reported AI Cruise Fuel Burn

[MBot]

For many years I have been using this little tool to find optimum speed and altitude for AI mission planing. A big problem in DCS is that AI is very inefficient at fuel management and frequently runs out of fuel unreasonably during missions. I think sometimes a contributing factor is excessive fuel burn in the AI flight model at usual flight profiles. I know that ED has told us for years that it wants to improve AI fuel management but we have not seen anything to this effect so far. So I thought I would support the issue with some data.

Following are measured best cruise altitude and speed (lowest fuel burn per km) for various AI aircraft. Please note this is only for AI controlled aircraft, even for types which are playable. Take the data with a grain of salt as this is also greatly weight dependent which changes constantly during a flight. The granularity of the measurements is 3000-12000 m altitude at 1000 m intervals and 500 to 1000 kph speed at 50 kph intervals.

Lowest fuel consumption per km:

Type	Altitude (m)	Mach	Comment
MiG-21	12000*	0.84	Higher may be even better
MiG-23	7000	0.57
MiG-25	9000	0.86
MiG-29	12000*	0.89	Higher may be even better
MiG-31	8000	0.85
Su-17	8000	0.58
Su-24	4000	0.59
Su-27	12000*	0.79	Higher may be even better
Tu-22M	4000	0.59
F-4	9000	0.77
F-5E	11000	0.79
F-5E-3	10000	0.78
F-14A	9000	0.68
F-14A-135-GR	9000	0.77
F-15C	12000*	0.79	Higher may be even better
F-15E	7000	0.71
F-15E S4+	9000	0.77
F-16C	9000	0.68
F-16CM	8000	0.67
F/A-18C	8000	0.76
F/A-18C Lot 20	12000*	0.79	Higher may be even better
Tornado IDS	5000	0.56
B-1B	7000	0.66
B-52	9000	0.59
E-3	9000	0.59
KC-135	5000	0.6

Some observations:

-Cruise speeds for swing wing aircraft are too low. MiG-23, Su-17, Su-24, Tu-22M and Tornado all cruise below Mach 0.6. As AI fuel burn rises rapidly above optimum speed, this this leads to excessive fuel consumption at tactical speeds. A pleasing example is Heatblur's F-14A at Mach 0.77, which shows that it can be done better even for AI flight models.

-Some outliers cruise best at very low altitudes. Su-24 and Tu-22M at just 4000 m, Tornado and KC-135 at 5000 m.

-Various heavies (B-52, E-3, KC-135) cruise best at very low Mach 0.6.

-Other aircraft look quite reasonable, especially the AI flight models of playable aircraft. An interesting outlier is the F-16CM at very slow Mach 0.67.

 

Attached is the full set of test scenarios. But you can easily take any mission, change the aircraft type and adjust the speed and altitude range you want to test in the triggers. Run the mission, wait 40 seconds for the measurements and the results will be presented.

FindBestCruiseEndurance_Missions.zip

[f-18hornet]

Thank you, reported for internal analysis.