Amateur Aerodynamics

One of the highlights of my last semester as an aerospace engineering student was a new class, Sustainable Aviation. Previously, this course was offered as a Special Topics class outside of the regular curriculum but it’s now part of the course catalog of electives in AE—and I think that’s great. Despite the current political climate in the US, sustainability is as much of a problem as ever and will continue to be, as humanity will have to grapple with issues of climate-changing pollution and resource usage into the indefinite future. And the longer we wait to address it, the more of a problem it will become; to put things in perspective, global mean surface temperature (GMST) averaged over the last three years has already exceeded the 1.5°C limit agreed to in the Paris accords.   Even though the semester is over and I’m no longer a student, sustainability is still on my mind. And it turns out, I’ve found the perfect example of one of the major challenges of sustainability right ...

  We’ve all read or heard about the fact that colder air increases aerodynamic drag due to its increased density, reducing your BEV range or ICEV fuel economy in winter. What most people don’t know is   how much   aerodynamic drag increases with dropping temperature, or how much benefit there is on a hot day. Is it significant? Let’s figure it out. Yes, we have a reindeer farm in central Illinois.  Merry freakin' Christmas. Standard Atmosphere Model   To do that, we first need an appropriate model of atmospheric parameters such as temperature, pressure, and density, and how they change with altitude.   In the Aerospace Engineering program I'm about to complete, we use the 1962 International Standard Atmosphere (ISA). This model was derived from decades of atmospheric measurements, from which a set of equations were developed that adequately reproduce variations in temperature, pressure, and density as altitude changes. Up to 36,089 ft, a  thermocline ...