[ACE-OF-ACES]

No problem! Yeah, it's just the same engine type that's certain...of course we're told that it's from a report that uses the standard Bf-109K4's performance as a baseline and calculates the improvement from a new prop, so that's something at least. The differences between the DB and DC seem to be simply that the DC can use C3 fuel so is later cleared for 1.98ata, and it has slightly worse performance at SL and slightly better performance at altitude.

Thanks Grunch!

So just to make sure we are on the same sheet of music you would recomend I use the same speed chart I am using now but replace the rate of climb chart with that first one you provided, ie both the 1.8ata

And the 2nd one would be for the K4-C3 1.98ata

On that note is there a speed chard for the K4-C3 at 1.98ata?