[brentce]

Here's my greatly simplified and admitedly speculative version of the 605 engine story (although assuredly it is well grounded).
.....

This other business about restrictions on the DC and ASC motors I do not challenge, haven't read anything about it but sure that's entirely possible. But doesn't detract from mechanical engineering.

Hi Vanir

Basically we are just going to have to disagree on this issue, buuut :wink: I do have to note that the DB605DB, DC and ASB, ASC all have the same (or virtually so) rated altitude for any given power setting. At 1.8 ata they all have a critical altitude/FTH of around 7500m at max speed, if converted to 1.98 ATA, that drops to 6000M since the supercharger cannot produce that level of boost above 6100m. These critical altitudes are rammed at top speed while the figures you're using appear to be the static ratings. This indicates that they used a supercharger of the same diameter and speed, but the new head and valve train of the D was better suited to the higher boost than was the A-based ASM/B/C. Of course a DB605DB and DC (as well as the ASB/C) are the same engine, just adjusted for C3 fuel and higher boost.

Anyway, I think we need to see the actual specs for the supercharger installed on each engine to know exactly where this falls. Certainly that's easier than trying to extrapolate the answer from various settings from disparate sources when engines of identical configuration could vary considerably in output and FTH.

Brent