Hello,
Interesting thread. Here's an interesting comparison chart I came across in a book:
DB605 Merlin XX
bore 154 137 mm
stroke 160 152 mm
displacement 35,7 27,0 l
compr. ratio 7,2:1 6,0:1
width 720 757 mm
height 1010 1046 mm
length 1740 1793 mm
frontal area 0,51 0,54 m^2
weight 745 658 kg
weight/hp 0,49 0,44 kg/hp
fuel usage 200 235 g/hp/h
oil usage 5 10 g/hp/h
fuel 87 100/130 oct
hp/litre 42,0 54,8 hp/l
hp/area of piston 0,67 0,8 hp/cm2
What points out from those stats is that the Merlin had better hp/litre ratio, altho it achieved this by using more fuel and oil. Merlin was also almost 100kg lighter but the size wise it was similar to DB605.
Also it should be pointed out that the materials and fuels that DB605 used were inferior to Merlin. For example where as 109G-2's DB605 cylinder tubes were made of cromium molybdene steel. In the G-6's DB605 they were only carbon steel. So the material shortages were hampering the development of german engines (and that severely affected their TBO intervals for the worse), as was the quality of the fuel.
[edit: my nice comparison chart were fux0red by the forum... anyone knows how to fix it?]
-teemu