Periodic Reporting for period 2 - UP Wing (Ultra Performance Wing)
Reporting period: 2023-07-01 to 2024-06-30
The Ultra Performance Wing project (“UP wing”) will validate, down select, mature and demonstrate key technologies and provide the architectural integration of high aspect ratio wing concepts for targeted ultra-efficient Short/Medium Range aircraft (SMR), i.e. ~150-250 PAX and ~1000-3700km (~500-2000nm) range.
Independent of future energy carriers, energy efficiency is continuing to be a crucial challenge for future aircraft design. Even near-term solutions based on SAF (kerosene-like) fuels cannot be successful without enabling technologies for a significant improvement in energy efficiency, contributing to a visible reduction in emissions. In any case significantly improved energy efficiency is the only lever for maintaining acceptable affordability of future aircraft in operations, as all sustainable fuels will be expensive and limited in availability in the first decades of introduction.
The wing plays the dominating role for a further drastically drag & weight improved aircraft. The more the product concept may change the more the wing design concept has to be adapted.
Two main challenges will be addressed covering most of the potential design space:
1) Configuration1: An aircraft equipped with a novel ultra-high performance wing using SAF (sustainable “kerosene-like” fuels) targeting TRL4 by end of UP Wing phase1 (Q1/2026)
2) Configuration2: An aircraft equipped with a novel ultra-high performance wing exploiting non-drop-in fuels such as hydrogen in cryogenic storage will be investigated, including different types of propulsions.
The ambitions of the “integrated wing component” are targeting an increased efficiency of 10…13% in terms of aerodynamic improvement (drag) at minimum weight for Configuration1, in order to contribute to the targeted product high level ambition of minimum 30% fuel burn reduction at aircraft level compared to a 2020 reference state of the art aircraft with conventional technologies.
An overall aircraft level driven approach is crucial: While the building blocks for ultra-efficiency are largely similar, the overall a/c concept differs between either a wing component providing the fuel storage in case (a) and in case (b) e.g. a “dry wing” concept. These different pathways result in strong variations of the overall planform concept (overall aircraft interface, landing gear concept front spar/rear spar and moveables integration space), the industrial degrees of freedom up to operational aspects in terms of maintenance and service.
The “product integration backbone” therefore will address both identified pathways. Both pathways can also cover a staggered approach along the timeline. While (a) more targets a shorter term feasibility with an entry into service target pre 2035, (b) will encompass the full range of opportunity of a sustainable aircraft including novel energy carriers and optimisation up to realistic physical boundaries.
The top-level ambition of the two mentioned product classes results into following high-level objectives:
1. Minimise global warming impact (via Green House Gas emission reduction) by providing cutting edge technology for energy efficiency, i.e. minimised aerodynamic drag and system/structural
weight and integration of novel propulsion concepts
2. Guarantee safety & operational compliance by ensuring flight controls, loads, handling quality and structural design compliance to regulations, with reliable architectural concepts and qualified validation of advanced technology bricks beyond todays range of confidence
3. Ensure product viability by ensuring compliance to realistic industrial environments and drivers, such as physical integration and installation principles.
4. Minimise development time and development risks by applying a concurrent end-to-end driven approach along an integrated virtual modelling chain, considering all engineering & industrialisation aspects.
Independent of future energy carriers, energy efficiency is continuing to be a crucial challenge for future aircraft design. Even near-term solutions based on SAF (kerosene-like) fuels cannot be successful without enabling technologies for a significant improvement in energy efficiency, contributing to a visible reduction in emissions. In any case significantly improved energy efficiency is the only lever for maintaining acceptable affordability of future aircraft in operations, as all sustainable fuels will be expensive and limited in availability in the first decades of introduction.
The wing plays the dominating role for a further drastically drag & weight improved aircraft. The more the product concept may change the more the wing design concept has to be adapted.
Two main challenges will be addressed covering most of the potential design space:
1) Configuration1: An aircraft equipped with a novel ultra-high performance wing using SAF (sustainable “kerosene-like” fuels) targeting TRL4 by end of UP Wing phase1 (Q1/2026)
2) Configuration2: An aircraft equipped with a novel ultra-high performance wing exploiting non-drop-in fuels such as hydrogen in cryogenic storage will be investigated, including different types of propulsions.
The ambitions of the “integrated wing component” are targeting an increased efficiency of 10…13% in terms of aerodynamic improvement (drag) at minimum weight for Configuration1, in order to contribute to the targeted product high level ambition of minimum 30% fuel burn reduction at aircraft level compared to a 2020 reference state of the art aircraft with conventional technologies.
An overall aircraft level driven approach is crucial: While the building blocks for ultra-efficiency are largely similar, the overall a/c concept differs between either a wing component providing the fuel storage in case (a) and in case (b) e.g. a “dry wing” concept. These different pathways result in strong variations of the overall planform concept (overall aircraft interface, landing gear concept front spar/rear spar and moveables integration space), the industrial degrees of freedom up to operational aspects in terms of maintenance and service.
The “product integration backbone” therefore will address both identified pathways. Both pathways can also cover a staggered approach along the timeline. While (a) more targets a shorter term feasibility with an entry into service target pre 2035, (b) will encompass the full range of opportunity of a sustainable aircraft including novel energy carriers and optimisation up to realistic physical boundaries.
The top-level ambition of the two mentioned product classes results into following high-level objectives:
1. Minimise global warming impact (via Green House Gas emission reduction) by providing cutting edge technology for energy efficiency, i.e. minimised aerodynamic drag and system/structural
weight and integration of novel propulsion concepts
2. Guarantee safety & operational compliance by ensuring flight controls, loads, handling quality and structural design compliance to regulations, with reliable architectural concepts and qualified validation of advanced technology bricks beyond todays range of confidence
3. Ensure product viability by ensuring compliance to realistic industrial environments and drivers, such as physical integration and installation principles.
4. Minimise development time and development risks by applying a concurrent end-to-end driven approach along an integrated virtual modelling chain, considering all engineering & industrialisation aspects.
During the Reporting Period 2 all work packages advanced well, recovering some of the delays from the previous reporting period and delivering significant results.
Work package 1: The airfoils of the baseline wing (B-wing) have been improved by optimization for cruise conditions. Also the design of the stretched wing (S-Wing) with an increased wing span compared to the B-wing was delivered. The design includes the definition of the moveables architecture, the wing aerodynamic performance and the assessment of flutter.
Work package 2: Aerodynamic and structural design optimizations were conducted for the so-called dry wing configuration. Likewise, optimization loops for the structural designs of the wing strut were performed as well as the aerodynamic optimization of the wing movables. For the upcoming transonic wind tunnel tests on gust load alleviation technologies, the flexible wind tunnel model was designed, including the aerodynamic and the structural design. Additionally, the final concept of the gust generator for the planned wind tunnel test was selected and provided to the subcontractor for mechanical design and subsequent manufacturing. With regards to the UV Lidar activities, the DLR-built Nd:YAG laser for the flight test in 2025 was integrated into the flight test sub-assemblies. Ground operational tests for the UV Lidar have been carried out successfully. In the area of high-lift systems aerodynamics design, CFD parametric studies of four morphing droop nose configurations were completed. Likewise, preliminary 2D analysis has been completed to assess the capabilities of the CFD code in predicting the aerodynamics performance of active vortex generators used as spoilers.
In work package 3 the structural concept for the flaperon was selected and first designs completed, considering the most critical load cases. Additionally, the design of the support structure, the integration of the kinematics at the support stations and the overall integration of the flaperon into the wing is progressing well. For the advanced leading edge the Preliminary Design Review (PDR) was passed. The flexible panel connecting the leading edge to the wing box was optimized. In the working area of surface coating, the location of specimen placement on the flight test aircraft and ways of specimen fixtures were concluded. The Preliminary Design Review (PDR) was closed for both, the Trailing Edge High Lift system and for the Leading Edge Device Actuation system.
Work package 1: The airfoils of the baseline wing (B-wing) have been improved by optimization for cruise conditions. Also the design of the stretched wing (S-Wing) with an increased wing span compared to the B-wing was delivered. The design includes the definition of the moveables architecture, the wing aerodynamic performance and the assessment of flutter.
Work package 2: Aerodynamic and structural design optimizations were conducted for the so-called dry wing configuration. Likewise, optimization loops for the structural designs of the wing strut were performed as well as the aerodynamic optimization of the wing movables. For the upcoming transonic wind tunnel tests on gust load alleviation technologies, the flexible wind tunnel model was designed, including the aerodynamic and the structural design. Additionally, the final concept of the gust generator for the planned wind tunnel test was selected and provided to the subcontractor for mechanical design and subsequent manufacturing. With regards to the UV Lidar activities, the DLR-built Nd:YAG laser for the flight test in 2025 was integrated into the flight test sub-assemblies. Ground operational tests for the UV Lidar have been carried out successfully. In the area of high-lift systems aerodynamics design, CFD parametric studies of four morphing droop nose configurations were completed. Likewise, preliminary 2D analysis has been completed to assess the capabilities of the CFD code in predicting the aerodynamics performance of active vortex generators used as spoilers.
In work package 3 the structural concept for the flaperon was selected and first designs completed, considering the most critical load cases. Additionally, the design of the support structure, the integration of the kinematics at the support stations and the overall integration of the flaperon into the wing is progressing well. For the advanced leading edge the Preliminary Design Review (PDR) was passed. The flexible panel connecting the leading edge to the wing box was optimized. In the working area of surface coating, the location of specimen placement on the flight test aircraft and ways of specimen fixtures were concluded. The Preliminary Design Review (PDR) was closed for both, the Trailing Edge High Lift system and for the Leading Edge Device Actuation system.
The findings achieved so far during Reporting Period 2 are confirming some of the major expected results beyond the state of art:
- Optimal control design approaches for dynamic gust load control at transonic speeds will be developed. They will take the combined requirements and the interaction of load control and flight control into consideration.
- The maturation of Ultra-Violet Lidar technologies to be used for a more effective dynamic gust load control.
- Highly integrated movable designs (wing leading and trailing edge) for high aspect ratio wings - structural and functional demonstration of the concepts for HAR wings
- Aerodynamic and structural design optimizations for the so-called dry wing configuration
- Optimal control design approaches for dynamic gust load control at transonic speeds will be developed. They will take the combined requirements and the interaction of load control and flight control into consideration.
- The maturation of Ultra-Violet Lidar technologies to be used for a more effective dynamic gust load control.
- Highly integrated movable designs (wing leading and trailing edge) for high aspect ratio wings - structural and functional demonstration of the concepts for HAR wings
- Aerodynamic and structural design optimizations for the so-called dry wing configuration