I'll use the numbers posted there :

https://www.hs.fi/kotimaa/art-200000613 ... 1bd4a3b646There's 11,089kg/h for mil thrust, 10.2kg/s for afterburner. The new KPP has been given as 63 seconds for accelerating from Mach 0.8 to Mach 1.2. Assuming it's at 30,000ft, Mach 1.2 equals 707 knots TAS.

Let's suppose that after that acceleration, you can maintain Mach 1.2 with mil thrust or barely more than that, so the 11,089kg/h =~ 24,450lb/h fuel consumption would be a good approximation. The number that floats around for normal cruise is some 5,000lb/h, and it's probably around Mach 0.9.

With a very napkinesque assumption, let's say the acceleration between 0.9 and 1.2 Mach is constant (and is the same as between Mach 0.8 and Mach 1.2), so it's 3.74 knots TAS per second ; integrate that between Mach 0.9 and Mach 1.2, and you've covered 29,230 knots-second, or 8.12nm, in those 47.25 seconds. The fuel needed for that acceleration, assuming it's full afterburner, would be around 1,063lb.

In comparison, staying at Mach 0.9 would have covered 6.96nm in that time, and burned 65.6lb of fuel. So you flew an extra 1.16nm, pretty much negligible for the rest of the calculations. And roughly an extra 1,000lb of fuel for the acceleration over staying at Mach 0.9.

At Mach 1.2, you got k1 = 707/24,450 = 0.0289nm/lb of specific range, while you got k2 = (3/4)*707/5,000 = 0.106nm/lb at Mach 0.9. So the question is when do we have x/k1 + 1,000 = (x+600)/k2, as that's the condition for equal total fuel burn for accelerating and then sustaining Mach 1.2, while covering an extra 600nm at Mach 0.9.

So you got x*k2 = (x+600)*k1 - 1,000*k2*k1 => x*(k2-k1) = 600*k1 - 1,000*k2*k1 => x = [600*k1 - 1,000*k2*k1]/(k2-k1) = [17.34 - 3.063]/0.0771 =~ 185nm.

So it means you that if you accelerate from Mach 0.9 to Mach 1.2 (about 8nm), then fly at that speed for 185nm, you've burned the same quantity of fuel as flying some 792nm at Mach 0.9.

Now one important thing to note ; the thing used around 7,464lb of fuel, so you probably don't want to fly at that speed for too long considering the reserves.

Everytime you don't tell the facts, you make Putin stronger.

Everytime you're hit by Dunning-Kruger, you make Putin stronger.