From: b102smi@utarlg.uta.edu (George M. Smiley)
Subject: Its a Carbon world out there [was: carbon brakes] 
News-Software: VAX/VMS VNEWS 1.41    
Organization: The University of Texas at Arlington
Date: Thu, 8 Oct 1992 00:34:00 GMT

(Toby Vaughn Padfinski) writes...
(George M. Smiley)...
>>I, for one, look for the day that engine builders begin to exploit
>>carbon-carbon technology to make such stuff as pistons and connecting
>>rods. Such designs would make for some very high-revving motors which
>>in turn would lead to more power. There exist motorcycle race engines
>>using both, but, they are few and far between. Why none in the self
>>proclaimed leader of motorsport engineering, F1 ? 
>	
>	In the latest issue of Popular mechanics, it shows a picture of
>an all-Carbon-composite? piston. I read it briefly on my way to a National
>Guard drill on a military bus, with about 768 other guys, so I don't
>remember all of the details, but they said they got something like 4%
>better fuel economy, and a boost in power, while NOx and hydrocarbon
>emissions were drastically reduced. The price was something like 40x more
>than an aluminum piston. If someone wants to look it up, I'd like to see
>the official results.
>	Anyway, I guess that would be just too great an expense, even for
>F1. Although, now that I think about it, I remember seeing something about
>not being able to use composites in stuff like connecting rods, because
>you can't really put a wrist pin in it, as well as the resin couldn't with-
>stand that much heat. But, if a piston could, I don't see why a rod couldn't.
>Kap Parfrey is the resident expert on composites here. Would you be so kind
>as to help here, Kap?????????
> 
>TOBY...
> 
>>Against the rules ? Infeasible for larger motors ?
> 
>>Andrew ?
> 
>>George.

This thread interested me enough to dig through some racecraft engineering
articles to see what I could come up with. Not much, these things are 
pretty well guarded. Anyways, as for cost, I don't know how much titanium
cost, but, it is a lot more than aluminum, and shouldn't be far behind
carbon composites. I have seen carbon rods and they work well. The rod
doesn't see that much heat so carbon fiber is used with metal wrist pins
pressed into it. This saves around thirty percent of the already high
price. However there is some concern over strength vs. price vs.
weight. Carbon composites have no give, they either take the pressure
or they shatter. On the other hand, the various metals used now have a
more elastic ability to absorb punishment. One can make a cabon rod
strong enough so it never breaks, but, it might be too large to fit 
inside the engine. One can't switch to carbon-carbon because it is
actually less strong than carbon fiber, its primary use is in items
exposed to heat greater than the 400 or so degrees Farenheit carbon
fiber can take.

Now, carbon pistons are really interesting. The manufacturing process
alone is very complex. The carbon-carbon must be coated to prevent the
rapid oxidation that occurs inside an engines combustion chamber. This
final coat also prevents the piston from soaking up oil in the motor, a
definant no-no. (Carbon-carbon is very porous). The end result is a piston
that weighs less than half of an aluminum piston and can withstand heat
temps up to 4000 degrees Fahrenheit. Imagine the possibilities of being
able to design a motor that utilizes such pistons. You have 3000 more
degrees of temperature to play with. No more worrying about keeping the
pistons cool, the temperature differential between intake and exhaust
could go skyhigh and your motor would become *more* efficient. Less
energy would have to be spent on the cooling system, horsepower goes
up from the freeier revving motor, gas mileage goes up from the increase
in efficiency. 

And we haven't even got to carbon fiber rims, carbon fiber suspension
pieces, carbon........
If I were Williams or Mclaren, I would unload some of those big driver
salaries, hire Damon Hill or Johnny Herbet for a million or two and give
the rest to Renault or Cosworth to build me an advanced motor. Then we 
fans could here Bob Varsha dust of his old line of:
'Folks, jump in the family wagon and rev the motor to 6000 rpms and it
will blow sky high. Well, these motors are about to do *three* times
that.'

George.