F-15 Eagle: History, Performance & Discussion

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I used Width under dopplerspeed and divided by 2. Look on MPRF search, 100m/s. I would say thats the bandwidth of the filter. The only way to test is to grab the plane and have someone just go slow as possible.

The code on one radar is not always the same for another. Best way to test is just flying it

while the changelog says it was changed it appears to be unchanged yet, maybe a dev accidentally put the F-15 changes on an earlier patchnotes

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This could be the case. There are no FM changes in 0.19 update.

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well the goodnews is that it seems the F-15 flight model change should be coming very soon, since it seems internally it was already fixed and will come in the next patch or so

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Could also be in reference to my first report about it underperforming at low speeds, who knows. Need more information.

No FM changes to F-15 in 2.33.0.19

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Lies no changes on 0.19 only on 0.20 which is in dev

only what changed, fuel flow 1100kg/min => 770 kg/min on sustaned turn on 0.62M

Its funny how a much more complex thing, imo, to fix without messing other things up is made in a few days. Hard to get it right to manuals specs if they available but then other stuff which is literally a single line code change with bunch of proof is simply not done
829bcaa6918ccd588402b2a11598ea92
Makes you think

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cries in AIM-54C T^T

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IRL N-019 radar

  • in HPRF search mode rejects targets with closing velocity smaller than figher ground speed + 150 km/h. Head-on targets only. No separate Look-up and look-down modes.
  • in MPRF search mode rejects targets with closing velocity ±150-190 km/h around main beam clutter centerline. Notching targets can’t be detected. No separate Look-up and look-down modes.
  • in HPRF and MPRF track mode there is NO ground clutter filtering at all. Target is tracked by unambiguous (HPRF) or ambiguous (MPRF) doppler speed (closing velocity) and by highly ambiguous (HPRF) or ambiguous (MPRF) range. If ground clutter appears in range and doppler speed gates the radar highly likely loses lock because ground clutter is not a narrow signal (by range and in some cases by doppler speed) and not detected.
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In the game before 2.33 we had hard notch filter in both PD track modes.

Since 2.33 notch filters were removed for both modes. But for MPRF track mode doppler speed and range ambiguity and how this ambiguity affects ground clutter effect on the radar is not modelled. Now in MPRF in look-down cases the track is lost for “notching” targets. IRL in MPRF track mode target returns and ground clutter separation by range is possible, but not always due the range ambiguity.

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Well said, I did not know the rejection closure rate of MPRF was around ±150-190 km/h. Pretty cool and good to know.

Notching, or drastically reduced closure rates of a supermaneuverable Su-27.
(If GJ would please stop limiting the alpha at speed.)

I was just looking at the changes to the Leclerc for 2.33.0.20 (not yet live)

While looking, I noticed that the F-15’s are getting changes to their flight model
Credit to Gszabi:

I only understand that the Oswald efficiency number is being increased by 0.1 (0.65 → 0.75), but I don’t know how to intrepret the other values being changed.

Edit: Also noticed the RateMaxLoadFactorMax being increased aswell by 1 (11 → 12)

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the main changes are:

MachCrit5 0.4–>0.35
MachMax5 1.0–>0.5
MultMachMax5 1.3–>1.5
MultLineCoeff5 0.05–>-0.6
MultLimit5 20.0–>1.2

basically now the induced drag curve (basically drag that occurs during maneuvering) starts at mach .35 instead of .4 then peaks at mach .5 instead of 1.0 and the curve ends at mach 1.5 now instead of mach 1.3

what this does is now the most induced drag occurs at a much lower speed instead of a much higher speed, so expect inferior energy retention at mediumish speeds but better retention at high speed. Ofcourse the F-15 already retains p well at high speed so to ensure that it doesnt straight up gain speeds in mouse aim turns instructor was loosened to pull harder to ensure that doesnt happen. Retention at high speed likely feels the same now but AoA and turnrate should both be better now as a result.

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Thanks!

Wont that make wing rip come back though?
Higher AOA and turnrate sounds like thats just whats going to happen

I don’t think its ± 150 kph. Manual states several figures but not 150kph. Here I see ±230kph and ±220 kph
007
and here you can detect a helicopter if its flying above 180 kph in HPRF
080

same thing with MPRF of overview mode. BVR(RWS)
012
±210 kph.

On this the manual states that you need closure to hold a track which I would take as a filter.
050
±150kph for tracking in MPRF beyond 15km and goes down to ±50kph.

When you look at the SU27’s radar. The figures are same - similar to these and the radar itself is just a bigger version of N019.
2023-12-16.
Detection of HPRF and MPRF when target it ± 210kph from MLC. Then there’s another which I don’t understand 300kph and 180 KPH for MPRF.
As for tracking you can see that it drops tracking as soon as speed is lower than ±150kph, like on Mig 29’s N019.
2023-12-16 (1)
As for the angle dependent filter, you can track no matter the aspect if antenna is above 3° due to the lack of filter and no MLC. But when the antenna is under 3° the target must be ±150kph around MLC as you can see. Which is for HPRF and MPRF. This leads to say they have filter and I don’t think the SU27 would be worse than the mig 29, similar but not worse.


As for now clutter being modelled and taken into account for tracking, would we see aspect dependent skin return(RCS)? It would have a bigger effect. No need to do a complex calculation of the reflection of the waves. Just set an RCS value for direct front aspect and make the rest dependent on angle through a polar function perhaps.
MIG21 RCS
5m^2 in the front is completely different from showing sides belly that having~ 300m^2 as RCS. Or the drastic drop in RCS that happens around 30° from the nose sideways. Could make you lose lock. This would change the dynamics quite bit and it shouldn’t really be hard to process as its just a value that depends on aspect which the game probably knows

2023-12-16 (2)

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I take my words back.
The F-15 is really bad, very bad. Even if it overperforms.
And here the problem is not in the aircraft itself, but in its armament; the AIM-7Ms are not only uncompetitive, they are also broken.
Perhaps the right decision would be to give him AIM-120.

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No

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