I'm planning to replace the fiberglass cowl on a Nobler ARF. What is the best tool / method / process to trim the needed cowl areas to offer clean cuts and to resist FG fraying.

    The first thing I would do with the stock cowling is epoxy another layer of fiberglass to the whole inside while it's still new and oil free. Liberally apply some acetone and a scotch brite to thoroughly clean it of any kind of mold release agents. At a minimum, I would epoxy some 1/64" plywood to where the anchor point will be to toughen those up, maybe even do this after epoxying another layer of glass inside. To cut the openings for air inlet, exhaust, and to clear the head. Draw in your outline, the rough out the inside area any way you want, and then use a fine sanding tool in a Dremel to work the edges out to your line. Work a little at a time and test fit as you go. These are just too flimsy as they come in the kit. I finished off two Nobler ARFs that had been previously abused by the previous owners and if I ever replace them, I may just build a balsa cowl but for sure will add glass cloth to any stock cowling that I may replace them with.
  Type at you later,
   Dan McEntee

    The first thing I would do with the stock cowling is epoxy another layer of fiberglass to the whole inside while it's still new and oil free. Liberally apply some acetone and a scotch brite to thoroughly clean it of any kind of mold release agents. At a minimum, I would epoxy some 1/64" plywood to where the anchor point will be to toughen those up, maybe even do this after epoxying another layer of glass inside. To cut the openings for air inlet, exhaust, and to clear the head. Draw in your outline, the rough out the inside area any way you want, and then use a fine sanding tool in a Dremel to work the edges out to your line. Work a little at a time and test fit as you go. These are just too flimsy as they come in the kit. I finished off two Nobler ARFs that had been previously abused by the previous owners and if I ever replace them, I may just build a balsa cowl but for sure will add glass cloth to any stock cowling that I may replace them with.
  Type at you later,
   Dan McEntee

Thanks for the recommendations as well as means and methods.