Optimizing Aerodynamics of a Truck: Part 3
![Image](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3q2d_6o_66fY9hy5mU0YULTqXwIfjComjN1oEjzlMTPeWIQ-g7IS7aX2hHaLrXb9Tm40hOrdpnDP8ovOgr8SHGu73RY4pe2JR5wSdTK6jes_Un0m0bqTLkTtRQ070e22HM7cn1qcR2NS8vRJNzm9P9dnuxd0pi2Tjs0WQZBZXojps2vW185WcItF8/w640-h360/20220524_120518.jpg)
Will this barn door reduce drag? Only one way to find out. In Part 1 of this series , I measured drag reduction on my 1991 Toyota pickup with the grill blocked and mirrors removed. In Part 2 , I did some qualitative flow testing, observing the behavior of wool tufts with a modified A-pillar and a bug deflector. Today in Part 3 we’ll go back to measuring drag reduction as we look at air dams. How Do I Decide Which Test to Use? Before we get into it, an anecdote. When I learned to drive, I remember my instructor taking us out onto a 4-lane highway to have us practice changing lanes. Look in the mirror, check that the next lane is clear, signal, and move over, she told us. When my turn came, I glanced at the mirror and began to move over. Driver’s ed cars had right-side brake pedals, and she stomped on it. There was a car in the other lane I was trying to move into. “See what you’re looking for,” she said. When testing aerodynamic modifications, see what you’re looking for. That