F.85 Data Sheet MJS-p-0266

Felsenthal, D-4, 1944

Serial Number or Date Stamp:

Country: USA Primary construction material: pl Case included?: no

General Description: Specialty circular slide rule

Length of 1 decade = 12 in, and overall scale length = 12 in. The largest physical dimension is 4 in.

Front Scales: TruAlt [ PressAlt Time ] AirTemp PressAlt

Back Scales: CalAirSpeed [ Press/DensAlt/AirTemp ] TruAirSpeed

Notes: Time Distance Computer Type D-4; WWII device; Property of U.S. Army Air Forces; fluorescent numbers on black background

References: https://www.madeinchicagomuseum.com/single-post/g-felsenthal/

Date Acquired: 07/08/2022