[obdl3945]

Hi, Jerry...

I've got the Airdoc publication as well, and I presume you're referring to the aircraft at the top of page 39. The caption states it's from I.Gruppe/KG2, so given that the aircraft letter is light-coloured, either white or yellow, it would likely have been coded U5+EH or U5+EL respectively, depending on whether it was 1. or 3. Staffel within the Gruppe. As you will no doubt have noticed, the aircraft on the front cover is also 20mm-armed, and coded 'D', but not shown at a sufficiently clear angle as to determine its full code.

Additionally, in Dornier 17 in focus by Chris Goss (Red Kite), towards the end of the book, under the heading 'Russia' at the bottom of page 91, another such armed machine, unit inknown, with the caption simply stating that it was installed for increased effectiveness at low level, and that this was a modification first used during the Battle of Britain.

I have to admit that my first thought was KG76, as their III.Gruppe was well-practised in low-level attacks such as the Kenley airfield attack during the Battle, and the account provided in Chris's book, page 66, states that the machines of 9.Stffel, KG76 (F1+?T) each had 20mm cannon for use against ground targets, and that this specific unit's crews were unique in having been issued with steel helmets for their protection.

Regards...

Paul