Ракеты в DCS

[Teknetinium]

3 minutes ago, Chizh said:

Above, I have already shown the incorrectness.

Not convincing, could you explain again? 

[Jack1nthecrack]

2 minutes ago, Chizh said:

Above, I have already shown the incorrectness.

Well, since we are basing things off of thought instead of facts now I can say that I THINK you are wrong Chizh. 

[Chizh]

1 minute ago, Jack1nthecrack said:

Well, since we are basing things off of thought instead of facts now I can say that I THINK you are wrong Chizh. 

Your right to think your way.

[Hoarfrost]

46 минут назад, Chizh сказал:

We have done a preliminary CFD research of the R-27ER. It turned out that in the game missile has less drag than the research shows.

Therefore, we will not change anything yet.

Опять -5, 15  процентов не в пользу Ред Тим)) Когда были произведены предварительные продувки р27эр? Что они ещё показали? Р27ЭР ещё медленнее должна быть)? Не проверяли  р77?

[Chizh]

33 minutes ago, Hoarfrost said:

Опять -5, 15  процентов не в пользу Ред Тим)) Когда были произведены предварительные продувки р27эр? Что они ещё показали? Р27ЭР ещё медленнее должна быть)? Не проверяли  р77?

Р-77 пока не проверяли.

Р-27ЭР продули, оказалось что ее сопротивление больше чем в игре. Пока в раздумьях. Будем уточнять геометрию модели, потом повторим. Но с большой вероятностью из Р-27ЭР выжать больше ничего не получится.

[Teknetinium]

24 minutes ago, Chizh said:

Р-77 пока не проверяли.

Р-27ЭР продули, оказалось что ее сопротивление больше чем в игре. Пока в раздумьях. Будем уточнять геометрию модели, потом повторим. Но с большой вероятностью из Р-27ЭР выжать больше ничего не получится.

As Pixxel mentioned, would not real tests from charts be more accurate then Produfka? 

Edited April 2, 2021 by Teknetinium

[FoxAlfa]

 

1 hour ago, Chizh said:

The R-27ER was blown through, it turned out that its resistance was greater than in the game. While in thought. We will refine the geometry of the model, then repeat it. But with a high probability, nothing else will be squeezed out of the R-27ER.

 

Could it be the difference between 3 sec burn at with a weaker sustain as in DCS instead of 2 sec burn with stronger sustain as in some tables that is causing the difference? 

The 2 sec burn would increase the range but reduce the speed, better long-range config in my opinion, R-27R should be for a closer range anyway. 

Current DCS config (if I am getting the math right) is 3sec at 7500kg and then 7sec at 1480kg vs 2sec at 7500kg and then 8sec at 2238kg. 
The energy sum is the same. 

 

Edited April 2, 2021 by FoxAlfa

[Hoarfrost]

1 час назад, Chizh сказал:

Р-77 пока не проверяли.

Р-27ЭР продули, оказалось что ее сопротивление больше чем в игре. Пока в раздумьях. Будем уточнять геометрию модели, потом повторим. Но с большой вероятностью из Р-27ЭР выжать больше ничего не получится.

А на сколько больше сопротивление? На сколько это может отразится на дальностях, и потери в маневрах? Получается что мы в ближайшее время получим р27эр с CFD?

Да ,а по 77-й если будет лофт, то по примеру 120-й с какого расстояния он будет, и с какого расстояния он не будет? Просто не понятно как это можно вписать в 50 км для мига, на разных высотах, и для j11 для большего расстояния. 

Edited April 2, 2021 by Hoarfrost

[Max1mus]

2 hours ago, Chizh said:

Р-77 пока не проверяли.

Р-27ЭР продули, оказалось что ее сопротивление больше чем в игре. Пока в раздумьях. Будем уточнять геометрию модели, потом повторим. Но с большой вероятностью из Р-27ЭР выжать больше ничего не получится.

 

Но как-то вы из AIM-120 +20-30% выжали, без лофта. Р-27Э и 120 были обы сделаны 7-8 лет назад. Как получилось, что это старое моделлирование было супер для Р-27Э, но американская ракета была на столько хуже чем сейчас?

 

Маленькая необъективность модели, скажим какой-то пессимизм со максимальный скорости, может сильно влиять на результат, тем выше высота пуска, чем хуже.

[nighthawk2174]

1 hour ago, FoxAlfa said:

 

 

Could it be the difference between 3 sec burn at with a weaker sustain as in DCS instead of 2 sec burn with stronger sustain as in some tables that is causing the difference? 

The 2 sec burn would increase the range but reduce the speed, better long-range config in my opinion, R-27R should be for a closer range anyway. 

Current DCS config (if I am getting the math right) is 3sec at 7500kg and then 7sec at 1480kg vs 2sec at 7500kg and then 8sec at 2238kg. 
The energy sum is the same. 

 

 

Problem is that if you keep the fuel weight the same for each stage this would bring the ISP for the first stage unrealistically low (~156sec) and the ISP for the second stage way too high (~354sec). Which unless the current fuel distribution between boost and sustain is also wrong makes the second option impossible.  Which begs the question where did the current fuel/thrust characteristics come from?

 

Проблема в том, что если вы сохраняете вес топлива одинаковым для каждой ступени, это приведет к тому, что ISP для первой ступени будет нереально низким (~156 с), а ISP для второй ступени-слишком высоким (~354 с). Что, если только текущее распределение топлива между наддувом и поддержанием также не является неправильным, делает второй вариант невозможным. В связи с этим возникает вопрос, откуда взялись нынешние характеристики топлива/тяги?

[Max1mus]

Пустите Р-27ЭР и AIM-120/AIM-7. Сравните скорости ракет до конца работы двигателей. По моему это более интересно чем сопротивление.

[FoxAlfa]

14 hours ago, nighthawk2174 said:

Problem is that if you keep the fuel weight the same for each stage this would bring the ISP for the first stage unrealistically low (~156sec) and the ISP for the second stage way too high (~354sec). Which unless the current fuel distribution between boost and sustain is also wrong makes the second option impossible.  Which begs the question where did the current fuel/thrust characteristics come from?

Yeah, true, ISP are off but the stage weights also seam arbitrary slaped on.

 

I did come across 2-8 sec split instead of 3-7 on other misslie forums and sources too.

 

Some of them were talking about new 2014 version with 9000kg stage instead of 7500kg... I didn't find the claim credible enough to share...

 

All in all 2-8 gives higher end speed at longer range but it takes longer to get there so I am not sure what is better.

 

If you were supposed to use R-27R at closer range I would go for that configuration, if the R-27ER was supposed to replace the R-27R I would go for 3-7... 

 

 

Edited April 3, 2021 by FoxAlfa

[Chizh]

17 hours ago, FoxAlfa said:

 

 

Может ли разница между 3-секундным прожигом с более слабым сустейном, как в DCS, а не 2-секундным прожигом с более сильным сустейном, как в некоторых таблицах, является причиной разницы? 

Двухсекундный ожог увеличит дальность, но снизит скорость, лучшая дальнобойная конфигурация, на мой взгляд, R-27R в любом случае должен быть для более близкой дистанции. 

Текущая конфигурация DCS (если я правильно понимаю) составляет 3 секунды при 7500 кг, затем 7 секунд при 1480 кг против 2 секунд при 7500 кг и затем 8 секунд при 2238 кг. 
Сумма энергии такая же. 

 

 

You can try different configurations by changing the parameters in the missile script missiles_data.lua

 

17 hours ago, Hoarfrost said:

А на сколько больше сопротивление? На сколько это может отразится на дальностях, и потери в маневрах?

Скажем в районе 10%. В любом случае если мы применим коэффициенты рассчитанные через CFD ракета будет летать немного медленнее и ближе.

 

Quote

Получается что мы в ближайшее время получим р27эр с CFD?

Пока нет. Нужно будет еще уточнять и выверять геометрию чтобы повторить опыты.

 

Quote

Да ,а по 77-й если будет лофт, то по примеру 120-й с какого расстояния он будет, и с какого расстояния он не будет? Просто не понятно как это можно вписать в 50 км для мига, на разных высотах, и для j11 для большего расстояния. 

Не могу ничего сказать. Про это ничего не известно.

 

[Chizh]

16 hours ago, Max1mus said:

 

Но как-то вы из AIM-120 +20-30% выжали, без лофта. Р-27Э и 120 были обы сделаны 7-8 лет назад. Как получилось, что это старое моделлирование было супер для Р-27Э, но американская ракета была на столько хуже чем сейчас?

Потому что изначально все коэффициенты для AIM-120 были поставлены от балды. Именно из-за того что по ней было больше всего неопределенностей, мы и стали ее исследовать в первую очередь.

 

 

[HWasp]

18 hours ago, FoxAlfa said:

 

 

Could it be the difference between 3 sec burn at with a weaker sustain as in DCS instead of 2 sec burn with stronger sustain as in some tables that is causing the difference? 

The 2 sec burn would increase the range but reduce the speed, better long-range config in my opinion, R-27R should be for a closer range anyway. 

Current DCS config (if I am getting the math right) is 3sec at 7500kg and then 7sec at 1480kg vs 2sec at 7500kg and then 8sec at 2238kg. 
The energy sum is the same. 

 

 

 

I've tried to do some very rough basic calculations:  (320 m/s at launch at 1000m)

 

- Current situation with the 3/7 setup : missile reaches around 1040 m/s, 3 seconds after launch, then 7 seconds later it ends up flying at around 935 m/s when fuel runs out

 

- With the 2/8 setup based on this doc: the missile would be around 800 m/s at 2 seconds with the 1st stage, then it would continue to accelerate reaching 1050 m/s 8 sec later.

 

trying to calculate the distances:

 

-currently missile is out of fuel 9 km from launch at 935 m/s speed

 

- I think with 2/8 setup: it would be out of fuel at 8,7 km from launch, but traveling at 1050 m/s  -----> the missile would travel around 1,2 km while decelerating from 1050 to 935 m/s

 

So overall I guess the missile would burn out at 0,3 km less distance from launch, but gain +1,2 km glide, so overall it could be around 0,9 km + flyout distance. 

 

It seems DCS uses a constant average acceleration for the first 3 seconds, and I used that to guess the speeds for the 2/8 config, so maybe the 1st stage speed would be lower still with the 2/8 setup, only around 760 m/s instead of 800 m/s

 

In this case gain would be lower, maybe just a couple hundred meters flyout distance.

Edited April 3, 2021 by HWasp

[Hoarfrost]

1 час назад, Chizh сказал:

Не могу ничего сказать. Про это ничего не известно.

 

Будет тоже проведена большая работа по р77? После р27эр? В этом году?

[FoxAlfa]

1 hour ago, HWasp said:

 

I've tried to do some very rough basic calculations:  (320 m/s at launch at 1000m)

 

- Current situation with the 3/7 setup : missile reaches around 1040 m/s, 3 seconds after launch, then 7 seconds later it ends up flying at around 935 m/s when fuel runs out

 

- With the 2/8 setup based on this doc: the missile would be around 800 m/s at 2 seconds with the 1st stage, then it would continue to accelerate reaching 1050 m/s 8 sec later.

 

trying to calculate the distances:

 

-currently missile is out of fuel 9 km from launch at 935 m/s speed

 

- I think with 2/8 setup: it would be out of fuel at 8,7 km from launch, but traveling at 1050 m/s  -----> the missile would travel around 1,2 km while decelerating from 1050 to 935 m/s

 

So overall I guess the missile would burn out at 0,3 km less distance from launch, but gain +1,2 km glide, so overall it could be around 0,9 km + flyout distance. 

 

It seems DCS uses a constant average acceleration for the first 3 seconds, and I used that to guess the speeds for the 2/8 config, so maybe the 1st stage speed would be lower still with the 2/8 setup, only around 760 m/s instead of 800 m/s

 

In this case gain would be lower, maybe just a couple hundred meters flyout distance.

 

Hey, thank you for doing calculations! I also got roughly ~10% range gain, but effective range against maneuvering target should be bigger ~10% since the missile in a better drag speed range longer.  Alos it would give that 10-15% range gain we are all hovering around.

So, my proposal for the change is to change R-27ER to 2, 7500 - 8, 2238 configuration and keep the current drag.

That would make sure that missile passes the graph range at all altitudes with some energy to spare, also increase its effective range without influencing the straight line one substantial. 

 

the trade-off is lower max speed of the missile... but again, ER wasn't made out performer R close range, but to go the distance.  

 

Of course, independent bugs with EO and Chaff should be fixed as well. 


 

Edited April 3, 2021 by FoxAlfa

[Max1mus]

52 minutes ago, FoxAlfa said:

 

 

the trade-off is lower max speed of the missile... but again, ER wasn't made out performer R close range, but to go the distance.  
 

 

ER is quoted to outspeed most missiles in terms of max speed. I think ED needs to look at the rocket motor simulation of the missile again.

[FoxAlfa]

3 minutes ago, Max1mus said:

ER is quoted to outspeed most missiles in terms of max speed. I think ED needs to look at the rocket motor simulation of the missile again.

Faster you go, more drag hurts you...when you have limited energy supply you don't want to overspeed it but keep it in certain speed range to get optimal performance.

[Max1mus]

1 minute ago, FoxAlfa said:

Faster you go, more drag hurts you...when you have limited energy supply you don't want to overspeed it but keep it in certain speed range to get optimal performance.

It makes absolutely no sense for R-27R to outspeed the R-27ER under any circumstances. For the same reason why AIM-54MK60 will outspeed the AIM-54MK47, and why AIM-54 will outspeed an AMRAAM. Maybe acceleration is a bit slower on ER:

But then by my understanding, a heavier missile will also carry more energy, which will take longer to bleed off, assuming the same shape.

[FoxAlfa]

4 minutes ago, Max1mus said:

It makes absolutely no sense for R-27R to outspeed the R-27ER under any circumstances.

Do the math, it won't outspeed it anywhere. 2-8 where just spread better the energy it already has... and also some sources point it uses 2-8 spread in RL. 

Edited April 3, 2021 by FoxAlfa

[Max1mus]

1 hour ago, FoxAlfa said:

the trade-off is lower max speed of the missile... but again, ER wasn't made out performer R close range, but to go the distance.  

 

Then i dont understand what you mean here

[HWasp]

ER could do maybe even 5000km/h down low, if all the fuel was used by the first stage only. (I'd like to try that tbh  ) Probably the missile would even fall apart at those speeds, no idea how much heating and pressure that thing could even tolerate...

[FoxAlfa]

22 minutes ago, Max1mus said:

 

Then i dont understand what you mean here

Well, 3-7 gives you fast accelerating missile with vastly better performance than R-27R sub 10-15 km, but pays the price with lower speed/maneuverability at range.
2-8 gives only better missile sub 10-15 km but better performance down the range.

All in all 3-7 would make sense if R-27ER was to replace R since you get more bang for the buck in the same range gap, 2-8 makes sense if you want the missile that has better performance down the range. 

 

Edited April 3, 2021 by FoxAlfa

[Max1mus]

23 minutes ago, HWasp said:

ER could do maybe even 5000km/h down low, if all the fuel was used by the first stage only. (I'd like to try that tbh  ) Probably the missile would even fall apart at those speeds, no idea how much heating and pressure that thing could even tolerate...

It would still be better than now. The ER does not benefit from this 7-8 second sustain motor at all, it gains practically no new speed...
 

Spoiler

Compare this to the AMRAAM or AIM-7 - it keeps happily accelerating to mach 4-5.

This seems like some 10 year old trick ED used to control maximum speed of missiles. If i remember right, the old AIM-120 would behave like this too, hitting a top speed and keeping it until the motor burned out.

Edited April 3, 2021 by Max1mus