Time Ruler

This is a simple and handy little device I use for my cross-country flights. It allows me to measure time with a ruler directly off my sectional chart.

Instructions

First, measure the time in minutes between any two points along your route of flight. Then fold the Time Ruler so that the number of minutes on the expanding scale spans the distance between your two points. For example, if it took 10 minutes to fly from A to B , find the point on the Time Ruler scale where the distance on the chart from A to B spans 10 minutes on the expanding scale, and fold the Time Ruler along that line. The Time Ruler is now set up. You can measure any other time interval directly off the chart using the folded edge, and you can read your groundspeed from the bottom of the Time Ruler scale.

WARNING:

Make sure that your printer prints out the Time Ruler at the proper scale by checking that the statute miles scale on the Time Ruler matches the statute miles scale on your sectional chart. If not, then your time measurement will be accurate, but the groundspeed read-out will be off.

The Time Ruler is available by ftp in portable document format (.pdf). Just print it out, and make photocopies to keep in your flight bag.

Return to Steve Lehar