early models of the 9M had quite iffy IRCCM which later models would resolve
But that still irccm, yes, worser than later models of 9M
Considerably worse than the IRCCM of the Magic 2 or the R-73 by quite a large margin at the time.
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Does anyone know what Load factor is used in this chart? Is it the normal load factor N_z like in the F-16 manual or the load factor n_z ?
(N_z is the forces perpendicular to the aircraft body divided by the aircraft weight, aka it is:
N_z = \dfrac{(Lift * cos(AoA) + drag * sin(AoA)}{Weight}
while n_z is perpendicular to the airflow: n_z = \dfrac{(Lift * + thrust * sin(AoA)}{Weight} ).
I’ve noticed at mach 0.3 sea level that both the F-16 and the F-15A are doing around 17 degrees per second, but the F-16 has an indicated load factor of less than 3 while the F-15 one is above 3.
Turn rate as a function of load factor n_z is: ω = \dfrac{g \sqrt{n_z^2-1} }{V} \dfrac{180}{π} , and in a sustained turn (right now not bothered to write how it is derived) in a sustained turn n_z = \dfrac{N_z}{cos(AoA)} .
If we take 2.9G as a value for N_z for the F-16, get n_z considering that AoA is ~23 degrees and we use the formula above (mach 0.3 at sea level is around 99m/s), we get exactly ~17deg/sec, which is the value of the manual.
Doing the same thing for the F-15A (AoA is close to 22 degrees) with the ~3.15G value we obviously get much more than 17 deg/sec, around 18deg/sec.
If instead we use 3.15G directly as n_z we get 17deg/sec.
So either the turn rate chart is wrong (discrepancy is too high for it to be just mach to m/s speed conversion due to air temperature/pressure) or the overload in the chart is n_z instead of N_z, which means that the aircraft is modelled wrong in game.
At higher speeds the F-15A seems to over perform in STR even if we consider the values in the chart as N_z (N_y in localhost because Russians use weird convention even for the axis of the frame of reference) .
F-15C instead seems to lack speed at high altitude, although @MaMoran20 already reported this and gaijin decided to be gaijin.
@MaMoran20 is there a thrust curve for the engine in that appendix for the manual? Because while they might not do adjustments for just speed at high altitude, they may adjust the thrust (at least they did so for other aircraft).
(before someone asks no, not going to bug report the sustained turn rate right now, when I’ll do (if I’ll do) it will be with other aircraft at the same time since at least half of planes above 11.0 seem to over perform right now, fm quality seems to have lowered considerably in recent years).
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FM are such a mess.
Appreciate your concern and dedication ;)
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I’m not a math expert by any means, just a few observations.
In the chart for the F-15A you see an engine trim of 97.7%. That means the engine is underpowered. This was used for peacetime because engine reliability was worse and thus expensive to operate. You need a chart for 102% trim, which is 100% of the F-100 engine thrust.
Maybe this picture will help you a little, but it’s for the F-15C…
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102% is already modeled in the game, though the chart you provided is for 97% trim as well.
The F-15’s IRL would NEVER operate at 102% trim in war time anyway, no plane would. Turbines used in fighter jets generally are not at 100% healthy thrust output due to wear and tear. Some fighters of the past operated at thrust percentages as low as 70%.
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Engine could even be without afterburner, the load factor should match with the turn time if the load factor is N_z.
If the load factor in the chart was n_z then the eagle is overperforming, and in that case one would need to calculate how much difference in thrust is there between the two engine trim settings.
Still said over performance is not too big and i’ll report that after checking other aircraft, as many overperform much more.
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Is that 102% trim number for high or low pressure rotor?
I do not know what the “trim” setting adjusts internally. I recall it was discussing RPM and thus also fuel flow - affecting thrust.
For example Al-31F normanly operates in combat at 101.5% for low pressure rotor and 99% for high, 98.5% and 96% for training.
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Don’t you mean peace time?
F-15 can operate at 102% trim only for something about 5 min
After the problem with the F-100 PW-100 engines was solved, the engine trim was removed. Thus, the pilot had 100% engine power available on demand. The other option was a VMAX switch which allowed the pilot to get above 100% power.
At 102% trim, it was possible to fly when the ground crew on the ground “switched” the engine to this setting.
these 102% or 97% don’t make any sense at all. Since the engine RPM depends on the inlet temperature
97.7% is this for which rotor? With this approach, you can do the same for the MiG-29 and Su-27
Wear also affects thrust
There are double standards from the Gaijin here. One is given an increased mode of operation, the other is not
Here’s an F-15C with a 220 engine.
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It turns out that this is not an RPM.And the thrust.As for the AL-31F, training,Combat,special