The authors study groups of rational loops of the neo-classical types, \(\text{SO}(n,\mathbb C)\), the conformal symplectic groups \(C\operatorname{Sp}(n,\mathbb C)\) and \(\mathbb G_2\). For maps into a Lie group, the notion of rationality is only defined after the choice of a representation. For a reductive group in most cases the adjoint representation or the standard representation are used. The authors generalize the concept of rationality of a loop to any representation. They describe sets of simple elements that are constructed explicitly as certain projections and prove then that those simple elements generate the rational loop groups of those types thus generalizing results Karen Uhlenbeck achieved for the rational loop groups of type \(\text{GL}(n,\mathbb C)\).