Flanker unable to pull 9G turns

[Skyhammer]

i noticed something very strange on all Flankers the can´t even pull 9 G turns at max something like 7.6- 7.9 G and and it doesn't matter without or with full weapons on the pylons. 

i only can achieve the 9 G  with the ACS or Override control stick limitation button and that brakes the wings instand 

that seems odd to me that the flanker can´t pull 9G in a high speed turn and the F-15 for example can well exceed the 9Gs without a problem

Flanker not even 9 G turn.trk F15 easy 9.5 G till blackout.trk Flanker high G turn.acmi

[Ironhand]

Unfortunately, I’m away from my computer for at least another week. So I can’t view any of the files you provided. But what was the aircraft’s gross weight, when the wings broke?

[Skyhammer]

vor 18 Stunden schrieb Ironhand:

Unfortunately, I’m away from my computer for at least another week. So I can’t view any of the files you provided. But what was the aircraft’s gross weight, when the wings broke?

weight was round about 27.200kg with fuel and only missiles at the wing tips

[Ironhand]

10 hours ago, Skyhammer said:

weight was round about 27.200kg with fuel and only missiles at the wing tips

Seems like a lot of weight for making 9 G turns. I’ve been there myself and the wings have never come off. But, then again, I almost never take off at or near max weight either. Out of curiosity, is your F-15 demonstration made with full or nearly full wing tanks? 

I’ll be interested in viewing the TRKs, when I get back.

[Skyhammer]

vor 11 Stunden schrieb Ironhand:

Seems like a lot of weight for making 9 G turns. I’ve been there myself and the wings have never come off. But, then again, I almost never take off at or near max weight either. Out of curiosity, is your F-15 demonstration made with full or nearly full wing tanks? 

I’ll be interested in viewing the TRKs, when I get back.

F-15 was 100% fuel otherwise clean loadout...

[Ironhand]

12 hours ago, Skyhammer said:

F-15 was 100% fuel otherwise clean loadout...

FWIW, 5,220 kg of fuel (56% fuel load in the ME?) for the Su-27 is considered the basic internal fuel load. The remaining 44% would be going into external fuel tanks, if the Su-27 had been configured that way. So I’m thinking that the Flanker in your scenario had to be close to 100% fuel. That being the case, the F-15 should be carrying full external fuel tanks as well to see how it compares.

 

[Skyhammer]

vor 18 Stunden schrieb Ironhand:

FWIW, 5,220 kg of fuel (56% fuel load in the ME?) for the Su-27 is considered the basic internal fuel load. The remaining 44% would be going into external fuel tanks, if the Su-27 had been configured that way. So I’m thinking that the Flanker in your scenario had to be close to 100% fuel. That being the case, the F-15 should be carrying full external fuel tanks as well to see how it compares.

 

Flanker with 56% fuel still  7.6 till 7.8 G without ACS or Override control stick limitation...the F-15 on the other hand can still pull 8.8G turns not long but it can

Flanker 56% fuel still 7.6 G max.trk F15 with 3 fuel tank 8.8G.trk

[Ironhand]

6 hours ago, Skyhammer said:

Flanker with 56% fuel still  7.6 till 7.8 G without ACS or Override control stick limitation...the F-15 on the other hand can still pull 8.8G turns not long but it can

Flanker 56% fuel still 7.6 G max.trk 453.69 kB · 0 downloads F15 with 3 fuel tank 8.8G.trk 218.63 kB · 0 downloads

Seems a bit low, maybe. Without the override, the aircraft should be limited to 8Gs with a GW of 21,400 kg at an airspeed of M=0.85 or less.

[Wyvern]

Use the Stick Override. thats because irl, the plane doesnt just let you properly pull 9g, 
Its no special mode or paddle switch like the F-18. All you do is pull harder on the stick, to pull through the limiter. It just adds a lot of resistance, similar to how FFB sticks work.
it cant really be simulated in DCS, at least on most sticks.
The reason you cant pull 9G, is because it irl would slightly bend/damage your airframe.
Meaning that in DCS you have to learn to balance your pull, to not pull too hard with the override.
Its not realistic, but neither is anything about the DCS Su-27 except from maybe its looks.... somewhat...

Edited April 22, 2024 by Wyvern

[okopanja]

6 minutes ago, Wyvern said:

Its not realistic, but neither is anything about the DCS Su-27 except from maybe its looks.... somewhat...

This!

[Ironhand]

4 hours ago, Wyvern said:

The reason you cant pull 9G, is because it irl would slightly bend/damage your airframe

You’re allowed to pull 9Gs in real life according to the manual, just not with a lot of fuel on board. GW needs to be something like 17,100 kg or less.

[average_pilot]

5 hours ago, Wyvern said:

Its not realistic, but neither is anything about the DCS Su-27 except from maybe its looks.... somewhat...

The PFM maybe?

[plaiskool]

Yes ACS off in order to pull above 9G otherwiswe he is protected.

Full load out 4xR73+2xR27ET+4R27ER  8.5Tons i can pull 9.7g

Flanker G light.zip.acmi G full load.zip.acmi

Clean with 35% fuel i can pull up to 13.2G
 

Edited April 24, 2024 by plaiskool

[Ironhand]

@Skyhammer

Finally home and took a look at two of your Su-27 tracks (Flanker not even 9 G turn.trk and Flanker 56% fuel still 7.6 G max.trk). The issue in both was airspeed. Yours was too low for the altitude. At 2000m, you need to be up around 900 km/hr to generate enough Gs to even hit the limiter. I took control of your Flanker 56% fuel still 7.6 G max.trk and sat on 8Gs for awhile just to show that the limiter is there and will limit you to 8Gs at that gross weight. And, just for clarity, I did not use the override at any point.

Ironhand-Skyhammer-Flanker 56% fuel 8G Limiter-No Override.trk

Edited April 26, 2024 by Ironhand

[P1l0t]

Above subsonic and supersonic true airspeeds, the airframe of the Flankers is too weak to carry such large G-loads. The early airframes, including the later J-11A and J-11B (Flanker copies), also suffered from this issue. On later models, such as the Su-27M and subsequent designs, the airframes were strengthened and are now able to withstand higher G-loads at both subsonic and supersonic speeds. So, it's not a mistake, it's actually designed like that in reality!

You can safely fly with Direct Control at a true airspeed of approximately 700 km/h. In this case, you can subject the airframe to any load without fear of the wings breaking off, this is a significant advantage in dogfights, for example. Because as long as you maintain energy, you can maneuver the Flanker at a higher angle of attack.

[Skyhammer]

vor 14 Stunden schrieb Ironhand:

@Skyhammer

Finally home and took a look at two of your Su-27 tracks (Flanker not even 9 G turn.trk and Flanker 56% fuel still 7.6 G max.trk). The issue in both was airspeed. Yours was too low for the altitude. At 2000m, you need to be up around 900 km/hr to generate enough Gs to even hit the limiter. I took control of your Flanker 56% fuel still 7.6 G max.trk and sat on 8Gs for awhile just to show that the limiter is there and will limit you to 8Gs at that gross weight. And, just for clarity, I did not use the override at any point.

Ironhand-Skyhammer-Flanker 56% fuel 8G Limiter-No Override.trk 311.48 kB · 0 Downloads

 

ok, thanks for your time and all the other user...i will close the topic then

[Chizh]

On 4/17/2024 at 3:04 AM, Skyhammer said:

i noticed something very strange on all Flankers the can´t even pull 9 G turns at max something like 7.6- 7.9 G and and it doesn't matter without or with full weapons on the pylons. 

i only can achieve the 9 G  with the ACS or Override control stick limitation button and that brakes the wings instand 

that seems odd to me that the flanker can´t pull 9G in a high speed turn and the F-15 for example can well exceed the 9Gs without a problem

Flanker not even 9 G turn.trk 680.19 kB · 10 downloads F15 easy 9.5 G till blackout.trk 348.72 kB · 8 downloads Flanker high G turn.acmi 157.34 kB · 8 downloads

Stick limiter depends on weight of plane
Try to press Y

9g is available for weight <= 17100kg/19500kg (Su-27/33)

[DummyCatz]

On 5/3/2024 at 1:51 PM, Chizh said:

Stick limiter depends on weight of plane
Try to press Y

9g is available for weight <= 17100kg/19500kg (Su-27/33)

On 4/22/2024 at 8:30 PM, Ironhand said:

You’re allowed to pull 9Gs in real life according to the manual, just not with a lot of fuel on board. GW needs to be something like 17,100 kg or less.

I cannot find a source of your claims.

From 27SK manual, m * Ny max = const = 171000kg for M < 0.85. So 9g should be available for weight < 19000kg, which equals to 171000 / 9.

171,000kg is the max allowed static force being put on the wing when M < 0.85. If you think it is 17,100kg as a weight, then you're wrong.

 

@Skyhammer you can also try testing with a weight of 19000kg. If it does not give you 9g then the OPR g-limit mechanic is not correct.

Edited May 24, 2024 by DummyCatz

[Ironhand]

9 hours ago, DummyCatz said:

…

From 27SK manual, m * Ny max = const = 171000kg for M < 0.85. So 9g should be available for weight < 19000kg, which equals to 171000 / 9.

171,000kg is the max allowed static force being put on the wing when M < 0.85. If you think it is 17,100kg as a weight, then you're wrong...

 

Just remembering wrong. You’re right, of course.