I would like to see if there is any possibility of testing, validating and actually demonstrating a potential design for drag-mediated rapid braking of an ultralight plane - possibly a solar plane. In reality, a drag coefficient is not really a constant - it varies with both density and speed.

Tests at low density can be done using altitude, but for the highest density points, I am not sure even what densities are ever available anywhere, and how to go about finding these locations.

At first I thought - Death Valley or the Dead Sea area at night, but they can still be fairly warm.

Then I thought the south pole is really cold but then I realized the altitude is quite high.

Then I thought flying over some arctic or antarctic area near sea level would be the highest density, but water can warm the air a bit.

Is there a known place where one could fly through the highest density air on Earth? Is there a world's record? I suppose one could at least analyze historical airport data, but you'd need temperature, pressure and humidity and synthesize a density.

Assume the craft is actually flying and has a pilot on board - no environmental chambers, wind tunnels or mine shafts.

  • 2
    $\begingroup$ You might try earthscience.SE if you don't get a good answer here; this isn't really an aviation question anyway (in my opinion) $\endgroup$ – Pondlife Aug 9 '16 at 16:02
  • $\begingroup$ @Pondlife Thanks - I understand. $\endgroup$ – uhoh Aug 9 '16 at 16:11
  • $\begingroup$ I'm voting to close this question as off-topic because it belongs on EarthScience.SE $\endgroup$ – SMS von der Tann Aug 9 '16 at 16:37
  • $\begingroup$ @SMSvonderTann et al. I've made an edit, it may speak to the oh-hold status. It's not always easy to judge how much background information to add to a question. Too much, and the focus of the comments becomes more like 'why would you want to do that?' and 'if I were you I'd...'. Too little and the question looks out of place. I'll try to find a better balance next time. Thanks! $\endgroup$ – uhoh Aug 9 '16 at 19:43
  • $\begingroup$ Asking for where air density is highest on earth is still better for Earth Science, regardless of why you want to know. Asking how you could do aerodynamic testing at high/low densities would be better suited here. $\endgroup$ – fooot Aug 10 '16 at 0:04

My candidate would be Verkhoyansk in Siberia, elevation 140 m. The average temperature in January is only -50°F, so this should be a perfect combination of low and cold to produce density records. They even have an airport conveniently located nearby (ICAO code UEBW), so flying there should only be a minor challenge.

To experience really dense air, you better speed up: Average temperatures are rising there, too. The coldest day ever in Verkhoyansk was recorded in February of 1892 already (-69.8°C).

I could not find a source for actual density measurements, but theoretically those conditions should yield 1.522 kg/m³.

Density calculator output

  • $\begingroup$ OK got it. So the 'recipe' is low-elevation inland, and as cold as possible. Somehow now Siberia seems so obvious. Compared to a standard atmosphere of 1.225 kg/m³, the drag would be roughly 25% higher there on a cold day. Thanks! $\endgroup$ – uhoh Aug 9 '16 at 19:15
  • $\begingroup$ Yep. I should have said drag at a given speed. $\endgroup$ – uhoh Aug 10 '16 at 1:33
  • $\begingroup$ @uhoh No, drag would not be higher. You fly slower, so dynamic pressure remains unchanged. But your take-off distance will be much shorter, so the 1200 m runway of UEBW will look like a 1600 m runway under standard atmospheric conditions. $\endgroup$ – Peter Kämpf Feb 9 '18 at 7:44
  • $\begingroup$ Oh, in reality (real pilot in real plane) of course. I meant with all other parameters held fixed, changing one "knob" at a time, in an abstract sort of way. Thanks for the follow-up! $\endgroup$ – uhoh Feb 9 '18 at 8:06
  • $\begingroup$ btw thank you for closing my question (in this case) and pointing me to Earth Science SE. I didn't know about the site, but it's quite helpful. Cheers. $\endgroup$ – uhoh Feb 9 '18 at 8:13

Any place in the arctic near sea level on a cold day would be much lower than the dead sea on a cool day.

Density Altitude Calculator

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