"As no range details are freely available (that I can Find) for the
F22, I got to thinking how to work out the rough ranges for CAP, Air
to Air, and ferry.
The only thing that I could come up with was the comparison method,
this is where I took a 'known' (by this I mean, what has been published) ranges, and compared them to the engine dry thrust and
fuel loads, my (big) assumption was that for every pound of thrust a certain amount of
fuel was required and that this would be fairly constant.
This figure would be comparable across engines designed in the last decade, with allowance made for larger or smaller engines.
Ok, a quick rundown.
I will start with the ferry range as this is the easiest.
The EF2000 can fly 2000 Nm (Nautical Miles) using 5700 litres of
fuel
+ 2 x 1000 litres drop tanks, total 7700ltrs , this gives a figure of
3.85 ltrs per nautical mile for an engine that produces 120kN dry
thrust.
This figure does not include any reserve
fuel, but as all aircraft
usually have this margin, it can for this purpose be ignored.
But now we have established a
fuel usage figure for ferry range for a
120kN class engine.
Now the
F22 can carry
11000 litres of
fuel internally, but the engines
produce 220kN of thrust, if we use the same ratio 220kN/120kN and
apply this to the
fuel we get 7.05 litres per Nm.
Ok the above is rough, and no doubt somebody will tell me larger
engines are more/less efficent, and I would like to know!!!.
So the ferry range for the
F22 is around
11000/7.05= 1560Nm using
internal
fuel.
With additional drop tanks (9000 litres) this extends to 2837Nm.
Using this figure of 7.05 ltrs per Nm, the
F22 can fly around 780Nm
combat radius, with no loiter time, using internal
fuel only.
The above is based on:-
- The ratio of fuel used on late generation engines is related to dry thrust figures, and that they remain roughly constant.
- The the aircraft/engines are similar in their roles.
- That ferry range is the most fuel efficient.
- That the 2400lbs of weapons does not affect range.