There's a great podcast where Einar Enevoldson talks about the Perlan Project: http://www.stitcher.com/podcast/airplane-geeks-podcast-podcast-feed/e/airplanegee

There's a great podcast where Einar Enevoldson talks about the Perlan Project: http://www.stitcher.com/podcast/airplane-geeks-podcast-podcast-feed/e/airplanegeeks-357-einar-enevoldson-and-the-perlan-project-39572525 http://www.stitcher.com/podcast/airplane-geeks-podcast-podca... He goes into some detail about how they have to design around the low Reynolds numbers at that altitude and other esoterica, very interesting.