I really like the.Greggs airplane series especially as he knows the technical side of aviation in detail. I am a hobby pilot with a bit of training time on Warbirds. Supercub, T9 Spitfire, Harvard, DH Vampire, L-39 Albatross and a Mig-15 (Santa Fe has flight school which has one). Thus I know a bit about this topic already and I can see that Gregg really knows his stuff.
He explains it well but not all subjects are easy to understand in this field.
Any other site recommendations.
Marc Steenbergen
PS Indy Neidell might remember the glider club beer I gave him at the fantastic meeting in Stow Maries in 1917;)