You need B-17:QOTS to play.
It works, BUT it is NOT FINISHED. Target Lists and Gazetteers must be completed and I may make changes in the rules. You need B-17: Queen of the Skies to play He-111: The Spade. Below you can find the play-test target list and gazetteer.
I am pretty sure that the files below are the latest, but as I have not worked on The Spade for many years I don't know. It has been play-tested and it works, but it will still need some tweaking.
The Spade - Rules:
Fighters: Download zip.
Handley Page Hampden (not sure if this variant is playable):
Rick Morey has created a very nice campaign for the Hampden.