Buzz
For countless people, the sight of a UPS truck is as thrilling as catching a glimpse of an ice cream truck. Drivers dressed in their standard brown uniforms are typically delivering something you need (or want) from Amazon or other mail-order businesses.
But these trucks come with some unique features. For instance, drivers avoid turning left whenever possible. (The company recommends against left turns because they disrupt traffic flow, resulting in lost time and wasted fuel.) You'll also often notice an unusual spinning device on the roof.
That strange apparatus is known as a Flettner ventilator, and its function is quite simple: it keeps the air circulating inside the vehicle. UPS trucks—which the company refers to as package cars—can't effectively use air conditioning since the doors remain open for easy access while drivers load and unload packages.
The Flettner ventilator helps keep the cabin and cargo area cool, especially in the summer months, by circulating air. These wind-powered ventilators spin when the truck is moving—or on windy days—moving air around. Flettner claims the fan can lower the truck’s interior temperature by 10 to 15 degrees. Flettner ventilators aren’t limited to just UPS trucks; they’re also commonly seen on Amazon delivery vehicles and other freight trucks.
If you're dreaming of owning a retired UPS package car, complete with a Flettner ventilator, you're likely out of luck. The company doesn’t permit the resale of its fleet vehicles. Older models are either repurposed for lighter internal duties or scrapped altogether.
