Iampaseo
The point I was trying to make, in my clumsy way, was that if only for some semblance of corporate continuity, designations have tended to be contiguous, with "JT", i.e. "jet turbine" being the same for P&W until a few decades ago when they went to a new system based, among other things, on the thrust of the engine. Until then, the sequential arrangement was quite clear, i.e. "JT-3" (J-57), followed by "JT-4"(J-75), etc. Of course, even this can still be confusing when one notes that the next developement, the "JT-8", has a LOWER(!!) military designation "J-52" than either the J-57, and J-75, both of which it is clearly a technological successor. In any case, as if that wasn't enough, I'm having a serious problem with the allegation, offered in several sites, that BOTH(!!!) the J-52, and the J-58 were scaled down descendants of the massive J-91.
As I've noted before, externally, the basic J-58 looks roughly like a J-75, minus the N-2 casing, as well as the distinctive "bump" in the diffuser casing of the J-57. By contrast, the J-52 (i.e. JT-8) looks like nothing more than a "miniature J-75 (JT-4)", at least as it appeared to me in the "dash-4" for each engine, as I gleaned when thumbing through each. Not insignificantly, the site claiming common ancestry with the J-91 then shows a cross section, allegedly of the JT-8 (J-52), that looks nothing at all like what I saw in the tech manuals. Specifically, the JT-3 through JT-8 had an N-1 in which the hub was parallel to the axis and the casing tapered inward, moving rearwardly, and an N-2, in which the casing was of a constant diameter while the hub increased as one moved towards the final stages. In the view provided at this one site, the arrangement was REVERSED(!!), giving an external profile unlike anything I'd even seen from P&W, and roughly resembling a RR Avon, but with the compressor divided into two separate sections.
Having been "professionally aquainted" with the JT-8 from both extremes, beginning with its first employment as the J-52, still too "hot" and unreliable to be used on a manned aircraft, instead driving the GAM-77 Hound Dog missile, of which the B-52 I crewed carried two, and its "fully tamed" ultimate application as the JT-8D turbofan, three of which, drove the B-727 airliner, countless numbers of which, I serviced, while employed at United Air Lines, after leaving the service, not to mention watchng the RM-8 afterburning version of the turbofan, drive the Saab J-37, a spectacular demonstrator at air shows of the real meaning of "specific excess power", I know what one looks like, and now stand even more confused about the P&W lineage than before. HELP!!!
P.S. Have also learned of a planned genuine turbofan version of the J-58 that was the first proposal for propulsion of the L-2000, along with other claims that the core of the actual JTF-17 was, in fact, nothing but a modified J-58.
Any info there, anyone?
Am at least realising substantial savings on haircuts, as ripping it out over this stuff seems to work fairly well.