The axial thrust provided by 6 identical mechanical helical springs on a plate clutch of a motor vehicle is 1.8 kN. Outside diameter of the coils is 28 mm and maximum compression is limited to 30 mm. Design the mechanical helical springs for the clutch (Display: selected material, d, D, C, OD, ID, Na, Nt, Ls, Lo, (Lo)cr, ns). Use as wound spring with square & ground ends. The wire sizes in stock are 3.175 mm, 3.225 mm, 3.325 mm, 3.325 mm, and 3.375 mm.