It looks like 1986 all over again
Amazing racket. ThanksI just picked up a mystery Adidas of my own from a collector in North Carolina, who got it from either Hans or a German seller a while back. Based on the aerofoil beam profile and butt cap, I would date it to 1988-1989, but it is furnished with individual grommets and no bumper! As there is no model name displayed on the frame, I am tempted to identify this as a prototype, even though it is fully finished like a production racquet. In the past, I had come across other prototypes that came with individual grommets and no bumper, so maybe that's another reason to see it as a trial racquet.
But what exactly were they trying to accomplish with this design? It's like a quarter-finished Madeline Hauptman string job with an entirely conventional center. One of Hauptman's rationales for her string pattern was to keep the strings from shifting on impact, so as to produce a more consistent ball response and reduce string wear. By ignoring the center of the string bed where ball contact actually occurs, this quarter-madeline string job is almost as big a pain in the rear to produce as the full version, but provides none of the benefits where it matters! The only thing I can think of is that perhaps the extra spiderweb would stiffen the periphery and cause the string bed to behave as though it was under somewhat higher tension than normal (especially away from the center line), thus improving control to some degree compared to a conventionally-strung racquet? There is also (very) slightly more mass surrounding the point of impact from the extra strings, which might improve stability without deadening the string response? The fact that we don't see many of these racquets around (this is the first and only one I've come across so far) suggests that whatever benefit they expected to derive from this design ultimately failed to justify the cost of implementing the overly complex features.
Just to be clear, this is a factory string job on an NOS frame. The (white) grommets are different for the holes that contain extra diagonal strings. If anyone here knows what this model is called, please chime in!