I have one of those apple peeler corer slicer things. I don't have a drier, but I make wonderful dried apple slices (nice and crisp) in my electric fan oven on its lowest setting - about 60 Centigrade. I lay the slices out on wire cooling racks and I can get 4 of those in the oven at once. If I put them in an airtight jar they keep their crispness, but even when they go a bit chewy, they don't spoil. Apples aren't ready here until September/October, so I'll be back from Worldcon before I need to attack the apple crop.