Assume a blade with radius \(R\) is rotating with angular speed \(\Omega\) at a constant forward flight speed \(U\). Show that the problem can be modeled as a variable free stream: \(U s=U \sin (\omega t)+\Omega R\). 

(i) What will be the values of \(\lambda\) and \(\omega\) in terms of \(\Omega\) and R? 

(ii) Assuming that effective span of this blade starts at the \(10 \%\) span from the root find an expression for the lift coefficient using the strip theory, 

(iii) comment on the validity of your answer in terms of three dimensionality and the existence of the tip vortices.