Sorry, I have to weigh in again. I probably have to blame myself for either not being precise or for having chosen the wrong approach to present my case.
As Greg Jein excellently concluded from the precise text of The Making of Star Trek
+ the starship status display from "Court-Martial" + the "Primary Phaser" schematic (http://startrekhistory.com/article4.html
) there is sufficient proof for the existence of "starships" that belong to a "Constitution Class".
The fact, that "Constitution" was an official name for one of the 12 starships selected by the producers, could
be a hint that some of these starships (e.g. those with a prefix beginning with "16") actually did belong to a "Constitution Class" but it is not hard evidence
(compare the USS Constellation
from TOS with the "Constellation Class" of TNG)!
Let's examine the "Primary Phaser" schematic in detail. A friend of mine from Australia who's very knowledgable about navy vessels in real life told me that the "Mark / MK" designation is exclusively used for devices (like the photon torpedos in ST) but never for naval vessels. Thus, I'm confident that the "MK IX/01" refers exclusively to the kind of primary phaser illustrated here as Scotty would apparently be interested what
kind of phaser he's looking at...
Where Greg Jein apparently failed, was the moment he insisted that the "MK IX/01" refers to the type of starship and
felt that "MK IX/01" refers to the USS Enterprise.
I think it's fair to say that everybody without a personal agenda would have immediately pointed out that the registry of the Enterprise
is "1701" which would have read "XVII/01" and not
"IX/01" or "901
Apparently, according to Jein's reasoning, the USS Eagle
) would be the only starship (next to a USS Constitution)
we could be certain of belonging to this "Constitution Class", if we were to follow Jein's theory.
TO CUT A LONG STORY SHORT:
The "Space Seed" script refers to Khan studying specifications of a "Constitution Class Starship".
This could be a historic design in the middle of the evolution path towards the Enterprise.
To understand how the Enterprise does
work, it is inevitable for an individual from the 20th Century to examine and grasp the technological (r)evolution.
Alternately the starships of the Enterprise Class may simply continue to use a basic, well proven technical design of an earlier Constitution Class.
There is no hint, mind hard evidence, whatsoever, that indicates that the Enterprise has to be a member of the Constitution Class!
To draw that conclusion remains entirely conjectural, but is neither compatible with the explicit "Enterprise Class Starship" statement from The Making of Star Trek
nor the in-universe explanation for "N° 1701" provided by Matt Jefferies.
Equally inconclusive is the quote from the novelization of TMP. In the proper context it merely does establish that the starships of the "Constitution Class" present the top-of-the-line in terms of firepower and armanent.
It has never been established that the starships of the 17th design like Enterprise
and her sister ships were supposed to have more firepower than the previous starships (of the 16th design).
Apparently, the Donatu V battle with the Klingons 25 years prior to events in TOS indicate a period of armed conflict requiring "battlecruiser" starships while - fortunately - by the more peaceful times of TOS "cruiser" starships are sufficient.
I'd like to think that for the war games in "The Ultimate Computer" the choice for an (inferior) starship of the 17th design was rather deliberate to show that the M-5 computer could easily beat two Enterprise Class sister ships + two heavier Constitution Class starships.