Calculating True Airspeed; Best Glide Speed
I’m a pilot. I think it’s in our nature to obsess over numbers. (And I’d really, really like - psychologically, if for no other reason - to see whether or not the plane I’m flying is a “150 knot” airplane...) True Airspeed There are several ways to calculate this: The simplest way to get a “pretty close” number is to take 2% of your calibrated airspeed, multiply it by how many thousands of feet you are MSL, and add it to the calibrated airspeed indicated. So, if I’m flying along at 145 mph indicated (calibrated, 143 mph) at 5,000', that works out to: ((143 * .02) * 5) + 143 = 157 mph true (÷ 1.15 = 137 ktas) A bit more accurate is the true airspeed calculator built into a Garmin GPS unit ( GNS430W , GTN650, etc), which factors in barometer, OAT, etc. (and will calculate your head/tail wind component too). There’s also the “4-way GPS ground speed” method, used, e.g., in this M20F evaluation . (That plane, a ’67 which was constructed differently and is generally faster t