TeX/Latex - Cómo hago un resorte con curvatura

Saludos.... Agradeceria de antemano que me indicaran como puedo dibujar un resorte sobre un semicircunferencia, que paquete y comando requiero?

\documentclass[letterpaper,12pt]{article}
\usepackage{pst-all}

\psset{xunit=1cm,unit=1cm,fillcolor=white,linewidth=.3mm,arrowsize=5pt,coilarm=.25cm,coilwidth=.25cm}
\unitlength1cm
\begin{document}
\begin{picture}(0,4)(1,0)
%\psgrid[subgriddiv=1,griddots=10,gridlabels=7pt](0,0)(18,4)%
\put(1,.5){%
\psline[linecolor=gray,linestyle=dashed](2,0)(2,2.5)%
\psarc(2,0){1.5}{0}{180}\psline(0,0)(4,0)%
\psarc[linecolor=blue]{<-}(2,0){1.3}{90}{180}\put(1.3,.6){$\ell_0$} %
\psline[linecolor=red]{->}(2,0)(3,1.1)\put(2.6,.3){\small$R$}%
\rput{0}(2.2,1.8){\psccurve[fillstyle=solid,linecolor=green](1,.3)(.5,.5)(0,.4)(-.2,-.1)(0,.1)(.3,.2)(.4,0)(.3,-.2)(-.1,-.1)(0,-.4)(.4,-.5)(1,0)}%
\multido{\n=172+-7}{13}{\rput{\n}(2,0){\rput{90}(2,0){\psCoil[coilheight=.7,coilwidth=.5cm]{0}{360}}}}%
}
%
\put(6,.5){%
\psline[linecolor=gray,linestyle=dashed](2,0)(2,2.5)%
\rput{45}(2,0){\psline[linecolor=gray,linestyle=dashed](0,0)(2.5,0)}%
\psarc(2,0){1.5}{0}{180}\psline(0,0)(4,0)%
\psarc[linecolor=blue]{<-}(2,0){1.3}{90}{180}\put(1.3,.6){$\ell_0$} %
\psarc[linecolor=blue]{<-}(2,0){.6}{45}{180}\put(2.5,.2){\footnotesize$\ell$} %
\psarc[linecolor=red]{<-}(2,0){1.3}{45}{90}\put(2.1,.8){\footnotesize$\triangle\ell$} %
\rput{-60}(3.4,1.2){\psccurve[fillstyle=solid,linecolor=green](1,.3)(.5,.5)(0,.4)(-.2,-.1)(0,.1)(.3,.2)(.4,0)(.3,-.2)(-.1,-.1)(0,-.4)(.4,-.5)(1,0)}%
\multido{\n=172+-7}{19}{\rput{\n}(2,0){\rput{90}(2,0){\psCoil[coilheight=.7,coilwidth=.5cm]{0}{360}}}}%
}
\end{picture}
\end{document}