Air-to-Air Missile Discussion

[Alfa]

No, both have the same guiding system.

 

Correct. It goes with the modular nature of the missile system -

one common autopilot section, two motor options and three seekerheads(IR, SARH and passive radar). The -R and ER differ only by the motor section.

 

It has a booster stage added to the motor, to increase the range.

 

No it has a different motor with more thrust(larger diameter) and added sustainer stage to increase range :) .

 

don't just asume If AIM-7 worked in certain way it doesn't mean R-27R has to work the same.

 

The SARH seekerhead(9B1101K) has a stated acquisition range of some 25 km against a target of RCS = 3m2.

[EtherealN]

Aim-120C never reaches over 3500km/hr at any altitude in FC1/2.

ER never reaches over 3800km/hr at any altitude in FC1/2.

At medium the AMRAAM is maxed at about 2800km/hr and ER at 3200km/hr.

 

Your mistake is that you are looking at only one variable.

 

Between FC2 and FC3, missile flight model was completely replaced with what can be called an AFM. One of the effects was that a previously hardcoded "speed limit" could be exceeded, but this does NOT mean they necessasrily reach longer. It all depends. Because while top speeds may have changed, so did drag behaviour. For example, in FC1/FC2, there effectively was no drag while the missile motor was active. (Limitation of missile SFM.) It's a completely replaced flight model, so don't just look at one single variable.

 

Basically, with FC3, missile tuning had to start over since the new FM changed everything. While the correct tuning is being chased, most missiles have had their own moments of "bad" performance, especially in cases where new FM behaviour interacts with seeker behaviour.

[EtherealN]

In FC1 you could make multiple AIM-120 kills launching at 50nm with TWS as long as you were angels moon, I can't see that happening now. The drag on the missiles seems more effective in FC3.

 

Hahah, yeah, no more automatic astronauts... :P

 

But we do get proper allowances for fastshooter tactics now, which is good.

[GGTharos]

If you simply state that the 7 can track without the data updates from the host aircraft, to up 22nm, then the ER must be even longer. Logic.

 

The fact is, AiM-7M SAR has a range of about 7-8nm, and radio until then.

The ER is about 18km (11nm) SAR range. And this is about accurately represented in DCS already.

 

That's not what our documents say. But if you have better info, bring it on.

[GGTharos]

Which is correct for non-maneuvering or minimally evading targets, and should be that way in FC3.

 

In FC1 you could make multiple AIM-120 kills launching at 50nm with TWS as long as you were angels moon

[Frostie]

same as others, why 120 so special?

Just responding to Experts view on AIM-120. You could actually make 60nm kills with R-27ER in FC1.

 

It was due to the rock solid immune to everything guidance and silence of TWS on RWR and by the time 120 went active, it was too late kinetically to evade it. But they tweaked its angular radar limits so, it's not a virtual death ray as it was in FC2.

 

Believe me, FC2 120C is slower in speed and lower in range than in DCS.

But so is the ER/ET and 77.

Try it yourself. Or if I really have to, I will take some screens of both.

 

They actually tweaked the gimbal limits on the seekers of ARH missiles during FC2 and did away with the find all 20nm maddogs for ARH and ET. The problem then was that the AIM-120 was way too slow and semi-easily dodged and without that find anything within 180 degree cone ability was pretty weak against low targets.

Edited October 28, 2013 by Frostie

[Pilotasso]

Just responding to Experts view on AIM-120.

 

there was no mention of the 120 in his post you quoted :)

 

Also FYI the 120 was around the 3rd best missile in FC1 on frontal aspect and around at 4th place in a tail chase, an improvement over Lockon 1.0 back in the R-27EA days, hence my surprise on your comments.

 

The only thing it was the best at was agility at short range (too much but then again partly because it was also too slow) but hardly anyone talks about that.

Edited October 28, 2013 by Pilotasso

[Dudikoff]

The AIM-7F is a very old missile, older than the R-27 and probably inferior in many ways.However, it has a similar size seeker that had a SARH range of 22nm against a 2sqm target (it actually had no datalink to speak of ).

 

It probably isn't unfair to assume that the R-27R's seeker can do about as well, given that it would probably have a better SNR than AIM-7F

 

Doesn't seem proper to compare the seeker ranges directly as in the case of AIM-7F the CW illumination by the launching platform is used (I presume the return signal should be much stronger than from the radar pulses) so no wonder the seeker range is longer than the R-27 monopulse seeker and there's no need for midcourse updates.

[Frostie]

there was no mention of the 120 in his post you quoted :)

 

Also FYI the 120 was around the 3rd best missile in FC1 on frontal aspect and around at 4th place in a tail chase, an improvement over Lockon 1.0 back in the R-27EA days, hence my surprise on your comments.

 

The only thing it was the best at was agility at short range (too much but then again partly because it was also too slow) but hardly anyone talks about that.

I don't know what you're yawning about, I responded to Experts claim that FC3 AIM-120 has the longest range when in actual fact you could get kills at much further range in FC1 . Get with the discussion.

[GGTharos]

I don't know about that. AIM-7M didn't get M-link until the retrofitted MH to P version AFAIK, and the M was monopulse. I really don't believe they'd cut down on range like that.

 

Doesn't seem proper to compare the seeker ranges directly as in the case of AIM-7F the CW illumination by the launching platform is used (I presume the return signal should be much stronger than from the radar pulses) so no wonder the seeker range is longer than the R-27 monopulse seeker and there's no need for midcourse updates.

[Kuky]

From 12000m maybe yea.

But from medium, no way!

ER's never reached Mach 4.5, neither did 120s and 77.

 

The angle limits were decreased in DCS to make them more realistic.

But the kinetic performance of all the missiles has been greatly improved over FC2.

 

The R-Max for ER even when at that high altitude is around 65km tops and that's for a head on fast going target... so it is actually not true that range of it has been extended, it's been reduced as back in FC2 I cold make kills with ER fired at same high altitude at 80Km distance :music_whistling: (of course this is on big not good manouvering targets like transports/AWACS etc but now you can't do that)

[GGTharos]

Kuky, from the diagram it is about 66km head-to-head M0.9 co-altitude at 10000m. I think the main limitation for the missile is the controlled flight time - so you're close to bang on.

For really high altitude targets, the missile will lose control (stall) at fairly high speed due to air pressure, so if you're attacking say an SR-71, your range might be 'only' 90km just because of the physics at that altitude. Shooting high-to-low changes things (higher missile average speed, more air to grab onto as the missile descends). This is the real advantage of high to low shots: Maintain a lot of speed in the dive if it is an optimal dive, and have a lot of maneuverability as you enter denser air.

 

Generally speaking the missile are capable of having more realistic behavior, but we have to understand what more realistic behavior is in order to tune them correctly. It's very easy to make the missile do whatever you want, but you pay for it with incorrect flight characteristics :)

Edited October 29, 2013 by GGTharos

[JunMcKill]

I did the translation from wikipedia from spanish and yes, you're right the translation of the doppler and IR is wrong.

 

http://es.wikipedia.org/wiki/Vympel_R-27

 

By the way, I never noticed when the russian SARH head activates in the R-27R or ER in the last stage of flight, only in the R-77 activates about 12 km from target. But both the AIM-120C and the AIM-120B did what the manual said about them, they activate the radar homing about 10nm from target. I have lot of tacview as evidence of what I'm talking about the ER radio guided bad flight perfomance, and the last search stage which never happens. The worst perfomance of the ER is when you launch from below to a very high enemy, even the missile reach the enemy height with enough energy they fly to "the infinite and beyond!!!" (keeping the lock all the time), the enemy defeat my aircraft radio emision and radar (because the ER guides using radio the 70% of flight isn't it?) with a couple of barrel rolls and no chaff.

Edited October 29, 2013 by JunMcKill

[GGTharos]

If you are shooting low to high you are putting your missile in a bad position: Low speed and low density air where the enemy is, so the missile has no lift. At high altitudes the missile needs to be very fast to have useful lift.

 

As for seeker/guidance issues, those are things for the future, no changes will be made now to the underlying code, only data adjustments.

[Buzpilot]

I don't know about that. AIM-7M didn't get M-link until the retrofitted MH to P version AFAIK, and the M was monopulse. I really don't believe they'd cut down on range like that.

 

I don't quite understand, the AIM-7M was introduced in 1982, what era are the Russian missiles from, 1980's too, or?

Will the new 'older' 3'rd party fighters also use this one, or will they make older versions?

 

The reason I ask, is that during 1999, Eritrean-Ethiopian War there was fired 24 R-27's (not sure what type), between Su27's vs Mig29's, and only one hit with a proximity fuse. And the DCS ones seem to have much better PK.

Edited October 29, 2013 by Buzpilot

[maturin]

As has been discussed ad nauseum, no one has any idea what the hell went on during that war.

[Dudikoff]

I don't know about that. AIM-7M didn't get M-link until the retrofitted MH to P version AFAIK, and the M was monopulse. I really don't believe they'd cut down on range like that.

 

Yeah, my previous assumption that perhaps CW offers a stronger signal is probably all but wrong and possibly the pulse signal offers a stronger reflected signal as the CW antenna is usually separate and smaller, no?

 

The M seems to have a digitial autopilot - I suppose it's used in the initial stage then as it's stated that this variant only requires target illumination in the mid and final stages? Though that would seem counterproductive in case the target course changes considerably during this stage so adding a possibility to provide mid course updates to the autopilot would make sense here (as you state they did later on).

 

Also, it is mentioned in a lot of places that the Sparrow also tracked the launching airplane's radar signals (the CW signal I presume) using the rear antennas so perhaps this was the technique used by earlier models (before the M) to bring the missile into SARH seeker range?

 

Does anybody have some source which provides detailed description of the missile's guidance procedure (especially the changes to it between the variants) or is this still classified?

Edited October 29, 2013 by Dudikoff

[Frostie]

I don't quite understand, the AIM-7M was introduced in 1982, what era are the Russian missiles from, 1980's too, or?

Will the new 'older' 3'rd party fighters also use this one, or will they make older versions?

 

The reason I ask, is that during 1999, Eritrean-Ethiopian War there was fired 24 R-27's (not sure what type), between Su27's vs Mig29's, and only one hit with a proximity fuse. And the DCS ones seem to have much better PK.

 

Real life is not a game, when launched on pilots don't go crazy and try and out turn their foe like they do online. They rely on support and common sense, I'm sure a lot of cat and mouse took place in those battles. Set up a Flanker vs Fulcrum mission in DCS between 2 well drilled squadrons using only 27r and 73's and I'm sure the outcome would resemble the EE war.

[GGTharos]

No one who models missiles cares about the E-E conflict because it isn't well documented.

 

The R-27 is an 80's missile.

 

I don't quite understand, the AIM-7M was introduced in 1982, what era are the Russian missiles from, 1980's too, or?

Will the new 'older' 3'rd party fighters also use this one, or will they make older versions?

 

The reason I ask, is that during 1999, Eritrean-Ethiopian War there was fired 24 R-27's (not sure what type), between Su27's vs Mig29's, and only one hit with a proximity fuse. And the DCS ones seem to have much better PK.

[GGTharos]

Yeah, my previous assumption that perhaps CW offers a stronger signal is probably all but wrong and possibly the pulse signal offers a stronger reflected signal as the CW antenna is usually separate and smaller, no?

 

I haven't seen those antennae so I can't say. Non-monopulse antennae needed to do extra work to get the target angle.

 

The M seems to have a digitial autopilot - I suppose it's used in the initial stage then as it's stated that this variant only requires target illumination in the mid and final stages? Though that would seem counterproductive in case the target course changes considerably during this stage so adding a possibility to provide mid course updates to the autopilot would make sense here (as you state they did later on).

 

Every missile needs a digital autopilot. It's what flies the missile, regardless of anything else.

 

Also, it is mentioned in a lot of places that the Sparrow also tracked the launching airplane's radar signals (the CW signal I presume) using the rear antennas so perhaps this was the technique used by earlier models (before the M) to bring the missile into SARH seeker range?

 

While I've heard of the missile beam-riding, this has never been confirmed by official docs. It only mentions SARH. The rear antennae are used to pick up the outgoing radar signal and compare it with the received signal at the seeker, thus being able to perform doppler computation :)

 

Does anybody have some source which provides detailed description of the missile's guidance procedure (especially the changes to it between the variants) or is this still classified?

 

There are no detailed descriptions of any missile's guidance procedure. You can get some information like the fact that SARH are tuned to the launching radar before launch, that they are CW/PD and may be mono-pulse, the type of seeker and maybe sometimes gimbals, as well as whether it has an m-link or not. But not always.

[Dudikoff]

Every missile needs a digital autopilot. It's what flies the missile, regardless of anything else. While I've heard of the missile beam-riding, this has never been confirmed by official docs. It only mentions SARH. The rear antennae are used to pick up the outgoing radar signal and compare it with the received signal at the seeker, thus being able to perform doppler computation :)

 

Thanks; just found the same information from some seemingly informative thread here:

 

http://www.secretprojects.co.uk/forum/index.php/topic,60.0.html?PHPSESSID=mcb9knjttmrlte2v3o2rp5jt50

 

I guess the Doppler shift computation is required for both conical scan and monopulse seekers, but it still puzzles me how those missiles are guided towards the target initially.. I mean, if they could detect the reflections from max range, there would be no purpose to retrofit them to support receiving mid course guidance updates, no? Perhaps inertial guidance is used towards some precalculated intercept point/direction, although then the target could perhaps escape the seeker cone by the time that point is reached?

Edited October 29, 2013 by Dudikoff

[GGTharos]

Pretty much very short inertial to SARH. Think about how FLOOD works.

 

Retrofitting them with M-link is useful for a few reasons:

 

An AIM-7F/M/P has a SARH range of 30nm against a fighter, 50nm+ flight range. Longer with a good loft trajectory.

 

In tail-chase scenarios, the seeker's range is reduced.

 

M-link can affect countermeasure rejection and target selection when there are multiple targets in the FoV.

 

You can attack lower RCS targets from max range.

 

Doppler isn't required for any of those seekers, but it's certainly nice to have in order to implement more advanced homing algorithm (augmented PN) and for CM and clutter rejection.

 

I guess the Doppler shift computation is required for both conical scan and monopulse seekers, but it still puzzles me how those missiles are guided towards the target initially.. I mean, if they could detect the reflections from max range, there would be no purpose to retrofit them to support receiving mid course guidance updates, no? Perhaps inertial guidance is used towards some precalculated intercept point, although the target could perhaps escape the seeker cone by the time that point is reached.

[Dudikoff]

Pretty much very short inertial to SARH. Think about how FLOOD works.

Retrofitting them with M-link is useful for a few reasons:

An AIM-7F/M/P has a SARH range of 30nm against a fighter, 50nm+ flight range. Longer with a good loft trajectory.

 

SARH seeker range of 30nm? That would explain just the basic short inertial phase, certainly. Do you have any links for the seeker range numbers?

 

Doppler isn't required for any of those seekers, but it's certainly nice to have in order to implement more advanced homing algorithm (augmented PN) and for CM and clutter rejection.

 

I thought it would be necessary for engaging low-flying targets at least to filter out the ground reflections?

 

Sorry to flood you with all the questions..

 

Regarding my earlier target ranging while in EOS mode, I found this description on the supposed modes on the MiG-23:

 

The SIST switch has 5 operating modes. „R, T-R, T, T-phi0, NAV.

The „R“ mode determines the onboard radar as a main targeting system. Also during ground attack the radar can measure distance to the target.

The „T-R“ mode means cooperation between the radar and the IRST, if the radar is jammed the IRST can pick up the target distance and vice-versa.

The „T“ mode prioritizes the IRST as a main targeting system. Also this mode is used in case of radar damage or hidden approach. The S-23E radar works in so called quasi-scan mode. The radar antenna is slaved to IRST sensor and is providing the data for the launch of R-23T.

In the „T-phi0“ mode the R-23T missile seeker is caged to the axis of the plane.

 

The modes TP (T I, T II, T III, T-phi 0-I, T-phi 0-II) are used in case of radar damage, jamming or hidden approach. The device TP-26Sh is used for target searching/tracking. Leading the aircraft into the target area is done via ARL-SML/Voice commands.

 

The search scan pattern in mode “T I“ is 60º in azimuth and 15º in elevation.

The search scan pattern in mode “T II” is 15º in azimuth and 6º in elevation.

The mode “T III” is automatically switched if the target is acquired in the “T II” mode. The “T III” mode has different parameters (target selection impulses-lines) compared to T II/T I.

If the target is acquired by IRST, the N003E radar switches to quasi-search mode. The radar antenna is slaved to IRST sensor and is providing the data for the launch of R-23T. The HUD brightness (IRST signal) can be set via the “USIL T” switch.

 

The modes (T-phi 0-I, T-phi 0-II) are used when radar activity isn`t required. The R-23T missile seaker is slaved to the IRST.

 

Perhaps the same principle is used in the 27/29, I'd have to check the cockpit photos if similar modes are there - if so, there should be an option to engage/disengage radar target tracking in EOS mode when target is locked; and the target should probably detect the target tracking if equipped with RWR.

Edited October 29, 2013 by Dudikoff

[pepin1234]

I don't quite understand, the AIM-7M was introduced in 1982, what era are the Russian missiles from, 1980's too, or?

Will the new 'older' 3'rd party fighters also use this one, or will they make older versions?

 

The reason I ask, is that during 1999, Eritrean-Ethiopian War there was fired 24 R-27's (not sure what type), between Su27's vs Mig29's, and only one hit with a proximity fuse. And the DCS ones seem to have much better PK.

 

What about if was used the R-27R? Do you know what Kind of air combat tactic was employ? You never know, you only know when a big coalition take the victory and after that, come all losers, excelent, not so good pilots to say their little history by Discovery Channel or Fox Documentary to say and explain with 3D fiction, fascinating explosion and plagued of manipulated Information and telling us how all they together have kill 3 or 4 fighters.

 

Come on!!

[pepin1234]

No one who models missiles cares about the E-E conflict because it isn't well documented.

 

The R-27 is an 80's missile.

 

The Pechora air-defence System is a 60's Hardware and the F-117 have been ridiculous shootdown in Serbia.

 

So your assumption about everything made for the USAF at the 90's is better than others make any sence.