The FW 190 V18/U1
Thanks to Ronnie Olsthoorn for contributing the line drawing of the FW 190 V18/U1, which formed the basis of this page.
Origins - FW 190 C Prototype
The FW 190 V18 was designed and built as a prototype for the high-altitude FW 190 C, and in V18/U1 form it had the DB 603 A engine driving a four-bladed propeller. The FW 190 C was a projected high-altitude fighter that never came to fruition; even so five prototypes were completed, the FW 190 V18, V29, V30, V32 and V33. Each of these aircraft had DB 603 inline engines, annular radiators, Hirth 9-2281 turbochargers and four-bladed propellers. The FW 190 V18 was coded CF + OY and received a white outline Balkenkreuz and Hakenkreuz. By 1944 the project had been halted by technical problems and opposition to use of the DB 603 (which was needed for other aircraft types).
Conversion - Ta 152 Prototype
However this was not the end for the FW 190 C prototypes, they went on to be modified and used as prototypes for the Ta 152 H.
The FW 190 V18/U1 CF + OY (Ronnie Olsthoorn)
The strange protuberance on the underside of the aircraft is the Hirth 9-2281 turbocharger. Note the nearly unchanged rear fuselage and canopy.
 D. Donald, Warplanes of the Luftwaffe, Grange Books, Rochester, 2000, p.81