Intrepid-class with raised pylons while at warp
The variable geometry pylon is a feature first introduced to Federation starships around 2370.
The warp nacelles have the ability to be raised into position for warp speeds, then lowered into a more streamlined position when at slower-than-light speeds. The Template:ShipClass starships were equipped with this feature, examples of which include the USS Voyager and the USS Bellerophon. (VOY: "Caretaker", DS9: "Inter Arma Enim Silent Leges" et al)
The pylons were raised anytime the ship's warp field was at power levels above idle, even if not used for propulsive effect. (VOY: "Learning Curve")
The Intrepid-class is the only starship class to be seen to incorporate this design feature within the canon Star Trek universe.
Background
- The first time the concept of variable-geometry warp nacelle pylons is mentioned anywhere is in the Star Trek: The Next Generation Technical Manual in the section dealing with preliminary concepts for future starships. The goal of these pylons is to improve engine efficiency by optimizing field stress when the ship travels extended journeys at warp 8+ velocity.
- According to the unpublished VOY Season 1 edition of the Star Trek: Voyager Technical Manual, by Rick Sternbach and Michael Okuda, it was suggested that because of the variable geometry pylons, warp fields might no longer have a negative impact on habitable worlds as established in TNG: "Force of Nature". According to the VOY Season 7 episode VOY: "Renaissance Man", Voyager's warp drive was however still a conventional space-time fabric harming conventional warp drive.