The Jeppesen CR-3 Circular Computer is a professional analog flight computer designed for pilots, student aviators, and flight instructors. This 6-inch circular slide-rule computer assists with a wide range of aviation navigation, flight planning, and performance calculations without requiring batteries or electronic devices.

Key Features

6-inch diameter circular flight computer for easy portability and cockpit use.
Solves both high-speed and low-speed flight planning problems.
Performs wind triangle calculations, including wind correction angle, true heading, and groundspeed.
Supports polar grid navigation and pressure pattern flying calculations.
Automatically compensates for temperature rise and compressibility effects.
Useful for calculations involving time, speed, distance, fuel consumption, density altitude, true airspeed, Mach number, and course corrections.
Durable construction designed for frequent aviation use.
Includes an instruction manual and vinyl carrying case. 
Applications

The CR-3 is widely used in:

Pilot training programs
Flight schools
Private and commercial flight planning
Aviation navigation instruction
FAA knowledge test and checkride preparation 
Specifications

Specification
Diameter 6 in (15.2 cm)
Type Analog circular flight computer
Manufacturer Jeppesen
Included Items

Typical Uses
Navigation, flight planning, wind calculations, performance computations