Fresh stuff from sukhoi.ru (Discussion)

[Insuber]

Originally Posted by luthier

That's called fresh news? That's as stale and putrid as most of the other "unofficial news" that creeps up on sukhoi all the time.

Don't you guys know by now that that forum is plagued by trolls and bitter grouches even more so than this one? If you can believe that.

If on this forum the glass is "only" always half empty, on sukhoi.ru the glass is fully empty, and that it's so empty it's about to collapse in on itself, and they've heard from somebody in the team that it's not even glass but petrified feces and it's all a huge conspiracy.

LOL ... you know Luthier, the lack of information created the strangest religions ...

[ACE-OF-ACES]

Hello BlackSix

I know your just the messenger..

So you may or may not know the answers to the following questions

Maybe the original person who submitted each can answer the following questions?

For example, what does item # 7 mean?, i.e.

Originally Posted by BlackSix

7. Will the dynamic stall be implemented in the Flight Model?

Just wondering what they meant by dynamic stall? It seems to imply that what we have now is static? Granted, from what I understand the standard 6DOF flight modeling only applies to flight, and that once a plane stalls (departs flight), 'other' code is used until 'flight' is re-established.. So, not sure what they were referring to with that question.

Was also wondering about # 12, i.e.

Originally Posted by BlackSix

12. Will the GUI be optimized? Today it's not practical.

Did the person that submit that item expand on it more than that? Would be interesting to know a little more detail as to what said person considers to be not practical/optimized

Was also wondering about # 14, i.e.

Originally Posted by BlackSix

14. Will the damage of a radiator by bullets produce a damage to the engine? Today you get the message "radiator leak" but the engine continues to run.

Is this person saying the engine will never die? Because depending on the 'rate' of the leak it could take some time for the engine to overheat such that it dies

Anyway any info would be welcomed.

And keep up the good work!

[Insuber]

Dynamic Stall: go to Wikipedia if you want. Today only the normal stall is modeled - not good for a flight simulator.
GUI: RoF is a good example.
Bullet damage to radiator: you can fly for a lot of time despite the message "radiator leak", at least in the 109, imo it is a bug.

Cheers,
Ins

[ElAurens]

Perhaps they mean accelerated stall?

Darn, you got me to post, and I was trying hard to stay away till after New Years.


Back to the cave...

[Skoshi Tiger]

Originally Posted by Insuber

Dynamic Stall: go to Wikipedia if you want. Today only the normal stall is modeled - not good for a flight simulator.

Cheers,
Ins

When you go to wikipedia and look up dynamic stall it redirects you to stall where it says

"Dynamic stall is an effect most associated with helicopters and flapping wings. During forward flight, some regions of a helicopter blade may incur flow that reverses (compared to the direction of blade movement), and thus includes rapidly changing angles of attack. Oscillating (flapping) wings, such as those of insects— including the most famous one, the bumblebee — may rely almost entirely on dynamic stall for lift production, provided the oscillations are fast compared to the speed of flight, and the angle of the wing changes rapidly compared to airflow direction.[22]"

Is this relavant for the fixed wing aircraft in this sim? If so how?


Cheers!

[Swoop]

Just had a session on ROF with some mates, second time online and not much sucess. Had 10 minutes to kill so jumped on the ATAG server in a Spit2 and what a blast, the speed and the feel. Took out a 109s elevator and shot up a couple of bombers. I guess what I'm getting at is this sim is just great fun and thankyou all for the hard work your doing

[ACE-OF-ACES]

Originally Posted by Insuber

Dynamic Stall: go to Wikipedia if you want. Today only the normal stall is modeled - not good for a flight simulator.

Ok looking at the wiki, i.e.

wiki dynamic stall:
Dynamic stall is a non-linear unsteady aerodynamic effect that occurs when airfoils rapidly change the angle of attack. The rapid change can cause a strong vortex to be shed from the leading edge of the aerofoil, and travel backwards above the wing. The vortex, containing high-velocity airflows, briefly increases the lift produced by the wing. As soon as it passes behind the trailing edge, however, the lift reduces dramatically, and the wing is in normal stall

Based on that looks like ElAurens is close to the mark.. basically an accelerated stall situation.. Thing that is interesting is it also states you get a brief increase in lift.. So other than the brief increase, it follows the standard stall def

Also note the wiki reference #22 is from here

Unsteady aerodynamics
Dynamic stall is a phenomenon that affects airfoils, wings and rotors in unsteady flows. It is due to changes, periodic or not, in the inflow conditions and/or angle of attack. In some cases, such helicopter rotors in advancing flight, dynamic stall is intrinsic to their state of operation.

A comprehensive review of CFD methods for dynamic stall has been published by Ekaterinaris and Platzer (1997); for physical insight, see McCroskey (1981).

In wind turbines it is the result of atmospheric turbulence, wind shears, earth boundary layer, etc. The aerodynamic characteristics are affected to an extend that depends on the frequency of the changes, their amplitude and the point of operation.

Other factors affecting dynamic stall are the Reynolds and Mach numbers and the geometrical shape. There other, maybe minor factors, like the vortex effects, blade flapping and bending, etc...

In the following discussion we will consider the airfoil dynamic stall, which is a particular case of rotor and wing stall. The airfoil is subject to two fundamental periodic oscillations: plunging and pitching.

A plunging oscillation is a periodic translation of the airfoil in a direction normal to the free stream. A pitching motion is a periodic variation of the angle of attack.

Looks like Skoshi hit close to home on that with the helo rotors.. Also reading that I get the impression this is geared more for a computational fluid dynamic (CFD) flight model than the standard 6DOF flight model.. Where the change in the atmosphere has more affect.. The question is will the user even notice the effect? That is to say at the design level it may be noted, or during flight testing it might show a spike in the data.. but would the user of the flight sim notice it?

All in all it appears the standard def of stall still applies in both, just the changes/turbulence due to the atmosphere causes it to stall a little sooner or little later depending on the situation

Originally Posted by Insuber

GUI: RoF is a good example.

example of what?

Originally Posted by Insuber

Bullet damage to radiator: you can fly for a lot of time despite the message "radiator leak", at least in the 109, imo it is a bug.

It would be a bug if it could fly forever.. In that I don't know if there was any sort of self sealing radiators in WWII?

[BlackSix]

So, what can I do with Dynamic stall? Remove the question?

question 12, new form:
Will the GUI be remade?
ok?

[furbs]

Yes...B6 and ask if we will see FSAA in CLOD, or where are the 2D clouds?

[jimbop]

11. Will the ghost dots issue be corrected? Today in online servers you see far contacts which disappear when you close in.

B6, can you please clarify whether this is about actual ghosts or the disappearing of real targets online? This can be fixed by MeshShowLod=1 but this hurts performance for many systems.