Gazelle and VRS

[Devrim]

I'm so sorry if this was mentioned in somewhere, but I couldn't find.

 

Can we enter vortex ring state with Gazelle? Last night I tried and tried. If I were in Ka-50, Huey or Mi-8, I would have already died many many times, but I can't die with Gazelle, because of VRS. :D

 

Is VRS modelled, or that means I can't manage her to enter in VRS...

 

Thanks.

[Ramsay]

I have crashed a few times due to VRS and lack of altitude for recovery but the Gazelle is a lot more forgiving than the UH-1H and Mi-8. With enough altitude a VRS is easily recoverable by pitching the nose down or side slipping left or right.

 

Note: The Gazelle is reluctant to enter a VRS if forward movement is kept above approx 20 km/h (10 knots).

 

I haven't flown the Gazelle as much in 1.5.4 u3 due to MP convoy desync's between host and client (late spawns/activations), so can't say if VRS has changed in u3.

Edited August 19, 2016 by Ramsay

[Pat01]

Corrected VRS will show in a next update.

 

EDIT: it's just been added to the change log

 

conditions to enter VRS should be

 

horizontal speed < 30km/h

vertical speed < -150m/min

pitch between 0 and 6° nose up

absolute roll < 3°

Edited August 19, 2016 by Pat01

[Aginor]

Cool, thanks for the update!

[Devrim]

I tried some experiments. At high alt, I moved collective full down, but I can't see a classic behavior of VRS. After a long fall, I just pulled collective and vertical speed gauge showed me that Gazelle did stable condition very very easily and in a very short time. It was like she had never tend to enter VRS.

 

...by pitching the nose down or side slipping left or right...

As you said you do side slip, or pitch down to gain speed, if you are close to the ground, I'm afraid, with Gazelle you won't need to do those. Just pull the collective. That sounds weird to me. :)

 

Edit: Oh, just saw the Pat's message. Thank you! :)

Edited August 19, 2016 by Devrim

[Devrim]

Perfect! Thanks Pat! :)

 

horizontal speed < 30km/h

vertical speed < -150m/min

pitch between 0 and 6° nose up

absolute roll < 3°

[Skulleader]

Corrected VRS will show in a next update.

Thanks Pat for this news, VRS is really important and immersive...

Skull.

[Frusheen]

Sorry missed this thread and posted a new one. Mods remove the new thread if you wish.

 

This is listed as fixed in today's patch but I'm finding it impossible to enter VRS. Tried a high altitude hover and full down collective. I manage to recover without any issue with no cyclic input to exit the vortex and no increase demand on collective.

[Devrim]

Same.

 

Maybe this is a light helicopter. We can't enter the VRS.

We want to die!!! :)

[Fredo_69]

BUG TEMPLATE:

 

Description: VRS nor simulated i Gazelle.

DCS Version: 1.5.4.57013

Steam: No

Map: Caucasus

SP/MP: SP

Reproducible: Yes

Step to Reproduce: Take-off climb straight upp, drop collective to floor... Watch sink-rate go to max and then raise collective to stop sinking. No VRS.

Screenshot/Video available:

Track Available: No

Mission File: No

Controllers:

Saitek Pro Flight X-55Rhino Stick (DZ:1 Sat X:99 Sat Y:99 Curve:15)

Saitek Pro Flight X-55 Rhino Throttle (DZ:0 Sat X:100 Sat Y:100 Curve:0)

CH Pro Pedals USB (DZ:0 Sat X:100 Sat Y:100 Curve:0)

Track-IR 5

OS: Windows 7 Home Premium

CPU: i7-3770K CPU @3,50GHz

RAM: 16 GB

GPU: NVIDIA GeForce GTX 760

Mods: No

Any Additional Information:

[Ramsay]

Description: I can confirm VRS is either missing or very much harder to induce in the latest public release.

 

DCS Version: 1.5.4.57288

Steam: yes

Map: Caucasus

SP/MP: SP

Airframe: SA-342M

Reproducible: yes

 

Step to Reproduce: Hold a stable hover, with zero forward speed, drop the collective and let the decent rate increase, the Gazelle will not enter a VRS and the decent can be halted by increasing the collective without the need to side-slip or pitch down.

 

Screenshot: Yes

 

Track Available: Yes

 

Controllers: X52 Pro (Throttle), MS Sidewinder FFB2 (cyclic), TrackIR

OS: Win 10 Pro

RAM: 12GB

GPU: GTX 670 2Gb

Mods: JSGME all disabled

 

Additional Info: In prior versions (perhaps 1.5.3 ?) VRS could be recovered from at a fairly low height (~50 m) but seemed to require a quick response from the pilot and side-slipping or pitching down not just an increase in collective (though the current behaviour makes me unsure of that now). Tacview file included. Ground effect was confirmed to be present. IAS and TAS are often higher then GS in TacView but this is because the Gazelle is falling quickly, not because of forward motion. There is no wind.

Edited October 6, 2016 by Ramsay

[Mt5_Roie]

So I have a gametrix 908 chair which simulates vibrations in DCS. it's pretty cool because it makes flying a bit more realistic. One cool part about it is that when you hit VRS - you feel it. So I've actually gotten better at recovering from VRS. Last flight I did was last night and I know I hit VRS at least twice in the latest 1.5.4 version.

[Ramsay]

No, problem, I've just seen a lot of comment and videos but no tracks or .acmi

 

As you can see during my test, I was hitting Pat01's parameters i.e. @ +00:02:56

 

• horizontal speed = 15.2 km/h
  
• vertical speed = -871 m/min
  
• pitch = 2.9°
  
• roll = 0.0°
  

 

but not entering VRS, so it seemed worth reporting.

 

... conditions to enter VRS should be

 

horizontal speed < 30km/h

vertical speed < -150m/min

pitch between 0 and 6° nose up

absolute roll < 3°

 

So I have a gametrix 908 chair which simulates vibrations in DCS. it's pretty cool because it makes flying a bit more realistic. One cool part about it is that when you hit VRS - you feel it. So I've actually gotten better at recovering from VRS. Last flight I did was last night and I know I hit VRS at least twice in the latest 1.5.4 version.

Edited October 6, 2016 by Ramsay

[Mt5_Roie]

So I was planning on making a video during my next scheduled test flight. But seems like helijumper beat me to it:

 

 

Either way, I have put in the request to get feedback on it from the actual pilots. So sit tight and wait for their response.

 

No, problem, I've just seen a lot of comment and videos but no tracks or .acmi

 

As you can see during my test, I was hitting Pat01's parameters i.e. @ +00:02:56

 

• horizontal speed = 15.2 km/h
  
• vertical speed = -871 m/min
  
• pitch = 2.9°
  
• roll = 0.0°
  

 

but not entering VRS, so it seemed worth reporting.

[Ramsay]

Ah, I see where the confusion arises if you are using Helijumpers video as a demonstration of VRS working.

 

The vibration and rapid VVI drop are representative of entering a VRS and is working. :thumbup:

 

The *real* bug is that once falling in a VRS, increasing the collective should do nothing or make it worse, not halt the descent.

 

Hence the need to side-slip or pitch down to break out of the vortex and get a clean air flow.

 

Feedback from actual pilots should clear things up.

 

So I was planning on making a video during my next scheduled test flight. But seems like helijumper beat me to it:

 

Either way, I have put in the request to get feedback on it from the actual pilots. So sit tight and wait for their response.

[Whisper]

Ah, I see where the confusion arises if you are using Helijumpers video as a demonstration of VRS working.

 

The vibration and rapid VVI drop are representative of entering a VRS and is working.

 

The *real* bug is that once falling in a VRS, increasing the collective should do nothing or make it worse, not halt the descent.

 

Hence the need to side-slip or pitch down to break out of the vortex and get a clean air flow.

 

Feedback from actual pilots should clear things up.

That's it, entering VRS may not be the issue , but the way to get out of it seems overly easy.

[Schmidtfire]

But isn't that good? I mean, VRS can be more than a handful to deal with sometimes :music_whistling:

[Frusheen]

Ah, I see where the confusion arises if you are using Helijumpers video as a demonstration of VRS working.

 

The vibration and rapid VVI drop are representative of entering a VRS and is working. :thumbup:

 

The *real* bug is that once falling in a VRS, increasing the collective should do nothing or make it worse, not halt the descent.

 

Hence the need to side-slip or pitch down to break out of the vortex and get a clean air flow.

 

Feedback from actual pilots should clear things up.

 

This is the issue. Helijumpers video shows it and I've spent another few hours testing and got the same results. The helicopter WILL enter VRS but once established its possible to get out of it with collective which is not realistic.

 

I also must question the parameters for the onset of VRS. Any kind of forward momentum no matter descent rate is enough to prevent its onset. I understood from manuals that it should be possible to enter VRS once the descent angle is over 30 degrees. At the moment that angle seems more like over 80 degrees.

 

I'll put a video together later of a track I saved which clearly shows the issue.

Edited October 6, 2016 by Frusheen

[myHelljumper]

You have a gazelle manual ?

[Ramsay]

You have a gazelle manual ?

I've only seen the SA-341G manual (which IIRC doesn't really discuss settling with power), hence the need for feedback from actual pilots.

 

Although the Gazelle's exact numbers will be different, I would expect it's behaviour to be similar simply due to the physics.

 

Source: http://www.copters.com/aero/settling.html

 

I don't have an issue with the onset of VRS (settling with power) myself, as the feature is present and can be adjusted later if necessary (the VVI needle drop has little to no lag compared to the huey/Mi-8 but OTOH players don't feel the descent rate in their 'butt', unlike RL, so I don't mind it - it may even be realistic).

 

Rather it is the recovery from what should be VRS that makes it 'appear' unmodelled.

VRS Recovery: http://www.aviationtoday.com/rw/personal-corporate/personal-ac/Flying-Through-the-Vortex_85872.html

Edited October 6, 2016 by Ramsay

[Frusheen]

I hadn't seen that graph for the 341 but it illustrates my figure of 30 degree descent angle being the boundary of the danger zone of VRS. That figure is quoted for many typical single rotor helicopters and has been established from extensive wind tunnel testing. It is quoted in a lot of helicopter flight dynamics reference material I have studied as part of the hobby.

 

EDIT: increasing collective pitch beyond OGE hover position in VRS should actually make the rate of descent increase rather than the current situation where the descent can be arrested.

Edited October 6, 2016 by Frusheen

[kintaro]

I hesitated to comment on the gazelle by polychop for a while now. But I got to a point where i need to write it out of my system.

Let me clarify that I understan how much work has been laid into this project and I am not in any way suggesting that it is not a sophisticated product.

(if someone can point me out to a reference where it is officially stated that this is still in beta that would ease on my soul a little)

Ok so about VRS with the gazelle:

Yeah its non existent (as of 1.5.4.57288 )

The mi-8 and the uh-1 had it in the betas as i think is a fundamental feature in helicopter simulation.

I dont want to mention all the other wierd things happenig that is aerodinamically is just not right with the gazelle. And the stuff that happens when the skids contact the ground...

As i said modelling helicopters must be hard work and its clear that a lot of work has been put in the gazelle. It looks incredible and the system modelling looks compelling. But as it is not stated that this is a beta (at least flight model wise) i have to say i am very disappointed. I hope i was just too angry to go trough all the threads and somewhere a lot of things are promised to be enhanced/added flm wise.

I have to state that i have never flown a gazelle but i have experience on mi-8 and as-350 so on medium and light class helicopters and I know VRS is a danger in every type.

Sorry for the long post, and hope this nice helicopter will improve in the future.

[myHelljumper]

Yeah its non existent

 

I think we don't fly the same helicopter :D

 

 

OTOH I agree that the recovering of the VRS might be too easy but I'm not an expert so I will trust the devs on this.

Edited October 16, 2016 by myHelljumper

[kintaro]

Im stating the same as the video you linked myHelljumper.

There is no VRS.

And recovery from VRS with this technique in real life is impossible.

You can't recover by increasing collective only. As stated before me, raising collective in VRS is counterproductive.

Edited October 16, 2016 by kintaro

[myHelljumper]

You don't see VRS in this video ?