When Diamond announced its diesel-powered Twin Star three years ago, we figured the company’s grasp on reality was, at best, tenuous. In the current market, who could possibly be interested in a new light twin? We were wrong, of course. Diamond has done well with the Twin Star and having flown the airplane, it reminds us of another light twin that appeared four decades earlier: Piper’s Twin Comanche.

Although they have little in common technologically, other than having wings, propellers and engines, the Twin Comanche and Twin Star share important attributes. Both are relatively light and small, are easy to handle and, above all else, they’re relatively fast and economical. …