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Flight Model Again V2


Focha

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Oh I'm not offended by such a statement. And if you tell me I have no idea abour helo flight dynamics I'm fine with it. Telling the same the developer is an insult, no matter which language you use since he for sure spent more time coding the FM then you on a real stick. We had a lot of these experts even telling Yoyo that he has no idea of Flight modeling...It's simply a lack of respect and respect is a two sided street.

 

I agree that the physics on a 727 and a A380 are the same, but transition courses are not only there to teach you where the instruments are. You will learn how the plane reacts under given conditions which can vary a lot between different models.

 

I also know that this is also a game and like it was said earlier I'm happy that the FM "feels" fine for real Gaz M pilots than to get a model strictly by the book (maybe like Jester told of the Flight safety sims).

 

Just my two cents here. Since this will not be the end of this thread I wanted to thank Polychop for their work. I hope you other guys find some fun with the module at last.

No it's still no insult. So because PC coded the Gazelle, they know everything about it or helicopter aerodynamics? And they cannot make mistakes? Lack of respect? Lack of respect would be if you know there is something wrong, but don't care about it. The people here don't get paid, but because of enthusiasm they want to help to enhance PC's product.

It might hurt at first, admitting there is something wrong, but in the long therm it would improve PC's credibility.

Again, noone here claims to know how many cm the stick would travel. But the complete absence of stick travel shows that dissymmetry of lift is not in the FM code, or at least not active. If you don't have to compensate dissymmetry of lift, you are not flying a helicopter. It is the major difference in flying a fixed wing aircraft compared to rotary wing aircraft. And a SAS is a stabilisation system. It is not meant to compensate this phenomenon. It compensates for local short therm air turbulences and to reduce workload for the pilot flying. For example the Huey's flybar is a kind of SAS, but a mechanical one.

 

It's okay if it "feels" fine for you. But for me it wouldn't, because it lacks fundamental parts of what makes a helicopter so specific.

 

OT: Transition courses include handling of the aircraft. But this is the smaller part. Normal-, Emergency procedures, instruments, performance, system knowledge and system operation are the important things there. Someone in the transition course knows how an aircraft flys and how to fly, and e.g. in the airliner section, you don't have to teach IFR procedures, but how to use this specific aircraft's instruments for that.

 

Fox

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Quick and dirty. Yeah I know I know, it looks like a 5 year old kid did it. And it took me days to draw this :D I didn't want to use copyright protected material. Simplified and not covering all effects. But it shows why you have to compensate changes in lift distribution with stick forward when going from hover to forward flight. It is a function of lift. It simply doesn't matter how the blades are constructed as long as they produce lift. This effect will always happen. It won't be compensated by SAS.

 

attachment.php?attachmentid=191416&d=1533375614

 

 

Fox

D13F98D0-A33A-4AF8-ABAF-C053AD950DCE.thumb.jpeg.4df35b3e3308c2d6a4fb325ed360a391.jpeg

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some people here forget the Gazelle is still in service with 2 major players :))))

as you fox...need more knowledge man both aviation & programming :))

you wish you had the opportunity to fly a 380 with your 727 exp, you don't qualify :))

Su34 & F111 a dream fullfilled in fsx...[sIGPIC][/sIGPIC]

i5 5600, 1050ti, 16 GVram, win10 , TM W hotas&rudder, waiting for 1060/1070 price fall or a new gpu family..f*&9 miners :)

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@Fox did you really fly an helo ?

 

No because your scheme is right ofc but it demonstrates the most basic principle of helo flight dynamics. You look very glad of it... Like if you kind of discovered some rare and misunderstood stuff. Arguing that devs ignore it while coding a FM is all about physics and maths and that this kind of scheme must be in the 5 first pages of any helo physics book looks a bit abusive for me. As well as assuming that noone ever designed a SAS to counter this extremly well known and basic effect.

 

Anyway you know, someone who comes and says to an helicopter module dev "you don't know anything about helicopters me I do" may not be taken very seriously... Kinda clumsy...

 

Nicolas


Edited by dimitriov
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@Fox did you really fly an helo ?

 

No because your scheme is right ofc but it demonstrates the most basic principle of helo flight dynamics. You look very glad of it... Like if you kind of discovered some rare and misunderstood stuff. Arguing that devs ignore it while coding a FM is all about physics and maths and that this kind of scheme must be in the 5 first pages of any helo physics book looks a bit abusive for me. As well as assuming that noone ever designed a SAS to counter this extremly well known and basic effect.

 

Anyway you know, someone who comes and says to an helicopter module dev "you don't know anything about helicopters me I do" may not be taken very seriously... Kinda clumsy...

 

Nicolas

Okay. You´re free to have that way of thinking. I was provocative. Now I got the response, and it tells me a lot.

 

 

I certainly don´t "look very glad of it... Like if kind of discovered some rare and misunderstood stuff". It makes me sad. Honestly. I wish I wouldn´t spent time posting here, but instead would love to fly the Gazelle with authentic behaviour.

 

 

Did/Do you fly helicopters? What does qualify you to know helicopter dynamics? I can ask you the same questions. A non pilot, but "helicopter module dev" is per se qualified to say this is right and this is wrong, but a non module dev person with knowledge in helicopter dynamics is not?

Very strange attitude. It is neither necessary to be a pilot nor a module dev to see these flaws.

 

 

But this doesn´t help. Facts might help. I showed(simplified, not including all effects) why a helicopter needs corrections with the cyclic when going from hover to cruise. Why is there no need for that in your Gazelle? It doesn´t matter if SAS is on or off. Can you explain that? A "It has a special bladedesign" can not explain this, unless the blade itself changes its shape during one revolution, so that on the advancing side it has a lower ca to counter the increased airflow, and on the retreating side it has a higher ca to produce more lift despite the reduced airflow(such blade don´t exist). And the Gazelle has no individual blade control, has it? (I know prototypes, e.g. in one German CH-53 this was tested, but was used to reduce noise, not to counter d-o-l)

 

If your module had correct calculations of basic helicopter dynamics, then these long ongoing questions about the Gazelle´s flight model would´t be here anymore.

 

No signs of dissymmetry of lift, fly by wire-ish flight behaviour (pitch stop at -45° and 0° as Focha found out). And I even didn´t fly your Gazelle. Just by watching the videos and reading reports of others like Focha I see enough to have a picture of the Gazelle´s FM. Sorry, but for me it doesn´t look like it has basic helicopter dynamics.

 

A SAS from the late 60s would counter dissymmetry of lift(d-o-l)..... even the modern ones don´t do that. These systems do what their name suggest. They sabilize. Against small turbulences and other things. And thus lessen the workload on the pilot flying. Focha would love a SAS in the AS350, as this thing is twitchy like its name says, a squirrel. Especially during hover.

 

These Stability Augmentation Systems have very limited control authority. They do not move cyclic stick. It is between the controls and the swashplate(hydraulics in bigger helos). But they give no feedback to the cyclic stick.

 

An Autopilot(when activated) does counter d-o-l. An Autopilot system does move the controls by changing the stickposition with the trim actuators, but can be pushed over by the pilot all the time.

 

If SAS and AP systems are deactivated (and they have to be deactivatable as every electronic system can fail) then there is only one possible thing that can counter d-o-l. Thats the pilot.

 

Does the pilot have to counter d-o-l in your Gazelle when SAS is deactivated? No. Hence even with you assumption of the SAS countering d-o-l, it is not in your FM even when SAS is disabled. Maybe a bug prevents the correct calculation. I don´t know. But if you say you know helicopter dynamics, then you actually should realize the problem quickly. But you don´t see it.

 

We only get: It feels like the real one. But no explanation.

 

 

So you claim to know helicopter dynamics, then explain why the Gazelle behaves the way it does and differ so much from other helicopters.

 

 

Why do I think the SAS does not counter d-o-l.

Let´s assume the SAS would counter d-o-l in a way that the cyclic wouldn´t move anymore, but the swashplate is tilted(you acknowleded that d-o-l does exist, so it has to be countered).

So you are flying at cruise and you cyclic is still "centered" and not forward.

Now the SAS quits due to gyro malfunction. What happens next?

 

Case 1: The SAS "servos" remain fixed in their last position. Everything is fine as long as you don´t want to brake. Because now you have less cyclic stick movement backwards. You don´t have full control authority anymore.

 

Case 2: The SAS "servos" move to the center position. That would cause a severe pitch up during fast fwd cruise. Very bad, don´t you think so? When hands free even worse.

 

Case 3: The SAS "servos" float inside their margin of control authority. Look at the sticktravel of the SA341 I posted. This would become a deadzone. Can you control a helicopter with such a huge deadzone?

 

For me it doesn´t seem to be a good idea to counter d-o-l with the SAS.

 

 

 

 

Whoops!

Clumsy smurf has finished.

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Quick and dirty. Yeah I know I know, it looks like a 5 year old kid did it. And it took me days to draw this :D I didn't want to use copyright protected material. Simplified and not covering all effects. But it shows why you have to compensate changes in lift distribution with stick forward when going from hover to forward flight. It is a function of lift. It simply doesn't matter how the blades are constructed as long as they produce lift. This effect will always happen. It won't be compensated by SAS.

 

attachment.php?attachmentid=191416&d=1533375614

 

 

Fox

The dual rotor configuration is a superb model for helicopter flight.

It is in essence... fundamental.

Two rotors simplify rotary craft to the Basic fundamental elements of flight.

Each blade needs to turn 180 degrees to effect the other so blade to blade interference is minimal. It is no surprise that the cheapest helicopters through the ages have employed the dual blade tilting rotor.

 

Indeed we may imagine one blade at 270 degrees and one blade at 90 degrees to learn our general lift geometry. If we did not have such a simple understanding of rotary lift we would have but a hand full of chopper pilots.... I guarantee that!

Do we expect a car driver to understand how the combustion engine works?

Do we expect the car driver to understand how friction is spread between the four tires of our car as we go around a corner?

To us this car analogy is simple physics but is relevent, imagine trying to teach the complexity of rotor flight to the mass off chopper pilots..... you have to simplify it.

Please Ifoxromeo redraw your lift diagram for a 3 bladed chopper. please explain how each retreating blade and advancing blade creates lift across the three blades.

I am not saying this thread is wrong..... I am just tired of the basics as an argument.


Edited by Rogue Trooper

HP G2 Reverb, Windows 10 VR settings: IPD is 64.5mm, High image quality, G2 reset to 60Hz refresh rate as standard. OpenXR user, Open XR tool kit disabled. Open XR was a massive upgrade for me.

DCS: Pixel Density 1.0, Forced IPD at 55 (perceived world size), 0 X MSAA, 0 X SSAA. My real IPD is 64.5mm. Prescription VROptition lenses installed. VR Driver system: I9-9900KS 5Ghz CPU. XI Hero motherboard and RTX 3090 graphics card, 64 gigs Ram, No OC at the mo. MT user  (2 - 5 fps gain). DCS run at 60Hz.

Vaicom user. Thrustmaster warthog user. MFG pedals with damper upgrade.... and what an upgrade! Total controls Apache MPDs set to virtual Reality height with brail enhancements to ensure 100% button activation in VR.. Simshaker Jet Pro vibration seat.. Uses data from DCS not sound.... you know when you are dropping into VRS with this bad boy.

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I am still following this thread with keen interest and curiosity. The general problem or issue has not changed over the last pages. People feel, some with real world helicopter flight experience, most without, that what they expect from a helicopter and what they experience with the Gazelle in DCS are in some respects at odds. Fair enough!

 

I know a am reiterating a point i have made multiple times; the issue could probably be put to rest if the developers would take the time to type up a 2-3 page desciption/analysis of A.) general helicopter design and flight mechanics (so we are all on the same page and the reader can directly relate to what the Gazelle's specifics are), and B.) how the Gazelle in particular is designed and why she behaves like what people expect her to in some respects, and why she differs and shows defiant behaviour from general helicopter flight dynamics. If this stuff were to be found in sufficient detail in the manual, a lot of this discussion back and forth would probably be void.

 

Either the devs feel they cannot take the time to write this detailed analysis from their busy work schedule, or they are not at liberty to make the Gazelle's particular design choices public record. Whatever it maybe, referring to the general argument that the SAS and particular tri-rotor and aerodynamic fuselage design are sufficiently responsible for the Gazelle's flight behaviour only goes so far.

 

Thus, devs; take the time and type up this in-depth analysis of why the Gazelle differs from the general case. Add it to the manual so everybody can learn from it. If you are not at liberty to disclose this information, state that and we know we have to look some place else. If you are at liberty to say, then you must know all about the Gazelle's design or you could not have implemented it at DCS full fidelty level. So let us know what you have researched during the Gazelle's creation for DCS!

 

I feel the main issue is; people are not upset that the Gazelle feels different from what they expect, but that they cannot reconcile their knowledge of helicopter design with the DCS Gazelle. I.E. they desire a proper explanation of how and why!


Edited by sc_neo
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Indeed this is so.

Something is not quite right in forward flight, she is supremely solid.

 

 

Also cross talk is not quite right when increasing the collective. it does not bleed into the nose of the airframe.

 

 

But she really is a superb hunter killer as is. The skill required to bring weapon to bare correctly is not lost on the models problems. in fact it probably requires a touch more work load.

I reckon small tweaks will bring this bird to lethal.


Edited by Rogue Trooper

HP G2 Reverb, Windows 10 VR settings: IPD is 64.5mm, High image quality, G2 reset to 60Hz refresh rate as standard. OpenXR user, Open XR tool kit disabled. Open XR was a massive upgrade for me.

DCS: Pixel Density 1.0, Forced IPD at 55 (perceived world size), 0 X MSAA, 0 X SSAA. My real IPD is 64.5mm. Prescription VROptition lenses installed. VR Driver system: I9-9900KS 5Ghz CPU. XI Hero motherboard and RTX 3090 graphics card, 64 gigs Ram, No OC at the mo. MT user  (2 - 5 fps gain). DCS run at 60Hz.

Vaicom user. Thrustmaster warthog user. MFG pedals with damper upgrade.... and what an upgrade! Total controls Apache MPDs set to virtual Reality height with brail enhancements to ensure 100% button activation in VR.. Simshaker Jet Pro vibration seat.. Uses data from DCS not sound.... you know when you are dropping into VRS with this bad boy.

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Okay. You´re free to have that way of thinking. I was provocative. Now I got the response, and it tells me a lot.

 

 

I certainly don´t "look very glad of it... Like if kind of discovered some rare and misunderstood stuff". It makes me sad. Honestly. I wish I wouldn´t spent time posting here, but instead would love to fly the Gazelle with authentic behaviour.

 

 

Did/Do you fly helicopters? What does qualify you to know helicopter dynamics? I can ask you the same questions. A non pilot, but "helicopter module dev" is per se qualified to say this is right and this is wrong, but a non module dev person with knowledge in helicopter dynamics is not?

Very strange attitude. It is neither necessary to be a pilot nor a module dev to see these flaws.

 

 

But this doesn´t help. Facts might help. I showed(simplified, not including all effects) why a helicopter needs corrections with the cyclic when going from hover to cruise. Why is there no need for that in your Gazelle? It doesn´t matter if SAS is on or off. Can you explain that? A "It has a special bladedesign" can not explain this, unless the blade itself changes its shape during one revolution, so that on the advancing side it has a lower ca to counter the increased airflow, and on the retreating side it has a higher ca to produce more lift despite the reduced airflow(such blade don´t exist). And the Gazelle has no individual blade control, has it? (I know prototypes, e.g. in one German CH-53 this was tested, but was used to reduce noise, not to counter d-o-l)

 

If your module had correct calculations of basic helicopter dynamics, then these long ongoing questions about the Gazelle´s flight model would´t be here anymore.

 

No signs of dissymmetry of lift, fly by wire-ish flight behaviour (pitch stop at -45° and 0° as Focha found out). And I even didn´t fly your Gazelle. Just by watching the videos and reading reports of others like Focha I see enough to have a picture of the Gazelle´s FM. Sorry, but for me it doesn´t look like it has basic helicopter dynamics.

 

A SAS from the late 60s would counter dissymmetry of lift(d-o-l)..... even the modern ones don´t do that. These systems do what their name suggest. They sabilize. Against small turbulences and other things. And thus lessen the workload on the pilot flying. Focha would love a SAS in the AS350, as this thing is twitchy like its name says, a squirrel. Especially during hover.

 

These Stability Augmentation Systems have very limited control authority. They do not move cyclic stick. It is between the controls and the swashplate(hydraulics in bigger helos). But they give no feedback to the cyclic stick.

 

An Autopilot(when activated) does counter d-o-l. An Autopilot system does move the controls by changing the stickposition with the trim actuators, but can be pushed over by the pilot all the time.

 

If SAS and AP systems are deactivated (and they have to be deactivatable as every electronic system can fail) then there is only one possible thing that can counter d-o-l. Thats the pilot.

 

Does the pilot have to counter d-o-l in your Gazelle when SAS is deactivated? No. Hence even with you assumption of the SAS countering d-o-l, it is not in your FM even when SAS is disabled. Maybe a bug prevents the correct calculation. I don´t know. But if you say you know helicopter dynamics, then you actually should realize the problem quickly. But you don´t see it.

 

We only get: It feels like the real one. But no explanation.

 

 

So you claim to know helicopter dynamics, then explain why the Gazelle behaves the way it does and differ so much from other helicopters.

 

 

Why do I think the SAS does not counter d-o-l.

Let´s assume the SAS would counter d-o-l in a way that the cyclic wouldn´t move anymore, but the swashplate is tilted(you acknowleded that d-o-l does exist, so it has to be countered).

So you are flying at cruise and you cyclic is still "centered" and not forward.

Now the SAS quits due to gyro malfunction. What happens next?

 

Case 1: The SAS "servos" remain fixed in their last position. Everything is fine as long as you don´t want to brake. Because now you have less cyclic stick movement backwards. You don´t have full control authority anymore.

 

Case 2: The SAS "servos" move to the center position. That would cause a severe pitch up during fast fwd cruise. Very bad, don´t you think so? When hands free even worse.

 

Case 3: The SAS "servos" float inside their margin of control authority. Look at the sticktravel of the SA341 I posted. This would become a deadzone. Can you control a helicopter with such a huge deadzone?

 

For me it doesn´t seem to be a good idea to counter d-o-l with the SAS.

 

 

 

 

Whoops!

Clumsy smurf has finished.

 

First of all, dimitriov is not a dev team memer as such. He tlks to us a lot yes and is part of the testers in later stages of the modules. He is the one who made the gazlle campaign, not more not less.

So he can not speak as developer and it is not his module or product.

 

2nd. Since you stated points of disymerty of lift etc etc and have not touched the module yourself, your opinion is based on others and videos. I have seen mutiple videos where people try to claim a or b but when I watched the videos closely, last time it was the compreisson with a CAPRI, I figured people fly the real life helos different then the Gazelle.

If you think no real physical based formulas are used in our code that is fine, but I can tell you that not a single hlicopter or plane would take off in DCS with a professional flightmodel if non of these formulars were present in the code of each individual product.

 

Other then that, there are reasons why I do not answer everything people write, like your last ost or the by other interpreted assault, which I did not take as such. I rather think, as soon someone starts to say we do not know helicopter dynamics it is the point where there is no need to further talk to that person, cause in the end there is no base for a solid conversation from that point. Other then that pericopitc precession, angular momentum,mushing, transient torque and so on and so on, are phrases I am very well aware of and thier physical effect and the resulting factors.

 

Have a nice day folks, and stop bashing eachother. No need to.

I got used to the crytics even if the flightmodel of ny future product is rock solid and verified by the guys that flew it for thousands of hours, there will be people that will tell us that this bird does not fly like it. I already have a verification idea for the future module if it is accepted by ED, but that verification would go through pn, cause for the upcoming planned module we have a very very huge community that is standing in the background and more then willing to help ID people or help with any other stuff we ask for.

 

Therefore, if you are not one of them, yu know less then me about the new bird and I am not even one of them.

 

So lets have some hapy rides in the Gazelle

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I am still following this thread with keen interest and curiosity. The general problem or issue has not changed over the last pages. People feel, some with real world helicopter flight experience, most without, that what they expect from a helicopter and what they experience with the Gazelle in DCS are in some respects at odds. Fair enough!

 

I know a am reiterating a point i have made multiple times; the issue could probably be put to rest if the developers would take the time to type up a 2-3 page desciption/analysis of A.) general helicopter design and flight mechanics (so we are all on the same page and the reader can directly relate to what the Gazelle's specifics are), and B.) how the Gazelle in particular is designed and why she behaves like what people expect her to in some respects, and why she differs and shows defiant behaviour from general helicopter flight dynamics. If this stuff were to be found in sufficient detail in the manual, a lot of this discussion back and forth would probably be void.

 

Either the devs feel they cannot take the time to write this detailed analysis from their busy work schedule, or they are not at liberty to make the Gazelle's particular design choices public record. Whatever it maybe, referring to the general argument that the SAS and particular tri-rotor and aerodynamic fuselage design are sufficiently responsible for the Gazelle's flight behaviour only goes so far.

 

Thus, devs; take the time and type up this in-depth analysis of why the Gazelle differs from the general case. Add it to the manual so everybody can learn from it. If you are not at liberty to disclose this information, state that and we know we have to look some place else. If you are at liberty to say, then you must know all about the Gazelle's design or you could not have implemented it at DCS full fidelty level. So let us know what you have researched during the Gazelle's creation for DCS!

 

I feel the main issue is; people are not upset that the Gazelle feels different from what they expect, but that they cannot reconcile their knowledge of helicopter design with the DCS Gazelle. I.E. they desire a proper explanation of how and why!

 

If you pay for such an analys I can ask on of the US Army pilots I talk to eery week, if he wants to gve a ecture to the general puplic about why the Gazele feels good enough for him as a pilot who does earn his money for flying helicopters indangerous enviroments.

 

I do not want to say that it is not worth to do so, but for month we are asked to answer x y z question abotu the flightmodel and are asked to give reasons why it flys that way, yada yada yada and people have recieved most answer numerous times. I think it is not on us to teach people how a helicopter flys, but including to this, not a single heicopter flys like the other. Since I have not flown the Gazelle in RL yet, I have to trust the guys that do fly it for living, like any other customer and make the best out of it with Patrick as a team. If anyone things, who has not flown the Gazelle in RL he knows better then the guys that do, please take the time and write a letter to the french army flightschool in Pau france, close to the spanih border and talk to them. They have our module, cause we gave it to them and we heard no complains so far, although I have to be fair that they have thier hands full with training the guys on Tigers and others next o the Gazelle and probabaly have not much time to answer, which they do not do often if we write. That said, enjoy your day

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First of all, dimitriov is not a dev team memer as such. He tlks to us a lot yes and is part of the testers in later stages of the modules. He is the one who made the gazlle campaign, not more not less.

So he can not speak as developer and it is not his module or product.

 

 

Yes I'd like this to be well understood either, tired of people thinking that I'm a dev every time I say something, I got paid once to deliver the campaign, helped my best during the Gazelle dev (which didn't mean a lot compared to the job Pat and Sven did), and now that's kinda all. I never ever gave an advice on the FM as long as Poly has pilots to give them, I simply helped finding bugs on the systems and tried to give a "customer" opinion on this or that before release and during few monthes after. If i was a dev, I would be more diplomat.

 

Nicolas


Edited by dimitriov
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Yes I'd like this to be well understood either, tired of people thinking that I'm a dev every time I say something, I got paid once to deliver the campaign, helped my best during the Gazelle dev (which didn't mean a lot compared to the job Pat and Sven did), and now that's kinda all. I never ever gave an advice on the FM as long as Poly has pilots to give them, I simply helped finding bugs on the systems and tried to give a "customer" opinion on this or that before release and during few monthes after.

 

Nicolas

 

And we are very happy and thanksful for your time and help, which also assured you a seat on the next beta team ;)

 

Alpha team testers are currently hard at work to adjust and tweak the details of nb2 :D, but since we have no contract yet with ED, we can not share anything about the NB2 at all

Sorry for that guys.

Including this line here.

We hope to show you our new baby this year at some point, we are working on it.

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ok, why this discussion is still on ? clearly not technical with facts :)) close it ! move on to next project :)

Su34 & F111 a dream fullfilled in fsx...[sIGPIC][/sIGPIC]

i5 5600, 1050ti, 16 GVram, win10 , TM W hotas&rudder, waiting for 1060/1070 price fall or a new gpu family..f*&9 miners :)

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The dual rotor configuration is a superb model for helicopter flight.

It is in essence... fundamental.

Two rotors simplify rotary craft to the Basic fundamental elements of flight.

Each blade needs to turn 180 degrees to effect the other so blade to blade interference is minimal. It is no surprise that the cheapest helicopters through the ages have employed the dual blade tilting rotor.

 

Indeed we may imagine one blade at 270 degrees and one blade at 90 degrees to learn our general lift geometry. If we did not have such a simple understanding of rotary lift we would have but a hand full of chopper pilots.... I guarantee that!

Do we expect a car driver to understand how the combustion engine works?

Do we expect the car driver to understand how friction is spread between the four tires of our car as we go around a corner?

To us this car analogy is simple physics but is relevent, imagine trying to teach the complexity of rotor flight to the mass off chopper pilots..... you have to simplify it.

Please Ifoxromeo redraw your lift diagram for a 3 bladed chopper. please explain how each retreating blade and advancing blade creates lift across the three blades.

I am not saying this thread is wrong..... I am just tired of the basics as an argument.

Actually the helicopter dynamics part of pilots training course is not simplified. It is reduced to explain the principle. After such a course you can´t calculate the forces that appear, but you know what is going on, so you are aware of helicopter specific behaviour.

 

The diagram shows the airflow at the 3 and 9 o´clock position, ignoring the rest of the clock. It is not a 2 bladed rotor that I painted. It is about the principle. The number of blades is not defined in my drawing. The number of rotorblades a helicopter has depends on several factors. But the principle is always the same. The details differ. More blades means among other things that, as you mentioned, the distance between the blades gets smaller and can cause more turbulences. But the advantages of more blades overweight normally the problems it can cause. I know of a helicopter with 1(yes a single) blade and a helicopter with 7 rotorblades.

 

The Bo 103 is this single blade helicopter and e.g. the CH-53K has 7 blades.

 

 

So the drawing remains the same for the principle of a 3 bladed mainrotor, when a blade is at the 3 or 9 o´clock position. The blades change their pitch with every revolution. It´s the sum of the forces along each individual blade and all blades together that creates the amount of lift and direction of lift all the time and at every position. It is a very dynamic process and best explained via-a-vis. That´s what makes a helicopter so different from a fixed wing aircraft.

 

 

Does that answer your question halfway?

 

 

Fox

 

 

 

p.s. just realized I drew a ccw rotor. Ofc the Gazelle has a cw rotor.

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I am still following this thread with keen interest and curiosity. The general problem or issue has not changed over the last pages. People feel, some with real world helicopter flight experience, most without, that what they expect from a helicopter and what they experience with the Gazelle in DCS are in some respects at odds. Fair enough!

 

I know a am reiterating a point i have made multiple times; the issue could probably be put to rest if the developers would take the time to type up a 2-3 page desciption/analysis of A.) general helicopter design and flight mechanics (so we are all on the same page and the reader can directly relate to what the Gazelle's specifics are), and B.) how the Gazelle in particular is designed and why she behaves like what people expect her to in some respects, and why she differs and shows defiant behaviour from general helicopter flight dynamics. If this stuff were to be found in sufficient detail in the manual, a lot of this discussion back and forth would probably be void.

 

Either the devs feel they cannot take the time to write this detailed analysis from their busy work schedule, or they are not at liberty to make the Gazelle's particular design choices public record. Whatever it maybe, referring to the general argument that the SAS and particular tri-rotor and aerodynamic fuselage design are sufficiently responsible for the Gazelle's flight behaviour only goes so far.

 

Thus, devs; take the time and type up this in-depth analysis of why the Gazelle differs from the general case. Add it to the manual so everybody can learn from it. If you are not at liberty to disclose this information, state that and we know we have to look some place else. If you are at liberty to say, then you must know all about the Gazelle's design or you could not have implemented it at DCS full fidelty level. So let us know what you have researched during the Gazelle's creation for DCS!

 

I feel the main issue is; people are not upset that the Gazelle feels different from what they expect, but that they cannot reconcile their knowledge of helicopter design with the DCS Gazelle. I.E. they desire a proper explanation of how and why!

Thank you. I agree, except "or they are not at liberty to make the Gazelle's particular design choices public record". Why would Airbushelicopter tell anyone classified information to write a specific software, but not allow the developer to talk about it. The software had to be classified as well.

 

 

Fox

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Since I look at the comments on the gazelle, despite all the explanations that could be given on the various posts, the subject goes round in circles.

A certain point of view is only very rarely used, or mentioned just to complicate the speech more.

I want to talk about the differences between the machines.

number of main rotor blades

dimensions

weight

fenestron / rotor

linked turbine

free turbine

engine power

Why then that these differences exist and are indisputable, should the different helicos have the same behavior in flight?

If the gazelle has a specific behavior it is simply because it was not designed like the other helicos. Initially it was a demonstrator whose specifications required a light helico very fast.All in its conception of departure was designed for high speeds.The French and British army were looking for a device to renew their helicos park.The gazelle was chosen for the sake of economy, to avoid bankruptcy, the firm that the manufactured.

It received a large number of modifications to make it operational in combat. The orientation of the specifications changed radically and the behavior of the machine in flight too. One could even say, by exaggerating for the demonstration, that the SA 342 is not comparable with the SA 341, except the external aspect.

It is obvious that the various modifications and implementations of systems, not originally planned, return to false information if we do not speak of the same machine.

it's even more obvious if we compare with the huey.

I mean that no type of helicopter is comparable except that it is a helico and it does not behave like an airplane.

And thank the devs for taking care to make a module that does not look like the others.


Edited by cromhunt
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Ok... After I read all the posts replies since my last reply... I regret to say that I give up.

 

It is incredible how a simply complex topic as this one turn out to all the directions except those that matters.

 

I, myself, as a helicopter pilot in real life know that every helicopter flies differently. Yet, every helicopter has the same principles of flight.

 

If Gazelle was a complex modern enough helicopter to use FBW system, I would stand down and don't comment some of the tests I've made and that reported earlier in this topic. But Gazelle is not a modern helicopter.

 

I believe to some extend the SAS system helps the workload of the pilot. As with the AS365 N1 I fly, that has AFCS with SAS, it make is more stable, but does not take out aerodynamic and forces effects that are common to all helicopter (at least conventional ones, meaning, one main rotor and one tail rotor/fenestron).

 

So I give up.

 

The reply from the Devs is that they have a team of real helicopter pilots that give feedback and said the FM is ok. The next argument is that the Gazelle is a different helicopter. And the last argument is that it is an attack to this module.

 

Yet, I didn't find any reply commenting the fundamental works of its hydraulic or servo electric mechanics linked with how the SAS works and how it feels more like an FBW system than an mechanical/magnetic link to the controls.

 

How do the developers justify that the cyclic position is returned to neutral (joystick neutral) and yet the helicopter maintains the attitude, with or without SAS engaged?

 

I am still waiting to see a reply from the developers explaining the critical tests I've made with Gazelle module and the comments I've posted earlier.

 

So, I give up. I am tired of trying to show that unless the Gazelle is a very complex machine, there are a number of things that for me, as a RL helicopter pilots, does not make sense.

 

I came here and asked, why is it that the Gazelle behaves like this, since it is completely different from what I would expect from a helicopter simulation.

 

The analogy is, that the Gazelle right now, seems more like Apache from Longbow 2, then from what I would expect from a 2018 simulation, since others have broken barriers in this kind of home simulation.

 

So, I apologize for starting up this topic again, it seems that people here don't like to be confronted with one with some knowledge as to offer.

 

Plus, and this is just personal opinion... Developer seemed like a kid replying why someone is in the beta team, in a public open discussion that as nothing to do with that.

 

Please, stick to the topic. But better, close it. From what I understand it just doesn't worth it.

 

I hope you consider my opinion regarding FFB joystick and the behavior that we are getting and again I stand my ground in saying that the Gazelle is a very special helicopter (if it is indeed how it is flying in DCS) because I've never experienced a helicopter like it... and I already flown a few in RL.

 

Kind regards and again sorry for expressing my view on your product. But I am also tired and feel that the review I have made it didn't serve for any purpose, and I lost a few minutes of my life doing that free review of your FM.


Edited by Focha
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Since I look at the comments on the gazelle, despite all the explanations that could be given on the various posts, the subject goes round in circles.

A certain point of view is only very rarely used, or mentioned just to complicate the speech more.

I want to talk about the differences between the machines.

number of main rotor blades

dimensions

weight

fenestron / rotor

linked turbine

free turbine

engine power

Why then that these differences exist and are indisputable, should the different helicos have the same behavior in flight?

If the gazelle has a specific behavior it is simply because it was not designed like the other helicos. Initially it was a demonstrator whose specifications required a light helico very fast.All in its conception of departure was designed for high speeds.The French and British army were looking for a device to renew their helicos park.The gazelle was chosen for the sake of economy, to avoid bankruptcy, the firm that the manufactured.

It received a large number of modifications to make it operational in combat. The orientation of the specifications changed radically and the behavior of the machine in flight too. One could even say, by exaggerating for the demonstration, that the SA 342 is not comparable with the SA 341, except the external aspect.

It is obvious that the various modifications and implementations of systems, not originally planned, return to false information if we do not speak of the same machine.

it's even more obvious if we compare with the huey.

I mean that no type of helicopter is comparable except that it is a helico and it does not behave like an airplane.

And thank the devs for taking care to make a module that does not look like the others.

 

Sure helicopters are comparable. Why wouldn't you compare? Wouldn't you compare a Cessna 172 with a Piper something? They have handling qualities that have to be the same, and obviously they fly differently. But they can be compared.

 

Often in RL you compare aircraft you fly. You even compare different models of the same helicopter... because they handle differently, but again, the essence is the same.

 

So, to question your certainties, yes, you can compare.

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First of all, dimitriov is not a dev team memer as such. He tlks to us a lot yes and is part of the testers in later stages of the modules. He is the one who made the gazlle campaign, not more not less.

So he can not speak as developer and it is not his module or product.

 

Okay. Now I got it. His post gave me the impression that he is part of the Polychop team.

 

 

 

 

 

2nd. Since you stated points of disymerty of lift etc etc and have not touched the module yourself, your opinion is based on others and videos.

 

Since the early access release of the Gazelle I´m watching videos about it.

Yes, I base my opinion about the Gazelle on these videos AND comments from users. I do recognize a valid or speculative claim. And as long as I don´t have the Gazelle I won´t say anything about the engine´s power output or the VRS, as the information I got about these things are not sufficient for me.

 

But for dissymmetry of lift a simple video or report of the status quo during forward flight and stick position is sufficient and these information exist from valid sources. Again I´m not saying the stick has to move XX.5 cm from the center. I don´t know how far it moves, but it has to move. I explained why.

 

 

 

 

 

I have seen mutiple videos where people try to claim a or b but when I watched the videos closely, last time it was the compreisson with a CAPRI, I figured people fly the real life helos different then the Gazelle.

 

And you claim that the SA341 does not fly like the SA342.

Quote:"In your video they use a 341L as far I can see, that has no SAS system. makes a huge difference."

 

I extremely doubt that there is any significant difference when comparing a unequipped SA342 (with or without SAS) with a SA341 in respect of flight dynamics. Less twitchiness, yes; less workload, yes. But one having to cope with dissymmety of lift and the other not? Really??

 

 

 

If you think no real physical based formulas are used in our code that is fine, but I can tell you that not a single hlicopter or plane would take off in DCS with a professional flightmodel if non of these formulars were present in the code of each individual product.

 

I have absolutely no idea how to code modules. But 3rd party modules do only underly EFM rules(or did that change? I was a while away from DCS) and EFM does only mean external flight model, it is no indication of sophistication per se. It´s in the hand of the 3rd party dev, not ED. ED requires only rigid body physics and contact model. Rest is up to 3rd party dev. It can range from SFM-like up to PFM-like. Hence, no quality indicator.

Quote:

 

"External Flight Model (EFM). Used by our partner developers, the EFM uses only a part of PFM - rigid body physics and contact model. What forces and moments are applied to this rigid body from aerodynamics and any other sources except the contact forces is up to EFM developer."

 

Here is the link to this post from Wags.

 

 

 

 

 

Other then that, there are reasons why I do not answer everything people write, like your last ost or the by other interpreted assault, which I did not take as such. I rather think, as soon someone starts to say we do not know helicopter dynamics it is the point where there is no need to further talk to that person, cause in the end there is no base for a solid conversation from that point.

 

Yes, if trolling becomes to severe, I would certainly do the same.

 

But there is a difference if someone is just saying your FM is wrong but doesn´t say why, and someone who shows arguments, why he thinks the FM is wrong. Maybe I was a bit too harsh that I said you don´t know helicopter dynamics. Sorry for that! But why don´t you tell us, why the Gazelle does differ from general helicopter behavior. Just by saying it has SAS is no explanation. How does this SAS work? Show some pictures. Special rotorblades. Why are they special and how does it change aerodynamics so that the observed behaviour can be explaned.

 

You said that you stop the conversation with someone who accuses you of not knowing stuff. Okay. But where did you explain the questions that were asked before the discussion got to that point?

 

 

Other then that pericopitc precession, angular momentum,mushing, transient torque and so on and so on, are phrases I am very well aware of and thier physical effect and the resulting factors.

 

Then you should be able to explain the behaviour. So please don´t tell us it is correct because someone says it "feels" correct. The "feel" is a nice bonus, when the rest is reasonable.

 

 

 

 

 

Have a nice day folks, and stop bashing eachother. No need to.

I got used to the crytics even if the flightmodel of ny future product is rock solid and verified by the guys that flew it for thousands of hours, there will be people that will tell us that this bird does not fly like it. I already have a verification idea for the future module if it is accepted by ED, but that verification would go through pn, cause for the upcoming planned module we have a very very huge community that is standing in the background and more then willing to help ID people or help with any other stuff we ask for.

 

 

Therefore, if you are not one of them, yu know less then me about the new bird and I am not even one of them.

 

So lets have some hapy rides in the Gazelle

 

If you pay for such an analys I can ask on of the US Army pilots I talk to eery week, if he wants to gve a ecture to the general puplic about why the Gazele feels good enough for him as a pilot who does earn his money for flying helicopters indangerous enviroments.

 

And Focha says it doesn´t feel good for him. So we have a standoff here..

(Sorry Focha for pushing you in front :))

 

 

 

 

 

I do not want to say that it is not worth to do so, but for month we are asked to answer x y z question abotu the flightmodel and are asked to give reasons why it flys that way, yada yada yada and people have recieved most answer numerous times.

 

I´m sorry, I missed these answers. Please, can you or someone else provide links to these answers.

 

 

 

I think it is not on us to teach people how a helicopter flys, but including to this, not a single heicopter flys like the other. Since I have not flown the Gazelle in RL yet, I have to trust the guys that do fly it for living, like any other customer and make the best out of it with Patrick as a team. If anyone things, who has not flown the Gazelle in RL he knows better then the guys that do, please take the time and write a letter to the french army flightschool in Pau france, close to the spanih border and talk to them. They have our module, cause we gave it to them and we heard no complains so far, although I have to be fair that they have thier hands full with training the guys on Tigers and others next o the Gazelle and probabaly have not much time to answer, which they do not do often if we write. That said, enjoy your day

 

That is what I personally don´t understand. Your explanation, why your Gazelle behaves like it does, is because someone, who even doesn´t reply often, says it is okay!? That is no explanation. It is just an opinion. And as I requested already.. Please ask these guys specifically about dissymmetry of lift and stick travel in the real SA342 Gazelle. Don´t ask them about feelings.

Thank you.

 

Yes I'd like this to be well understood either, tired of people thinking that I'm a dev every time I say something, I got paid once to deliver the campaign, helped my best during the Gazelle dev (which didn't mean a lot compared to the job Pat and Sven did), and now that's kinda all. I never ever gave an advice on the FM as long as Poly has pilots to give them, I simply helped finding bugs on the systems and tried to give a "customer" opinion on this or that before release and during few monthes after. If i was a dev, I would be more diplomat.

 

Nicolas

 

 

I had the impression you were from the Polychop team. I won´t make this mistake again.

 

 

Comments in red

 

 

Polychop. Explaining stuff might be difficult and take a lot of time. But it helps dramatically for the reputation. ED´s Yo-Yo is a fine example for that.

And because of him I bought the Yak-52 blind, full price, Persian Gulf, full price, the Hornet, full price(okay I used the bonus from the Yak and PG..), didn´t wait for a sale, just to support ED.

 

I bought 3rd party modules in pre sale, that were a pure disappointment when released(for me personally). Won´t do the same thing again. There are devs that deserve the credit of trust, and some don´t. I honestly ask you to make a step back, take the time, explain with physical justification, why the real Gazelle differs from other Helicopters. This will put a lot of trust in you and will silence the ongoing FM discussion.

 

 

 

Fox

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Sincerely guys, you are making a whole mountain for not so much. In french community i know a lot of people who simply enjoy the Gazelle. Perhaps are there lacks, none of them really disturbs me nor them. So perhaps something was badly understood by devs, or badly seen by test pilots. I may not have your knowledge, and I understand your opinion and it may be true btw (Fox, I reacted to the way you were talking to Borchi, I didn't even read the discussion before...). Still here is my very humble point of view :

 

First : I do never comment what I don't try. Let me give you a nice illustration on how it looks :

 

A ferrari drives down the road.

 

"this ferrari, it doesn't drive like one"

- ah yeah ? You drove it ?

- No, but I saw videos on YT of people driving it.

-.......

 

A FM is thousands and thousands lines long, and is btw a little part of the simulator when it comes to a whole combat helicopter, so speaking like if the whole module is crap because of something missing in the FM is IMO a bit exagerated. You are (this is my opinion) ruining the reputation of some people who work hard while you could simply propose your help on Discord in private, or candidate to beta test teams, which would be far more productive. But you don't. You prefer yelling, imagining that after 10 pages, a lot of people read you.

 

You know, having seen everything from the interior shew me that dev is not simple, for multiple reasons. It's a very long and painful job in fact, I still don't understand how can people have fun doing this ^^, I remember the whole team being very stressed at the release because they hoped to release the best product possible. Even if I only was the campaign maker, and that I was only with them for 6 months, and already paid btw, I was completely stressed too. Because Pat, Sven and me shared the same feeling : They spent a lot of efforts in the Gazelle, me in the campaign, and time was now for judgement. And let me tell you this : some people here were really stinky.

 

There were lacks at the release on the FM, but right at the beginning the way of exposing the issues was the following : "You Polychop are ignominous liers and incompetent morons". I even remember someone asking for the identity of the test pilots. Fact is that you are not prepared for such behavior, specially when you spent so many efforts in the work. They did their best to fix the various lacks that were signaled, during two months, 4-6 h a day, on my own Teamspeak, with beta testers, pilots, mechanicians etc.

 

It was a collective work from several actors, not only devs. We have several Gazelles in our squad, and while I prefer my Kamov that I fly for 6 years (Simply for its combat capabilities), it's a real pleasure to fly it.

 

Perhaps isn't their best enough for you, but it's enough for me, as well as for most people I know in the community (and believe me, I know a shit load of people in it) . I may surely not be neutral (nor are you, you both are IMHO far too emotional), but I know for having worked with them that they work far more for passion than for money.

 

So for me, as well as for other people I know in french squads (a lot of them directly coming from the ALAT btw), the Gazelle is now a finished product, with sometimes some bugs because of unscheduled updates from ED, and perhaps are there some lacks in the FM, here or there (I cannot judge, I don't know.), but there is no need anymore to spend a lot of time on it. The next module will take lessons from the first product, and so they will avoid a lot of problems they had with the Gazelle. Still, and as Sven said, it is highly possible that both the big up from Army pilots and from several very well qualified engineers will not be enough to satisfy everyone. The simmer is never happy. He is a sad little boy.

 

So for the future, if you have real concerns about the FM, and of course devs are not perfect and can be wrong while you can be right (I don't know, not my job, and sincerely, I don't give a **** ^^), get in private, instead of coming here to sum up a 5 years work to one mistake in public like you tend to do...

 

With all respect, may god bless my diplomacy, the first French quality, and thanking Pat, Sven and all the people who work in the dark for everything,

 

Nicolas

 

PS : Joking, I don't know a **** about diplomacy either, which is a bad point for a future lawyer.


Edited by dimitriov
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Stop making the discussion about us vs them. It's very simple. For some the FM doesn't add up and we'd like to help fix that because at this point the gazelle simply does not behave like a helicopter hanging from a rotorsystem but rather a helicopter mounted on one. (pivoting).

 

 

But I ask the question again and this the easiest answer there should be in this conversation:

 

Is SAS reactionary? If so, how can it predict instability before it happens and thus make it this stable. Because if it is reactionary there first has to be an imbalance for it to 'stabilize'. Btw how can something be this stable when SAS is disabled/gyro's never spun up. Flying helicopters simply means dealing with the current imbalance that pops up

 

 

 

The simple fact is, it's too stable. It is a show of having something wrong in the aerodynamic model.

 

Saying the rotor blades are 'special' makes me want to scream. Since then you clearly have no clue what the Faero are and why they happen. AFAIK they are simply made out of composites and high inertia blades. If there is something special that cancels out wing tip vortices and all that fun then please let me know. I'll run to Bell/Boeing/Whoever to tell em I have a design that can make all their helicopters awesome for €50million in cash.

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