A conventional shoulder-wing design with conventional empennage, no component of the BJ-1 exceeds 18 ft (5.5 m) in length, in order to facilitate building and storage in a domestic garage. Construction throughout was of wood, apart from a few mouldings (like the nosecone) made of fiberglass. The BJ-1 Dyna Mite first flew in 1966. The rough building sketches from Ben Janssons prototype design from 1963, were refined by Hank Thor and the BJ-1B Duster plans were released in 1971 featuring a lighter weight, extended wingspan and a lower canopy that required the pilot to fly it semi-reclined. By 1977, more than 200 sets of plans had been sold. In total 371 sets of plans were sold and DSK (Duster Sailplane Kits) sold about 169 kits.