I've owned and built planes with just about every type of cowl fastener you can imagine. The overcenter latches with a hinged cowl like on some Pipers like the SuperCub, Tomahawk or like was on Larry's TriPacer are about the simplest for quick and easy access to the engine, but the latches are somewhat expensive to buy. Screws through the cowl are dirt simple to design and inexpensive, but take longer to access the engine. Using camloc or Southco 1/4 turn fasteners is like using screws, only makes access to the engine much quicker. And then there are the piano hinges. I've owned one plane with them and really disliked how the hinges were always binding when trying to get the cowl back together again. I've seen both good and bad installations with piano hinges, but having dealt with them quite a bit over the last 40 years, the piano hinges are my last choice for attaching a cowl. Although they make for a clean looking cowl installation, not many pilots are going to be willing to pull the hinge pins to look at the engine regularly before flight.
Quick and easy access to the engine means you will look under the cowl more often. Making cowl access difficult means you are going to be less likely to see your engine as often. No fastener system is perfect, but pick one that makes access easy. I used camlocs on my KR and am happy with the quick access. However, the hinged cowl doors with overcenter latches like my SuperCub makes for instant access, so my engine gets a good visual inspection before every flight. I find that I don't look under the cowl of the KR nearly as much as I do the Cub, simply because the access is more difficult. Something else to think about is combining the systems. For instance. straight piano hinges along the side of the firewall to attach the lower cowl and camlocs for the upper cowl or hinged split upper cowl halves with Southco fasteners for quick and easy access. The cowl is usually one of the last things you build, and in my opinion is one of the more difficult parts to build, but it's also one of the parts of the plane you will be putting on and taking off more than any other part. So make it easy on yourself not only for building, but for long term maintenance and inspections. -Jeff Scott Los Alamos, NM
