The deflection δ of the closed coil helical spring is
Where: W is the axial load
R is radius of the coil
n is the number of turns of coil
C is the modulus of rigidity
d is the diameter of the wire of the coil
1
\(\frac{{W{R^2}n}}{{8C{d^3}}}\)
2
\(\frac{{64\;W{R^3}n}}{{C{d^4}}}\)
3
\(\frac{{128\;W{R^3}n}}{{C{d^2}}}\)
4
\(\frac{{64\;W{R^2}n}}{{C{d^2}}}\)