Ракеты в DCS

[nighthawk2174]

58 minutes ago, TaxDollarsAtWork said:

Then why did one of your sources say this

 

 

"

Buyers of Russian aircraft may soon be left without the R-73 melee missiles, which "catch up" with the enemy aircraft due to the infrared homing head. These missiles work on the "fire and forget" principle and remain one of the most formidable weapons of destruction of aircraft. The most recent modifications of the rocket (RMD-2) have an all-aspect multi-site seeker with a dual-band cooled photodetector, the sensitivity of which is twice as high as the basic version. These devices, which are called MK-80 "Mayak", have been produced by the Kiev plant "Arsenal" since Soviet times. "

I've seen the dual band on some sites refereed to as the "MK-80M"

[Chizh]

2 часа назад, TotenDead сказал:

Да, занятно, конечно, что тебя так задело, что я тебе указал на оффтоп, что ты мне 20 баллов накинул -_-

Могу еще

1 час назад, TaxDollarsAtWork сказал:

Then why did one of your sources say this

 

 

"

Покупатели российских самолетов могут в ближайшее время остаться без ракет ближнего боя Р-73, которые «догоняют» самолет противника за счет инфракрасной головки самонаведения. Эти ракеты работают по принципу «пустил и забыл» и остаются одним из самых грозных средств поражения авиатехники. Самые свежие модификации ракеты (РМД-2) имеют всеракурсную многоплощадочную головку самонаведения с двухдиапазонным охлаждаемым фотоприемником, чувствительность которого вдвое выше базовой версии. Эти устройства, которые называются МК-80 «Маяк», еще с советских времен производит киевский завод «Арсенал»."

This is a misinterpretation by journalists. MK-80 seeker has one spectrum range.

[TotenDead]

12 часов назад, Chizh сказал:

Могу еще

 

Спасибо, я их коллекционирую

[Max1mus]

On 6/18/2021 at 10:39 AM, Маэстро said:

Hello, I'm not in charge of development plans.

Regarding R-27ER range... we already say that unfortunatley chart quality is not very good. There is no any chace to perfectly match this charts with any realistic drag and thrust values. Say, if we adjust missile to match chart at 5km rear hemisphere it wont match all other points! Current drag values for 27ER/ET is good compromise to be close to all chart  points at a time.

Here another one chart with new/old 27ER performance comparison. As you may see  missile achive official numbers at least at 10km altitude
 

It still underperforms in 2/3 areas, and im not sure this even includes the energy reserve (if its not factored in, its still all 3 areas), hardly a good compromise. A good compromise would be the adjustments GGTharos suggested, it would match 1km and 5km. At 10km, i guarantee you that with battery life and the 150+ m/s energy reserve factored in, you would end up not far from the current value.

A different question, you did have this chart - why did the missile underperform in all 3 areas for this many years?

Edited June 20, 2021 by Max1mus

[GGTharos]

7 minutes ago, Max1mus said:

It still underperforms in 2/3 areas, and im not sure this even includes the energy reserve (if its not factored in, its still all 3 areas), hardly a good compromise. A good compromise would be the adjustments GGTharos suggested, it would match 1km and 5km. At 10km, i guarantee you that with battery life and the 150+ m/s energy reserve factored in, you would end up not far from the current value.

A different question, you did have this chart - why did the missile underperform in all 3 areas for this many years?

 

 

This tuning has to do with the old FM.  The new FM should be able to better match all the ranges, but it's not so easy - the old FM simply cannot though, and IMHO it has a lot to do with the way the drag cure is represented.

Old FM is not possible to match anything but one of the ranges, all others will be off.  Matching 1km should bring yo close to the 5km but you cannot tune 1km AND 5km (or 10km).  You can only tune one of them.

 

It has been requested a long time ago to tune for the low altitude with old FM, ED never did this.  They may or may not now, and either way only the new FM can bring a clearer view and resolution to this problem as a whole.

 

You can basically ignore/forget the 150m/s and 2-3g stuff when it comes to this.  You cannot simultaneously tune all of this in the old FM - you can try and maybe get close, but it just doesn't contain enough information for this.

If you look at the new FM, it's basically simulating 10x the variables just for the FM, along with new systems like the autopilot and actuator controls etc.

[Max1mus]

2 minutes ago, GGTharos said:

It has been requested a long time ago to tune for the low altitude with old FM, ED never did this.

My question was why.

[Max1mus]

12 minutes ago, GGTharos said:

You can basically ignore/forget the 150m/s and 2-3g stuff when it comes to this.

Why? It literally proves that "possible launch" means the missile must be able to overshoot the target with a significant amount of extra energy.

[Chizh]

25 минут назад, Max1mus сказал:

A different question, you did have this chart - why did the missile underperform in all 3 areas for this many years?

 

Because we did not take into account the speed required to proximity fuse work, 150 m/s. 

[Max1mus]

1 minute ago, Chizh said:

Because we did not take into account the speed required to proximity fuse work, 150 m/s. 

Do the markings posted by Maestro respect that required speed, or is that just pure kinematic ability?

[Chizh]

1 минуту назад, Max1mus сказал:

Why? It literally proves that "possible launch" means the missile must be able to overshoot the target with a significant amount of extra energy.

R-27 can do it now. It has a good amount of energy on the target.

[Max1mus]

12 minutes ago, Chizh said:

R-27 can do it now. It has a good amount of energy on the target.

What i am asking about is these markings. They compare the old and new missile capabilities. Is that kinematic ability MINUS >150 m/s or ability to destroy the target in DCS?

PS: No, it cannot. Ive given you tracks showing the missile fall behind the target well within the declared range. I dont know what else to say.

Edited June 20, 2021 by Max1mus

[Chizh]

OK, I'll see it in a week when I return from vacation to Moscow.

[Max1mus]

On 5/12/2021 at 7:26 PM, Chizh said:

Еще раз. И для GG тоже.

у старых AIM-9 было очень заметное ограничение на угол целеуказания. Даже у ракет 9L/M этот угол составляет +-28 градусов, против 45 градусов поворота координатора на сопровождении.

In DCS, the AIM-7M has significantly less range than the R-530D, especially at the 0.5km mark. And the DCS gap between a non-lofted AIM-120B(A) and the AIM-7 is also bigger than described in this document.

Edited June 20, 2021 by Max1mus

[dundun92]

1 minute ago, Max1mus said:

non-lofted AIM-120B(A)

Just a note, but as far as I can tell the whole AIM-120A cant loft thing appears to be a myth. I was under that impression as well, but after doing some digging, I simply cant find any sources supporting this claim. For example, weapons manuals for the F-16 mention the loft steering cues without making any distinction between the 120A and B, same with the F-18 weapons manual.

[Jack1nthecrack]

Maximus could you post some tracks of the R-27 missing the 150 m/s closure rate at the specified ranges?

[nighthawk2174]

2 hours ago, dundun92 said:

Just a note, but as far as I can tell the whole AIM-120A cant loft thing appears to be a myth. I was under that impression as well, but after doing some digging, I simply cant find any sources supporting this claim. For example, weapons manuals for the F-16 mention the loft steering cues without making any distinction between the 120A and B, same with the F-18 weapons manual.

The early 90's F15 weapons manual also makes mention of lofted steering cues for the amraam.

[Max1mus]

Then the russians were either horribly wrong with their estimations on lofting missiles, or something is up with non-draggy missiles at very high altitudes in DCS. But the range relationship in that document between 530, 7M and 120 is not represented in DCS. The difference between 7M and 530 is even reversed.

The fact that the AIM-9M outspeeds and outranges the AIM-7MH at altitudes like 40.000ft adds more questions.


@Jack1nthecrack Check Maestros post from a few pages ago (last page?) He did the testing and marked the points on the chart. I couldnt find the original posts so i will just re-post them:

ER_falls_behind (1).trk - 1000m in ZPS, around 9.6km (less than on the graph). Missile even falls behind.
I skipped 5000m, but the differences there are also extreme
10.000m_not_enough_energy_fast.trk - 10000m. Missile hits, but with not enough energy reserve, and the launch distance also seems to be a bit within the chart range.
10.000m_battery_life.trk -  10000m This one shows how close the ER is to running out of battery life up there (i shot slightly further here and it already ran out). A bit less drag - and it would not be limited by energy, but by electronics (it might barely already be). This could very well explain the smaller gap between fast and slow speed at high altitude, which from what i understood, is the reason why some in ED do not believe the graphs.

Edited June 21, 2021 by Max1mus

[GGTharos]

36 minutes ago, Max1mus said:

The fact that the AIM-9M outspeeds and outranges the AIM-7MH at altitudes like 40.000ft adds more questions.

 

It's really not that surprising.  The sidewinder's rocket motor is all-boost and at a higher acceleration than even the AIM-7s own boost stage. 

As a projectile, the AIM-9M has the ability to gain a lot of speed (well over M3) and is limited by available power.

 

At high altitude the AIM-7's sustain stage plays a role, but not quite as large ... think of it this way.

10g for ~ 3.5 sec + 2g for ~ 11 sec

vs

14g for ~5sec.

 

The sustain motor won't get you quite to the same peak as a boost motor for the simple reason that it's going to get a bigger acceleration fraction eaten up by air resistance.  You would certainly get the lines to cross on a graph at some point, but not with these two missiles at high altitude.

Edited June 21, 2021 by GGTharos

[BlackPixxel]

Aim-9M is missing the wobbly movement in DCS that would limit its kinematic performance a bit.

Edited June 21, 2021 by BlackPixxel

[GGTharos]

We have flyout graphs for the AIM-9.   No amount of mentioning 'wobbly movements' or anything else like that makes any sense.  Compare to those graphs and see if its different.

[tavarish palkovnik]

For all skeptics  to try show how difficult is to calculate kinematic and dynamic trajectory of just single one rocket not having enough inputs. And after that, multiple it with all rocket types in DCS…give those guys huge credit for their work.

 

So, R-27ER in horizontal flight. To do this mathematic easiest is to equalize vector and value of weight with vector and value of lift force. With assumed thrust to time function and with this postulate G=Y , coefficient Cn can be calculated. With having Cn and with assumed Cy function now angle of attack can be calculated. Lifting due to aerodynamic surfaces rotations I haven’t included, even without it job is complicated.

 

With having angle of attack which in this postulate is always present next step is to increase Cx coefficient due to fact of such “nose up” flight. For that again you have to estimate corrective coefficient function, let’s call it Kt f( Alfa ). 
Cx is also estimated, I involved i58 as 1,25 in active and 1,5 in passive respectively. 
And haven’t change it with altitude, as it should be changed, approximately each 5 km makes increase of roughly 5%. By now lot of assumptions, estimations and free will neglecting.

 

Anyway when everything is arranged machine is ready to keep rolling and to calculate trajectories.

 

 

 

This is at 5 and 10km with v0 500 and 600m/s respectively. While second one is quite corresponding to what in that time major Krupennikov gave us, first one is not. Forgot to say, thrust is also in function of altitude what I neglected in this math as well. I expected to be opposite if I matched values at 10km but never mind. Want to say that I think increase of Cx with altitude should take more then what increase of thrust with altitude will give.

 

Machine keeps further, now with 250 and 305m/s at 1-5-10km. These are v-t and D-t diagrams, velocity and travel with time, for v0=300m/s at 1, 5 and 10 km.

 

 

 

 

After for a while and observing results although not matching fully I still found something what I should call pattern. 
Seams that for 1 and 5 km altitudes value of available overload and let’s take it as 3g is limitation. Fun fact is that at 10km according to this math of mine available overload of 3g fits to 60 seconds, means dead this or that way.

Available overload calculated with same assumed Cy f(M) and with assumed 12 deg maximal allowable angle of attack. Assumptions, assumptions and assumptions 

And plus one more, shooting in ZPS should be with +150km/h in favor of fighter to get close to what diagram of launching zones present.

 

 

Easy job? No, it’s not an easy job to get even some kind of results. Easier is to comment and I would be very pleased for comments about this, comments of any kind.

 

 

[GGTharos]

Just a quick comment @tavarish palkovnik, I'm reasonably certain that you're good up to 17 degrees of AoA for mid-body wing controlled missiles of this era

[tavarish palkovnik]

All right, Cy function to get down a bit and to have Cn with 17 deg at time when needed.

Fact is that obtaining of horizontal flight is with reasonable angles much under 12 or 17 so increased or reduced Cy will not affect a lot induced Delta Cx and by that velocity in function of time.

[tavarish palkovnik]

And by the way, rocket having such wings near to the center of gravity usually and by purpose doesn’t do high angle of attack compared to others. I doubt is it even 10 in this particular case.

Edited June 21, 2021 by tavarish palkovnik

[GGTharos]

I agree with you, just stating some numbers I have read about other similar missiles.

 

For canard controlled missiles you get higher AoA available, and even more for tail-controlled.  I doubt that in any case they can exceed 30 (although the R-77 is rumored to be controllable at 150 which is weird)