Cruise speed

["REUBEN ERICKSON" <HEYRUBE@xxxxxxxxxxxxxxxx>]

I will try one more time. I think Mr. Fred D. was on vacation the last time
I asked this. Does anyone know the basis of the 2500 fpm piston speed index
used by R&T in the 50s and 60s to establish max cruising speed of a car?
Why did it disappear from usage? Is it still valid or has modern technology
superceded it? 

Having some experience with limits and fatigue in the helicopter industry,
I suspect that there is an rpm beyond which one is encountering accelerated
wear or fatigue. I asked a friend of mine at the Nevada Auto Test Center
who replied that the manufacturerers knew the answer but that I wouldn't
stand a snowball's chance of getting it. He also added that the engines
weren't the limiting factor anyway, that the transmissions were the
problem. Of course, he was speaking of automatics. Apparently, automatic
transmissions haven't advanced as much as I thought they had.

I invite response. One person did reply previously to speak of max piston
ring speed as a  limit but didn't amplify.

Rube Erickson 

------------------------------