Brandon: You're deep in the underbelly of the Omega 13! Oh, it must be spectacular.
Gwen: It doesn't look like much to me. There's just these few walls and this dumb spinning fan that's in every single...Everything's Better with Spinning. That's why in any Air-Vent Passageway or air shaft, there will inevitably be one: A giant spinning fan. It usually seems to serve no purpose, other than to convey to the viewer that there is air flow there. Sometimes it will be spinning slowly, casting ominous shadows; often it will be a Deadly Rotary Fan of Doom if a character can come into contact with it. But it will always be there, somewhere.
- At the bottom of the Omega 13 shaft in Galaxy Quest is the ubiquitous dumb spinning fan - which is lampshaded by Gwen:
Brandon: You're deep in the underbelly of the Omega 13! Oh, it must be spectacular.Gwen: It doesn't look like much to me. There's just these few walls and this dumb spinning fan that's in every single...
- At the top of the fizzy lifting drink shaft in Willy Wonka & the Chocolate Factory.
- There's one in the air duct in The Fifth Element.
- In Aliens, an giant duct van casts an eery shadow in the scene where they find Newt in the duct system.
- In the air shaft in Alien3.
- Blade Runner arguably made the "big fan+steam+light shining through" a staple of Cyberpunk-Noirish media.
- Total Recall (1990). These can be found in the Martian colony's walls, where they pull in fresh air from other areas. At one point the Big Bad Cohaagen turns them off in one area in an attempt to suffocate the mutants who support Kuato.
- Seen in Iron Sky - ZCE.
- The heroines of Silent Hill find themselves in a duct system with a huge fan rotating in the background. See here.
- The hitwoman of Columbiana is not only small enough fit in an air duct but through the blades of the fans in them.(Which may or may not break one's suspension of disbelief that one so tiny can last in fights with those who...are not)
- In the Doctor Who episode "The End of The World", the Doctor having to get to a switch blocked by gigantic spinning fans in a giant air conditioner area.
- Alias: One episode ended on a Cliffhanger with Sydney struggling not to get pulled upwards through an air vent into a huge fan.
- Lord Zedd's lair in Mighty Morphin' Power Rangers has one right behind his evil throne.
- They're in almost every air duct in Half-Life.
- And in an air duct of Nova Prospekt in Half-Life 2.
- All over in the Underworld regions of Silent Hill. You're given the idea there must be huge air shafts behind them, but they're behind grates and inaccessible.
- There's one in the air vent of Gehn's study in Riven. Weirdly, the protagonist is able to squeeze into the tube once it's been turned off, even though the gap between the blades is a few inches at most.
- Some tunnels in the Metroid Prime series contain these. A few can be destroyed.
- Completely averted in Metal Gear Solid. Crawling around air ducts is a necessity, and there's not a single fan to be found in any of them.
- Deus Ex and Deus Ex: Human Revolution have duct fans as dead ends.
- A common element in the sewers levels of Crash Bandicoot 2. A few would even be so fast that one has to destroy it by ricocheting a nearby enemy (said enemy respawns after a few seconds for more ammo).
- Duke Nukem 3D starts out on a rooftop, with no way down except for an air duct that runs along the side of the building. Of course, Duke must shoot or kick the useless fan out of his way first.
- Shows up in the backdrop of the hazardous industrial world of Limbo.
- Happens in the Amerigo cinematic for StarCraft I .
- In The Secret of NIMH, as the mice and rats are escaping NIMH through an air vent a fan blows most of the mice to their deaths because they were lighter.
- In the third Futurama movie the crew sneaked into Mom's Alaskan base through the vents, the outer intakes had giant, red-hot spinning fans... one of which grazed Fry's butt.
- Obviously, air ducts do need to have a fan in them somewhere, but nearly all modern HVAC systems use centrifugal fans instead of the "axial" fans that appear in fiction. Centrifugal fans have lots of real-world engineering advantages (cheaper, quieter, more reliable, easier to scale up) but wouldn't look nearly as interesting from inside the duct, which is what matters in fiction.
- And that "somewhere" is usually special rooms that also contain air filters, AC, heat exchangers, dampers etc. These things is usually fitted into units that make it impossible to see a fan at all if one crawls around in the ducts. (Filters on the sucking side, dampers on the blowing and the other stuff somewhere in the middle.)
Hello, Unknown Troper. You'll need to get known to lend a hand here.