WRT the machining marks on the R27 engine block, what looks like a "large" surface variation is actually really small - we've got a couple of end plates that were CNC machined to the much the same surface finish. I just went and ran a finger over the machining ridges - the ridges are barely discernable to human touch. Machining those down to a finer surface finish will be really expensive and time consuming - seeing as how Renault have obviously cut the budget on anything that is aesthetics related
that probably won't happen..... then again I do remember my fracture mechanics lecturer going on about machining marks acting as crack initiation zones, so maybe someone should tell them surface finish isn't just about aesthetics .
Any ideas why the "leaked test" pictures show the rear mid-wing support to be a double element structure while the "official release" photos show only a single central support element?