Quote:
Originally Posted by Langy
True, but I used the F-22's maximum range (total) to figure out how much fuel endurance each fuel tank supplied. It was 10 minutes per tank. Six hours at cruise seems excessive for any normal jet engine.
Other jet engines can be much more efficient - an A-10 Thunderbolt II has a very long ferry range, giving it a time in the air of around eight hours, but when used in combat it might have an endurance of between two and four hours (depending on what the stats mean on the A-10's Wikipedia page).
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There's much more to an aircraft's range, endurance and speed figures than wikipedia is going to tell you.
For example: You're using the supercruise speed and the F-22's listed range to determine it's endurance, which will lead to some funny numbers. Supercruise is not the 'cruise speed' of the F-22. It's the top speed at which the F-22 can fly without engaging afterburners, which are horribly inefficient from a fuel burn perspective. Off of the top of my head, I'd say that it's maximum range is found at a speed roughly half of that at which it supercruises - giving us an endurance of three hours. Furthermore, it's maximum-range speed is different from it's maximum endurance speed - I'd guess maximum endurance is found at a speed roughly 70% of maximum range speed, giving us about four overall hours of flight time. Guesstimating from what I know about the fuel burn of an F-16 at high altitude (about 3000 pounds per hour, plus or minus 1500 depending on loading, speed, and altitude, doubled for two engines, divided by 26000 pounds of total fuel) gives us about 4.33 hours of endurance - not the six hours that spaceships claims, but close enough and with enough fudge factors that I'd call it a good approximation.
Supercruise on the F-22 corresponds to about Mach 1.5 - I'd guess that the top speed for the F-22 at full burn and at high altitudes with empty bays and almost-dry tanks will fall at about Mach 2.2 - Basic fractions reveal that that's a top speed of 1790 MPH, and because of the altitude differences in which those numbers are achieved, it might be much more. - Again, it doesn't match up with the values in spaceships, but I'd call it fairly close, and I also don't know about the assumptions made in spaceships about the realm of flight in which those numbers are achieved.