That bend is needed in order to change rotational motion of the blades into the linear motion of moving air.
It is most likely the momentum that carries the blades spinning, when you switch the fan off the energy doesn't completely disappear , it exists and still pushes the blades round.
On the blades
Keeps your fingers and other things out of the fan blades.
Clockwise
Likely causes- the blades have a buildup of dirt/dust, making them unbalanced. Use spray cleaner, wipe blades clean. Other possibility- bearings of fan motor have worn, permitting fan to wobble. Replace fan motor.
One thing that happens is the fan blades on the transmission get bent up into the drive belt and the fan blades throws the belt. The right way to fix is is to replace the fan, but you can bend the fan blades down by hand without removing anything and it seems to work just as well.
It's because the blades are getting jammed up and your challenge is to find out what it is.
Check the blades of the radiator cooling fan. If any of the blades are damaged, bent or broken, your vehicle will vibrate severely when the fan motor is on. Note that auto manufacturers often offset the fan blades so that they are not evenly spaced around the shaft. Engineers have determined that fans make less noise when the blades are offset, so there really is no way for you to just look at a fan to see if it's bent. You'll need to examine it to see if anything is missing or a piece is damaged. Also look for mud, debris or anything that has stuck to the blades that may result in an off-balanced blade.
The fan blades are turned by an electrical motor.
A twin window fan is considered to have two fan blades. Holmes is one of many manufacturers of such a fan. In reality, a window fan will have at least three blades per fan unit with a twin fan have 6 blades total.
the park tab is bent. it is a thick piece of metal that must be bent back slightly toward the wiper motor with a hammer or plyers. I assume this issue started when there was snow/ice on the windshield?
The fan blades.
Replacement fan blades can be bought from a number of stores. Retail stores including Home Depot and Lowes sell fan blades. Online Amazon and the auction site eBay have a range of both new and used replacement fan blades.
a fan moves air with fan blades.
Sounds like one of the fan blades are loose, or bent or out of balance. By saying whopping noise points to a problem with uneven air currents.
nothing a fan with three blades is just weaker and smaller than a fan with four blades! <3
it will make fan heavy and thus consume more power as compare to 3 blades fan