This is truly an awesome looking project. Great work Cpt. Kipard. I only recently discovered the Skylon while reading about SSTO on wikipedia and decided to try recreate it in KSP. I have no modding skills what-so-ever, so I used mod parts from various packs. Mainly B9, KW Rocketry, RetroFuture and Hangar. It's been a lot of trial and mostly error. My version isn't quite as close to scale as yours, though. Made my fuselage using 3.75m parts (couldn't find a 5m cargo bay to my liking), but probably longer. It's length is roughly equal to 8 of the B9 HL 8m Cargo bays. The reason for this post is, that I recognize some of the flight problems you describe, with take-off speeds and mystery forces inducing yaw and roll, during ascent and re-entry. I still have these problems, but I managed to fly anyway. And I wanted to share these pictures as a fellow Skylon enthusiast. http://imgur.com/a/qwhvi