Greg Locock wrote: ↑
Tue Jan 18, 2022 10:50 pm
How do you mean? TVs are why your engine has a harmonic damper, and why some camshafts run a metal rubber metal drive cog.
As you change the v angle you'll change the phase relationship between left and right hand banks. I've never done TVs while varying V angle. So, supposing you had zero degrees, you've got a big I6, explosions and inertial forces from each bank are in phase, or 180 degrees you've got a boxer and the forces are 180 degrees out of phase (probably wrong in detail).
I've just found this paper, which looks like a great start. https://www.enginehistory.org/Piston/Be ... nalVib.pdf
He mentions Ker Wilson, a beautiful set of books that we had at Lotus (we had a great library), and which I devoured.
Also on the site you linked Greg: http://www.enginehistory.org/Piston/fo/FO.shtml
V12 firing order arrangements can be viewed, & in a fair number of variations, allowing
comparisons between engines, such as for example the differences between two large
R/R V12 types flown in Spitfires; Merlin/Griffon (which, with individual ejector exhaust
stub-pipes, can clearly be audibly distinguished on vid, for those who may care to check).
Another look at the illustrations in this article shows crankshaft torsional vibration/harmonics
amelioration/suppression palliatives employed by R/R for the Griffon, in addition to F.O. change.
Also worth noting - is a fundamental difference between 180 degree (horizontally opposed/flat)
12cyl engines though.
Almost all of them are not of "boxer" type featuring a crank-throw per con-rod (the Subaru 12cyl F1
attempt is one example, though) - even the Porsche 917 flat 12 was not a pair of their "boxer" flat
sixes joined in tandem, just a typical rod-pair shared-journal V12 crank - albeit mounted in a crank-
case opened out to a 180 degree angle, as the Ferrari BB 512 was too, (so despite any badging or
not, the "Boxer" nomenclature was applied - but the "boxer" claim was pure bullshit 'ad-speak')...
(A bit like 'quad-cam' but worse IMO, for being wrong technically & not simply being used as an
obvious 'dumb-down' hype-term).