The Hirth turbo supercharger was an exhaust-driven unit that provided pressurized air to the engine thereby boosting performance at high altitude. On the V18, hot exhaust gasses were captured at the engine exhausts by heavy gauge steel exhaust tubes that ran to the trailing edged of the wing conveying the hot gasses to the Hirth unit on the belly. To protect both airframe and pilot from the extreme heat generated by these tubes, alloy sheet coverings were affixed to the fuselage sides.
In addition, the V18 was fitted with enlarged wing-to-fuselage fillets within which the tubular exhausts snugly fit. Additional airframe modifications included an enlarged vertical stabilizer and rudder (similar to that used on the Ta-152) and a four-bladed propeller.
Initial flight test results were disappointing. Chief Focke Wulf test pilot Hans Sander reported excessively high coolant temps and pronounced engine over-heating. Despite this, modification and testing of the V18 (and other similar prototypes) continued. The Känguruh made 66 flights totaling 42 hours of flight time. When the project was cancelled in 1944, many of the surviving airframes were incorporated into development of the D-9 Dora and the ultimate version of the Fw-190 series, the Ta-152