6 ms·
Did a little bit of a back of the envelop calculation on the subject, so this maybe completely bogus, be aware. It would seem like the temperature that the pil
by pwnna 12y ago
Did a little bit of a back of the envelop calculation on the subject, so this maybe completely bogus, be aware.
It would seem like the temperature that the pilot experienced upon ejection at Mach 1 at 15000m (when they broke apart) would be about -13C, which is reasonably survivable[1]. The pressure experienced is probably around 22kPa absolute, which in theory will generate anywhere between 6 - 20g[2]. Not pleasant, but survivable.
Given these, it takes a lot of luck to survive those conditions (1/5th atmosphere, extreme acceleration, low temperature when he falls), but it might be more survivable than we think (this is much better than exploding and ejecting at lower altitudes)
[1]: Calculation via the stagnation temperature at that speed for the standard condition at that altitude (Temperature ~= 217K, P ~= 12kPa)
[2]: Stagnation pressure on him in the front of the body (23kPa), ambient at the back. Average male body surface area is about 2m^2, depending on the geometry you might be able to get down to a quarter of that. Throw in the mass of the pilot (70kg? 90kg?), you should get accelerations in those ranges.
Edit: some more interpretations
- Florin_Andrei 12y ago> this maybe completely bogus, be aware Well, much over 20g is not very survivable, so I'd say you're in the ballpark at least.
- pwnna 12y agoI doubt he got anywhere near 15g. As the pilot had a seat strapped to him when he was ejected, adding to his mass. On top of that I assume that he had much less surface area due to sitting down, although that one is much more speculative.
- durandal1 12y agoYour temperature is just plain wrong, the standard atmosphere model states -6.5°C per 1000m. This is means that the temperature was -97.5C below surface temp. So -70C is more likely. http://en.wikipedia.org/wiki/International_Standard_Atmosphere http://en.wikipedia.org/wiki/International_Standard_Atmosphe...
- pwnna 12y agoWhich temperature? For ambient (T), I'm using http://www.wolframalpha.com/input/?i=temperature+at+15000m http://www.wolframalpha.com/input/?i=temperature+at+15000m as the data. Also see http://en.wikipedia.org/wiki/Atmospheric_temperature#mediaviewer/File:Comparison_US_standard_atmosphere_1962.svg http://en.wikipedia.org/wiki/Atmospheric_temperature#mediavi... The temperature experienced by the pilot as he was ejected was is calculated as the stagnation temperature (temperature on the surface of his clothing, or where the speed of the air = 0), which at Mach 1 would be around -12C. However this temperature will decrease as he slow down. Luckily it should take only about.. 45 seconds for him to get around 5000m, which becomes much more survivable. Edit: from that page you linked, it says: > Between 11 km and 20 km the temperature remains constant.
- mariuolo 12y agoCould the low temperature have helped with regard to thin air? I'm no expert, but I seem to recall that cold limits the damage from hypoxia.
- teraflop 12y agoHypothermia does provide some protection against hypoxia-induced brain damage. However, exposure to air at -13C for only a few minutes is very unlikely affect your core body temperature enough to cause hypothermia. And anyway, the time taken to fall from 15km to a more tolerable altitude would probably not be long enough to cause that type of damage in the first place.
- lutorm 12y agoThat lapse rate is only valid in the troposphere, afaik.