From what I’ve heard, medieval fletching was usually applied straight. Go figure, I think it’s harder to fletch straight than it is to fletch offset (feathers are naturally curved).
I am the author of the fletching article in the magazine. I have not had the pleasure of examining any original European artifacts because I live far across the pond. I’m not a highly opinionated academic, just a guy who has been experimenting with different materials that would have been historically available in Europe (goose feathers, linen thread, etc). How can anyone say exactly how an arrow was fletched in medieval times without actually seeing it done. All I know is that the method in my article has worked for me and I wanted to share it. I’ve loosed enough arrows to learn what holds up and what does not. Of all the methods I’ve tried, birch pitch is the most durable option.
I’m sure that different techniques were used at any given time, in any given part of Europe. A lot of it probably depended on what materials they had at hand and how much time they could dedicate to the task, at least in the early days. In my experience, the most efficient way to fletch heaps of medieval war arrows would have been to use some type of hide glue brushed on once the feathers were bound in place. Still a time consuming task by modern standards. I don’t remember any references to birch pitch being used in the later medieval days. It’s just too time consuming. A beeswax and pitch mixture has to be applied the same way, also time consuming. But then again, Mary Rose was probably carrying primo archery gear, and the glue may have been beeswax and pitch. Probably the bigger question is whether the Mary Rose arrows represent the typical medieval war arrow or highly polished pieces of gear.