[Co de Swart]

I've got a photo here of a JG26/Fw 190 that will give some solution, but I took the same question to some 'schwarze Mann' who told me, this 'hole'/'gap' was for a kind of maintenance.
I showed ex-Fw 190-pilots Richard Wittmann and Werner Molge the same, showed them the photo of this FW 190 with a kind of "trichterformig' maintenance device in this 'hole'.
They confirmed, this was for 'maintenance'.
When you give me your E-mail, I'll scan en send you this explaining photo.
J. de Swart, NL.