Su27 Wing Thing

[GGTharos]

I'm not saying that this approach is better than the care-free handling design paradigm, indeed modern Su-27 variants (Su-30MKi, Su-35 etc.) also have the same sort of fly-by-wire system that modern western types have, to some extent, but these were the reasons why the Su-27 control system was designed in the way we see it in DCS.

 

This was done in consultation with pilots. The fact that they changed the stability artificially and the implementation of the stick shaker as well as some other features, I would say they designed it to be as 'care-free handling' as the equipment of the time (as well as philosophy and pilot opinion) would allow.

[Fri13]

Again my understanding is that the intent of the designers was specifically not to design the Su-27 to have care free handling. This also goes for the MiG-29. The theory was that while it's completely possible for the pilot to carry out manoeuvres that are suicidal or that lead to destruction of the aircraft, it allows very highly trained and experienced pilots to be able to get more out of such an aircraft than the same pilot would be able to do in an aircraft that imposes artificial limits on pilot input commands.

 

That sure is totally correct that skilled pilots would need to be able pull any vehicle or tool to their limits, sometimes even above those.

 

But I would thought that just a such agile aircraft there would be a limiter that you need to flip off before you can go over those.

 

After all the Su-27S should have multiple switches or something for commanding safety systems, wasn't that one of the things in the first place when the "S" button was implemented to allow Cobra to be done, that it would have been wrong limiter or something?

 

Like example in Mirage 2000C it is just to have the G-force limiter for A-A and A-G loads.

I would have expected to have similar so you can't pull Su-27S even by accident over to break it unless you really meant to do that.

 

But, as said, if there are own "soft limiters" that you need to go over like a FF stick to pull over the force threshold, then it is so simple.

[SinusoidDelta]

FWIW here are some papers I've found pertaining to the Su-27:

 

Generation Of Su-27 Fighter

 

USE OF AEROELASTICITY; MULTIDISCIPLINARY INVESTIGATIONS

 

The “Use of Elasticity” Concept and Flight Safety in View of Advanced Airplane Designs

[SinusoidDelta]

It looks like some changes were made to the FBW system:

https://forums.eagle.ru/showpost.php?p=2941506&postcount=38

Su-27. Flight control system with AOA and G-limiter has been adjusted

[Ironhand]

It looks like some changes were made to the FBW system:

https://forums.eagle.ru/showpost.php?p=2941506&postcount=38

Hopefully the AP will handle low airspeeds better as well. Guess we'll see what the changes bring.

 

 

Darkfire,

 

Not sure if the attached might be of any use, if you're still dealing with G loads. It's an Excel spreadsheet I created. Fill in the figures for the aircraft gross weight, airspeed in Mach, and your observed G value in the F2 view. The formulas will calculate the max operational G load for aircraft weight and airspeed (based on the chart out of the manual) as well as calculate how much over or under that max load your observed G was.

[Pronin]

Has anyone tested the Flanker in 1.5.5?

 

Anybody have any reports as to what is different?

[HiJack]

Has anyone tested the Flanker in 1.5.5?

 

Anybody have any reports as to what is different?

Not out yet....

[JunMcKill]

Hopefully the AP will handle low airspeeds better as well. Guess we'll see what the changes bring.

 

 

Darkfire,

 

Not sure if the attached might be of any use, if you're still dealing with G loads. It's an Excel spreadsheet I created. Fill in the figures for the aircraft gross weight, airspeed in Mach, and your observed G value in the F2 view. The formulas will calculate the max operational G load for aircraft weight and airspeed (based on the chart out of the manual) as well as calculate how much over or under that max load your observed G was.

 

Nice excel, the gross weight in pounds?

[Ironhand]

Nice excel, the gross weight in pounds?

Thanks. I find Excel to be extremely useful from time to time.

 

Sorry, at some point in reformatting it, I omitted the (Kg) from that particular heading. Gross weight needs to be in kilograms so that it matches the formulas from the Su-27 manual. I suppose it'd be easy enough to convert the formulas for pounds but whenever I think Russian aircraft, I'm thinking in metric. So it's never occurred to me to do so.

[DarkFire]

Hopefully the AP will handle low airspeeds better as well. Guess we'll see what the changes bring.

 

 

Darkfire,

 

Not sure if the attached might be of any use, if you're still dealing with G loads. It's an Excel spreadsheet I created. Fill in the figures for the aircraft gross weight, airspeed in Mach, and your observed G value in the F2 view. The formulas will calculate the max operational G load for aircraft weight and airspeed (based on the chart out of the manual) as well as calculate how much over or under that max load your observed G was.

 

Awesome! Thanks! Still testing but I might wait till 1.5.5 is released then re-test it to see if anything has changed.

 

At the moment I have a sort of master worksheet containing every Su-27 performance analysis I've ever done. Would you mind if I copy & paste your formulae in to my work sheet? I'll post it when I'm done with the G testing, probably on Sunday some time provided 1.5.5 is released tomorrow (patches are usually on a Friday I think?).

 

Edited to add:

 

From the 1.5.5 patch notes:

 

Su-27. Flight control system with AOA and G-limiter has been adjusted

Su-27. Autopilot has been adjusted

Su-27. Tires strength has been adjusted

 

:notworthy: :notworthy: :notworthy: :notworthy: :notworthy:

 

Edited November 3, 2016 by DarkFire

[Ironhand]

Awesome! Thanks! Still testing but I might wait till 1.5.5 is released then re-test it to see if anything has changed.

 

At the moment I have a sort of master worksheet containing every Su-27 performance analysis I've ever done. Would you mind if I copy & paste your formulae in to my work sheet? I'll post it when I'm done with the G testing, probably on Sunday some time provided 1.5.5 is released tomorrow (patches are usually on a Friday I think?).

Be my guest. I think you might have to "unprotect" the worksheet to order to copy the formula(s) but there's no password. Obviously you'll have to change the reference cells in the formulas.

[DarkFire]

Be my guest. I think you might have to "unprotect" the worksheet to order to copy the formula(s) but there's no password. Obviously you'll have to change the reference cells in the formulas.

 

Thanks, I'll crack on with testing. Hopefully the patch will have dropped by the time I'm home from work tomorrow.

[JunMcKill]

The update is available now!

[Belphe]

The update is available now!

 

54 minutes and 17 seconds until I finish work...

[Ironhand]

54 minutes and 17 seconds until I finish work...

 

:) Unfortunately I still have many more hours than you to wait...

[red_coreSix]

New limiter works perfect for me, I did not manage to rip my wings at all. It doesn't let you pull enough Gs unless you use the relax or S button :thumbup:

[Pronin]

New limiter works perfect for me, I did not manage to rip my wings at all. It doesn't let you pull enough Gs unless you use the relax or S button :thumbup:

 

I'm so glad. Basically we flew hard mode for the last half year.

 

It feels so stable and safe now. I'm in love.

[Falcon_S]

...DCS Su27 is only for ballet.

 

....

 

No more ballet. Now is time for RnR.

 

 

Su27 Wing Thing topic can be [CLOSED]. :pilotfly:

 

SU27 is fixed. Thanks devs! :thumbup:

[Ironhand]

...

 

 

Su27 Wing Thing topic can be [CLOSED]. :pilotfly:

 

...

Oh, I'm sure that won't be the case. At least now, however, losing your wings is less likely to happen unexpectedly.

[jackmckay]

 

Finally :thumbup:

I'll drink in that name!

:drunk:

(Russian style)