Focke-Wulf Fw 190A poor high-altitude performance

[kennethklee]

The poor performance of the Fw 190A above 20,000 feet is well-known. As best I could ascertain, the reason for this limitation was ineffective superchargers for the Fw 190's BMW radial engine. The Republic P-47 Thunderbolt had excellent high-altitude performance with its radial engine, which was attributed to a large degree to its supercharger. The Germans seem to have effective superchargers for their inline Daimler-Benz and Junkers Jumo engines, so I am curious why an effective supercharger was not able to be developed for the BMW radial engine. (Searching on Google was fruitless for me.) Am I missing the real reason(s) for the poor performance of the Fw 190A at altitude?

Thanks,
Kenneth