The prototype of the DHC-3 Otter, first flown in 1951 as CF-DYK-X, received an 'experimental' military serial but remained with the DHC factory and was used as a flying wind tunnel in 1957-58, carrying a DHC-4 Caribou model with an enormous vertical tail. It also tested the external carrying of a canoe by the Otter. Note the traditional wheel covers with DH logo. Photo from: Nationaal Archief (Netherlands)
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