Advances in Canadian Aviation
Refining a Proven Design – The Twin Otter
(Republished from the 29 January 1965 issue of The Voxair)
The de Havilland Aircraft of Canada has made considerable progress with the tooling, jigging and building of the first batch of five Twin Otters since the project was announced last September.
Although similar to the Otter (DHC-3) in fuselage cross section and basic wing form, the Twin Otter (DHC-6) inevitably calls for extensive tooling. While the first five aircraft will go through final assembly at the rate of one per month, tooling is designed to handle an output of two aircraft per month after DOT and FAA certification.
By the end of November, engineering information had been issued for five thousand of an estimated six thousand nine hundred parts per aircraft. Several of the major sub-assemblies for the first aircraft were then nearing completion and some second and third sets were in work. In the jig for the cockpit unit the framework was ready to accept skinning. Substantial progress was to be seen in the main wing assembly, fuselage rear end, cabin side panels.
Main assembly of the first, airframe is due to be completed late in January. The second set of components have been allocated for structural tests. The four other aircraft of the initial batch will follow at monthly intervals.
The final set of Pratt & Whitney PT-6 turboprop engines to power the Twin Otter have been delivered and are being made up into their individual power plants.
The PT6A-6 originally scheduled for this aircraft has been replaced by the PT6A-20 giving an additional 50 S.H.P. per engine, for maximum continuous power output which greatly increases single engine performance.
The first flight is scheduled for June 1965, leading to the certification, which is programmed for completion by the end of that year.