Vintage Pilot Air Navigation Tools

Vintage Felsenthal MB-4 Air Navigation Dead Reckoning Computer with Leather Case

This item is an authentic Felsenthal Type MB-4 mechanical computer used for air navigation and dead reckoning calculations. It features a circular flight computer (E6B style) for computing wind triangles, time, speed, and distance. The attached slide rule component is used for calculating density altitude and airspeed corrections. It comes in a durable leather pouch for protection and portability. 13.5" x 6"

This manual, analog flight calculator was an essential piece of pre-GPS cockpit gear used by military and civilian pilots to determine critical flight factors like wind correction, true airspeed, fuel consumption, and distance. This complete set includes the dual-sided mechanical computer, a clear plastic navigation alignment slide, and the original brown textured protective case.

There are handwritten pilot notes that the pilot penciled in shortcut formulas for quick in-flight math calculations to use for time, distance, direction, and course corrections.

Item Specifics

• Brand: G. Felsenthal & Sons Inc.
• Model: Type MB-4Type: Dead Reckoning Flight Computer / Military Navigation Tool
• Country of Manufacture: United States
• Era: Vintage (circa 1950s–1970s military/civilian aviation era)

Key Features:

• Dual-Sided Design: Features a logarithmic circular slide rule on one face and a polar coordinate wind-drift plotting grid on the reverse.
• Formulas Printed on Frame: Includes quick-reference calculation guides for True Heading (TH), True Course (TC), and Magnetic Heading (MH).

This is a vintage item that may have imperfections, pencil markings and signs of wear consistent with use and age.