Full Details

Name and Model Number Felsenthal Altitude
Correction Computer
Country of Origin USA
Date of Manufacture Box dated 1948. Probably used in WWII
Front Scales Altitudes and temperatures
Back Scales none
Scale Length Spiral, about 48"
Type of Rule Disc
Construction Black fibrous material
Area of Use Military
Comment Attractive spiral scale circular rule made for U. S. Air Force.
Rarity RR
Donor Collection of Clay Castleberry
Match Number 271
(Click Picture for Details)

In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen
(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD.
• RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace.
• RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale.
• RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale.