1. aircraft bh [mm] 12450 880 880 c0;h [mm] 206 bw [mm] ≈ 34000 2400 1300 c0;w [mm] 452.5 lf [mm] ≈ 34000 2400 2050 df [mm] ≈ 4000 282 280 number at the horizontal tailplane. For a typical tailplane geometry (aspect ratio 4:5 and taper ratio 0:42) Reynolds numbers about Re ≈ 1:0·106can be realised in the test section of the wind tunnel MUB with a cross section of 1:3m square. In our concept the span of the tailplane is about 68%ofthetestsectionwidthleadingtoameanaerodynamic chord of 200mm. The main wing is clipped and serves as the model support. Out of the variety of possible aircraft geometries a typical single-aisle, 100 seat aircraft was chosen to form the geometric base of the generic model. The dimensions of the closed test section determine wind tunnel wall interferences as mentioned by Krynytzky2and require an aerodynamic redesign of the main wing to keep the level of downwash at the tailplane.
2. At first an industrial airfoil for horizontal tailplanes was analysed using the airfoil code XFOIL by Drela.5Concerning the pressure distribution, this airfoil was compared to two airfoils of the LWK-series showing flow separation in wind tunnel tests via leading-edge stall (LWK 80-120) and trailing-edge stall (LWK 80-150) (investigations conducted by Althaus6). From the results displayed in figure 6 at equal cp;minand α close to cl;maxit is obvious that both LWK airfoils show a steeper gradient in the region of pressure increase. Both LWK airfoils have a shorter laminar separation bubble in comparison to the industrial airfoil, denoted by the plateau length of the pressure distribution. This indicates that the industrial tailplane airfoil does not separate via leading-edge stall, despite the appearance of a laminar separation bubble.
3. 0 0.2 0.4 0.6 0.8 1.0 -0.1 0.0 0.1 x/c
4. industr. HTP airfoil, α-α0=-14° LWK 80-120, α-α0=10.9°,XFOIL LWK 80-120, Experiment[Althaus] LWK 80-150, α-α0=13.8°,XFOIL LWK 80-150, Experiment[Althaus] x/c
5. A. Layout of the Model and Instrumentation The structural layout in figure 8 shows the resulting wind tunnel model. It can be divided into a front part generating the necessary flow conditions at the horizontal tailplane, including the main wing and the fuselage up to the disjunction ahead of the HTP, and a rear part, consisting of tail and tailplanes with 30% chord flaps. Rear fuselage and the horizontal tailplanes are manufactured of carbon fibre reinforced epoxy. The complete fuselage is 2050mm long and has an axially symmetric section of 280mm in diameter. The rear