A bush plane flew a scale model of a bigger plane

An aviation-history post shows a de Havilland Canada DHC-3 Otter flight-testing a scale model of the DHC-4 Caribou. Rather than rely only on a wind tunnel, engineers carried the model aloft on a working aircraft to see how the design behaved in real air. It is a charming reminder of how mid-century aircraft makers often tested ideas with improvised hardware, before simulation did most of the work.