Red Line

[A. Maberry]

I've seen red lines on speedometers but I usually associate them with
tachometers. I remember having a 1963 Buick Electra once that had a sort
of adjustable red line on the speedometer dial which one could set at a
particular speed and caused a buzzer to go off when the car exceeded that
speed.
As Jim points out the red line isn't supposed to tell you the maximum
speed, or the maximum RPM of the engine, but of the maximum safe speed or
RPM.

allen
maberry at u.washington.edu

On Mon, 31 Mar 2003, James A. Landau wrote:

> In a message dated 3/31/2003 4:22:32 PM Eastern Standard Time,
> mworden at WIZZARDS.NET writes:
>
> > Dict Amer Slang traces  verb use from red line WWII (To cross a soldier's
> > name off
> > the payroll for some wrongdoing) through 1973 (denial of loans based on
> > race), to
> > established use in the 1990s (achieve maximum speed, ie had the car
> > redlined),
>
> The "red line" on the airplane speedometer was from _Private Pilot Manual_
> Englewood CO: Jeppesen Sanderson, Inc, 1984, and was long-established usage
> then.  I'm pretty sure the care I learned to drive on in 1963 had a redline
> on the tachometer (I think it was at 5,000 RPM).  Also "achieve maximum
> speed" is incorrect.  The redline is the maximum SAFE speed or maximum
> ALLOWABLE speed.  The existence of a redline implies that the engine is
> capable of going faster and therefore the operator has to be warned.
>
>             James A. Landau
>             systems engineer
>             FAA Technical Center (ACB-510/BCI)
>             Atlantic City Int'l Airport   NJ   08405   USA
>