v12 or v10

[saviour stivala]

Two-of-four.
The crankshafts of the three most famous opposed cylinder flat-12 racing engines.
The 1969 Porsche 912 4.5L flat-12 opposed horizontal cylinder racing engine.
The crank was like that of an in-line six, with each throw rotated at 120 degree to its neighbour and with each rod-journal carrying two con-rods big-end side-by-side. Steel backed multi-layer bearing shells were used for each main and rod bearing. Rod bearing journals were 52mm. this was the longest crank Porsche had made, In its final form measuring 31.3 inches end-to-end. Analytical studies forecast large amplitudes of vibration at both ends of the shaft. But at its centre vibration was a node. A point that remained at rest. Porsche decided to power not only camshafts but all drives, from the engine output as well as for its accessories. From the centre of the crank, a straight –cut drive take-of gear with 32 teeth was formed at the centre of the crank. It was flanked by 2-larger 66mm main bearings, the remaining main bearings, 3 each end, were 57mm diameter, bringing the total main bearing count to 8. So that the centre gear could be hardened to the degree necessary, the crank was forged of chrome-nickel-molybdenum alloy steel. Set in ball and needle bearings adjoining the centre split of the crankcase were shafts above and below the crank, both driven by its central gear, the lower shaft took drive to the clutch at rear of engine. Its driven gear had only 31 teeth, one less than the gear on the crank (because pairs of gears last longer if the same two teeth do not contact each other on each revolution). A small step-down gear set at the front face of the output shaft gear powered a pack of oil-pumps at 0.54 times crank speed. One was a pressure pump, with gears 64mm wide, and the others were separate 42mm scavenge pumps, one drew oil from front of crankcase while the other had a pick-up about two thirds of the way to rear. The main and big-end bearings was feed oil at 70psi. Because the crank had no power take-offs at either end, it was an easy matter to arrange a direct delivery of oil to the rod bearings through drillings in each end of the shaft.

[J.A.W.]

Yeah, you do realise that Porsche-Design had successfully raced 12 cyl Grand Prix cars for Auto-Union
~30 years previously (now Audi, along with Porsche & VW (VW was also originally a Porsche-Design effort).

[Tommy Cookers]

.... each throw rotated at 120 degree to its neighbour .....

again ....

the angles are ..... 0 240 480 480 240 0 deg
or alternatively .... 0 120 240 240 120 0 deg
depending on the sense of the cylinder numbering relative the sense of the crankshaft rotation

[Bandit1216]

I think "sequential turbocharging" refers to multiple turbochargers set up to operate in a "staged" sequence ie one turbo at low air demand, two turbos at higher demand etc.

Operating multiple turbochargers in series is generally referred to as "compound turbocharging". (Not "turbo-compounding" that is something different)

Well, if you take an engine that even generates power in the inlet stroke because of the high turbo pressure, I think turbo compounding as well as compound turbo is kinda true.

F1 engines are also turbo compound nowadays if you ask me. Only the axle is replaced by big 3 wires

[Tommy Cookers]

Counterweights act as inertial dampers & as a location for add-on pendulum balancers:
http://www.epi-eng.com/images/Engine/en ... aft_12.jpg

counterweights don't act as inertial dampers because they don't move relative to the crankshaft

[echedey]

gentlemen to see it is supposed that the optimal angle of the v12 is 60º that is like better works the engine v12, but ferrari put it to 75º and worked wings 1000 marvels without problems none is more was the best v12 that manufactured ferrari in the 1995 that engine only arrived to 15000 rpm but that the previous engines opened some problem in putting it to 75º and that did not give problems?

[Jolle]

gentlemen to see it is supposed that the optimal angle of the v12 is 60º that is like better works the engine v12, but ferrari put it to 75º and worked wings 1000 marvels without problems none is more was the best v12 that manufactured ferrari in the 1995 that engine only arrived to 15000 rpm but that the previous engines opened some problem in putting it to 75º and that did not give problems?

“Only” 15000 was quite a lot back then. And 75 degree was to lower the cog. Renault even had a 110 degree V10 not much later.

A racing car is the sum of many compromises, almost never ideal anywhere.

[saviour stivala]

That Renault wide angle V-10 was the only V-10 F1 engine to have gear drive from crankshaft to right side camshafts at rear and to left side camshafts at front.

[J.A.W.]

.... each throw rotated at 120 degree to its neighbour .....

again ....

the angles are ..... 0 240 480 480 240 0 deg
or alternatively .... 0 120 240 240 120 0 deg
depending on the sense of the cylinder numbering relative the sense of the crankshaft rotation

T-C, no need for equivocation..
Indeed the article s-s has cribbed is correct, since relative to each other, crankshaft front-to-rear,
each crankpin is indeed rotated by 120 degrees, same as every even-fire inline 3/6/V12/H24.

BSA/Triumph were proud to expound on their crankshaft manufacture for their late`60s triples,
whereby the forged steel crank was formed into a 120 degree orientation by post-forge re-twisting,
something Laverda was unable to emulate, & why the Italian concern went 'odd-ball' 180 for theirs..

[saviour stivala]

Three-of-four.
The crankshafts of the three most famous opposed cylinder flat-12 racing engines.
The 1970 FERRARI 312B 3-litre flat-12 tipo 015 was the third and last opposed cylinder flat-12 engine produced by FERRARI. The first was a T.O.H.C 2-valve with belt drive to cams 1.5-litre ( F102B) designed & developed by Guliano De Angelis/Angelo Bellei. The second was the enlarged (4943cc) 4-valve FIIOB was developed into the F113A and F113B. Forghieri started with a clean sheet of paper. The crankshaft short stroke helped keep the engine compact. Forghieri innovated boldly in the 312B bottom end. Its 6-throw crankshaft was conventional enough with 2-rods big-ends sharing one pin side-by-side. But after tests on the 2-litre hill-climb engine proved its feasibility the crank was carried in only 4-main bearings. Roller bearings were used, which required a build-up crankshaft for the assembly of the 2-cente main bearings, but blow-ups in early testing led to a switch to a one-piece crankshaft and plain bearings at the 2-centre main bearings. With rollers only at the ends. The crank was machined from a solid billet of steel alloyed with manganese and aluminium to obtain a suitable surface for use with the roller bearings. After the change to a one-piece crank, failures continued. A study of the crank’s resonant characteristics showed that the attached mass of flywheel brought the torsional movements of largest amplitude to a weak point on the crank. Pirelli technicians helped Forghieri develop a rubber coupling between the crank and flywheel that shifted the largest amplitude to a portion of the crank that could tolerate it. Forghieri had favoured roller bearings throughout the bottom end because they require less oil, which meant the less of it would be splashing around inside the crankcase, wasting power on oil foaming and heating. Rollers for the rods were tried but given-up as too difficult and complicated and replaced by conventional bearing shells on 36mm journals. Both titanium and steel rods 110mm long were used. The inner surface of the crankcase was shaped closely to the radius swept by the rods big-ends. The FERRARI engine benefitted from having constant crankcase volume, free from compression losses by having each group of four cylinders chambered by main bearings panels.

[J.A.W.]

Counterweights act as inertial dampers & as a location for add-on pendulum balancers:
http://www.epi-eng.com/images/Engine/en ... aft_12.jpg

counterweights don't act as inertial dampers because they don't move relative to the crankshaft

Ah, no.. not correct T-C, the inertia/rotational weighting vis a vis recip' functions is a damping factor.

T-C, if you check the linked JVE journal article, you may gain elucidation/realization on the dynamics..

https://www.jvejournals.com/article/19933

[J.A.W.]

Two-of-four.
The crankshafts of the three most famous opposed cylinder flat-12 racing engines.
The 1969 Porsche 912 4.5L flat-12 opposed horizontal cylinder racing engine.
The crank was like that of an in-line six, with each throw rotated at 120 degree...

Check this link, it features an earlier Porsche-Design G.P. flat 12 engine, a 'blown' 1.5 litre AWD..

https://bringatrailer.com/2018/07/12/te ... at-12-4wd/

[saviour stivala]

‘’Check this link. It features an early Porsche design’’. Thanks for the link but that link is not new to me. The 1949 Cicitalia 1.5-litre flat-12 is in fact included in the ‘’50 OF THE MOST FAMOUS RACING ENGINES’’ page on here. Technically advanced and famous as it me be, it could not be regarded on the same level of achievements as the three horizontally opposed cinder flat-12’s that actually raced and so proved themselves.

[Tommy Cookers]

.... each throw rotated at 120 degree to its neighbour .....

again ....
the angles are ..... 0 240 480 480 240 0 deg
or alternatively .... 0 120 240 240 120 0 deg
depending on the sense of the cylinder numbering relative the sense of the crankshaft rotation

.. Indeed the article s-s has cribbed is correct, since relative to each other, crankshaft front-to-rear,
each crankpin is indeed rotated by 120 degrees, same as every even-fire inline 6/V12/H24....

wrong
about half a billion times - one for each engine made the way I say

the crank throws aren't 120 deg relative to each other front-to-rear
they are in 'mirror image' about the mid-length ie cylinders 3 and 4 have zero angle 'relative to each other'

this symmetry is what cancels all the inertial forces and moments within the block - so notionally zero vibration
no crankshaft fitting the S S or J.A.W description will have this complete cancellation
RETRO-EDIT if the bit above is untrue - it makes no difference

this not a crankshaft description for 2 strokes of course

[Tommy Cookers]

Counterweights act as inertial dampers & as a location for add-on pendulum balancers:
http://www.epi-eng.com/images/Engine/en ... aft_12.jpg

counterweights don't act as inertial dampers because they don't move relative to the crankshaft

Ah, no.. not correct T-C, the inertia/rotational weighting vis a vis recip' functions is a damping factor.
https://www.jvejournals.com/article/19933

please indicate where or how your linked article tells us that