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Missile Dynamics - A discussion

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Kuky

Kuky

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Just did 2 tests in latest build

 

Su-27 armed with 2x R-27ER flying at 17000m at around 1.9Mach

Enemy is F-14A also flying at 17000m around 1.8Mach

 

So not quite 20km altitude and Mach 4 closure, but close enough I think

 

F-14A pops up on Radar in High PRF Search Mode (not TWS) around 120Km... I could achieve STT lock at around 100km.

 

First test:

R-27ER fired at Rmax and second R-27ER little bellow it so, 100km and 90km respectively.

 

F-14A did try to evade both shots (typical AI mode to dive in a beam and accelerate and both missiles did not hit.

 

Both R-27ER still had little over 2200kmph speed as they passed the F-14A not close enough to trigger the fuse

 

Second Test:

R-27ER fired at 80km and 70km distance... first missile did hit, it was pretty much a direct hit with F-14A going fully into pieces.. second R-27ER no longer had anything to do and was unhappy :D

 

My conclusion is:

 

Radar should be able to pick up the F-14A further out as at such closure rate and high up and no clutter... seems that regardless of altitude and closure speed the Radar range is exactly the same which definitely isn't right and hopefully some day we should get it better modeled.

 

The Rmax of the R-27ER is close to what you can find on the net but now depends to see how AIM-120 stacks up, if it has much more range than R-27ER than this is definitely screwed up (I'll do next F-105C with 2x AIM-120C against Su-27 at same altitude and speed)

 

The R-27ER, although I feel it had enough speed at final stage when closing to target (it still had little over 2000kmph so around mach 1.8) it did not hit, and I guess in reality maybe it shouldn't hit as target did maneuver, BUT I also think because the target went into a dive and gravity was still assisting the missile and with that speed remaining in the missile it really should have hit.

 

The second R-27ER fired at 90Km I fee should have hit, but it didn't. Again fired at shorter range than Rmax and target only went into dive and beam, the missile still had enough speed. I would call this very questionable outcome. Also, both missiles fired at 100km and 90km range I feel were flying/aiming too far behind. If they were leading a little more ahead they would definitely hit.

 

The R-27ER fired at 80km had no issues hitting that F-14A and slammed right into it.


Edited by Kuky

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Kuky

Kuky

Posted
Posted (edited)

I just did F-15C and I think both F-15C and Su-27 radar detection/lock ranges are pretty much the same.

 

The AIM-120C though when fired from Rmax went into loft trajectory and actually had less chance of hitting the Su-27 for two reasons:

 

The lofting was very high (I think they went above 21km alt and Su-27 was more smart in how to evade than F-14A (maybe its because of different missile fired at them?). While the F-14A only went into beam and dive (and little pull/roll in between), I think because after I fired the 2x AIM-120C and went into slight dive to keep better STT lock (to have radar looking-up) the Su-27 went into shallow dive also probably as it was going to engage me (and F-14A was happy to continue flying straight even though he's been STT locked and fired at) and this created more altitude difference between high lofting AIM-120C's and Su-27. End result was, AIM-120C's have lost most of their energy while still being high... and were in some 40-50° dive angle still trying to follow Su-27 which by this time was already much lower, still in burner and heading away from them... the AIM-120C stood no chance at all.

 

@IvanK

I'll do 10000m alt 0.95Mach next

 

PS: with F-15C test AIM-120C had around 48nm Rmax (around 89km) so it's bit less than R-27ER, two missiles were fired around 47nm and 43nm


Edited by Kuky

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Kuky

Kuky

Posted
Posted

10000m 0.95Mach Su-27 vs F-14A

 

R-27ER Rmax displayed on HUD is roughly 64km

R-27R Rmax displayed on HUD is roughly 42km

 

I fired R-27ER at at Rmax and second at 60km, both didn't have enough energy to track the F-14A which again just went into beam/dive.

 

Before I did this test I setup Su-27 and F-15C and forgot the F-15C will have his ECM on, anyway checking in F10 I was able to tell when I was 60km away and fired R-27ER at 60km in HOJ mode... then second R-27ER seconds after. They both failed pretty badly as the moment F-15C went evasive (going into about 40° dive and beam/notch continuing the diving turn away, I noticed both R-27ER stopped tracking and went for something behind the aircraft (must be either Chaff or they lost track) as in that moment aspect of the F-15C in respect to missile was exact 90°.

 

PS: I'm not very good in F-15C so bit harder for me to use its avionics and units :P I'll go and check Rmax at least for AIM-120C at this alt/speed

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Kuky

Kuky

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Posted (edited)

10000m 0.95Mach F-15C vs MiG-25PD

 

AIM-120C Rmax displayed on HUD is 33nm (around 61km)

 

I fired the Aim-120C at Rmax (around 60km) and second at 30nm (around 55km), first missile went into high loft, second went off the rail straight then started climbing into loft also. First Aim-120C reached 13.5km alt before what looked like to me was going active as in that moment it did very sharp turn downwards, second missile reached 13km before it did the same.

 

The MiG-25PD went evasive as missiles went active and again (as expected from AI) went into a dive and beam... the AIM-120C's didn't have enough energy to follow... the MiG-25PD went back into climb but AIM-120C's could not follow.

 

 

So guys that actually know some fair s**t about missiles bring on the conclusions. :D

 

What I can see is R-27ER has little more range, it looses lock in beam/chaff very easy (I think this to be wrong as it's too easy to do this) and for AIM-120C, well the lofting kills it


Edited by Kuky

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Kuky

Kuky

Posted
Posted

10000m 0.95Mach MiG-29S vs F-14A

 

R-77 Rmax displayed on HUD is 50km

 

Fired R-77 at 50km and second at 45km, they behaved exactly the same as AIM-120C (going into loft) then doing very sharp turn downwards when getting active... again AI went into beam/dive and both missiles had no energy to follow the F-14A.

 

Seems very clear even when firing any missile at Rmax it's never hit, unless you happen to fly into it. Even when target doesn't evade Rmax shot is pretty much useless.

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159th_Viper

159th_Viper

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Yeah, the AE range in-SIM is pretty low atm. Definitely not right.

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Kuky

Kuky

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Posted (edited)

I just did another, more accurate test, I setup AI to fly straight and level and not use chaff or evade the missile so I can get better accuracy wether missile should hit target at specified Rmax

 

Setup is always at 10000m altitude, speed is set at 0.95Mach for both shooter and target

 

Note: test were done in Testing build not latest public beta version

 

Rough error in distance measurement is +-1km / 0.5nm

Rough error in time measurement is +-0/5sec

Rough error is top speed +-1%

_Missile_______________________BurnTime__TopSpeed__ToFTT

R-27ER
......
Rmax: 64km
(35nm)
...
09
sec
...
4511
Km/h
...
67
sec

AIM-120
C
..
Rmax: 61km (33nm)
...
13
sec
...
3422
Km/h
...
72
sec

AIM-120
B
..
Rmax: 57km (31nm)
...
12
sec
...
3179
Km/h
...
78
sec

AIM-7
........
Rmax
:
57km (31nm)
...
14
sec
...
2979
Km/h
...
61
sec

R-77
..........
Rmax: 49km
(26nm)
...
10
sec
...
4058
Km/h
...
55
sec

R-27R
........
Rmax: 41km
(22nm)
...
06
sec
...
3196
Km/h
...
49
sec

All missiles achieve Hit on non-maneuvering target when fired at Rmax with exception of AIM-7. Seems the AIM-7 guides itself tad too low and just as it's about to fly into the target it has to pull its nose up but doesn't have energy to do so, therefore it misses and flies by. AIM-7 fired at 30nm (just under its Rmax of 31nm) achieves Hit.

 

Anyone know how does this compare to real missile charts?

 

EDIT: added rocket engine burn time, missile top speed and ToFTT (Time-of-Flight-to-Target) time


Edited by Kuky

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GGTharos

GGTharos

Posted
Posted

This compares fairly well to IRL charts/hud displays/opfor intel data wherever it can be found. They're all more or less within expected ballpark.

 

I just did another, more accurate test, I setup AI to fly straight and level and not use chaff or evade the missile so I can get better accuracy wether missile should hit target at specified Rmax

 

Setup is always at 10000m altitude, speed is set at 0.95Mach for both shooter and target (I'd say error in distance measurement is +-1km)

R-27ER
......
Rmax
...
64km

AIM-120C
..
Rmax
...
61km (33nm)

AIM-120B
..
Rmax
...
57km (31nm)

AIM-7
........
Rmax
...
57km (31nm)

R-77
..........
Rmax
...
49km

R-27R
........
Rmax
...
41km

All missiles achieve Hit on non-maneuvering target when fired at Rmax with exception of AIM-7. Seems the AIM-7 guides itself tad too low and just as it's about to fly into the target it has to pull its nose up but doesn't have energy to do so, therefore it misses and flies by. AIM-7 fired at 30nm (just under its Rmax of 31nm) achieves Hit.

 

Anyone know how does this compare to real missile charts?

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Alfa

Alfa

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Doesn't look too far off as far as ranges go - the only two things in your findings that look a little suspect IMO is the burn time of the R-27ER, for which only 9 sec sounds very low for a two-stage engine. The other is the lofting logic, which from your decription sounds porked.

 

I just did another, more accurate test, I setup AI to fly straight and level and not use chaff or evade the missile so I can get better accuracy wether missile should hit target at specified Rmax

 

Setup is always at 10000m altitude, speed is set at 0.95Mach for both shooter and target

 

Rough error in distance measurement is +-1km / 0.5nm

Rough error in time measurement is +-0/5sec

Rough error is top speed +-1%

_Missile_______________________BurnTime__TopSpeed__ToFTT

R-27ER
......
Rmax: 64km
(35nm)
...
09
sec
...
4511
Km/h
...
67
sec

AIM-120
C
..
Rmax: 61km (33nm)
...
13
sec
...
3422
Km/h
...
72
sec

AIM-120
B
..
Rmax: 57km (31nm)
...
12
sec
...
3179
Km/h
...
78
sec

AIM-7
........
Rmax
:
57km (31nm)
...
14
sec
...
2979
Km/h
...
61
sec

R-77
..........
Rmax: 49km
(26nm)
...
10
sec
...
4058
Km/h
...
55
sec

R-27R
........
Rmax: 41km
(22nm)
...
06
sec
...
3196
Km/h
...
49
sec

All missiles achieve Hit on non-maneuvering target when fired at Rmax with exception of AIM-7. Seems the AIM-7 guides itself tad too low and just as it's about to fly into the target it has to pull its nose up but doesn't have energy to do so, therefore it misses and flies by. AIM-7 fired at 30nm (just under its Rmax of 31nm) achieves Hit.

 

Anyone know how does this compare to real missile charts?

 

EDIT: added rocket engine burn time, missile top speed and ToFTT (Time-of-Flight-to-Target) time

JJ

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Kuky

Kuky

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Posted (edited)
Doesn't look too far off as far as ranges go - the only two things in your findings that look a little suspect IMO is the burn time of the R-27ER, for which only 9 sec sounds very low for a two-stage engine. The other is the lofting logic, which from your decription sounds porked.

 

Just double checked again to make sure I didn't make a mistake (and I didn't) this is what burn time R-27ER has in latest build... what should its propellent burn time be in RL?


Edited by Kuky

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Alfa

Alfa

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Exactly right... I double checked again and in latest build R-27ER has 09sec burn time... what should its propellent burn time be in RL?

 

I don't know Kuky - thats why I said it looks suspect :) .

 

But it does look strange - both when compared with the burn time of the US weapons(also two-stage), but in particular with the R-77, which has a single stage engine.

JJ

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Frostie

Frostie

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Posted (edited)

The lofting logic is indeed nuts.

When lofting a shot surely the nose needs to be elevated to fire the shot and shouldn't there be a cue so as the if the launch angle is not achieved the loft solution will not activate?

 

If you fire on a target some 160km away at 14000m 1.4mach the 120C will fly for 110km.

 

Also Kuky check your speeds, at 10,000m 0.95mach the AIM-120C achieved a top speed of 5300-5500km/h for me depending on launch angle.


Edited by Frostie

"[51☭] FROSTIE" #55

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ohmyflanker

ohmyflanker

Posted
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I just did another, more accurate test, I setup AI to fly straight and level and not use chaff or evade the missile so I can get better accuracy wether missile should hit target at specified Rmax

 

Setup is always at 10000m altitude, speed is set at 0.95Mach for both shooter and target

 

Rough error in distance measurement is +-1km / 0.5nm

Rough error in time measurement is +-0/5sec

Rough error is top speed +-1%

_Missile_______________________BurnTime__TopSpeed__ToFTT

R-27ER
......
Rmax: 64km
(35nm)
...
09
sec
...
4511
Km/h
...
67
sec

AIM-120
C
..
Rmax: 61km (33nm)
...
13
sec
...
3422
Km/h
...
72
sec

AIM-120
B
..
Rmax: 57km (31nm)
...
12
sec
...
3179
Km/h
...
78
sec

AIM-7
........
Rmax
:
57km (31nm)
...
14
sec
...
2979
Km/h
...
61
sec

R-77
..........
Rmax: 49km
(26nm)
...
10
sec
...
4058
Km/h
...
55
sec

R-27R
........
Rmax: 41km
(22nm)
...
06
sec
...
3196
Km/h
...
49
sec

All missiles achieve Hit on non-maneuvering target when fired at Rmax with exception of AIM-7. Seems the AIM-7 guides itself tad too low and just as it's about to fly into the target it has to pull its nose up but doesn't have energy to do so, therefore it misses and flies by. AIM-7 fired at 30nm (just under its Rmax of 31nm) achieves Hit.

 

Anyone know how does this compare to real missile charts?

 

EDIT: added rocket engine burn time, missile top speed and ToFTT (Time-of-Flight-to-Target) time

 

Was this test in the latest version of FC3?

I had a test and the results was different from yours.The top speed of AIM-120C is surely higher than that of R-27ER.

R27ER vs AIM120C.trk

Tacview-R27ER vs AIM120C.txt.rar


Edited by ohmyflanker
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Kuky

Kuky

Posted
Posted (edited)
Also Kuky check your speeds, at 10,000m 0.95mach the AIM-120C achieved a top speed of 5600-5800km/h for me depending on launch angle.

 

All of the test are done ix exact same conditions... flying at exact same speed, altitude and wings level and shots were taken at displayed Rmax, so yes, if you nose up and fire it will have bit more range added due to improved firing condition (to give it more range).

 

Also mind you I wasn't testing this in latest public version but latest testing build (obviously missiles are being worked on)

 

Alfa, I am starting to think R-27ER burn time is possibly off, if not, Russians use some pretty fast burning rocket propellent... but also I can't believe R-27ER is just little longer range than 120's, I think it should be more, at least 20km more range... possibly this is cut due to shorter burn time.


Edited by Kuky

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Frostie

Frostie

Posted
Posted
All of the test are done ix exact same conditions... flying at exact same speed, altitude and wings level and shots were taken at displayed Rmax

 

Also mind you I wasn't testing this in latest public version but latest testing version.

Are we mixing data up here with different versions. Shouldn't you be posting this in a non public forum or something.

"[51☭] FROSTIE" #55

51st PVO "BISONS"

Fastest MiG pilot in the world - TCR'10

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Kuky

Kuky

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Posted
Are we mixing data up here with different versions. Shouldn't you be posting this in a non public forum or something.

 

No, reason I did these test is because you posted your results yesterday... I thought it would be good idea to put that in ED bug tracking.... but realised after I did it that I should test in latest test build... so I did that and as you can see things are being worked on and changed and are likely to be changed bit more... we on same page now?

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Frostie

Frostie

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Posted
No, reason I did these test is because you posted your results yesterday... I thought it would be good idea to put that in ED bug tracking.... but realised after I did it that I should test in latest test build... so I did that and as you can see things are being worked on and changed and are likely to be changed bit more... we on same page now?

Yes Kuky, no problem, just a little heads up to save the confusion.

Latest build means latest public version to me.

"[51☭] FROSTIE" #55

51st PVO "BISONS"

Fastest MiG pilot in the world - TCR'10

https://100kiap.org

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