[REPORTED]Wings snap at low g's - ED Forums
 


Notices

Reply
 
Thread Tools Display Modes
Old 03-17-2019, 07:49 PM   #1
BlackPixxel
Member
 
BlackPixxel's Avatar
 
Join Date: Nov 2015
Posts: 367
Default [REPORTED]Wings snap at low g's

Hi,

when flying fast (in the following case 1.4 mach) the wings of the Su-33 appear to become very brittle. They will just brake off at rather gentle g loadings.

Here they snap at 5.2 g's:
https://youtu.be/pnhfWd3_o0A

Is this intentional? It seems more like a wrong config, and it only happens hat higher speed. At low speed the plane can handle the g's at you would expect.

When accelerating and reaching a certain speed, the plane starts to do a sudden pitch change and the trim is off. Maybe this is the speed at wich the wing snap mode is initiated?
BlackPixxel is offline   Reply With Quote
Old 03-18-2019, 06:55 AM   #2
draconus
DCS Ground Crew
 
draconus's Avatar
 
Join Date: Nov 2017
Location: Poland
Posts: 3,028
Default

I wouldn't call 5G turns gentle. Was the Automatic Control System off? How heavy you were?
There is the speed region where it's not possible to control pitch by trim alone but it shouldn't be relevant.

Last edited by draconus; 03-18-2019 at 01:31 PM.
draconus is online now   Reply With Quote
Old 03-18-2019, 08:47 AM   #3
BlackPixxel
Member
 
BlackPixxel's Avatar
 
Join Date: Nov 2015
Posts: 367
Default

ACS was not disabled, not sure about the weight, fuel was around 5 tons and 2 ER's where already fired.
BlackPixxel is offline   Reply With Quote
Old 03-18-2019, 11:49 AM   #4
Miroo
Junior Member
 
Miroo's Avatar
 
Join Date: Apr 2011
Location: Algiers
Posts: 26
Default

Quote:
Originally Posted by draconus View Post
I wouldn't call 5G turns gentle. Was the Automatic Control System off? How heavy you were?
There is the speed region that is not possible to control pitch by trim alone but it shouldn't be relevant.
What would you call a gentle turn in combat situation ?

As we know @Mach 1.3 we still within the aircraft G factor limitations of 6.5G.
__________________


I7 7700K@5.2GHZ+ NZXT X62 AIO Water cooling MSI Z270 Gaming M7 + CORSAIRE VENGEANCE PRO 16GB @3200MHZ DDR4 + MSI GTX1080ti gaming edition+ SSD SAMSUNG 850EVO PRO 128 Go + SSD SAMSUNG 850EVO PRO 240 Go + HDD SAMSUNG 1 To+ HDD SEAGATE 3 To
Asus ROG Swift PG348Q / Oculus rift
Case Coolermaster Mastercase 6 + CORSAIRE RM750W
Thrustmaster Hotas Warthog +Logitech G rudder pedals
Miroo is offline   Reply With Quote
Old 03-18-2019, 01:15 PM   #5
Ironhand
Veteran
 
Ironhand's Avatar
 
Join Date: Aug 2004
Location: New Hampshire, USA
Posts: 4,382
Default

Quote:
Originally Posted by BlackPixxel View Post
Hi,

when flying fast (in the following case 1.4 mach) the wings of the Su-33 appear to become very brittle. They will just brake off at rather gentle g loadings.

Here they snap at 5.2 g's:
https://youtu.be/pnhfWd3_o0A

Is this intentional? It seems more like a wrong config, and it only happens hat higher speed. At low speed the plane can handle the g's at you would expect.

When accelerating and reaching a certain speed, the plane starts to do a sudden pitch change and the trim is off. Maybe this is the speed at wich the wing snap mode is initiated?
Out of curiosity, had you already been pulling high Gs numerous times in that aircraft (assuming you were online and not taking a fresh aircraft each time). I ask because aircraft fatigue is modeled and, so, if the airframe was already severely stressed, it's possible to break something at lower Gs.

Also, when this issue had appeared in the Su-27 many moons ago, people were posting Tacview files/videos and it turned out that the in-cockpit G-meter was showing roughly 8 Gs when Tacview report was only showing 5 or 6. Just saying. Did you notice them coming off with a 5G reading in the cockpit or was it only later that you saw 5 Gs and thought WTF, there's a problem?
__________________
http://rsoro.host22.com/Flankertraining_Images/Flankertraining_Banner-1a.jpg

Win 10 Pro x64, ASUS Z97 Pro MoBo, Intel i7-4790K, EVGA GTX 970 4GB, HyperX Savage 16GB, Samsung 850 EVO 250 GB SSD, 2x Seagate Hybrid Drive 2TB Raid 0.

Last edited by Ironhand; 03-18-2019 at 01:18 PM.
Ironhand is offline   Reply With Quote
Old 03-18-2019, 01:42 PM   #6
Coxy_99
Veteran
 
Join Date: Mar 2015
Location: UK
Posts: 3,696
Default

A fresh aircraft is taken everytime its not the same aircraft, You only have to pull slight and the wings fall off, Maybe because they fold lol, But maybe tacview thing?

Last edited by Coxy_99; 03-18-2019 at 01:52 PM.
Coxy_99 is offline   Reply With Quote
Old 03-18-2019, 03:18 PM   #7
Ironhand
Veteran
 
Ironhand's Avatar
 
Join Date: Aug 2004
Location: New Hampshire, USA
Posts: 4,382
Default

Quote:
Originally Posted by Coxy_99 View Post
A fresh aircraft is taken everytime its not the same aircraft, You only have to pull slight and the wings fall off, Maybe because they fold lol, But maybe tacview thing?
OK. Can somebody provide a short track? I just spent some quality time in the -33's pit boring holes through the sky. I was only able to take the wings off once and that was by exceeding the G limits for gross weight/Mach>1.25. Well, actually, those were for the Su-27 but I don't have the real-world manual for the -33. Hopefully those numbers are close enough.
__________________
http://rsoro.host22.com/Flankertraining_Images/Flankertraining_Banner-1a.jpg

Win 10 Pro x64, ASUS Z97 Pro MoBo, Intel i7-4790K, EVGA GTX 970 4GB, HyperX Savage 16GB, Samsung 850 EVO 250 GB SSD, 2x Seagate Hybrid Drive 2TB Raid 0.
Ironhand is offline   Reply With Quote
Old 03-18-2019, 04:20 PM   #8
Coxy_99
Veteran
 
Join Date: Mar 2015
Location: UK
Posts: 3,696
Default

MIROO would be best to ask, Ill ask and post here.
Coxy_99 is offline   Reply With Quote
Old 03-18-2019, 04:44 PM   #9
Ironhand
Veteran
 
Ironhand's Avatar
 
Join Date: Aug 2004
Location: New Hampshire, USA
Posts: 4,382
Default

Quote:
Originally Posted by Coxy_99 View Post
MIROO would be best to ask, Ill ask and post here.
OK Thanks.

Quote:
Originally Posted by Miroo View Post
...

As we know @Mach 1.3 we still within the aircraft G factor limitations of 6.5G.
Ummm. Where are you getting that G number from? Based on BlackPixxel's description of the situation, it'd be closer to 5.4, wouldn't it? But, again, that's based on the Su-27 manual as I don't have the manual for the Su-33. If you have it, would you mind sharing?
__________________
http://rsoro.host22.com/Flankertraining_Images/Flankertraining_Banner-1a.jpg

Win 10 Pro x64, ASUS Z97 Pro MoBo, Intel i7-4790K, EVGA GTX 970 4GB, HyperX Savage 16GB, Samsung 850 EVO 250 GB SSD, 2x Seagate Hybrid Drive 2TB Raid 0.
Ironhand is offline   Reply With Quote
Old 03-18-2019, 05:36 PM   #10
BlackPixxel
Member
 
BlackPixxel's Avatar
 
Join Date: Nov 2015
Posts: 367
Default

It does indeed seem to be a fatigue thing. In the example I showed in the video at an earlier point 10g where pulled.

But it is still very fragile: In this tacview with a fresh plane with 4xER, 2xET, 2x73 and 2xECM with 50% fuel the maximum g loading was 7.7 for a short time. Then after releasing and pulling again it snapped at just 5.7g.

One other thing: In the Su-27 it is impossible to snap wings by pulling hard, because the g limiter is working everytime at any speed.
In the 33, the g limiter fails to work at high speeds. The plane is pulling as if override was enabled and just breaks appart as a result.

I am thinking whether the code behind the g limiter of the DCS Su-33 may just be a copy of the limiter of the 27, without taking the changed flight model into account (for example the 33 follows inputs on pitch much more aggressive than the 27 in DCS)
Attached Files
File Type: zip Tacview-20190318-191649-DCS_.zip.zip (22.0 KB, 17 views)
BlackPixxel is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 10:30 AM. vBulletin Skin by ForumMonkeys. Powered by vBulletin®.
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.