Yesterday after work, my wife and I had to run some errands, you know the kind, grocery shop, pilgrimage to Menards for something for the house, and then we stopped to grab a bite to eat. On our way back home I noticed a UPS truck out on the road with something spinning on the roof, so I snapped a picture of it and asked Google what the heck is this thing, and the answer was much simpler than any idea I had about it. That white thing on the top is to help keep the inside of the truck cool during the summertime!

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When I first saw it spinning on top of the truck while it was being driven down County Road 75, I thought oh no the GPS housing is loose! But as we got a little closer I could just make out a small opening on the object. I then noticed whenever the truck stopped this thing would stop unless the wind started to blow then it would start spinning again. Well, I was completely wrong about the GPS guess, and I even found out the actual name of the spinning thing too.

Image Credit: Paul Shea/TSM
Image Credit: Paul Shea/TSM

The spinning white thing on top of the truck actually has a name, it's called a Flettner ventilator and it's job is to circulate air inside the back of the truck to keep both the packages and the temp in the back of the truck cool.

You might be wondering why doesn't UPS just put in an A/C unit? Well, that would be an option but UPS vehicles are constantly making stops to deliver with the door opening so much it wouldn't make much sense, so instead trucks are being outfitted with these Flettner ventilators.

The next time you see one of these vents spinning on the road, test your passengers to see if they know what it is, and if they don't know, tell them about it!

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