The development history of the Armstrong-Whitworth FK3 is partially obscure and was, in its time, essentially unusual. Clarity and chronology might have been more securely established if only there were a correct and dependable listing of the earliest FK-numbered types. If any such list ever existed its composition and content have still to be discovered consequently obscurity persists to this day.
* If download links doesn't work. Please write a comment.Windsock Mini Datafile 13 - AW FK.3 (little ack) Download via usenet