What Are the Military Uses for Slide Rules?

The military used a variety of slide rules.

The government issued slide rules with specialized scales for different branches of the military. Most military versions had standard scales on the front and specialized scales on the back. Others slide rules were specific to the use.

Army

The U.S. Army used slide rules for field artillery with scales for elevation, drift and range. Triangulation scales had graduations in yards, meters and mils. Some of the slide rules were ranging charts. The Army began to use slide rules extensively in 1943, and they are still used today in some training situations.

Air Force

Many of the Air Force navigation slide rules were circular. These have scales for air speed, temperature rise, course, altitude and drift for navigational computations. B-29s had slide rules specific to the plane to calculate fuel usage. Aerial-photo slide rules had scales for ground size, ground speed, image size, focal length and altitude. The Air Force had load-adjuster slide rules specific to different model planes. These calculated load weight to distribute weight evenly.

Foreign Military

Other countries had their own versions of these slide rules. Most were similar to the U.S. versions and did similar calculations.

References

• The Slide Ruler: Military Rules
• Slide Rule Museum: Military Slide Rules
• Slide Rule Site: Specialized Rules
• Time: Artillery: Slide-Rule Boys
• Army: New York National Guard Train on New Weapon in the Florida Sun