Batz, thanks for posting that part from LEMB, I didn`t know it was discussed also there. Also thanks for putting the discussion on track again - I was bit worried when I saw the first comments.
The 1.42ata boost for DB 601E was allowed from May 1942, according to butch`s post from the old bui forums :
Yes and according to several other Messerschmitt and Daimler-Benz documents the engine had to be derated because of overheating hence the loss of speed. Check for instance the F-4/Z or F-4/R1 manuals as well as the August 1941 issue of the DB601E manual. The full boost was not officialy re-instated until may 1942.
Butch
But now I have read butch`s comments on this on LEMB, so it`s could be cleared in February 1942.
I suspect such new allowences didn`t actually happen from one day to another, what I suspect that these official dates were actually the time by when ALL the engines were recycled in the factories were modified in the neccesary way run at higher boost -and only then DB issued a general note.
BUT individual engines, that were already modified long before must have had an indication of this on their Motor Cards, so, in real life it was likely that the modified engines already run on increased boosts while the others, non-modified ones were still restricted.
Can anybody confirm this or give a better idea?
It appears that the legacy of old Green books still haunt, and performance figures given for F4 are a strange mix of Kampfleistung and Notleistung, but in general the true performance is greatly understated. From these figures, I now understand why LW aces had such preference to the F-4 vs. ealrly G models... at full boost, the F4 was very comparable to the G-2 in performance at most altitudes. I really wonder if there are actual F-4 climb figures exist for 1.42ata - considering the 1.3ata avarage initial climb rate is already impressive at 18.5m/s .
This speed performance figures, and the original data if possible, should be forwarded to Oleg Maddox of Il-2 Sturmovik. Clearly the F-4 figures are only for 1.3ata in Il-2. Most of the fighting on the EFront did place with F-4s when 1.42ata was cleared.
Re : ammo loads...
The F-4 cannon load is clear. 200 rounds. See the Ladeplan, as presented in Otto/Radingers 109F-K.
There`s more confusion. It`s often suggested that from G-4 onwards the ammo box capacity was reduced to 150 rounds, because of the larger tires and lack of space. Personally I doubt that to some extent, taking the actual space gains from making the box 50 rounds smaller... very tiny. But, it counts more in this regard the British evaluation report of G-14 from the 412 xxx series as on the Lair, provided by George Hopp. It has the large tires, in fact the plane itself is probably a G-6 converted to G-14... yet the British report mention the cannon`s ammo tank CAPACITY is 200 rounds, but only 150 rounds are loaded...??
Just some food for thought.
