investigating MiG-29 G load

[TeddyThePilot]

В 26.10.2025 в 04:19, AeriaGloria сказал:

Hello, it seems to be that MiG-29 can not reach the stated instantaneous G load, and it is low enough that it also can’t reach the full envelope of the sustained turn rate numbers. 
 

Here is a track with 2x APU-470, and 2x R-60, and 50-55% fuel in order to reach 13,000 kg gross weight, which seems to be the most common testing metric other then the same with 2x R-73. 
 

in addition there is a max G load graph we see in both books and manuals that goes from below 300 kmh to 900 kmh, showing over 20 deg/s at 900 kmh “with missiles.” And there is a sentence in the “practical aerodynamics” manual that states:

“For example, the maximum speed of turn in a steady position of the aircraft without weapon mounts at an altitude of 1,000m, Mach Number 0.8, with 50% of remaining fuel (aircraft weight 13,000 kg) is 19.5-20° a second.”

Partway through the track I also jettison the R-60 to show a “without missile load” configuration. 
 

Images are from Yefim Gordon or GAF TO-1 from Amazon. According to instantaneous turn chart, we should approximately have little issue hitting 9 G at lower altitudes from around Mach 0.55-0.85, or around 700-1000 kmh at lower altitudes. And above this speed the transonic zone is reducing elevator authority until around Mach 1.05-1.1 (according to practical aerodynamics.) Instead, we are limited to basically 8 G from below 900 kmh, which should be our maximum rate 9 G speed. 

 

MiG29gload.trk 855.7 \u043a\u0411 · 0 загрузок

Some same images with more quality
 

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[Кош]

Is it because of insufficient thrust or insufficient lift? Can you also try K quality test and climb test?

[TOT_53]

Sustained_turn_rate_test_flight.miz

Sustained turn rate  measure tool for more precision, by Petri"Bushmanni" Auvinen. Write measured turn rate to dcs log file .

[AeriaGloria]

2 hours ago, Кош said:

Is it because of insufficient thrust or insufficient lift? Can you also try K quality test and climb test?

I can try, but I have seen people do climb tests that turned out almost exactly perfect to the manual. I did many tests for climbing for my BVR climb profile video, and I can say it always climbed with enough time to match manual and only the smallest amount of extra fuel use. 
 

I have a feeling another cause of this behavior when it comes to instantaneous turn not sustained, is the damper. It does not “relax” when you give stick input like American CAS systems, so it is always resisting a turn. I know the damper changes reaction level based on altitude, Mach number, AOA, perhaps it needs a little tuning to be less aggressive at this speed and altitude. That of course wouldn’t solve sustained turn rate, but IMO that seems closer than instantaneous turn rate anyways. 
 

I guess as a bandaid you could even tune it just for this AOA/Speed/altitude region. The MiG-29 does have increasing stability until 15 degrees AOA, and it definitely feels like it might be too stable in this region that the elevator doesn’t have the leverage needed. 

Edited Tuesday at 12:22 PM by AeriaGloria

[Кош]

1 час назад, AeriaGloria сказал:

I have a feeling another cause of this behavior when it comes to instantaneous turn not sustained, is the damper.

Good catch! Did you try to disable the damper?

[AeriaGloria]

7 hours ago, Кош said:

Good catch! Did you try to disable the damper?

Keep forgetting, will try! 

[AeriaGloria]

13 hours ago, Кош said:

Good catch! Did you try to disable the damper?

Never mind. I find little difference with damper on or off. Whatever it is, it is not part of the instant G issue

[AeriaGloria]

Something that may play a part. I notice with full bomb load it I still have enough trim to fly level at full afterburner. Manual says that with full bomb load you don’t have enough trim to stop pitch up at high speed. So there is some “pitch up force” missing 

Will upload track soon