SZD-31 Zefir 4 V02 (Polygon mesh 3D model) is available on CGTrader for $69. Original author: Dreamscape. Specs: 14451 polys, 7821 verts.
STL (Stereolithography, filesize: 260 KB), OBJ (OBJ, filesize: 550 KB), DWG (AutoCAD, filesize: 289 KB), DXF (DXF, filesize: 291 KB), LWO (Lightwave, filesize: 149 KB), TEXTURES (Textures, filesize: 1.46 MB), MAX (Autodesk 3ds Max, filesize: 165 KB), OTHER (Other, filesize: 435 KB), 3DS (3D Studio, filesize: 131 KB)