[Paul Thompson]

Hello Kutscha,

I did know that, that feature of the DB design was a major contibuting factor to the superior performance of the BF 109F compared with its contemporaries. Do you know where to find the compression ratios for other German engines of the period?

The problem with the later higher-boost DB 605s that they remained far behind the Merlins. The DB 605 was beginning to fall apart at 1.98 ata, while at least some later Merlins could cope with +25 lb boost, the equivalent of 2.76 ata:

1.98 ata / + 13.94 lb./sq.in (PSI) boost
2.27 ata / + 18 lb./sq.in (PSI) boost (serious calculation error above corrected here)
2.76 ata / + 25 lb./sq.in (PSI) boost

The question that this raises is why the Luftwaffe was never able to put the DB 605L or equivalent two-stage supercharged version into service. Do you know whether this was a raw materials problem (not enough of the right metals) or a manufacturing problem (inability to mass produce the right alloys) ?

Regards,

Paul