Unfinished FM's and top speeds - Flanker, F-15, Gripen

I did a comparison of top speeds between these jets, on both sea level and around 5200-5300m of altitude where you avoid contrails because high altitude top speed is somewhat irrelevant anyway. The test is made with clean aircraft and min fuel.

At 5300m max afterburner(gripen on just 101% or else rip wings)

At 5300m stage 1 / 101% throttle (Gripen same as before)

Sea level top speed

So, apart from the Gripen being able to supercruise and having low drag, but still, I was not expecting these results… Actually I was expecting to be the other way around, the F-15 to be the faster, then Flanker, and finally Gripen. In-game the Gripen on 101% afterburner is almost as fast as the f-15 going full blast at 110% while only producing like 33% of its thrust (on 101%)

Apart from speeds, I think the FM’s are decent, but I feel like the F-15 is overperforming in energy retention and underperforming in AoA.

I am by no means an expert on the issue and I would like to know everyone else opinion.

1 Like

I think that the jets are starting to become powerful enough to expose some of the limitations of the physics engine.


Here are some graphs for these three planes at the alts you describe. In the gripen’s case its low drag makes all the difference. The F-15A just loses thrust at high speed letting the su-27 which is even draggier pull away. Pretty sure this is historical, as the F-15C has the more powerful engines to go mach 2.5.

F-15’s sea level speed is accurate, 1.18/1.19 at sea level, its actually slightly overperforming at 5300m, should be around M1.48

Just to show where the F-15 is best, at 10000 meters it trounces both planes. Unfortunately, the graph cannot go beyond 2000 kph. WT just benefits low level speed over anything else.

Ohh, so I was expecting F-15C performance on the A variant.

Is the gripen speed realistic? Going over 2000kph @ 5200m while producing 6700kgf on “stage 1”?

The max speed is mean to be mach 2.0 at altitude, but I don’t know what altitude that is. I know it is also meant to supercruise, but I’m not sure if anyone has specifics on that.

probably at 20-40K feet considering thats where jet engines tend to be most efficient