RPM -- F1 vs Road Car

[Reca]

First, is the extensive use of tungsten slugs in the counterweights. Apparently, it worked OK, but to me it seems a rather risky approach in an extremely high rpm race engine. One of those slugs coming loose at 17,000 rpm would do a lot of damage. A better approach to maximizing counterweight MOI at minimum mass, would be a more sophisticated counterweight shape (ie. a minimum thickness inner web and maximum thickness outer web, thus putting the counterweight mass where it counts).

The problem is packaging, there’s very little clearance on the two sides of the counterweight itself, hence if it was made only of steel (without the high density inserts) it would be inevitably thicker and would significantly increase the crankshaft (and engine) length.

As for the distribution of the counterweights on the length, as you can see the counterweights on the cranks at both ends have 3 slugs instead of the 2 present on the other 6 counterweights, so it looks like the distribution of masses has been evaluated, maybe that one is what they found to be the optimal one, at the time, with that engine.

BTW, you mentioned you have seen crankshafts without counterweights, was that the same crankshaft of the Ford V8 you mentioned in the other thread ?

[bcsolutions]

I thought that the crankshaft had to be made only from steel, surely if the counterweight inserts are Tungsten then the crankshaft is illegal?

[riff_raff]

bcsolutions,

Nice catch!

The Ferrari crank Reca linked was from the '99 F1 car(?), but I think the '99 reg's were the same as they are now, with regards to crankshaft materials:

"5.5 Engine materials :
5.5.1 The basic structure of the crankshaft and camshafts must
be made from steel or cast iron."

I suppose you could make an argument one way or the other. Tungsten alloy is "non-ferrous" and therefore illegal. But are tungsten counterweight slugs part of the "basic crankshaft structure"?

It's common knowledge that Ferrari gets away with pushing the rules more than other teams in F1. Look at what they are getting away with this year with regards to testing:

http://www.grandprix.com/ns/ns14873.html

[Reca]

Nice try, everything is good to bash Ferrari...

But are tungsten counterweight slugs part of the "basic crankshaft structure"?

Surely a lawyer could write a 100+ pages documentation with the most farcical interpretations of this rule, but, can we please use a bit of logic ? High density inserts are not only allowed, but, very likely, commonly adopted. I’ve seen an Asiatech 2001 crankshaft and it has them.
Then just read the 2006 rules for the V8 :

5.14.4 Crankshafts must be manufactured from an iron based alloy.
No welding is permitted between the front and rear main bearing journals.
No material with a density exceeding 19,000kg/m3 may be assembled to the crankshaft.

It’s evident they want to put a limitation on the material used for the inserts, would they put this kind of limitation if they weren’t allowed ?

It's common knowledge that Ferrari gets away with pushing the rules more than other teams in F1. Look at what they are getting away with this year with regards to testing:

That’s not the right thread to talk about it but as you certainly know the testing limitation isn’t a rule. It’s a gentlemen agreement and Ferrari didn’t have any obligation to subscribe to it.
And what you call “common knowledge” is nothing but gossip from fans on the web. You should talk with people who worked in F1 in the recent years, you would be surprised by what some other teams do in term of pushing the rules.

Edit :
in my last post I forgot this part

Remember a few years back (1993?), the Ferrari V12 F1 engine had a cast iron block.

Yep, for many years Ferrari used cast iron block, since the last turbo engines, 1987&1988 IIRC, and continued to use it for the V12 until 1994. The last V12 in 1995 had a steel block.
Anyway AFAIK also BMW and Honda turbo engines had cast iron block.

[bcsolutions]

5.14.4 Crankshafts must be manufactured from an iron based alloy.
No welding is permitted between the front and rear main bearing journals.
No material with a density exceeding 19,000kg/m3 may be assembled to the crankshaft.

Reca, i don't wish to be fastiduous but i can't find any evidence relating to current regulations allowing the use of non iron based counterweights. The current FIA regulations state only:

5.5.1 The basic structure of the crankshaft and camshafts must be made from steel or cast iron.

Or am i looking in the wrong place?

The 2006 regulation that you posted appears to display two additional sub-regulations regarding material density and welding, is this then something new for the teams to consider in 2006?

[John G]

hi
an interesting Java applet is at

http://www.wfu.edu/~rollins/piston/anim ... ractive_2/

where you can change the crank parameters and see the effect on maximum piston speed and acceleration.

Question along these lines: can anyone quote a figure for the maximum FORCE which a piston should be subjected to? Since we can find the acceleration, then multiplying by its mass gets us the force it is subjected to at or near TDC. Are there guidelines for the upper limit this should be
for a given material? I have a vague recollection of seeing this long ago.

thanks!

John MA - USA

[riff_raff]

Reca,

5.14.4 Crankshafts must be manufactured from an iron based alloy.
No welding is permitted between the front and rear main bearing journals.
No material with a density exceeding 19,000kg/m3 may be assembled to the crankshaft.

It’s evident they want to put a limitation on the material used for the inserts, would they put this kind of limitation if they weren’t allowed ?

I believe the density of tungsten is 19,250 kg/m3, slightly over the limits you quote.

John G,

mean piston speed and accelerations are only part of the overall design problem. The total resultant dynamic forces and couples within the crank train due to its particular kinematics are what matters. These forces produce stresses (bending, compression, torsion, etc) within the crank/conrod/piston components that must be within limits for the chosen materials and structural configurations. Another thing that must be considered is how engine vibrations (due to inertia unbalance) will affect the chassis. Adding crankshaft counterweights can significantly increase engine mass and rotational MOI because they are steel (or tungsten). The trade-off is that they reduce engine vibration, main bearing loads and crankshaft stresses.

[Reca]

Reca, i don't wish to be fastiduous but i can't find any evidence relating to current regulations allowing the use of non iron based counterweights. The current FIA regulations state only:

5.5.1 The basic structure of the crankshaft and camshafts must be made from steel or cast iron.

Or am i looking in the wrong place?

The point is that, as long as the basic structure of the crankshaft is made of steel or cast iron, you can attach any material to it. The inserts are just that : parts, made of an high density material, attached to a, steel or cast iron, crankshaft. They don’t constitute the basic structure of the crankshaft.

I posted the 2006 rule because it’s a further confirmation that that’s how FIA consider the inserts.
For the next year they introduce a limitation on the density of the material used for the inserts and to identify these parts rule says “material assembled to the crankshaft”. Until now it wasn’t necessary to identify these parts with precision, because there wasn’t limitation on them, the only limitation was on the material used for the basic structure of the crankshaft. If the inserts weren’t allowed then the addition for 2006 limiting the density wouldn’t be necessary.

I believe the density of tungsten is 19,250 kg/m3, slightly over the limits you quote

Yes, for 2006, no limit for 2005 or earlier years.
Certainly the choice of 19000 kg/m3 as limit isn’t a coincidence, just like it wasn’t a coincidence the limit on the specific modulus of young they imposed few years ago. Anyway considering steel is about 7800 kg/m3, there’s a big range to play with.

[riff_raff]

I just took a look at the 2006/2007 engine regulations. It must be a 2.4L V8 with a maximum bore dia of 98mm and minimum bore spacing of 106.5mm. The minimum engine weight must be 95kg. No VVT or variable geometry intakes. You can only use a single fuel injector per cylinder and the ignition system must be a conventional spark plug- no plasma discharge systems allowed. Also, no solenoid or hydraulic valve actuators.

As for engine materials, no ceramics, no intermetallics and no MMC's. And aluminum alloys cannot contain more than 5% Be (no AlBeMet alloys).

For cryin' out loud, these guys are starting to sound like NASCAR!!!