Ракеты в DCS

[Chizh]

17 часов назад, Gahab141 сказал:

Разве у 31БН по 2 пилона на проскость? Или моделька БМовская?

Да, модель БМ, а в нутри БН.

[musolo]

1 hour ago, Chizh said:

Да, модель БМ, а в нутри БН.

кабина вроде тоже от  БМ что радует)

F-14A бот имеет только одну ракету оказывается. Aim-54C. Первоначальной Aim-54A у него нет, что странно.

А почему русский парк ботов застыл в 1992 году? Ботов никто не запрещает ведь делать по закону? Хоть Су-27СМ, хоть Су-30МК, хоть Су-35 и Су-35С? Никаких легальных препон нет же, так ведь?   

Edited January 14, 2022 by musolo

[tavarish palkovnik]

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Edited April 23 by tavarish palkovnik

[BlackPixxel]

2 hours ago, tavarish palkovnik said:

Are you able to extract thrust to time function of this case? Is it possible or is it ''hidden'' in program?

Here is the motor configuration of the R-33 in DCS, it is close to what you read from the graphs:

Boost: 4 s, 37280 N, 15.4 kg/s

Sustain: 16 s, 13950 N, 5.9 kg/s

So it has 156 kg of rocket fuel.

In DCS the missile weighs 520 kg.

 

What do you mean with fuel doesn't burn that way? That the fuel burn is constant in each stage (simplification of the game) or something else?

 

Regarding the R-27E motor: Yes, the end result will not change, but it is just about getting a realistic value for the missile that is in line with the official data, and not taking some third party data and saying that the real manual is wrong.

What does affect the R-27E in DCS is that because of using the third party data, the boost/sustain ratio got weakened alot, so now the missile lost its initial acceleration, meaning that at closer ranges it now takes longer for it to hit. Meanwhile the manual gives a much stronger value for the boost, and also the PDF about the proposal of using the R-27 as a surface to air missile shows a much larger boost/sustain ratio than we have right now in DCS.

Edited January 14, 2022 by BlackPixxel

[Chizh]

4 часа назад, musolo сказал:

А почему русский парк ботов застыл в 1992 году? Ботов никто не запрещает ведь делать по закону? Хоть Су-27СМ, хоть Су-30МК, хоть Су-35 и Су-35С? Никаких легальных препон нет же, так ведь?  

Сразу после F-22, F-35, Rafale и Typhoon.

Но пока планов нет. В любом случае это не тема данной ветки.

[tavarish palkovnik]

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Edited April 23 by tavarish palkovnik

[tavarish palkovnik]

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Edited April 23 by tavarish palkovnik

[Chizh]

1 час назад, Gahab141 сказал:

Еврофайтер уже на горизонте. Так может хоть одного полусовременного бота добавим красным? Хоть тот же 31БМ, раз уж моделька уже есть

Это будет иметь смысл если в планах появится Р-37. 

[okopanja]

@Chizhgiven the fact, that more and more sources and calculations are done on the subject which contradict the DCS burn time of R-27ER, would it be possible to present your own calculation and sources, given the great work you did for AIM-120?

IMHO: this would be a way better way to prove/dispute the currently implemented DCS values, other than simply disputing the matter.

P.S. apologies for using English, but I prefer not to write using google translate.

[Chizh]

2 часа назад, okopanja сказал:

@Chizhgiven the fact, that more and more sources and calculations are done on the subject which contradict the DCS burn time of R-27ER, would it be possible to present your own calculation and sources, given the great work you did for AIM-120?

IMHO: this would be a way better way to prove/dispute the currently implemented DCS values, other than simply disputing the matter.

P.S. apologies for using English, but I prefer not to write using google translate.

When we done full wind-tunnel tests of the missile, we'll make a report as for AIM-120.

[tavarish palkovnik]

Just from the curiosity and my wish to see it, who will be kind to show me thrust diagram of R-27ER momentarily used in DSC. For example at 10km altitude. 


 

[BlackPixxel]

4 hours ago, tavarish palkovnik said:

Just from the curiosity and my wish to see it, who will be kind to show me thrust diagram of R-27ER momentarily used in DSC. For example at 10km altitude. 

Boost: 2.5 s with 5600 kg and 22.86 kg/s

Sustain: 5.5 s with 3500 kg and 14.8 kg/s

 

Ratio of boost to sustain thrust is a bit less than I would expect. The other simulated chart in the R-27 SAM proposal also suggests a higher boost/sustain ratio:

[tavarish palkovnik]

 

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Edited April 23 by tavarish palkovnik

[BlackPixxel]

The constant thrust in the two stages is just a simplification. So instead of having a complex curve, divide it into two sections and take the average values of those sections.

 

According to this table, the impulse per weight of the R-27ER should be 94.

So if you say that in DCS it carries to much fuel, does the its fuel mass have to be reduced while increasing the average ISP to keep that value at 94?

[tavarish palkovnik]

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Edited April 23 by tavarish palkovnik

[tavarish palkovnik]

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Edited April 23 by tavarish palkovnik

[BlackPixxel]

7 hours ago, tavarish palkovnik said:

No willing to contribute and discus 

I think you are the only one who knows the missile maths, so we cannot contribute to that, only read

You mean at higher altitude the rocket motors have more impulse than at lower altitudes? I wonder if that is simulated in DCS.

[tavarish palkovnik]

That’s true, impulse giving real thrust (расчетный импульс) should be calculated from specific impulse (удельный импульс) taking in consideration pressure values. Specific is like said usually given in ratio 40:1 and for example motor burning at 10km in buster phase is let’s say in ratio 100:0,265 (bars)

To correct myself, coefficient K in upper formula is more related to the looses in burning process, some of fuel mass will not contribute making thrust force and with K it is included.

To return on pressure, which value will be used for “pa” … it depends of how nozzle is executed and on expansion of gases. If gases will expand all to the atmospheric pressure (pressure at exit of nozzle is equal to atmospheric pressure) maximal thrust will be at disposal.

That’s why motors of space rockets in upper stages have nozzles as big as bells on churches so that gas can expand to the level of low pressure as it is up there.

Unfortunately for constructors of A-A missiles, they must make compromise with nozzles because those can be used at low level and high level flights.

Conclusion…thrust is variable and that is a fact.

Just as second fact and that is, drag coefficient in turbulent air flow, what is mostly case, for sure will be increasing with altitude (viscosity, Reynold’s number etc) 

Motor gives, drag takes!

[GGTharos]

16 hours ago, BlackPixxel said:

I think you are the only one who knows the missile maths, so we cannot contribute to that, only read

You mean at higher altitude the rocket motors have more impulse than at lower altitudes? I wonder if that is simulated in DCS.

It was certainly simulated for the 'Missile SFM' and it's likely so for the new FM they're using right now.   Missiles in 'SFM' had somewhere around +7% thrust at 12km compared to SL.  Don't quote me on the numbers though, it's been a very long time.

The change of altitude/pressure also changes the burn time along with manufacturing tolerance realities, and thus you have two sources for the cause of this range.

So any number you see for thrust, burn time etc should be followed by a question like 'at what pressure'.  

Edited January 22, 2022 by GGTharos

[tavarish palkovnik]

Great sentence…”at what pressure” 

Pressure is the one and main only one making significant differences. In my language, pressure is the one fu..ing chickens in the yard 

 

[Чарик80]

Основным оружием бомбардировщиков Ту-95МС и Ту-160 на протяжении нескольких десятилетий остается изделие Х-55 и его модификации, в т.ч. новейшая ракета Х-555. Нет такой ракеты как Х-65, пытались сделать Х-65С противокорабельную.

[Chizh]

11 часов назад, Чарик80 сказал:

Основным оружием бомбардировщиков Ту-95МС и Ту-160 на протяжении нескольких десятилетий остается изделие Х-55 и его модификации, в т.ч. новейшая ракета Х-555. Нет такой ракеты как Х-65, пытались сделать Х-65С противокорабельную.

Считай что Х-65 это Х-555.

[Чарик80]

Вот это Х-555

 

[Чарик80]

Х-65СЭ,разница очень заметна

[Vladimir_V_T]

После обновления Феникс перестал поражать цели с дистанций близких к максимальным. Понятное дело, что по маневрирующим целям стрелять с 70-ти миль - бесполезное занятие, но всякие Ту-160 и Ил-76 он раньше с 70-ти миль сбивал без проблем. Сейчас же ракета (при пуске с таких расстояний) теряет цель сразу после включения своей ГСН. Такое впечатление, что её ГСН не хватает угла обзора, т. к. она пытается пикировать на цель, практически, под прямым углом. К сожалению не могу выложить трек, т.к. на F-14 они у меня никогда не совпадают.