Баги, проблемы Великолепной Восьмерки

[cw4ogden]

There's really only one sticking point here.  Can you get into VRS above ETL?

That is a simple yes or no answer.

If you answer yes, that's a different debate.  It would beg the question: "How?"

If you answer no, it is incumbent upon you, or ED to see if the flight model is wrong, or if our testing methods are to blame.  We did the due diligence.  We obtained the data incumbent upon us as required by ED in the form of the track files to submit a bug report.  Yet, I can not tell, at this point, if you've even viewed or considered the evidence.  You seem to be dismissing it as out of the realm of being possible.

To build a cathedral, you need to lay the first stone.  And that stone is can you get into VRS at or above ETL?  Nothing else contributes to the conversation until you weigh in on that question, and it's ramifications.  The ramifications being to explain what's going on in the track files, if it isn't VRS above ETL.  Because we have to start with the foundation of being in agreement on the basic facts.  

Edited June 1, 2021 by cw4ogden

[Wadim]

1 час назад, cw4ogden сказал:

There's really only one sticking point here.  Can you get into VRS above ETL?

That is a simple yes or no answer.

If you answer yes, that's a different debate.  

If you answer no, it is incumbent upon you, or ED to see if the flight model is wrong, or if our testing methods are to blame.  We did the due diligence.  We obtained the data incumbent upon us as required by ED in the form of the track files to submit a bug report.  Yet, I can not tell, at this point, if you've even viewed or considered the evidence.  You seem to be dismissing it as out of the realm of being possible.

To build a cathedral, you need to lay the first stone.  And that stone is can you get into VRS at or above ETL?  Nothing else contributes to the conversation until you weigh in on that question, and it's ramifications.  The ramifications being to explain what's going on in the track files, if it isn't VRS above ETL.  Because we have to start with the foundation of being in agreement on the basic facts.  

 

Answered in a personal.

[milit]

52 минуты назад, Wadim сказал:

Answered in a personal.

А почему в личке?

Мне, например, тоже интересно, есть какие-либо аргументы, кроме уже озвученных по данному вопросу.

[cw4ogden]

From the FAA handbook on helicopter flight.  Note the passages in BOLD text.  

 

Vortex Ring State Vortex ring state (formerly referenced as settling-withpower) describes an aerodynamic condition in which a helicopter may be in a vertical descent with 20 percent up to maximum power applied, and little or no climb performance. The previously used term settling-with-power came from the fact that the helicopter keeps settling even though full engine power is applied. In a normal out-of-ground-effect (OGE) hover, the helicopter is able to remain stationary by propelling a large mass of air down through the main rotor. Some of the air is recirculated near the tips of the blades, curling up from the bottom of the rotor disk and rejoining the air entering the rotor from the top. This phenomenon is common to all airfoils and is known as tip vortices. Tip vortices generate drag and degrade airfoil efficiency. As long as the tip vortices are small, their only effect is a small loss in rotor efficiency. However, when the helicopter begins to descend vertically, it settles into its own downwash, which greatly enlarges the tip vortices. In this vortex ring state, most of the power developed by the engine is wasted in circulating the air in a doughnut pattern around the rotor. In addition, the helicopter may descend at a rate that exceeds the normal downward induced-flow rate of the inner blade sections. As a result, the airflow of the inner blade sections is upward relative to the disk. This produces a secondary vortex ring in addition to the normal tip vortices. The secondary vortex ring is generated about the point on the blade where the airflow changes from up to down. The result is an unsteady turbulent flow over a large area of the disk. Rotor efficiency is lost even though power is still being supplied from the engine. [Figure 11-3] A fully developed vortex ring state is characterized by an unstable condition in which the helicopter experiences uncommanded pitch and roll oscillations, has little or no collective authority, and achieves a descent rate that may approach 6,000 feet per minute (fpm) if allowed to develop.

 

A vortex ring state may be entered during any maneuver that places the main rotor in a condition of descending in a column of disturbed air and low forward airspeed. Airspeeds that are below effective translational lift (ETL) airspeeds are within this region of susceptibility to vortex ring state aerodynamics. This condition is sometimes seen during quick-stop type maneuvers or during recovery from autorotation. The following combination of conditions is likely to cause settling in a vortex ring state in any helicopter: 1. A vertical or nearly vertical descent of at least 300 fpm. (Actual critical rate depends on the gross weight, rpm, density altitude, and other pertinent factors.) 2. The rotor disk must be using some of the available engine power (20–100 percent). 3. The horizontal velocity must be slower than effective translational lift. Situations that are conducive to a vortex ring state condition are attempting to hover OGE without maintaining precise altitude control, and approaches, especially steep approaches, with a tailwind component.

 

When recovering from a vortex ring state condition, the pilot tends first to try to stop the descent by increasing collective pitch. However, this only results in increasing the stalled area of the rotor, thereby increasing the rate of descent. Since inboard portions of the blades are stalled, cyclic control may be limited. The traditional recovery is accomplished by increasing airspeed, and/or partially lowering collective to exit the vortex. In most helicopters, lateral cyclic thrust combined with an increase in power and lateral antitorque thrust will produce the quickest exit from the hazard.  This technique, known as the Vuichard Recovery (named after the Swiss examiner from the Federal Office of Civil Aviation who developed it) recovers by eliminating the descent rate as opposed to exiting the vortex. If the vortex ring state and the corresponding descent rate is allowed to progress to what is called the windmill brake state, the point where the airflow is completely up through the rotor, the only recovery may be an autorotation. Tandem rotor helicopters should maneuver laterally to achieve clean air in both rotors at the same time. For vortex ring state demonstrations and training in recognition and recovery should be performed from a safe altitude to allow recovery no less than 1000 feet AGL or the manufacturer’s recommended altitude, whichever is higher.

 

To enter the maneuver, come to an OGE hover, maintaining little or no airspeed (any direction), decrease collective to begin a vertical descent, and as the turbulence begins, increase collective. Then allow the sink rate to increase to 300 fpm or more as the attitude is adjusted to obtain airspeed of less than 10 knots. When the aircraft begins to shudder, the application of additional up collective increases the vibration and sink rate. As the power is increased, the rate of sink of the aircraft in the column of air will increase. If altitude is sufficient, some time can be spent in the vortices, to enable the pilot to develop a healthy knowledge of the maneuver. However, helicopter pilots would normally initiate recovery at the first indication of vortex ring state. Recovery should be initiated at the first sign of vortex ring state by applying forward cyclic to increase airspeed and/ or simultaneously reducing collective. The recovery is complete when the aircraft passes through effective translational lift and a normal climb is established.

 

 

 

Hence, my point.  VRS and flight above ETL are mutually exclusive.

 

Source: https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/helicopter_flying_handbook/media/hfh_ch11.pdf

Edited June 1, 2021 by cw4ogden

[thunderstorm09]

Everyone deep into the manuals I guess, proper answer about this question you will get soon.
With respect

[Wadim]

21 минуту назад, thunderstorm09 сказал:

Everyone deep into the manuals I guess, proper answer about this question you will get soon.
With respect

Already received.
Man has no brake.
Speaks, speaks ... but does not understand the meaning.

Don't understand the essence.

Edited June 2, 2021 by Wadim

[YuKoN]

16 минут назад, Wadim сказал:

Уже получен.
У человека нет тормоза.
Говорит, говорит ... но смысла не понимает.

Вадим, объясните же нам смысл. По существу вопроса вы так ничего и не сказали

[Wadim]

6 минут назад, YuKoN сказал:

Вадим, объясните же нам смысл. По существу вопроса вы так ничего и не сказали

Как это не сказал?
И видео привёл, и методику отработки тестирования, и скорости!
Что вам ещё нужно???

[YuKoN]

Видео видел, методику нет. И о чем это говорит?

Основной вопрос был о том, что в режиме висения режим вихревого кольца наступает при 5м/с, а при горизонтальной скорости 30км/ч при вертикальной 3,5м/с у  нас в ДКС. В реале это так же, или нет?

Edited June 2, 2021 by YuKoN

[Frogen]

Парни, не горячитесь, и не требуйте немедленного ответа. Кому интересно, действительно интересно, начните с изучения аэродинимики,

Идут конструктивные переговоры. На всех, возможных языках. Это не быстро.

И по теме, есть среди Вас специалист по аэродинамике, который бы смог ПРАВИЛЬНО и понятно для всех перевести явления с русского на английский. Разговорный тут не "катит". Люди работают, но это не бысто, повторюсь, однако..

Нужен очень узко специальный английский, тот, который используют американские пилоты, или на край, англичане.. 

Что бы было понятно. как пример Терминология ИКАО

Снижение , предпосадочный маневр - Approach.... 

Аварийное снижение  emergency descent heading

Edited June 2, 2021 by Frogen

[Wadim]

18 минут назад, YuKoN сказал:

...

Основной вопрос был о том, что в режиме висения режим вихревого кольца наступает при 5м/с, а при горизонтальной скорости 30км/ч при вертикальной 3,5м/с у  нас в ДКС. В реале это так же, или нет?

 

Скрытый текст

Методика была в другом сообщении...

Нет. Не так.
При уменьшении скорости без взятия шага вертолёт и так увеличивает вертикальную скорость.

Параметры зависимости перехода в режим вихревого кольца по поступательной скорости не достаточно изучен. 

Однозначно ясно одно - чем больше поступательная скорость, тем легче выйти из этого режима.
Посему, мы исследовали только вывод из полного вихревого кольца. Это когда вертикальная скорость более 10 м/с, и вертолёт не реагирует на шаг.

Как научного работника, эта тема меня заинтересовала.

Как реального лётчика - нет.
 

[Frogen]

13 минут назад, Wadim сказал:

  Показать содержимое

Методика была в другом сообщении...

При уменьшении скорости без взятия шага вертолёт и так увеличивает вертикальную скорость.

Это особенности аэродинамики вертолёта, при пилотировании на II режиме.  ТО, что вдалбливают курсантам с 1 курса. И в теории , и на практике.. Как ни странно, но это прекрасно смоделировано в мат.модели Ми8.

Там еще много есть особенностей, но это не тема этой темы.. 

Но, этот фактор играет важную роль в формировании пограничных состояний в режимах от ГП до моторного планирования (в том числе и с гашением скорости) до попадания в ВК. 

Читаем и изучаем аэродинамику )). 

Edited June 2, 2021 by Frogen

[jager_jager]

Как NS430 починить нет информации?

 

Edited June 2, 2021 by jager_jager

[Frogen]

6 минут назад, jager_jager сказал:

Как NS430 починить нет информации?

 

Не знаю, как скрывать картинки, но сделать их маленькими, очень просто. Выделить и потянуть за край. (кому надо, посмотрит в полном формате, и форум не загромождён)

 

По теме.. ) Если это 2d версия, то по умолчанию она выводится в правый нижний угол. Что то придумывали?

Перезапуск.

Ремонт

Удаление модуля и переустановка. 

Edited June 2, 2021 by Frogen

[SL PAK]

Может это глюк от настройки графики "масштабирование интерфейса"?

[Vital061270]

У меня модель 2D. Да, Frogen прав. По умолчанию, навигатор падает в правый нижний угол. Но мышкой его можно таскать куда угодно по экрану. И увеличивать и уменьшать его размер, тоже можно мышкой, (навести курсор на угол навигатора, зажать лев кнопку мышки и тащить)

на "полтиннике " не работает (там своего барахла итак хватает)

Edited June 3, 2021 by Vital061270

[sLYFa]

17 hours ago, Wadim said:

  Reveal hidden contents

Методика была в другом сообщении...

Параметры зависимости перехода в режим вихревого кольца по поступательной скорости не достаточно изучен. 

То, что это очень сложный процесс с точки зрения аэродинамики, никто не спорить. Но как пытался объяснить англоязычный товарищ, с нарастающей скоростью, когда площадь НВ, не подвергнутая влиянию струи того же НВ (что как раз является причиной ВК, где НВ засасывает свою же струю), увеличиваетя, переход в режим ВК должен происходит на меньших вертикальный скоростях, чем в режиме висения. В ДКС, как раз наоборот. 

Я понимаю, что ФМ десятилетней давности наверное никто уже ковырять не будет. Надеюсь у Ми-24 будет правильно. 

 

 

[thunderstorm09]

То, что это очень сложный процесс с точки зрения аэродинамики, никто не спорить. Но как пытался объяснить англоязычный товарищ, с нарастающей скоростью, когда площадь НВ, не подвергнутая влиянию струи того же НВ (что как раз является причиной ВК, где НВ засасывает свою же струю), увеличиваетя, переход в режим ВК должен происходит на меньших вертикальный скоростях, чем в режиме висения. В ДКС, как раз наоборот. 
Я понимаю, что ФМ десятилетней давности наверное никто уже ковырять не будет. Надеюсь у Ми-24 будет правильно. 
 
 

Приветствую! Я не рядом с компом и не могу посмотреть треки. Поэтому прошу самостоятельно сделать табличку со своих треков по параметрам: скорость с шагом 2 км/ч, вертикальная, шаг, высота. Буду признателен! Это для анализа процесса.

[thunderstorm09]

Начиная с 60 км/ч

[Tinkie]

On 5/31/2021 at 9:39 PM, cw4ogden said:

if you don't have vertical or near vertical descent - No VRS.

 

Here is the main reason of misunderstanding. You take the view, that the vertical speed is a point. It's wrong. Vertical speed is a result of an aerodinamical processes in main rotor and not in the contrary. To be simple - vertical descend is already a process wich is not aerodinamically stable and it already produces mini-vortexes on rotor blades. Just decrease main rotor pitch to the critical and that mini-vortexes will drive you into the full blade stall. The same as is it will be on the fixed wing a/c. What will happen on the fixed wing plane in the stall mode if you will pull the stick? It will go deeper. The same is with rotor winged, in VR you pulling rotor pitch ang gets down faster. 

 

Don't take in mind the speed. Just imagine the processes in main rotor. Really, you can get absolutly the same results in the horisontal flight. Just it will cause an immediate structure crash due to overlimits. 

 

Sure, it's a very simplified explanation and it don't take into account a lot of things, such engines power and so on, but on my point of view it's an easiest way to understand.

[cw4ogden]

31 minutes ago, Tinkie said:

 

Here is the main reason of misunderstanding. You take the view, that the vertical speed is a point. It's wrong. Vertical speed is a result of an aerodinamical processes in main rotor and not in the contrary. To be simple - vertical descend is already a process wich is not aerodinamically stable and it already produces mini-vortexes on rotor blades. Just decrease main rotor pitch to the critical and that mini-vortexes will drive you into the full blade stall. The same as is it will be on the fixed wing a / c. What will happen on the fixed wing plane in the stall mode if you will pull the stick? It will go deeper. The same is with rotor winged, in VR you pulling rotor pitch ang gets down faster. 

 

Don't take in mind the speed. Just imagine the processes in main rotor. Really, you can get absolutly the same results in the horisontal flight. Just it will cause an immediate structure crash due to overlimits. 

 

Sure, it's a very simplified explanation and it don't take into account a lot of things, such engines power and so on, but on my point of view it's an easiest way to understand.

You seem to be mixing rotor tip vortexes with vortex ring state. Not the same thing.  
 

One is a normal phenomenon always present, the tip vortices.

 

VRS is an abnormal flow state with vortexes developing inboard due to combination of induced flow and rate of descent.
 

if you look at a VRS diagram you see that both vertical speed and approach angle are critical. Stay below 30 degrees or keep your rate low enough, it should be manifestly impossible to encounter VRS.  I think you misunderstand the phenomenon if you are saying it can be encountered in all modes of flight.

You can't get into to VRS above ETL because you are not recirculating the same air. That air is behind you before it's induced flow can be a factor.  
 

By this logic, if I can get into VRS at any airspeed, why no VRS in cruise flight with collective reduction?  

You need specific criteria to encounter VRS.  
 

In any discussion of VRS, Russian or American, the very first criteria listed is always vertical or near vertical descent.  

This is a low airspeed phenomenon by its very nature.  

 

http://www.svvaul.ru/nashi-resursy/knigi-onlajn/aerodinamika/604-pilotirovanie-vertoljota-na-rezhime-malykh-skorostej#:~:text=Самопроизвольное

 

33 minutes ago, Tinkie said:

Just decrease main rotor pitch to the critical and that mini-vortexes will drive you into the full blade stall.

How do you decrease rotor pitch to a critical angle and achieve a blade stall?  This seems to makes no sense.  

Edited June 5, 2021 by cw4ogden

[cw4ogden]

41 minutes ago, Tinkie said:

Don't take in mind the speed. Just imagine the processes in main rotor. Really, you can get absolutly the same results in the horisontal flight. Just it will cause an immediate structure crash due to overlimits. 

No, you just physically can't get VRS in horizontal flight above ETL airspeeds.  And no, just no to that last sentence.  Show me a cruise flight VRS accident or any VRS accident that caused a structural failure in flight.  Ridiculous.

46 minutes ago, Tinkie said:

but on my point of view it's an easiest way to understand.

If VRS was easy to understand, we wouldn't be having this conversation.  

[cw4ogden]

Look at the two blue lines. 

 

If I keep my rate of descent above the horizontal blue line - No VRS is possible.

If I keep my approach angle shallower than the blue line - No VRS is possible.

 

If I want to know the airspeed range it occurs, the 1.0 on the bottom of the graph is correlated to ETL.  Above 1.0 horizontally also No VRS is possible.

This is what I am saying.  Everything you need to know is in the graph, if you know what you are looking for and understand the concept of VRS.

Edited June 5, 2021 by cw4ogden

[Tinkie]

1 hour ago, cw4ogden said:

You seem to be mixing rotor tip vortexes with vortex ring state. Not the same thing.

 

Don't think instead of me. I undestand and know the difference.

 

1 hour ago, cw4ogden said:

VRS is an abnormal flow state with vortexes developing inboard due to combination of induced flow and rate of descent.

 

Yes and no. 

 

Rate of descend is SECONDARY to the fact that rotor is placed in locked thoroidal inertial flow. And that thoroidal flow is forming NOT BECAUSE of descend. Against of this, it is produced because of some processes in main rotor. One of them, for example, forced braking manueure, when you do not descend, but loose RPM. Or something else what will cause drop of rotor revolutions or engines power (just as an example). THIS will cause placing into VR. Inertial flow can be produced by any reason. And descend (really, not descend, but any axial movement of the rotor in the plane, perpendicular to the main flow) is not a reason. The reason is loss of lift (or thrust) that puts you into VR. Do you remember about tail rotor VR? Is there descending? No, there is not. But there is the same process, when by some reason the rotor is placed into locked intertial flow system. (Maybe not locked, but ringed? English is not my native). 

 

1 hour ago, cw4ogden said:

How do you decrease rotor pitch to a critical angle and achieve a blade stall?

 

Sure, increase.

 

1 hour ago, cw4ogden said:

By this logic, if I can get into VRS at any airspeed, why no VRS in cruise flight with collective reduction?

 

Because of you are in the mode 2. And the ring will be flown out. But it's possible if you'll switch off SPUU and give a pedal too much -- you can get into the tail rotor VR. And yes, it can be done with zero vertical speed and on speeds from zero, up to 80-100 kmh, wich are in mode 2. Not so easy, but absolutly real.

 

1 hour ago, cw4ogden said:

Look at the two blue lines. 

 

Sorry, but I will not. I can show you a lot of pictures too, but you'll not find there the "vertical speed". 

 

[cw4ogden]

1 hour ago, Tinkie said:

 

Don't think instead of me. I undestand and know the difference.

 

 

Yes and no. 

 

Rate of descend is SECONDARY to the fact that rotor is placed in locked thoroidal inertial flow. And that thoroidal flow is forming NOT BECAUSE of descend. Against of this, it is produced because of some processes in main rotor. One of them, for example, forced braking manueure, when you do not descend, but loose RPM. Or something else what will cause drop of rotor revolutions or engines power (just as an example). THIS will cause placing into VR. Inertial flow can be produced by any reason. And descend (really, not descend, but any axial movement of the rotor in the plane, perpendicular to the main flow) is not a reason. The reason is loss of lift (or thrust) that puts you into VR. Do you remember about tail rotor VR? Is there descending? No, there is not. But there is the same process, when by some reason the rotor is placed into locked intertial flow system. (Maybe not locked, but ringed? English is not my native). 

 

 

Sure, increase.

 

 

Because of you are in the mode 2. And the ring will be flown out. But it's possible if you'll switch off SPUU and give a pedal too much -- you can get into the tail rotor VR. And yes, it can be done with zero vertical speed and on speeds from zero, up to 80-100 kmh, wich are in mode 2. Not so easy, but absolutly real.

 

 

Sorry, but I will not. I can show you a lot of pictures too, but you'll not find there the "vertical speed". 

 

Vertical speed is the vertical axis of the graph. It is labeled V/V for vertical velocity and has a one to one correlation, as indicated by the two “1.0‘“s .  All you need to do is figure out your ETL airspeed and set the horizontal 1.0 at thus speed.  
 

The chart is telling you it’s a one to one correlation.  There is only one airspeed, approach angle and rate of dissent for any given flight profile, and it can be found on the chart

 

Now convert units to vertical speed.  

 

Example:  1 kph = 0.28 m/s

 

if you ETL airspeed is roughly 50kph based on highest estimate I’ve seen.

 

50 x .28 = 1.0 on the chart.  That’s how that works.  Now look at the lines I drew because if you understand that you understand what I’m saying.

 

50 x .28 sets the 1.0 at 14 m/s .  That’s fully developed vortex ring state.  Middle of the circle labeled 1.0
 

you can interpolate to approximate where the top edge of the envelope is, by measuring the distance between zero and the top of the VRS envelope, and the 1.0 line.  This is why the chart is universal, it is dictated by your particular aircraft’s ETL speed varies only slightly by airframe.  

 

if you do not understand the chart you do not understand VRS.

 

I get what you’re saying that theoretically in forward flight This can happen because the rotor is inducing a flow always.  And I get that you can put a rotor system into a vortex ring state with unusual maneuvers.  But those maneuvers still have to make you descend into your own downwash. 
 

Which you physically cannot do it but airspeed above ETL.  
 

To go from high speed to descending into one’s own downwash, your velocity vector must move straight below the rotor wash.  That can happen in any number of flight angles and approach profiles.  But they must conform to the chart.

 

You have to be going down in your own air.  

this can be caused by the pilot  rapid decelerations and standing the aircraft on its tail.  But you have put your velocity vector into your down wash.  In this case, the deceleration has tilted your rotors upwards into the oncoming flow.

 

in forward flight , Your induced flow has to remain in the area of the rotor system  long enough for you to sink into it.  And air speeds above about 30 km/h to 40 km/h, your induced flow is well behind the aircraft before it can be ingested into the rotor system again.

 

Everything you need to know is in the chart you refuse to look at.

 

Edited June 5, 2021 by cw4ogden