Based on the standard Starfleet design tree and hull components of the time, the Federation-class starships were bulkier sisters of the Constitution-class heavy cruisers. The dreadnoughts employed a different arrangement from Constitution-class, including a forward-facing shuttle bay, a four dish sensor/navigational deflector / tractor beam dish arrangement (including a single aft sensor dish) and most prominently, a third nacelle, all design elements largely abandoned in future starship development. (Star Trek III: The Search for Spock)
Ships of the class Edit
Background information Edit
The Federation-class starship was originally seen on a display in the Starfleet Academy's training simulation in Star Trek II: The Wrath of Khan. The display was a page pulled directly from Franz Joseph's Star Fleet Technical Manual.
The Technical Manual lists the USS Federation as being the prototype of the class.
The Motion Picture originally contained a voice-over in the beginning of the film for the dreadnought USS Entente, NCC-2120. This was a direct reference to the Technical Manual and its entries for Federation-class dreadnoughts. (The manual was heavily used as a reference for the first film.) While this line of dialogue remains intact on the laser-disk, VHS, and Beta releases of the film, the Director's Cut DVD explicitly muddles the track, making the line difficult to hear.
The concept of a three-nacelle starship has been derided by some as contrary to Gene Roddenberry's design requirements for Starfleet ships, violating both the "pairs" rule and the "nacelle line of sight" rule, but there is nothing in canon that mandates these rules (it is also possible that three-nacelle starships used only two of their nacelles at any given time, and the third is considered as spare, in case one of used nacelles would be rendered inoperable).
There are two ships that violate the "pairs" rules: the Niagara-class and the "off-timeline" version of the Galaxy-class are canon three-nacelled ships. There are many ships that violate the line of sight rules as well as several single nacelle vessels, including the Freedom-class, Kelvin-type, and Saladin-class. It is worth noting that Gene Roddenberry personally signed off on the Federation class in 1973, the schematic for the class is seen in canon, and one of her class is explicitly mentioned in the only Star Trek movie of which Gene Roddenberry himself was in charge.