F-15C uses 2 x Pratt & Whitney F100-229 afterburning turbofans, 29,000 lbf (129 kN) each 2 x 29,000 = 58,000 | mathematically will spend 58,000 lbf, but in real life there limiter is not possible to spend more than 52, 000 lbf, F-15C maximum consumption at low altitude is 52,000 lbf.
In DCS World it consumes 63,000 lbf.
in real life if I have 13,454 pounds and I am consuming 12000 lbf I can fly a little more than 1 hour
In DCS world if I have 13,400 pounds and I am consuming 12,000 lbf I can fly a little more than 30 minutes.