Seen at Arado’s Brandenburg factory in October 1943 are three examples of “Brandenburg 110” alongside a pair of Heinkel He 177s. The PIs at Medmenham noted that the aircraft second from right had a slightly different planform, suggesting its flaps were deployed.

A photo-reconnaissance picture of an example of Rechlin 104 beside a Junkers Ju 88 at Trondheim-Vaernes, Norway, in July 1943. Note how the shadows cast by the airframe show a deep forward fuselage and a long thin tailboom raised high off the ground, suggesting a tricycle undercarriage configuration.

The Ar 232 V1 prototype, which was powered by a pair of BMW 801 engines, first flew in the summer of 1941, and was fitted with 11 idler wheels with low-pressure tyres on independently-sprung legs beneath the fuselage.

The mystery cargo aircraft at Rechlin in June 1943.

Транспортный самолет Арадо Ar 232B-0
The Arado Ar 232B Transport (fitted with four BMW Bramo engines instead, requiring a small increase in wingspan) with the main oleo legs "broken" to lower the aircraft onto the secondary wheels.

The RAF’s first picture of what would become known as “Rechlin 104” on the Erprobungsstelle’s airfield at Rechlin on June 26, 1943, taken by a photo-reconnaissance aircraft and issued with Interpretation Report L. 77. Photo-interpreters estimated the wing­span at between 103 and 105ft, hence “Rechlin 104”.

The strikingly accurate artist’s impression of the four-engined Ar 232B drawn by Peter Endsleigh Castle, whose work later became well-known through his regular contributions to RAF Flying Review and other aviation magazines from the 1950s onwards. Castle joined MI6’s Air Intelligence Branch as a 21-year-old in May 1939.

The eyewitness sketch drawn and annotated by a member of the Norwegian Resistance who had seen the aircraft arrive at Trondheim. The drawing reached the UK in October 1943 and its captions were translated into English.

This rather naive sketch was "made from memory" in July 1943 by an eyewitness at Vienna’s Aspern airfield. The observer engaged the Germans on the airfield and ascertained that the aircraft was powered by a pair of Gnome-Rhone engines.
The sketch shows what looks like twin booms trailing from the engine nacelles, suggesting the observer may have also seen a Gnome-Rhone-engined twin-boomed Gotha Go 244 transport aircraft and conflated it with the BMW-powered Ar 232.

A general arrangement drawing of Rechlin 104 from January 1944 based on eyewitness descriptions and PRU images. Note the tail ramp as described in the earlier Norwegian intelligence. Speculation about the aircraft ended on D-Day+4, when German aircraft recognition material about it was found in Normandy.