The 91 was designed in the 1930s to fulfil an order of Pan Am, they were looking for a small airliner to serve in their river routes (China’s Yangtze and Brazil’s Amazon). The result was this advanced, but somewhat funny looking single engine flying boat with its engine mounted on a pylon high above the fuselage. The “Baby Clipper” turned out to be a quite efficient aircraft, but sadly it didn’t enjoyed a long production run; in fact only 4 were built.
Depicted in this lovely photo is the “Virgen de Chamorro,” the first prototype. Its gained that nickname when it took part in the Spanish Civil War. Curiously it was bought by the Republicans, but operated by the Nationalists after they captured the ship which was taking it to Spain.
By the way, I’m a BIG fan of this engine configuration.