R-27ER/ET double miss (Su-27 vs F-15)

[Cmptohocah]

Hello everyone,

 

the other day while I was playing online, I had something happen to me that seems to be regular occurrence since I switched to new version of FC:

 

My ER's (and also ET's but not as important) seem to be very inefficient in hitting their targets. I was attributing this to 'my poor engagement/enemy quick reaction' factors and, as I taught at the time, inferior speed of the ER's compared to 120's.

 

It was only until I recently watched a track of my 1v1 engagement against a F-15 (online server). that I realized that my ER's are in fact faster than AMRAAM's but they fail to hit the target. I am sharing the video I have made (recorded track and superimposed TacView) and would like to hear your taught on the matter.

 

Quick intro:

 

1. after flanking the F-15 and picking up a lock warning, I go into offensive and manage to brake the lock (assumption) and acquire the bandit at some 25km out, 5k+ alt at roughly 12 o'clock.
   
2. soon after that I get a launch authorization and fire my R-27ER [00:15]
   
3. R-27ET follows at [00:19] and the enemy starts a steep dive for the deck
   
4. R-27ER initially starts going towards the ground trying to pull lead, but suddenly changes it's direction and starts tracking F-15 again [00:26] but instead of going straight towards it, flies by like a dud. Meanwhile the R-27ER starts intercepting from the moment it leaves the pylon and ends up in the dirt.
   
5. HUD shows that radar lock was lost for a moment [00:34] but in the other window it is clear that ER was already on the way towards the Moon.
   

 

My questions:

How come the two (ER & ET) decided to take such strange trajectories?

 

 

Are IR missiles supposed to pull lead, and what information do they use to calculate potential impact point?

 

 

Regards,

Edited August 4, 2015 by Cmptohocah

[EngineerFalcon]

The video does not seem to be working for me, but since you mention online play, have you checked your ping ? You could be receiving an incorrect position for the aircraft, hence the strange trajectories.

[pepin1234]

 

fJ_WyptmuYk

 

Regards,

 

video here

[BlazexX23Xx]

That is a Su-33,just saying.

Edited August 4, 2015 by BlazexX23Xx

[Svend_Dellepude]

Looks like he notched you.

[karambiatos]

You know you could upload that acmi you got there.

[DarkFire]

Something I've noticed from watching my own ACMI tracks and Rage's very extensive missile testing series is that while the R-27Ex missiles are VERY fast, they seem to loose energy incredibly quickly after the motor burns out. Tracking and decoys are other issues - they appear to be rather susceptible to decoys unfortunately and also appear to have a narrow acceptable gimbal limit for the seeker head.

[*Rage*]

Its difficult to make out what happened there from the video. Upload the tacview!

[pepin1234]

1Th: the 27ET should be launched first, not after.

2Th: You should pull over to the same side he move.

3Th: he was 5000 m higher than you and 25 km range. He do the right defense, diving hard and notching so your missile get missed.

 

Your mistake was stay in the same altitude when he was already totally in defensive maneuver. If you get more altitude at the moment he dive you probably don't miss the lock because your higher altitude angle don't let him get hide behind the mountain.

[GGTharos]

My questions:

How come the two (ER & ET) decided to take such strange trajectories?

 

Which part is strange? The ER lost lock, probably due to chaff. The ET did what it was supposed to do since your target was probably helping it along by using afterburner, and flew itself into the ground.

 

Are IR missiles supposed to pull lead, and what information do they use to calculate potential impact point?

They don't calculate an impact point. They use a guidance law called the 'Proportional Navigation Law', like most missiles. IR missiles thus only use the line-of-sight motion - they turn to stop this motion, so that the target is not moving from the perspective of the missile.

 

Radar guided missiles can potentially enrich this with additional information, just as closure and distance.

 

More modern missiles or SAMs may calculate an impact point, but pretty much anything up to and including AIM-7M, R-27 uses some variant of PN.

[GGTharos]

The faster you go, the higher the drag force.

The larger diameter, the higher the drag force ... you get the idea.

 

Something I've noticed from watching my own ACMI tracks and Rage's very extensive missile testing series is that while the R-27Ex missiles are VERY fast, they seem to loose energy incredibly quickly after the motor burns out. Tracking and decoys are other issues - they appear to be rather susceptible to decoys unfortunately and also appear to have a narrow acceptable gimbal limit for the seeker head.

[DarkFire]

Understood, particularly as supersonic aerodynamics are very different to sub-sonic aerodynamics. Last time I did a class on aerodynamics was 20 years ago, I need to dig out some of my old books & re-learn things :thumbup:

[Cmptohocah]

Thank you for the replies, gave me some new insight into what happens inside FC 3.0.

[=4c=Nikola]

He's high and fast, you're low and slow. You attacked at ~22km, that's too far away for that position. You lost radar lock and missile guidance. I must say that was pretty poor performance by him, as he had leverage to defend by energy only. He went completely defensive for no reason since your missiles was no threat for him.

Edited August 10, 2015 by =4c=Nikola

[ShuRugal]

The faster you go, the higher the drag force.

The larger diameter, the higher the drag force ... you get the idea.

 

let's not forget that missile drag forces in DCS are still a WIP, and have been known to be excessive for some time.

[Slipp]

Is it fair to say that currently in DCS, AIM-7M, AIM-9M vs R-27R and R-73 is the most fair fight that F-15 and Su-27 can do in this sim?

[GGTharos]

If you're looking for weapon/systems parity then that's a fair-ish assessment I think.

[Slipp]

If you're looking for weapon/systems parity then that's a fair-ish assessment I think.

 

Since you're knowledgeable about this, do you maybe have an idea how to balance it out even more? For late 80's or very early 90's scenario.

[GGTharos]

There's no way to achieve straight-up balance. Try as you might, someone will feel shafted, or you'll end up crippling one things or another.

 

There's no point, just learn to work with what you have in the face of your opponent.

[Slipp]

There's no way to achieve straight-up balance. Try as you might, someone will feel shafted, or you'll end up crippling one things or another.

 

There's no point, just learn to work with what you have in the face of your opponent.

 

Sounds reasonable enough. :)

 

I'll stick with the oldest equipment available to the planes and that should do the trick.

 

Thanks for the input.

[SgtPappy]

Since you're knowledgeable about this, do you maybe have an idea how to balance it out even more? For late 80's or very early 90's scenario.

 

There's no way to achieve straight-up balance. Try as you might, someone will feel shafted, or you'll end up crippling one things or another.

 

There's no point, just learn to work with what you have in the face of your opponent.

 

Yes. 1980's all the way please! That way, everyone's got SARH missiles. Sure the AIM-7 will have the advantage but there will be more balance for those who hate AMRAAMs, my F-15 won't be able to run and kill you at the same time and I will be happy flying in a Cold War scenario :)

 

I've been telling others that when the F-14 comes out, hopefully there will be way more 1980's missions to satisfy the Top Gun feel and to make a timeframe more logically associated with the F-14A/B.