A most curious He 100 photo

[RolandF]

To me it looks much like a He 100. Especially because the same seller offers a 2nd pic of a similar fighter - and that´s for sure a He 100:

[RolandF]

Another photo of this series is an obviously elder Do 17 with a brand-new unpainted Do 17Z cockpit unit - maybe a prototype.

The 1st He 100 - surely this is no Italian plane because windshield and triangular rear window are quite characteristic for the Heinkel fighter - seems to have a chin radiator of semicircular shape below the engine. The belly radiator otherwise characteristic for the He 100 is not visible. The 2nd He 100 seems to have an even deeper chin radiator under the tarpaulin.
Regarding the sophisticated cooling system of the original He 100 this seem to be attempts to evaluate some more conventional radiator systems.

Regarding the Do 17Z conversion the time of the photographs seem to be not later than ´40, maybe even ´38-39. One might figure this could be a possible testbed for a proposed Jumo 211 installation into the He 100 which needed a different cooling.

Regards

Roland