Quite the opposite was true of the trends across the Atlantic, in the United States. A fast development of the much lighter air-cooled radial engine also resulted in streamline cowlings for this type of power plant, which greatly improved the aircraft’s aerodynamics. That made these engines much easier to maintain (compared to inline engines), having no complex cooling installations. It was of particular importance to the US Navy: having a shorter length, these engines allowed concentration of a greater number of aircraft onboard aircraft carriers. The greatest contributor to the promotion and development of radial engines was American company Pratt&Whitney, which willingly sold licenses for its products, and this was how the production of radials was launched in early 30s at the German BMW.
In the autumn of 1937 the Reich’s Ministry for Air (Reichsluftfahrministeruim – RLM) ordered the Technical Department (Technisches Amt) to come up with guidelines for a new fighter aircraft. The RLM people were perfectly aware of the fact that one type of fighter with the Luftwaffe might be insufficient in case of an unavoidable military conflict. On top of that, the RLM was notified by the intelligence that other superpowers were going to equip their air forces with at least two types of modern fighter aircraft. Therefore, in the spring of 1938 aircraft factories received the guidelines for a new fighter aircraft that was in the future to join the Bf 109 in combat. As Daimler Benz was working at the top of its capacity, hardly keeping up to its engine delivery schedules, the specs were given to Focke Wulf Flugzeugbau AG in Bremen, a factory preferring radial engines.
Kurt Tank knew that radials were especially liked in Italy, where they were successfully used on newly built Fiat and Macchi aircraft. But the Italian products could provide insufficient power, just like the French Gnôme Rhône, which only encouraged spiteful smiles on the faces of German designers. However, apart from easier handling, radial-fitted fighters were also more resistant to damage. Therefore Italian fighters left a deep imprint on the memories of British airmen in fights over Greece and North Africa.
An even greater surprise to the Allied pilots came from Japan, where the outstanding Mitsubishi A6M Zero carrier-borne fighter was introduced into service and outclassed all the enemy constructions over the Pacific in 1941-1942, proving that the proper use of the radial engine could result in high speeds. Apart from its well-designed radial engine, the Zero had a very light construction, and its incredible agility and armament of 20 mm cannons let it quickly rid the Pacific sky of enemy aircraft. Its entering service over China in 1940 supported Tank’s arguments in the promotion of his own novel design.
![Lower part of the FW 190 fuselage. Two main fuel tanks were mounted in these nitches by means of special tapes [photo via Marian Krzyżan]](images/nicewatermark/occnvai297focke-wulf-fw-190-vol-icati95aviation-of-ww2iti688limitstart1-03_fw190shopkage1.jpg "Lower part of the FW 190 fuselage. Two main fuel tanks were mounted in these nitches by means of special tapes [photo via Marian Krzyżan]")
When Kurt Tank presented the initial guidlines of his design, it turned out that he would have to fight a real bureaucratic battle for his project. The man responsible for equipping the Luftwaffe at the time was a famous WW1 ace, General Ernst Udet, a very good friend of Willi Messerschmitt, the latter owing him very much. Now all signs seemed to be showing that Tank’s construction was going to die before ever seeing the world. However, disturbing bills that Udet received from the RLM forced him to verify his initial aversion to radial-propelled fighters.
Udet’s biased attitude changed when it came out that the Heinkel 100 and 112 that were being designed turned out to be unsatisfactory constructions and series production was given up. Even more disturbing was that the two chief manufacturers of water-cooled inline engines – Junkers in Dessau and DaimIer-Benz in Stuttgart-Unterturkheim – were unable to increase production volumes in the nearest future and deliver the required number of motors for the hurriedly built aircraft. In view of the problems with production of one type of inline engines used for different aircraft, it was a masterstroke to launch production of a radial-fitted fighter. It allowed manufacture of new aircraft without troubling the factory with engine delivery-related issues, as happened in the case of the He 111. Owing to this unexpected coincidence, the design submitted to the RLM by Kurt Tank was eventually approved.
An engineer team was detached for further development of the project, which was designated FW 190, for Kurt Tank was then technical director at the factory and was unable to devote himself to only one project. But he constantly supervised the team led by engineer Rudolf Blaser, who was assisted by engineers Willi Käther and Ludwig Mittelhuber as well as the chief of design department, engineer Andreas von Fählmann.
In the summer of 1938 the RLM placed an order for three prototypes propelled by the powerful 18-cylinder BMW 139 air-cooled engine. It was a new product from the BMW that had been developed by combining two 9-cylinder banks taken from the BMW 132 engine. This unit delivered a maximum power of 1550 HP (1140 kW), which definitely surpassed the inline DB 601 or Jumo 211. If the design proved satisfactory, it would help avoid overload to the production lines and the Daimler Benz engine delivery schedule. As if by irony, the FW 190 design, which Kurt Tank named Würger (Shrike) and which owed its origin to the BMW engine, almost ceased to exist due to this very power plant.
