Natural laminar flow wings were flight tested, within a project called BLADE. A new outer laminar wing was fitted on the legacy A340-300 wing.
A large scale, low speed wind tunnel test in the DNW-LLF (Large Low speed Facility) was offered aiming at generating high quality data allowing flight clearance for the BLADE Flight Test Demonstrator providing know how for performing representative test for future laminar wings.
Wind tunnel results complemented results from CFD, especially in ground effect and stall conditions. Further testing allowed the assessment of basic longitudinal & lateral handling qualities characteristics of the large scale wind tunnel model.
Main objectives for the test were as follows:
- Check the installation effect of the outboard panel on the A340-300 Airbus flying demonstrator aircraft MSN 001, designated BLADE aircraft. This aircraft has an outer wing natural laminar flow (NLF) panel. Several sub goals are distinguished.
- Design study, ground effect, downwash and handling qualities (effect of flaps, aileron, spoiler, downwash, tails) in longitudinal and lateral direction.
- Study of the wing flow and stall behaviour mainly by use of tufts. Complementary information will be obtained by use of Infra-Red boundary layer transition detection.
- Deformation measurements by means of an optical measurements technique to establish the local attitude changes due to wing torsion. This information may help analysts to compare experimental NLF panel flow behaviour with theoretical results.
- In order to have a reference for the aerodynamics BLADE results, a set of back-to-back tested polars will be included for the A340 standard civil aircraft layout.
In the framework of the CleanSky project (Breakthrough Laminar Aircraft Model wind tunnel testing in Europe) designated with the acronym BLAME (project number: 632417 - Call identifier: SP1-JTI-CS-2013-02 - Topic addressed: JTI-CS-2013-02-SFWA-03-013) low-speed aerodynamic tests were carried out on a A340-300 aircraft model, designated as model 408DB1. The tests were performed in the closed 8 m x 6 m test section of the DNW-LLF low-speed wind tunnel. AIRBUS has adapted a 1:10.6 scale model of a A340-300 such as to represent the BLADE (breakthrough laminar aircraft demonstrator Europe) flying demonstrator. The BLADE aircraft was equipped with a natural laminar flow (NLF) panel.
To attain information about the transition location on the natural laminar flow panel Intra-Red Thermography was successfully applied in a large low speed wind tunnel under atmospheric conditions. Valuable knowledge on other measurement techniques (such as Stereo Pattern Recognition used for deformation measurements) was gathered in relation of the application of the techniques in large low-speed facilities.
Performance and handling quality assessment in a world class wind tunnel facility of the BLADE demonstrator aircraft.