model has been used to define the proper characteristics of the elastomeric components and provide the best vibration reduction while controlling the overall motion of the engine.
Late involvement of LORD in this project, as well as the tight schedule and several update of the engine manufacturer requirements, limit the possibility to evaluate and develop innovative solutions to reduce noise and vibration.
Elastomeric components have been manufactured and tested in our US facilities, following the LORD aerospace Quality system, and test methodologies established for certification testing of engine mount systems.
The metallic structure has been designed and justified following the aerospace certification rules and requirements, so it can sustain the specified loads within the very challenging envelope space define to optimize the aerodynamic properties of the pylon.
The final design of the metallic structure is the results of multiple iterations based upon several update of loads requirements from the Engine Manufacturer affecting significantly the initial and update schedule and scope. LORD has leveraged its years of experience in project management in order to absorb the delays create by the update requirement and deliver the engine mount system in accordance to the engine manufacturer schedule.
The Open Rotor ground test is schedule to start early 2017. LORD will support the engine manufacturer until the end of the project even if remaining activities are not going to be covered by the CleanSky initiatives

Project Context and Objectives:
Originating in mid to late 1970’ies NASA concept studies, the open rotor engine has been shown to offer significant fuel savings over traditional ducted engines. By the mid to end of 1980’ies various demonstrators were built by General Electric and P&W/Allison, and finally flight tests conducted by McDonnell Douglas using an MD-80 series aircraft and by Boeing on a 727 series aircraft. The drop of fuel price in the late 1980’ies, combined with airline concerns on engine noise and technology maturity, however led to the cancellation of the open rotor projects.
Today, recent calls for increased environmental performances in aerospace along with research on open rotor blade design have renewed interest in open rotor engine architecture. In Europe, open rotor engines now feature on the SAGE 1 and SAGE 2 Clean Sky initiatives and is considered by Airbus as engine on their A30X, their next all-new single aisle airplane. This new generation of open rotor engines have led to a number of proposed aircraft architecture changes, as can be seen in figure 1 below in the A30X concept shown.

For example, the increase of blade diameter and necessary ground clearance on one hand and the increase of noise on the other have led to concept designs with the engines mounted on the aft fuselage and above the horizontal tail portion. This creates the necessary clearances and the blended horizontal / vertical tail provides some measure of far-field noise reduction. This concept however presents a challenge to the pylon and mounting system design, needing to mount the open rotor engine with a projected weight of 5 metric tonnes in an upright V-tail configuration.
The scope of the project is limited to the engine mounting system, which will attach the engine on one side by the means of links and bearings and integrate into the pylon structure on the other.

Aircraft engine mount systems in use currently are designed to transmit the engine thrust force to the airframe and to retain the engine on the aircraft under all specified certification conditions. This is normally achieved by the use of a two plane mounting system with lateral and vertical loads reacted at each plane and thrust being taken out at one of the two mounting planes. For some aircraft specific compliant elements, usually made from an elastomeric or metallic mesh material, are designed into the mounting systems to allow for isolation of the engine vibration from the airframe and a reduction in transmitted dynamic forces. This is usually done to provide for improvement in the aircraft interior cabin environment but also provide a reduction in airframe vibration benefiting the life of other airframe mounted equipment. The all metallic mount systems without compliant elements are typically termed as hard mounts and the systems with compliant elements are often termed isolated engine mounts.
Hard mount systems are typically designed to provide only 6 degrees of constraint to the engine and are often termed as isostatic mount systems. Using this approach, the compliance of the components within the system does not enter into the load calculations. These systems use bearing and linkages to control loading directions and to accommodate any thermal motion or misalignment. The hard mount systems are not designed to provide isolation of the engine vibration from the airframe, but are primarily structure to retain the engine on the aircraft and transmit thrust loading.
Hard mounted systems are typical on under-wing mounted engines and large commercial aircraft as well as some larger business aircraft with aft fuselage mounted engines. Examples include the Boeing 737-600/700/800, Airbus A320, and Bombardier CRJ.
Isolated engine mount systems are designed with the same structural requirements as hard mounted systems, but an additional compliance is added to provide additional isolation. These systems can be either isostatic or include additional constraints. As the stiffness in an over constrained compliant engine mounts is a known and controlled value, load distribution in these system is calculated using finite element approaches.
Elastomeric or metallic mesh elements are incorporated into the isolated engine mounts to provide the controlled compliance. The resulting mounts can provide isolation of the engine vibration while controlling the engine static motion.
Elastic engine mount systems are typically used on turbofan aircraft with aft fuselage mounted engines or on occasion with under-wing mounted engines. Aircraft using isolated systems include both small/medium business jets as well as larger commercial transports. On aircraft with fuselage mounting, the engine proximity to the passenger cabin and the direct noise/ vibration path found on these aircraft often requires the additional reduction of this type of mount system to meet the interior cabin noise and vibration goals. Examples of aircraft using isolated engine mounts include Boeing MD-90, Boeing 737-300/400/500, 767, 757, Embraer EMB145, Dassault Falcon F7X, and Cessna Citation X.
A variation of the isolated aircraft engine mount systems that was introduced by LORD to provide additional noise and vibration reduction was the Fluidlastic engine isolator. These isolators use an internal fluid mass and flow system within an elastomeric isolator to generate internal dynamic forces resulting in an effective reduction in the transmitted force to the airframe.

This project is related to the SAGE 2 counter-rotating open-rotor engine demonstrator, focused on the creation of an engine mount system capable of mounting the open rotor engine demonstrator. As such, the primary objectives of this project are:
1. Mount the SAGE2 open rotor engine demonstrator to the test stand.
2. Evaluate innovative noise control means within the mounting system.
3. Assess certification challenges as they may pertain to the engine mounting system.
4. Effectively transfer engine mounting design knowledge from the US technical centre to the European based technology group.

Project Results:
Despite a late involvement into the program, LORD was able to develop an EMS Concept to accommodate all the engine motions and reduce the energy transmitted to the pylon within 2 months.
LORD works closely with the Topic Manager to support the regular and ongoing changes in the requirements; though managed to accommodate design changes while manufacturing already started and support a delivery date in accordance with Open Rotor project schedule needs.
The Open Rotor engine weight and installation configuration, represented an important challenge for the EMS to sustain the Engine loads and reduce vibration within an extremely limited envelope space available. LORD EMS design maximise the use of the available space around the engine and inside the pylon without compromising the accessibility in order to facilitate the assembly of the complete system.
LORD EMS design integrates some unconventional manufacturing processes for Primary Structure Element, as TIG welding on the 2 main arms used to hold the engine on the cradle. Manufacturing processes and design parameters have been developed in collaboration with European Manufacturer and in accordance to Aerospace certification justification best practices.
Even if a deep optimization of the dynamic behaviour was not possible due to integration and time constrain, the Open Rotor engine dynamic model owned by Topic Manager shows Elastomeric mounts characteristics defined by LORD provide a 44% reduction of the energy transmitted to the Pylon in comparison to a rigid attachment solution.

Potential Impact:
The expected impact of the project efforts was to develop and demonstrate an engine mounting system capable of providing engine isolation to reduce airframe vibration and of meeting certification requirements. The work effort has utilized currently proven technology and has adapted this technology to meet the environmental and vibration level requirements of the SAGE 2 demonstration engine. The engine mounting system has therefore enabled the use of open rotor engines, with their associated savings in fuel consumption, while minimizing the vibration and therefore structures borne noise to the airframe.
The ground test has been rescheduled by the Engine Manufacturer and is supposed to happen during the first quarter of 2017. LORD will continue to support the Engine Manufacturer during that phase, taken into consideration that these activities are not going to be covered by the CleanSky initiatives, the project has been terminated on December 1st, 2016. Based on the results of the test and the outcome, LORD and the Engine Manufacturer will investigate the opportunity to publish the results as part the lessons learned and project closure activities.
A common dynamic model between Topic Manager and LORD Corporation is under development in order to efficiently correlate the dynamic behaviour of the Open Rotor Engine Mount System with the Engine ground test results. This model will provide Topic Manager and LORD Corporation the tool to identify possible optimisation of the EMS to increase the vibration reduction performance.

The primary objective of the project was to demonstrate how existing proprietary LORD technology can be adapted to the unique requirements of the open rotor engine and enhance its performance. Development of new IP was not a primary objective, and as such there was currently no plan to disseminate foreground IP. During the course of the project, there has been no IP created. Therefore, no patent application has been generated during the project

List of Websites:
We have not been able to develop a public website for the project.
Main contact details are:

Yannick Jacob - Manager, EMEA Mechanical Engineering acting as Research and Technical Lead for the project -
Alex Guyot Garcia - Senior Manager, Controlling - EMEA acting as Project Manager/Coordinator and Legal Entity Representative for the project -

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