Ракеты в DCS

[milit]

4 минуты назад, Маэстро сказал:

requested TAS

"Required TAS" seems to be closer

[tavarish palkovnik]

However I consider all these velocity values on ILS or HUD as IAS-indicated airspeed, current and required IAS, текущая приборная скорость и заданная приборная скорость.

From required IAS in this case 790km/h can be assumed that speed of target is around 640km/h=790-150.

 

If algorithm of missile trajectory is done in missile's absolute coordinate system, it means with missile vs target true speed, then you can not use speed values indicated on ILS and such algorithm.   

 

PS...and maybe I'm totally wrong and values while RLPK is active are indeed TAS 

Edited June 23, 2021 by tavarish palkovnik

[Silver_Dragon]

12 hours ago, BlackPixxel said:

It seems so

 

Su-27SK, no a Su-27S

[Chizh]

16 часов назад, BlackPixxel сказал:

You will propably find out that when correctly recreating the scene from the HUD photo the missile in DCS will "overperform", but that is just because the DLZ in the real Su-27 shows less ranges than the charts as additional safety margin. The Su-27 DLZ simulator that Chizh has shows the same behaviour.

It seems to me that you are confusing something. The DLZ simulator shows approximately the same numbers as in the nomogram.

[BlackPixxel]

1 minute ago, Chizh said:

It seems to me that you are confusing something. The DLZ simulator shows approximately the same numbers as in the nomogram.

 

DLZ sim shows about 15 % less than the chart.

[Chizh]

11 минут назад, BlackPixxel сказал:

 

DLZ sim shows about 15 % less than the chart.

Why do you think so?

[BlackPixxel]

2 minutes ago, Chizh said:

Why do you think so?

 

Look at your own posts and compare the range to the chart.

 

Roughly 15% less each time.

[Chizh]

Not so easy.

At altitudes of 5 and 10 km, the simulator shows a little less. But at an altitude of 1 km, it is shown close to the nomogram.

[BlackPixxel]

[Chizh]

R-27ER

Altitude 1 km. Head-on.

Speed: 1100

• Chart: 28
• Sim: 27.89

Speed: 900

• Chart: 25.5
• Sim: 25.39

 

 

[BlackPixxel]

I compared rear hemisphere, the HUD photo shows rear hemisphere.

[FoxAlfa]

Yes, those 13-15% seem to be consistent, and if we add overmatch for the chart we would get the same number.... R-27R and T got similar improvements after changes, so maybe adjustment in that percentage would be good?

it would be match and or overmatch the chart by just a bit in 1k and 5k range like it should.... for 10k we are getting in battery and other limits problem.

[Chizh]

6 минут назад, BlackPixxel сказал:

I compared rear hemisphere, the HUD photo shows rear hemisphere.

The chart is very inaccuracy in the rear at 1 km. Curve is not reasonable.

Nevertheless, in the forward hemisphere, the data are almost the same. This suggests that your 15% hypothesis is not valid.

[FoxAlfa]

34 minutes ago, Chizh said:

The chart is very inaccuracy in the rear at 1 km. Curve is not reasonable.

Nevertheless, in the forward hemisphere, the data are almost the same. This suggests that your 15% hypothesis is not valid.

With all due respect, to quote you from our missile discussion: "Think about what limits the range of a missile when launched into a tail-on?
There is only one limitation - the energy of the missile, that is, the range at which the missile can intercept the target."

And you were completely right, same here I would preferer that missile matched the tail-on range instead of head-on.

I will run some test to confirm.

Edited June 23, 2021 by FoxAlfa

[Max1mus]

1 hour ago, FoxAlfa said:

Yes, those 13-15% seem to be consistent, and if we add overmatch for the chart we would get the same number.... R-27R and T got similar improvements after changes, so maybe adjustment in that percentage would be good?

it would be match and or overmatch the chart by just a bit in 1k and 5k range like it should.... for 10k we are getting in battery and other limits problem.

 

What makes the least sense is that the R-27R was made to match the same graphs, but with the ER its suddenly inaccurate...

[Max1mus]

9 hours ago, tavarish palkovnik said:

I truly belive that speed values on this ILS are not true speed but indicated speed.

Velocity 1040km/h or 290m/s should be 355m/s of true speed and if 790km/h or 220m/s is aimed that could mean that velocity of target is around 640km/h (180m/s). This is again not true speed of target which at 5400m should be 230m/s.

 

With those two values, 355m/s against 230m/s, and with checking trajectory, I'm getting that in second 36th missile will have it's true speed of 390m/s and it will travel for 27900 m.

27900 - 36*230 = 19620m

 

In case 1040km/h is true speed and accordingly 640km/h is true speed of target....after 40 second missile will have speed of 355m/s, will travel 28400m -> 28400 - 40*180 = 21200m 

 

With your scenario, we get the same result.
HUDfootage_polkovnik_scenario.trk

Missile has the necessairy additional speed 2.3km behind the target. Thats over 10%. Plus the 2-3G energy reserve minus maybe 100 km/h closure speed because the target is slightly cranking. But even without any provisions, the missile falls behind here.

[Chizh]

3 часа назад, FoxAlfa сказал:

With all due respect, to quote you from our missile discussion: "Think about what limits the range of a missile when launched into a tail-on?
There is only one limitation - the energy of the missile, that is, the range at which the missile can intercept the target."

And you were completely right, same here I would preferer that missile matched the tail-on range instead of head-on.

I will run some test to confirm.

 

You don't seem to really understand what the problem is. Look at the strange break in the curve at 1 km. This is a freehand edit, not reasonable.

 

Please see

 

And another nonsense of the ranges disbalance

 

These nomograms can be used for a qualitative assessment, but the exact values should not be grabbed here. They are not accurate.

 

[FoxAlfa]

12 minutes ago, Chizh said:

You don't seem to really understand what the problem is. Look at the strange break in the curve at 1 km. This is a freehand edit, not reasonable.

No, I completely agree that freehand has deficiencies. Just looking space between 10km and 20km is different 20 and 30 and etc. 

 

I am commenting track and RL picture.

 

Missile in DCS can't reach the target under those circumstances and this closes we can get to tail-on RL picture. 

Also, manual instructing the pilot to fire two missiles one on Rmax1 and other on Rmax2 also point that missile should be at least some reserve energy left.

So, since we all agree the graph has deficiencies, can you reevaluate missile performance based on this picture once you return from you vacation? 





 

[Max1mus]

1 hour ago, Chizh said:

You don't seem to really understand what the problem is. Look at the strange break in the curve at 1 km. This is a freehand edit, not reasonable.

 

Please see

 

And another nonsense of the ranges disbalance

 

These nomograms can be used for a qualitative assessment, but the exact values should not be grabbed here. They are not accurate.

 

High altitude - battery life. And less drag, missile can travel at slower speeds longer. Speed difference makes a bigger gap.

Low altitude - Missiles with big rocket motors over slick designs will have a smaller gap. Less time spent at slow speeds, more at high speeds. Compare it with the AIM-54.

If anything, the inconsistency is that there is not a way bigger gap at high altitude than at 5km. The high missile should spent more time at slow speeds. But the explanation is battery life being the limitation, not energy.

Edited June 23, 2021 by Max1mus

[Chizh]

1 час назад, FoxAlfa сказал:

Missile in DCS can't reach the target under those circumstances and this closes we can get to tail-on RL picture. 

Please describe clear circumstances so I can check. 

 

54 минуты назад, Max1mus сказал:

High altitude - battery life. And less drag, missile can travel at slower speeds longer. Speed difference makes a bigger gap.

Low altitude - Missiles with big rocket motors over slick designs will have a smaller gap. Less time spent at slow speeds, more at high speeds. Compare it with the AIM-54.

If anything, the inconsistency is that there is not a way bigger gap at high altitude than at 5km. The high missile should spent more time at slow speeds. But the explanation is battery life being the limitation, not energy.

 

You are trying to explain mistakes that have arisen from the  manipulation of this nomogram.
The DLZ simulator gives in this case the values that are more correct.

 

Altitude = 1 km, rear hemisphere.

• Speed = 900 km/h
• Max Range = 8.47 km.

 

• Speed = 1100 km/h
• Max Range = 7.95 km.

[Max1mus]

27 minutes ago, Chizh said:

Please describe clear circumstances so I can check. 

 

You are trying to explain mistakes that have arisen from the  manipulation of this nomogram.
The DLZ simulator gives in this case the values that are more correct.

 

Altitude = 1 km, rear hemisphere.

• Speed = 900 km/h
• Max Range = 8.47 km.

 

• Speed = 1100 km/h
• Max Range = 7.95 km.

What does the DLZ simulator show for this situation?

[BlackPixxel]

In all rear hemisphere cases (1 km, 5 km, 10 km) the DLZ sim shows 15% less than the chart, so we can assume that the DLZ has some extra safety margin.

 

The "errors" in the hand drawing of the chart can not result in the missiles having consistenty 15% more range in the chart than in the sim, in all three altitudes.

[FoxAlfa]

2 hours ago, Chizh said:

Please describe clear circumstances so I can check

Max1mus posted the picture and track worth investigating... DCS missiles doesn't reach target in those circumstances.

1 hour ago, Max1mus said:

What does the DLZ simulator show for this situation?

 

[Max1mus]

5 hours ago, Chizh said:

You don't seem to really understand what the problem is. Look at the strange break in the curve at 1 km. This is a freehand edit, not reasonable.

 

Please see

 

And another nonsense of the ranges disbalance

 

These nomograms can be used for a qualitative assessment, but the exact values should not be grabbed here. They are not accurate.

 

As a little experiment, i tested the AIM-54A Mk60 in game under the same conditions (In the rear hemisphere). Cutoff speed is target speed+150 m/s. /EDIT: 150m/s!



The lowest value has the smallest difference, medium bigger and highest has the biggest. It should be like this on the R-27ER too.

The 60s battery life just stops it from following that trend up into very high altitudes. (R-27ER TOF for the slow target at 10km is around 55s). And some slight maneuvers would increase that time to 60, even if it had less drag. Remember what the Su-35 pilot said about reserve energy for maneuvering.
 

And infact, your in game R-27ER as tested by Maestro follows that trend precisely. Look at it. The gaps are like on the chart in game. Its simply worse than on the chart. But not different.
 

Spoiler

 

Edited June 23, 2021 by Max1mus

[Chizh]

6 hours ago, FoxAlfa said:

Max1mus posted the picture and track worth investigating... DCS missiles doesn't reach target in those circumstances.

 

What is target params?