Well, you might ask the Sikorsky archives but, somehow, I doubt they would know. My guess is that it is just what it says in the article, a model. That indicates to me that it is not necessarily related to a formal project.
As a Sikorsky fan, I find the many illustrations in the Sikorsky Archive Newsletters interesting but most of them seem, I my opinion, to be artist impressions which were distantly related to a real life project. I would therefore be reluctant to consider them as 'projects'.
Possibly the letters DS, that have been referred to various times, means Design Studies. When does a 'design study' become a 'project'? I do not know, but I would guess a 'project' is something that you do against an identified requirement by a potential customer of group of customers.
What I am trying to say, of the many Sikorsky drawings we see, the best that you may get is a file number of the drawing, and not a real S for Sikorsky number. The only one that would know this file number are the guys at the Sikorsky archive.
But keep posting these nice pieces of art work.
