circumnavigating the globe?

is it possible to circumnavigate the globe in infinite flight possible?

if it is, at what height am i the fastest? as i tend to realise at a certain point i begin losing ground speed

at what height am i most fuel efficient?

and at what height and speed would it be the most efficient to fly?

if it makes any difference, i plan on flying the a350 to achieve this feat

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It kind of depends on your definition of circumnavigation. If you’re flying on/near a great circle you will need to stop (most planes twice or more, some can do it in one stop). If you fly a shorter circle you can conceivably make it without stopping in a 77L. An A350 will have to stop once unless you get really creative with your definition of circumnavigation.

If you’re worried about speed just get an F22 and go Mach 3 and stop every 45 minutes. Otherwise don’t worry about speed and focus on efficiency.

Presuming you use a 77L, M 0.84 and start at FL290. Step to 360 at 36% load and 370 at 29% load. You will get about 32:50-33:05 with this so make sure your circle is at least 30 minutes less than that. This is a relatively small circle but it is the closest you can get without trying some ground effect shenanigans.

If you must, it’s FL280 until about 35% and then 320 after that. Maximum is about 25:20 so you should be able to complete a great circle flight with just 1 stop provided you pick your time and departure accordingly.

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oh i see, wow. is the longest ranged plane the 777L? anyways i was hoping on flying close to the equator just for the fun of it.

also still learning here, but why is doing a step climb more efficient? would’ve thought fuel flow would remain the same throughout or be more efficient if i stayed at a certain level?

speaking of efficiency, you have to consider Coriolis effect, from that you can determine at what latitude you’ll have the most tailwind/headwind

at what height am i most fuel efficient?

from my experience, I gradually gain ground speed as I climb up until about FL300. I usually cruise at FL310-FL320. higher than that, I’ll lose some ground speed because of the lower pressure and the change of wind direction (watch attached videos).

but here’s my take: you have to pay attention to geographical conditions besides the Coriolis effect. why? gulfs and peninsulas are formed because of the wind! from there you could deduce the wind direction if you have no idea where the wind goes according to Coriolis effect.

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oh yea, i’ve actually been trying to research on where i can fly the best tail wind, since it allows faster speeds.

thank you for the videos tho, im currently still learning about it in both real life and in the sim heh.

i’ll be sure to take a look at the videos once im free:)

why is doing a step climb more efficient?

perhaps the fact that the higher you climb, the colder the air will be, and according to Carnot cycle,

η = 1 - T_ambient/T_max

thermal efficiency increases as the ambient temperature decreases. jet engine thrust is a result of accelerated airflow, which is the result of heating the air. a jet engine can heat the air up to hundreds of degrees Celcius, thus making a big difference between the engine and ambient temperature (see this article for more detailed explanation).

also, because the higher you climb, the less dense the air will be, there will be less drag, making it more fuel efficient although you’ll end up losing some ground speed.

“but why doing the step climb? you only explained the climbing thing!”
when you’re climbing, you’re exerting force in 2 directions: forward and upward (against gravity), but you know that you’re heavy because of the fuel, so you have to burn some fuel first until you get lighter at some point and the continue climbing. a fully loaded aircraft usually consists of 20-30% of load being passenger/cargo and the rest is the fuel itself. you can’t unload your passengers/cargo mid-flight but you can burn some fuel to make your aircraft lighter.

The air is thinner so you need less thrust to fly there, which offsets the extra thrust you need because of the altitude. This swings favorably when you are lighter.

You can check out my step climb guide here:

ah i see, that does make a lot of sense. thank you for the insight. i do know that the higher altitude have lower drag, but due to the thinner air, i would expect my engine to have to work a little harder to maintain the speed?

oh great, thanks, that would help a lot, i’ll have a look:)