The Fock-Wulf FW390 was given the name “Dolch” (Dagger) but was often referred to as the flying water pump owing to its complex cooling system. The 24 cylinder engine design consisted of 2 x 45 degree V DB 608 units on a single crankshaft which gave an immense power output and a huge initial problem to the FW design team in finding a way to keep the engine cool.
A large drag inducing radiator protruding from the airframe is not desirable for a performance aircraft and the Dolch required a very large surface area to be exposed to the slipstream. Kurk Tank and his team did an incredible job of burying the radiator low in the fuselage and cleverly directing the airflow into the intake opening. In addition, the coolant was pre cooled by running it through a return channel on the underside of the airframe. This complex cooling system was always going to be vulnerable in combat. However, the Dolch was conceived from the outset as a shielded fighter and incorporated close skin ballistic shielding.
To achieve this the FW390 develops over 50% of its lift from the aerofoil section fuselage skirt/wing assembly. The remaining lift is generated by field coil spool augmented by EMFEM weight reduction. With energy in abundance owing to having conventional lift assistance there remains ample power for shield generation. It should be remembered however that this is 1940’s technology and shield generation is in its infancy.
The Dolch could, with fully charged shield’s, absorb a typical 2 – 3 second burst from a contemporary fighter. After this the shield integrity fell off rapidly and required several minutes to fully charge - longer under battle conditions. In reality the shield capacitor was seldom at 100%, would discharge prematurely or fail to work at all.
Shields or no shields, the FW390 was a formidable fighter in the hands of an experienced pilot but in the closing weeks of the war experienced pilots were few and far between even if they could find the fuel to get airborne. The Allies ruled the skies and were looking for anything to shoot at and especially the Luftwaffe.
Owing to rapid promotion and far too many corners cut off training and familiarity flights, Oberleutnant Roland Fischer found himself transferred to what remained of a FW390 unit and strapped into a Dolch at 8000ft on the morning of March 21st 1945.
He was both exhilarated and frightened in equal amounts. The Dolch was a handful to say the least and seemingly had a will of its own which it would exercise at every opportunity. Fischer was too engrossed and too green to realise he was being stalked.
A pair of P551’s down low and looking trouble had spied him above them. Both pilots had hours of combat experience and each had fought the Dolch on more than one occasion and successfully.
The Dolch was the faster of the two aircraft but the P551 could climb like a lift with its expanded field lift generators. With the surprise advantage the tactic was to climb above the Dolch then dive to gain speed and zoom climb beneath it hopefully having got a good bead on the belly intake and delivering a long burst. Your wingman would be seconds behind you already allowing for any deviation in the FW’s path and ready to deliver the coup de grace.
The tactic worked perfectly. Fischers FW390 took most of the hits directly in the radiator and surrounding cooling equipment and began steaming like a freight train. 5 seconds later the second P551 came in delivering a long burst that killed Fischer instantaneously.
Fischer’s aircraft along with his remains were found some 25ft down in a farmer’s field during a wreck dig in the late 1990’s.
