The Enterprise, both TOS, DIS and Kelvin has 3 fins on the back of its nacelles. On the Kelvin-Enterprise, these actually open when the ship goes to warp, much like the deflector. But while the deflector aleays had a very clear purpose, I don't think I've ever heard anyone mention the fins, especially since they dissapeared in TNG. So, I'd love to know wether there are canon mentions of these fins.

  • 4
    Maybe you can provide some pictures, please? And highlight those fins somehow? I am not sure what you are talking about.
    – virolino
    Commented Nov 29, 2022 at 6:23
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    I think he means the parts labelled as "light grey intercooler" in this model painting guide. culttvman.com/main/…
    – Pete
    Commented Nov 29, 2022 at 6:44
  • You can see the fins easily on the Kelvin timeline Enterprise--when it is preparing to go to warp, the fins will rise up. Commented Nov 29, 2022 at 14:12
  • @Pete You're right--they're called "intercoolers" on blueprints. Commented Nov 29, 2022 at 14:18

1 Answer 1


The "warp fins," as some people call them, seem to be intercoolers. They serve as a cooling system for the warp engines. You can see a pair of fins at the end of each nacelle on the TOS Enterprise in the link provided by Pete in the comments and the blueprint below (from Cygnus X-1):

enter image description here

They are labeled as the "Post-Stage Flux Intercooler Assembly" (item no. 16). You can also see the fins clearly on the newly updated (again) DISCO Enterprise.

Another sheet from the same blueprints, however, shows that the fins are "Post-Stage Flux Tuners" (item no. 28):

enter image description here

The Star Trek reboot people really decided to emphasize the fins (for some reason), so they stand out (literally) when the Enterprise goes to warp:

enter image description here

This is what you were describing when you said that the fins/intercoolers "open."

After the original Enterprise, the intercooler fins disappear. The Excelsior class does have fins on its nacelles, but they are not intercoolers.
Although the intercooler fins disappear, the intercoolers are not gone, but placed elsewhere in the nacelle. The "engine intercoolers" (item no. 9) are shown in the Enterprise-D blueprint below:

enter image description here

So the fins seem to have served primarily as warp engine intercoolers before the fins were removed and the intercoolers were moved.

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