Kurt Tank didn't want a racehorse; he wanted a cavalry horse. When the RLM asked for a companion to the Bf 109, Tank proposed a radial-engine fighter that could operate from rough fields, absorb battle damage, and still get home. The Fw 190 V1 flew on 1 June 1939, powered by a BMW 139 radial that turned the cockpit into a sauna—chief test pilot Hans Sander said it was "like sitting with both feet in the fireplace." The redesigned BMW 801 and its "Kommandogerät" engine-control computer solved the heat problem and gave the Würger devastating firepower. When it entered service in 1941, the Fw 190 out-climbed and out-rolled the Spitfire Mk V, forcing the RAF into a hurried scramble for the Merlin 61. Over 20,000 were built in fighter, fighter-bomber, and ground-attack variants.