|Quoting TF39 (Reply 4):|
old type of fastener - pronounced like Zeus or Zoos. It is a quick-opening, quick-action type of fastener. We had them on inspection panels, APU cowelings, etc. Google "Zeus fastner" to see the images.
Dzus fasteners, I hated them because they didn’t last.
Quite often the “S” spring the fastener latched on to would rust out or just break from use, the open jaws that grabbed the “S” spring would break off or open wide enough that it would not grab the spring, the slot in the head of the Dzus fastener would wear out and last but not least, they would rust.
The cowling on my 1964 C-150 was held on with PK
sheetmetal screws, which were time consuming to remove every time I worked on the engine, so I converted the cowling over to Dzus fasteners, which reduced the time to remove the cowling, but were nothing but problems with all the above mentioned.
In my restoration of my airplane, I probable will change over to cam locks if the holes in the cowling are not to big to take the locks, I had to enlarge the holes to take the Dzus fasteners
In the early C-150’s the cowling was mounted directly to the fuselage, so the cowling was exposed to engine vibrations, which caused cracking in parts of the cowling like the upper and lower nose caps. These vibrations also resulted in some of the cowling screws working loose, especially if the tinnerman clips that the screws attached too were worn out.
Cessna in later models shock mounted the cowling to eliminate these problems.