ACFA 2020 was a collaborative research project funded by the European Commission under the Seventh Research Framework Programme (FP7). The project dealt with innovative active control concepts for ultra efficient 2020 aircraft configurations like the blended wing body (BWB) aircraft. The Advisory Council for Aeronautics Research in Europe (ACARE) formulated the "ACARE VISION 2020", which aimed for:
- 50% reduced fuel consumption and related CO2 emissions per passenger-kilometre;
- reduction of external noise by 4-5 dB and by 10 dB per operation in the short and long terms, respectively. Meeting these goals is very important to minimise the environmental impact of air traffic but also of vital interest for the aircraft industry to enable future growth.
Blended Wing Body type aircraft configurations are seen as the most promising future concept to fulfil the ACARE VISION 2020 goals because aircraft efficiency can be dramatically increased through minimisation of the wetted area and by reduced structural weight.
The main objectives of ACFA 2020 were to provide robust as well as adaptive multi-channel control architectures for loads alleviation and improvement of ride comfort and handling qualities on BWB type aircrafts, as well as the design of a new ultra efficient 450 passenger BWB type aircraft. The objective of the designed controllers is an ambitious improvement of ride comfort and handling qualities, as well as load reduction on BWB type aircraft. Due to the unconventional placement of control surfaces, BWB type aircrafts require multi-channel control architectures for manoeuvres as well as for active rigid body and vibration control. This is regarded as technology step compared to state-of-the-art single-channel controllers generally used for conventional aircraft configurations.
Moreover promising algorithms such as adaptive feed-forward control and neural network control for active control of BWB type aircrafts will be investigated in ACFA 2020. These multi-channel algorithms will be applied to the large flying wing aircraft designed in the VELA and NACRE project as well as to a newly designed ultra efficient 450 passenger aircraft. For this 450 passenger aircraft design a flying wing and an ultra wide body fuselage aircraft with carry-through wing box will be compared and the configuration which promises highest efficiency with respect to fuel burn will be retained for a more detailed design. Based on the attained loads reduction due to the developed active control systems, the structure of this new 450 passenger aircraft will be resized with the goal of an ambitious weight saving for further improvement of fuel efficiency.
The BWB configuration also offers a great potential for the minimisation of noise signature through integration of the engine over the rear fuselage or in the airframe and also due to the generally higher wing area/weight ratio, which allows for a simplified high-lift system. The structural weight of BWB type aircrafts can be further minimised thanks to the effect of active MIMO control developed in ACFA 2020. Therefore ACFA 2020 strongly contributes to meet the ACARE 2020 goals.
Blended Wing Body aircraft design:
The pre-design of a 450 passenger blended wing body aircraft is finished. Major objectives for aircraft efficiency were achieved.
Dynamic Modelling of NACRE Blended Wing Body Aircraft:
Dynamic models are forming the basis for the controller design. For the large NACRE blended wing body aircraft the generation of dynamic models based on a refined Finite Element Model and aerodynamic data.
Verification of the real-time performance of an adaptive feed-forward control concept:
In order to reduce turbulence induced structural vibrations an adaptive feedforward control concept of EADS-IW is verified by flight tests with the ATTAS aircraft of DLR. Information from a flight log sensor at the nose boom is used to compensate structural vibrations caused by turbulences.
Innovating for the future (technology and behaviour): a European Transport Research and Innovation Policy
The results of this project need further research on the same areas as this project.