The Skyloc (Similar to Camloc®) design has been the preferred cowling and panel fastener throughout the aviation industry for many years. Two common series have been used on general aviation aircraft since the 1960s. The large, 4002 Series, has become the most widely accepted fastener because of its ease of operation and durability.

Many kit aircraft designs have utilized hinge as a method of fastening cowlings. It is simple to obtain and its use is very straight forward. Proper installations are extremely clean in appearance. But, even the best designs leave much to be desired for cowling removal and installation. Once you have seen or worked with a Skyloc cowling, you'll agree, it's simply great!

SKYBOLT makes purchasing the proper components for your next cowling design very simple. In fact, our new SK245 Adjusting Receptacle allows you to use any stud length for just about any application. Put another way, one stud length fits just about any application when you use the SK245 Receptacle. Backed with our experience, you can design your cowling using Camloc fasteners with confidence and ease of installation.

Let's discuss a few of the most common questions and considerations when using 1/4 turn fasteners for an aircraft cowling:

How many fasteners do I need?

Answer - Look at any Cessna 152, 210, 310, or 400 series. Or Beech Baron or Duke, to name a few. Three to four inches between fasteners is plenty unless a cowling is considered structural. So, depending on the width and length of the cowl, we simply figure one fastener every four inches around the firewall and down the sides. The forward side holes may reduce to three inch spacing. The crucial consideration is the ability of the cowling to carry a load between fasteners. For the hinge design, the load is carried consistently along the cowling fastening surface. With a fastener design, such as a screw, a Dzus®, a Camloc®, or our Skyloc fastener, the load becomes concentrated. All commercially produced cowlings, therefore have some kind of rib or doubler structure at or adjacent to the fastener to carry the air load.

An engine cowling is subject to a surprisingly high load from internal ram air equivalent to inflating a tire with 4 to 5 PSI of pressure. Many cowlings are designed to attach to a mounting strip and mate flush with the fuselage. In the case of the cowling attach points at the firewall, an internal reinforcement strip beginning 1-1/2 inches from the rear edge will allow the normal clearance between the mating surfaces, yet this reinforcement (doubler, or channel) will adequately carry most aerodynamic air loads imposed on the cowling. The same logic applies to the side mounting surfaces and the nose of the cowling. Take the opportunity to look at any Cessna, Beech, or Piper cowling to see clearly the logic of this paragraph.

What is the minimum distance I should allow from the edge of the cowling to the center of the fastener?

Answer - Allow a minimum of 5/8" from the edge of a fiberglass cowl to the center of the fastener. If you measure from the cowling edge 5/8" and drill a center pilot hole, you will have adequate material to mount the Camloc fastener, and in the case of the 4002 series fastener, the 4002 grommet.

How much width should I allow for the inside support strip (Receptacle mounting Strip)?

Answer - You must take into consideration two things: First, the 5/8" minimum spacing from the fastener center to the cowling edge. This will determine the center of location for the receptacle which is mounted to the inside of the support lip. However, you must allow for the width of the receptacle so that it is fully mounted within the limits of the support lip. A support lip of 1-1/8" will allow locating the fastener grommet center 5/8" from the cowling edge and insure that the SK245 receptacle is mounted properly to the inside support lip.

Click Here Additional Information and Photographs of Cowling Installation