G-10s were not made from old airframes, they were produced alongside the G-14 as an evolution of the G-6 with DB605D and MW-50 while the G-14 was the evolution of G-6 with DB605AM with MW-50.
It is true some of the first airframes used for the G-10 were from new airframes intended to be used for G-6s, or from airframes planned for mounting the DB605AM (G-14) in case no DB605AM were available. Hence the twin data plate found on some G-10.
The AH G10 has the performance of C3 fuel and 1.98 ata. C-3 wasn't used by 109 units until '45. Even then C-3 wasn't widely available amoung all the 109 gruppes. Most C3 fuel was used by 190 gruppes.
Butch posted the below in this thread
http://www.hitechcreations.com/forums/showthread.php?s=&threadid=108817&highlight=FuelAccording to a document dated late January 1945 coming from DB the 1.80 had just been cleared following serious troubles (pre-ignition) reported by the unit testing the 1.80 ata boost. It is also noted that following the clearance of the 1.8ata boost the 1.98ata operational tests could now begin but with concern about the sparkplugs thermal resistance IIRC.
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C3 was not used by 109 units until the 1.98ata boost was cleared, they relied on B4+MW-50 so that C3 could go to the 190 units. And even after the clearance only few gruppen got it because of shortages due not only to C3 production but also to C3 delivery to the units.
in March 1945 only two units of the Luftflotte 6 both equipped with G-10 were using C3, one being IV/JG 4 the other being II/JG 11, and no K-4 units at all.
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AFAIK 1.98ata boost was cleared late february but it seems to have been slowly introduced into service, i suspect the adjustments needed on the engine and the change of sparkplugs type (supply problems ???) took longer than expected. From other documents i know that C3 and B4 had severe quality problems beginning in late 1944. While it was not much of a problem with low boost, it had some serious effect on higher boost, so it might also have slowed down the introduction of 1.98ata boost. At least DB documents underlined the need for cleaner fuels than those in use at that time.
You can safely assume that by march 1945 1.98 ata boost was being introduced, unfortunately i do not have much details for April 1945, but i doubt it would have changed much, given the situation.
My book(s) will takle the 109 development, history and technical side.
Anyway you look at the G10 wasnt in service until late 44 and the AH G10 has the performance of a Feb Match '45 limited G10.
The common 109 in service would have been the 109G-6 just like the one we have in AH. The G-10 doesnt belong in this type of set up.
Neither does the p38L, it came into service after the 262 and D9.
The allied planes would be D11, p51b, B26 A20g and B17.