It was planned to built 6 experimental models for the "Höhenjäger 2", four of them, the Fw190V18U1, Fw190V29, Fw190V30 and Fw190V31 were realised.
The changes referred primarily to the installation of the turbine. The Fw190V29-V31 got greater wings with a span of 12,3 m and a pressurized cabin.
Dietmar Hermann