[Leica] noctilux factoid of the day

[jhnichols at bellsouth.net (Jim Nichols)]

Frank,

I began civilian engineering work in 1953.  My first really serious 
assignment was to adapt a set of supersonic nozzle shapes that had been 
computed by Telecomputing in Pasadena into a family of contours for a 
16x16x54-foot flexible wind tunnel nozzle covering the Mach number range 
from 0.6 to 1.6.  All of the scaling, boundary layer correction, and plate 
curvature calculations were done on Friden and Marchant machines.  These 
were not simply "adding machines".  They could do multiplication and 
division to around ten decimal places, and one of the Fridens could extract 
square roots.  I can't speak for Civil Engineering, but for Mechanical and 
Aeronautical Engineering purposes, they were the only way to go.  I used 
slide rules, from the P&E 6-inch pocket size to the K&E 20-inch giant, but 
not for precise calculations.  Surely the Leica optical guys had access to 
this same technology for precise computations.

Jim Nichols
Tullahoma, TN USA
----- Original Message ----- 
From: "Frank Filippone" <red735i@earthlink.net>
To: "'Leica Users Group'" <lug@leica-users.org>
Sent: Friday, April 25, 2008 7:05 AM
Subject: RE: [Leica] noctilux factoid of the day


> Good point......  Not so sure about the use of adding machines in
> engineering circles......Persona;;y I never saw them used in that
> environment, nor my Dad... who was a Civil Engineer starting in 1941.
>
> I think that adding machines again were an accounting issue, not an
> engineering issue..... but I am not sure
>
> Of course there are and were tables.... books of logarithms ..... that 
> were
> used.  Calculating Square Roots using tables is quite trivial....
>
> Frank Filippone
> red735i@earthlink.net
>
>
> Have you guys never heard of Friden or Marchant desktop calculators? 
> These
> were way more accurate than my old K&E slide rule.  Friden even made one
> that calculated square roots.  All of the checkpoint calculations for our
> digital data reduction programs were done by hand by some talented ladies
> using these machines.
>
> Jim Nichols
>
>
>
>
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