oLAF - Evaluate the potential of active load alleviation for efficient long-range aircraft

Influence of active load reduction
Effect of active load alleviation on the distributions of aerodynamic loads (left) and bending moment (right)

What potential for increasing efficiency is offered by the use of active load alleviation technologies in the design of long-range aircraft? Researchers in the DLR project Optimal Load Adaptive Aircraft (oLAF) are investigating this central question. Advantages of the extensive use of load alleviation technologies include:

  • reduced structural weight
  • lower fuel consumption
  • reduced operating costs
  • lower emissions

With the objective of a highly integrated design process driven by load reduction aspects from the outset, DLR researchers in oLAF are designing and optimizing a load-optimal long-range aircraft - using predominantly high-fidelity coupled numerical methods for aerodynamics, structures, aeroelasticity, loads, flight control and systems. Incorporating the new load-reduction concepts developed in the project, the researchers will evaluate the effects of aggressive load control on performance, operations and maintenance in comparison to a reference design that only considers conventional load alleviation measures (according to today's industrial state of the art). At the same time, existing simulation methods and processes for the multidisciplinary analysis, design and optimization of loads-adaptive aircraft will be further developed and the additional potential improvements resulting from the process enhancements will be evaluated by applying them to the design task. The central result of the project is the actual virtual product of an aircraft design with maximum load reduction that stands up to evaluation from an industrial point of view.

The Institute of Aerodynamics and Flow Technology is leading the project together with the Institute of Aeroelasticity. Among other things, the scientists coordinate all design stages towards the loads-optimal aircraft with regard to a consistent overall aircraft design, including the performance of multidisciplinary wing optimization, detailed aerodynamic optimization and performance evaluation. They also perform detailed analyses of the effectiveness of selected control surface-based technologies for load control and redistribution. The Institute of Aerodynamics and Flow Technology is leading the design of the oLAF validation and demonstration experiments on active load control, focusing on the aerodynamic design of the wind tunnel models and associated instrumentations. The scientists are also involved in further developing DLR’s modular and efficient collaborative MDO process for aircraft design based on high-fidelity numerical methods.

oLAF - Optimally Load-adaptive Aircraft
1/2020 - 12/2023
  • DLR Institute of Aerodynamics and Flow Technology (Coordinator)
  • DLR Institute of Aeroelasticity (Coordinator)
  • DLR Institute of Propulsion Technology
  • DLR Institute of Composite Structures and Adaptive Systems
  • DLR Institute of Flight Systems
  • DLR Institute of Maintenance, Repair and Overhaul
  • DLR Institute of System Architectures in Aeronautics
  • DLR Institute of Software Methods for Product Virtualization
  • DLR Institute of System Dynamics and Control
  • Systemhaus Technik (DLR)
  • German-Dutch Wind Tunnels (DNW)


Institute of Aerodynamics and Flow Technology