I was wondering if it is possible for a fighter jet to fly around the world and stay in daylight? For the Southern and Northern Hemisphere, the time and speed of daylight is different during seasons. So if not at the equator, would it be possible at the Hemisphere with different seasons?
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18$\begingroup$ What's your exact definition of "fly around the world"? You could fly in a very small circle around one of the poles to cross every longitude in just a few seconds, but I wouldn't really call it around the world. $\endgroup$– IvoCommented Oct 14, 2022 at 7:48
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11$\begingroup$ Concorde stayed in moon shadow for more than an hour to study sun's corona during full solar eclipse link $\endgroup$– user21228Commented Oct 14, 2022 at 8:04
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4$\begingroup$ Why specifically a fighter jet? Some specialised aircraft like Air Force One are designed to handle this for 50h straight, when refuelled in the air. $\endgroup$– MastCommented Oct 14, 2022 at 17:57
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1$\begingroup$ Can you clarify whether the Question assumes "… fly around the world… " to be on a great circle? To me it should, but several Comments here seem to suggest spinning on one foot round either pole would fit the bill… $\endgroup$– Robbie GoodwinCommented Oct 16, 2022 at 19:39
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4 Answers
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Even near the equinox, when the day length is essentially the same over the entire world, this is possible.
At the equator, not so much; you'd have to average around Mach 1.5, including slowdowns for aerial refueling, to "make the sun stand still", though if you start at dawn and only need to get back by dusk, you gain another 12(ish) hours -- which, however, would still require an average speed of about 1000 km/h. Possible, but having aerial tankers in the right places at the right times, over potentially hostile territory complicates things, not to mention the greatly extended flight path needed to avoid overflying places that don't permit it pushing the required average speed back up to the 1300 km/h range.
But if you fly far enough north or south, you could do this in a Cessna, providing only that you could somehow carry twenty-four hours of fuel. Seems kind of like cheating, like those grade school riddles where you walk an hour south, an hour west, and an hour north and return to your starting point.
But in a fighter jet, with aerial refueling over the South Atlantic and South Pacific, you could circumnavigate at around the 45th parallel without having to overfly anywhere too hostile -- and given 36 hours to fly, only need to average around 600 km/h, which is well below "jet fighter" speed.
answered Oct 13, 2022 at 18:46
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5$\begingroup$ Better be a 2-seat fighter, if you plan to stay up for 36 hours straight! For 12 hours, with enough waivers (and help from the flight surgeon), you might could do it single-seat (i.e. an F-22). I think that & a lot of work by the diplomats may be the best bet. $\endgroup$– Ralph J ♦Commented Oct 13, 2022 at 19:24
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8$\begingroup$ Note that the standard definition of ‘circumnavigation’ requires crossing the equator twice. $\endgroup$ Commented Oct 13, 2022 at 20:46
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11$\begingroup$ The category of "hostile" nations will naturally depend on the aircraft's nationality, of course - raising the associated question of which country's air force is best placed to achieve this... $\endgroup$ Commented Oct 14, 2022 at 7:51
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10$\begingroup$ @DarrelHoffman Actually, ISS is too low -- higher orbits have longer periods. But in fact, you can't hover above the day side until you get all the way to the Sun-Earth L1 point, where at least one solar weather observation satellite sits -- and that's close to a million miles out. $\endgroup$ Commented Oct 14, 2022 at 14:37
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8$\begingroup$ Any Great Circle that's not over the equator will cross the equator twice. $\endgroup$ Commented Oct 14, 2022 at 15:30
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You can stay in perpetual daylight with a regular jetliner.
- During northern summer, you operate out of Iceland. You take off in the evening, circumnavigate the north pole and land back in Iceland in the morning. The trip is only 5000km, but you have to stretch it up to 12h depending on season.
- During northern winter, you operate out of New Zealand and circumnavigate the south pole every night, a trip of 8000km. You also have to stretch it up to 12h depending on season.
- On spring equinox, you fly from New Zealand to Iceland, a distance of 17700km along the westbound route (AKL-NRT-KEF). You have 12h from sunrise to sunset and you gain another 13h time shift by flying west. 17700km in 25h is easily doable, even with a fuel stop.
- On fall equinox, you fly from Iceland to New Zealand, a distance of 16800km along the westbound route (KEF-AKL). You have 12h from sunrise to sunset and you gain another 11h time shift by flying west. 16800km in 23h is easily doable, even with a fuel stop along the way.
A jet fighter is ill suited for this mission, it lacks range and endurance. Use a random jetliner with >12h endurance and >9000km range.
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2$\begingroup$ Why do you get extra time flying eastbound? $\endgroup$– ReidCommented Oct 14, 2022 at 19:59
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2$\begingroup$ If one had a pair of bases in Alaska and Iceland, and another in New Zealand and Chile, I would think one could greatly reduce the required flight times during Northern and Southern summers, if the plane set out from each base each evening, landed at the other base in the morning or afternoon, and could then refuel and wait until that evening before setting out for the first base. $\endgroup$– supercatCommented Oct 16, 2022 at 17:06
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1$\begingroup$ @supercat - I don't think that will help. Iceland-Alaska-Iceland is about 11000km or 12h flight time. Iceland-Pole-Iceland is a lot shorter and you can return to Iceland after less than 12h usually (nights in Iceland are rather short around midsummer). Only close to the equinoxes you have to loiter at the pole and wait for sunrise in Iceland. $\endgroup$ Commented Oct 16, 2022 at 17:45
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1$\begingroup$ @RainerP.: Punching values into a great circle calculator, I get a distance of 4,472km between 71N156W (Wiley Post–Will Rogers Memorial Airport) and 66N18W (Grímsey Airport). How were you figuring the 11000km distance? $\endgroup$– supercatCommented Oct 16, 2022 at 18:17
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If you use the FAI definition for setting round the world speed records the rule states a trip minimum of 22,847 miles and all longitude lines must be crossed below 66deg latitude. If you start at sunrise on the longest day of the year at 66deg you get 24hr for a full day plus 20hr of daylight to sundown, or 44hr.
22,847mi/44hr is 519mph ground speed. If you can avoid head winds this is doable in private jets, as well as commercial and military jets. You may not even need to refuel in the air if you have extra tankage.
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1$\begingroup$ Doesn't the jet stream go west to east and you need to fly east to west? That would be a 100 mph head wind. Also you switched latitude and longitude in your description. $\endgroup$ Commented Oct 15, 2022 at 2:03
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If you time this correctly, starting just past dawn near the equinox, then you have 24+12 = 36 hours.
This is less of a problem than other answers suggest. The around the world (crossing the equator) record is currently held by a Concorde flight with a time of ~33 hours, which is easily fast enough. I can't find exact times for every stop, but I think they may have stayed in daylight the whole way based on start/end times. Also they were supposedly only airborne for ~25 hours, maybe the Concorde is quite slow to refuel? But that is good if you only care about yourself and not the plane, as probably having a bunch of Concordes and switching planes instead of refueling would cut off several hours.
(Per Bianfable in comments, this is not so much the time spent at each individual refueling stop but the number of refueling stops--so you will need quite a few Concordes to really get to that minimum time. If my math is right you can theoretically get the minimum time with only four Concordes, but that also requires some of them to fly multiple legs, i.e. they would fly an early leg and then turn around and fly the other direction to meet you for a later leg....)
This is poorly documented, but what little documentation I'm finding suggests that the previous record for this was a hair over 36 hours in a Gulf Stream which is also very nearly fast enough, just in case you don't have a Concorde to hand. (It makes sense that a Gulf Stream or other business jet would be good for this, since they are basically for rich people who want to get places in a hurry without having to stop too much along the way.)
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1$\begingroup$ On supersonic flights Concorde can only stay in the air for 3½ to 4 hours. It'll burn about 80 t of fuel in that time, so refueling will take quite a while. 25 h airborne for 33 h total time seem reasonable to me. $\endgroup$ Commented Oct 14, 2022 at 14:51
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3$\begingroup$ It is important to note though that the Concorde cruised a lot faster than any fighter jet (only SR-71 cruised faster but that is not a fighter). Most fighter jets don't cruise supersonic at all (supersonic flight requires continuous afterburner, which uses too much fuel for long flight) and the best is around Mach 1.2. Compared to Concorde around Mach 2. $\endgroup$ Commented Oct 14, 2022 at 20:26
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$\begingroup$ @JanHudec apparently the best is around Mach 1.5: en.wikipedia.org/wiki/Supercruise#Military_use $\endgroup$– naschCommented Oct 14, 2022 at 21:29