HOLDING STRUCTURE AND MECHANISM FOR THE DISCRETE MODIFICATION OF THE INCIDENCE OF AERODYNAMIC MODELS FASTENED OUTSIDE THE TEST CHAMBER OF A SUBSONIC WIND TUNNEL

摘要

The invention relates to a structure for holding a model to be tested outside an aerodynamic tunnel, when the aerodynamic loads occurring on the model while testing exceed the measuring capacity of the external balance which a subsonic wind tunnel is provided with. The claimed structure comprises two frames (1 and 2) whereto there are fastened some pairs of horizontal beams (3, 4 and 5, 6), on each pair of horizontal beams (3, 4 and 5, 6) there being fastened some frames (9 and 10) by means of four elbow pieces (7 and 8), each frame having a horizontal plane symmetry axis which coincides with a reference horizontal plane of a model (M) to be tested, the frames (9 and 10) being stiffened by the horizontal beams (3, 4 and 5, 6), each of them with two bracings (11 and 12) on each closed contour of the frames (9 and 10) there being located a seating plate (13 and 14) whereon there are mounted some roller friction bearings (15 and 16), the model (M) to be tested being provided at its ends with two rotation axles (17 and 18), some mobile indexing plates (19 and 20) being secured to the rotation axles (17 and 18) by means of some clamping washers (24 and 25) and sliding on some fixed indexing plates, attached with some screws to the seating plates (13, 14), the fixed indexing plate (26) being provided with some indexing holes (28) located on the same circular arcs as some indexing holes (23) on the mobile indexing plate (19) in a range of angles from -15° to + 25°, with a pitch of 1°, symmetrically located in relation to the horizontal reference plane of the model (M) to be tested.