Patent RU-94032640-A (RU)
Inventor: AMIR JANTS G A
IPC: G01M9/08
Filed: 1994-09-08
Abstract: FIELD: experimental aeromechanics, in particular, designing and manufacture of models intended for tests in wind tunnels for investigation of problems of aerodynamics, flutter, divergence, reversal of controls, buffeting, aeroelastic stability of air- craft with control system. SUBSTANCE: the offered aerodynamic model has flexible frame 1, coverings 2 connected to the frame girders by means of ribs or frames. The coverings use the main (5) and additional cells of the wing, empennage or fuselage. The main cell of the slotless covering of composite material, for example of the wing, enveloping the frame from the top, sides, front and end, as well as the lower - additional cell of the slotless covering adjoining the main one with minimum possible gap 8, without any shoulders, have a stiffening, for example, in the form of foam plastic skin 9 connected to the ribs. The additional cell of the covering (and its parts of ribs 10) are connected to the upper (5 and 11) ones with the aid of locks 12 binding together the parts of slit ribs. The main parts of ribs 11 are connected to the frame-each with the aid of its attachments 13. Model finishing masses 14 are secured mainly on ribs. Ailerons, control surfaces, spoilers, model control linkage are also mounted on ribs. Vent holes in the covering are formed by discrete toes 15 or by continuous bands with calibrated vent holes, to which vent lines 16 are brought from the model inside. From the outside the vent holes are closed with a thin layer of transparent composite fabric 17, the holes are opened only before the test of the model in the wind tunnel. The front (8) and rear (9) cells of the covering are made detachable, if the profile of the hollow flexible frame is brought up to the wing profile. In the offered method first manufactured in the flexible frame of the model, for instance, the wing spar. Ribs with holes in their central part are manufactured and secured at the same time. Each of the ribs is composed of two parts; the main and additional ones connected by means of locks fixing the relative position of the parts. The rib main part enveloping the spar section from the top,, front and end of the spar has attachments to the spar rigidly connected to the mating members of the spar attachment. The ribs are removed and rigidities of spars in bending and torsion are measured. The main parts of the ribs are installed on the spar again, then the additional parts of the ribs are connected to them with the aid of locks. A skin made, for example, of foam plastic that stiffens the covering is sticked to the ribs over the entire outline of the profile. Venting of the covering is accomplished with the aid of discretely arranged toes or continuous bands with calibrated vent holes. For connection of the intramodel vent lines to the connections of the vent toes or bands feed ducts are formed in the composite covering with the aid of needle caps. A slot is cut between the main and additional cells of the covering. The covering cells are removed, and the frame spar rigidity is brought up to the necessary one in a similar way, for example, by sticking of additional layers of composite. Finishing loads, control linkage are installed, vent lines are connected, the main and then the additional covering cells are mounted. EFFECT: expanded abilities of aerodynamic and aeroelastic modelling due to manufacture and use of a universal model or its main replaceable components for highly accurate, operative and economical investigations of a complex of problems. 2 cl, 3 dwg