Here are some load indices calculated in the Rafale reference system:
AIM-9L = AIM-120 = 3 (+ 3.66 pylon)
And for the following loads the pylon has an index of 2
- AN-AAQ-28 Litening Targeting pod: 2.93
- ALQ-131: 6.28
- Mk-82: 1.67
- Mk-83: 2.09
- Mk-84: 4.18
- CBU-87: 9.79
- CBU-97: 9.79
- LUU-2: 3.77
- GBU-10: 5.94
- GBU-12: 4.27
- GBU-38: 1.67
- GBU-31: 4.18
- CBU-103: 9.79
- CBU-105: 9.79
- AGM-65 dual: 3.35
Now we're going to add weapons to the two aircraft, which will change the drag index of the Rafale and the initial and final weights of the F-35 and Rafale. I'll take 2 air-to-air missiles and 2 MK-84 bombs:
The mass of the AIM 120 is 161.5 kg and that of the MK-84 is 894 kg.
The empty weight of the F-35 is 13290 kg, with 2 AIM 120 it is 13613, with 4 AIM 120 it is 13936 and with 2 Mk 84 and 2 AIM 120 it is 15401 kg.
The index of the F-35 with its payload bay is 212.38 and it can fly 2820 km with 4 AIM 120, i.e. at an empty weight of 13936 kg, in these conditions its take-off weight will be 13936 + 8278 = 22214 kg.
We can calculate the range of the
F-35 when empty:
We have a take-off weight of 13290 + 8278 = 21568 and therefore ln 21568 - ln 13290 = 0.566 and on the other hand we have ln 22214 - ln 13936 = 0.466 for the F-35 configured as Air Air. So the F-35's empty range will be 2820 *0.566/0.466 =
3425 km.
We can also calculate the range of the F-35 loaded with 2 MK 84 and 2 AIM 120:
we have a take-off weight of 15401 + 8278 = 23679 kg and ln 23679 - ln 15401 = 0.430 which gives a range of 2820 * 0.430/0.466 = 2602 km
Finally, we can calculate the range of the F-35 loaded with only 2 AIM 120, which will be the average between 2820 and 3425, i.e. 3122 km.
To calculate the
combat range of a loaded F-35, we take the average of the outward and return flights and divide by 2. So for the F-35 with 2 Mk 84 and 2 AIM 120 this gives:
(2602 + 3122)/4 =
1431 Km
For the Rafale we have the following elements:
Rafale with 3 x 2000 l drop tank:
- Index: 220.5
- Range: 3700 Km
- Empty weight: 10580
- Take-off weight: 20184.5
Rafale with 3 x 2000 l drop tanks, 2 MK-84 and 2 MICA:
- Index : 246.18
- Empty weight: 12592
- Take-off weight: 22196.5
Rafale smooth:
- Index: 159
- Range: 2532.5 Km
- Empty weight: 9850
- Weight on take-off: 14550
Rafale with 2 MICA
- Index: 172.3
- Empty weight: 10074
- Take-off weight: 14774
The mission comprises 3 phases:
- Heavily loaded flight during which it will consume all the 6000 litres contained in the Drop tanks, i.e. a mass of 4904.5 kg over a distance D that is easy to calculate.
- Flight with the weapons but without the drop tanks towards the target at a distance X to be determined.
- Return to base with only the air-to-air missiles.
First we calculate the missing range:
Rafale with 3 x 2000 l drop tank, 2 x MK-84 and 2 x MICA:
The Rafale will be able to travel 3700*220.5/246.18 =3314 km to take account of drag.
To take account of mass, we consider ln 20184.5 - ln 10580 and ln 22196.5 - ln 12592, i.e. 0.646 and 0.567.
The range with the drop tank and weapon will therefore be 3314*0.567/0.646 =
2909, which is the performance on the outward journey for 9604.5 kg of fuel.
On the return journey, we saw that the smooth aircraft had a range of 2532.5 km for 4700 kg of fuel, but we have to take into account the weight and drag of the missiles.
For the drag we go from index 159 to 172.32 and therefore the range is reduced 2532.5*159/172.32 = 2339
For the weight, we go from 9850 kg to 10074 kg unladen and we add 4700 kg for the full fuel tank.
We therefore have ln 14550 - ln 9850 and ln 14774 - ln10074, i.e. 0.39 and 0.383, which further reduces the range to 2339*0.383/0.39 =
2297, still for 4700 kg of fuel.
Calculating the distance D
This is the distance covered during the first phase, when the aircraft is heavily loaded and will consume all the 6000 litres contained in the fuel drop tanks, i.e. a mass of 4904.5 kg
it will therefore fly in these conditions 2909*4904.5/9604.5 = 1485.5 km.
Then he will fly to the target with his weapons and without his drop tank over a distance X and finally he will fly back with the air-to-air missiles over a distance X + 1485.5 km.
With the weapons and without the drop tanks, the Rafale's index is 159 + 25.68 = 184.68, whereas with the air-to-air missiles and without the drop tanks, its index is 172.32, so it will have to fly the 2X distance at an average index of (184.68 +172.32)/2 = 178.5.
We can calculate how much fuel will be needed to cover the 1485.5 km on the return journey, to find out how much fuel is available to cover 2X.
At 4700 kg, we have a range of 2297 km, so to travel 1485.5 km we would need to consume 4700*1485.5/2297 = 3040 kg, so to do 2X we have 1660 kg of fuel, which would allow us to travel an extra 811.5 km if we had no bombs to carry, but which we will reduce by using the average index of 178.5 and the average weight of 10968 empty and 15668 with a full tank.
The reduction due to drag is therefore 811.5*172.32/178.5 = 783.
For the reduction due to the masses we consider ln15668 - ln 10968 and ln14774 - ln 10074 i.e. 0.357 and 0.383 which gives a distance of 783*0.357/0.383 =729.8 km which gives X = 364.9 km and the "
combat range" of 1485.5 + 364.9 =
1850.4 km