tornado F2/F3

Cold war, Korea, Vietnam, and Desert Storm - up to and including for example the A-10, F-15, Mirage 200, MiG-29, and F-18.
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basher54321

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Unread post08 Apr 2020, 13:16

hornetfinn wrote:Also those RAF F-4 fighters were getting old and needed replacement fairly soon anyway. Besides I don't think F-4 could be upgraded with even remotely similar radar performance and range/endurance that Tornado ADV had. Upgrades for F-4 then had AN/APG-65/66 level radars and those are clearly less capable than AI.24 for long range BVR combat against bombers.




Yes the first part is certainly true - Ian Black had written they were 5000+ hour frames when they were retired. Yes there were plans to upgrade them but they would never have been considered replacements for the F.3 - it was always the other way around regardless.

Have seen claims it had twice the endurance of the F-4 but nothing concrete on what the reality was.
Last edited by basher54321 on 08 Apr 2020, 13:32, edited 1 time in total.
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Unread post08 Apr 2020, 13:31

hornetfinn wrote:Basically Phoenix listened to radar signals from AN/AWG-9 or AN/APG-71 and used that for guidance as data link solutions at the time were not good enough. So when F-14 radar was scanning in TWS mode, AIM-54s would use those target returns for guidance. Then when closer to target, they would switch to active-radar homing for terminal guidance. So F-14 radar could search and track multiple targets the whole time in TWS mode. Phoenix would get SARH updates every two seconds as F-14 radar does a single scan in those two seconds. So the missile received only a short illumination from the target during SARH phase, hence called something like "Sampled Data Semi-Active". Not nearly enough for terminal homing definitely, but good enough for initial guidance.



That is useful thank you - clears up where that mode is used. The modes listed for the AIM-54 include Sampled Data Semi-Active, Continuous Semi Active mode, Active and HOJ. It looks like the Continuous Semi-Active mode can only be used to guide an AIM-54A at a single target.
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Unread post08 Apr 2020, 16:10

Not trying to go off topic, but isn't that article incorrect? The world's greatest living jet ace is Giora Epstein with 17 kills.

edit: Upon further examination, one of Epstein's kills apparently was a helicopter.
Last edited by f-16adf on 08 Apr 2020, 18:13, edited 1 time in total.
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madrat

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Unread post08 Apr 2020, 16:16

basher54321 wrote:That is useful thank you - clears up where that mode is used. The modes listed for the AIM-54 include Sampled Data Semi-Active, Continuous Semi Active mode, Active and HOJ. It looks like the Continuous Semi-Active mode can only be used to guide an AIM-54A at a single target.

Turning on the CW antenna does not turn off the main antenna. A lot more takes place then simply waving some electromagnetic energy back and forth across an area. TWS isn't exactly only listening for a simple radar return, it is deliberate tracking of a potential target using filters during a wider area scan and remembering radar returns within the filter parameters to discern probables from improbable targets. With the CW antenna being its own standalone unit then it makes sense that you could use CW to target the nearest target in a mass and still use TWS to target other targets independent of the CW antenna. AIM-7M seems to have given the more modern fighters a way to hone in on specific targets available through filtering in combination with the highly-granular picture afforded through modern PD technologies. I doubt any fighter since the F-15A was restricted to targeting one single target at a time. Even early Flankers suggest they had the ability to target two at a time. I wouldn't doubt that F-14 could target more than two with Sparrow. They fire Sparrows in pairs, so it is not likely they would need to target more than two at a time when they only typically carried four per flight.
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hornetfinn

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Unread post09 Apr 2020, 12:33

madrat wrote:
basher54321 wrote:That is useful thank you - clears up where that mode is used. The modes listed for the AIM-54 include Sampled Data Semi-Active, Continuous Semi Active mode, Active and HOJ. It looks like the Continuous Semi-Active mode can only be used to guide an AIM-54A at a single target.

Turning on the CW antenna does not turn off the main antenna. A lot more takes place then simply waving some electromagnetic energy back and forth across an area. TWS isn't exactly only listening for a simple radar return, it is deliberate tracking of a potential target using filters during a wider area scan and remembering radar returns within the filter parameters to discern probables from improbable targets. With the CW antenna being its own standalone unit then it makes sense that you could use CW to target the nearest target in a mass and still use TWS to target other targets independent of the CW antenna. AIM-7M seems to have given the more modern fighters a way to hone in on specific targets available through filtering in combination with the highly-granular picture afforded through modern PD technologies. I doubt any fighter since the F-15A was restricted to targeting one single target at a time. Even early Flankers suggest they had the ability to target two at a time. I wouldn't doubt that F-14 could target more than two with Sparrow. They fire Sparrows in pairs, so it is not likely they would need to target more than two at a time when they only typically carried four per flight.


I don't think there were separate CW antenna in F-14, Tornado ADV or any other relatively modern fighter jet. AFAIK, all used the one antenna and there was just separate CW illuminator/RF transmitter for CW. That is used to inject CW energy into the emissions of the pulse or pulse doppler fire control radar. Since they use the same antenna, both emissions are sent to the same direction and have the same beam width. There is no room for separate CW antenna inside fighter aircraft nose cone. There has been separate radars for CW target illumination in navy ships like AN/SPG-62 used in Ticos.

It's definitely possible to track multiple targets with MSA radar using advanced radar signal processing techniques but only within the beamwidth of the radar (or close to it). For SARH the MSA radar needs to continuously be pointed towards the target during the end game or the illumination will end and missile not be able to guide itself towards the target. But within the beamwidth of the radar, it could propably track at least two targets simultaneously and also illuminate them with CW for missiles to guide to. Of course that could work only within very limited volume, but could be useful in some situations.

Another possibility would be to launch missiles with long intervals so there is enough time to switch from one target to another. Basically during the initial phase the missiles could do that "sample data semi-active" type coarse guidance or data link updates to guide the missiles towards targets. When first missile gets close, the radar would switch to single target tracking and continous illumination of that target. When the missile hits, the radar would search and track for the second target and do the same thing again. However that would require rather long time between the missile launches (or actually them hitting the targets). I'm not convinced that it would work in real life very well. Maybe against very steady targets with wide separation in distance but not in azimuth.

I've also seen those claims about two targets being tracked and engaged with SARH missiles and MSA radars for both F-15 and Su-27 later variants along with some other fighters. I could definitely see Tornado ADV also being capable of that. I think it was real but very limited capability.
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basher54321

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Unread post09 Apr 2020, 15:29

hornetfinn wrote:
I've also seen those claims about two targets being tracked and engaged with SARH missiles and MSA radars for both F-15 and Su-27 later variants along with some other fighters. I could definitely see Tornado ADV also being capable of that. I think it was real but very limited capability.


Indeed considering they would both need to be fully guided to end game - you would would want 2 very close and cooperative targets.

There are definitely some aircraft that could not support multiple AIM-7F/M shots going from the available manuals however the Tornado F3 will have to remain a mystery until such information becomes available.
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Unread post10 Apr 2020, 05:38

Secret projects has a detailed post on Tornado and Foxhunter. https://www.secretprojects.co.uk/thread ... onics.371/

The CW antenna is definitely it's own unit. Both antenna share a common dish. BTW below is AWG-10, not AWG-9.
Image

The Pheonix gave it an edge over the F-18, but they both shared the same handicap when firing Sparrows.
Image

I think sometimes people confuse a track with a scan. The Pheonix flew much longer ranges and could tolerate deviations from the signal as it scanned because it was built to do just that. The Sparrow on the other hand requires illumination by the main lobe. The main lobe cannot scan beyond the area of a target when firing Sparrow for obvious reasons, whereas the scan could be much more broad when using Pheonix. The waveform of a return may present targets separately depending on many factors, especially if there is a distance difference. The AIM-7M was fed information specific to the target so that it was able to tune into just the intended target. By giving the missile some target information specific to one target, the missile was also able to filter out potential distractions and do some additional filtering to maintain aspect on a target mostly on its own based upon return information. Early Sparrow were not so smart and simply flew to the most strong radar return using an intercept logic.
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hornetfinn

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Unread post27 Apr 2020, 09:37

madrat wrote:Secret projects has a detailed post on Tornado and Foxhunter. https://www.secretprojects.co.uk/thread ... onics.371/

The CW antenna is definitely it's own unit. Both antenna share a common dish. BTW below is AWG-10, not AWG-9.
Image


I don't see any CW antenna, just one antenna with two feedhorns (main feedhorn and CW illuminator feedhorn. IFF system there is a separate antenna system as it uses totally different wavelenght and doesn't interfere with the main radar operations that much. The CW illuminator just adds CW signal to the main beam.

In more modern MSA systems with slotted array antenna, there is no separate feehorns at all but radar signal is fed from behind the antenna. Here is good info about how things progressed from AWG-10 to AWG-9 and AN/APG-63:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a142103.pdf

AIM-7F SPARROW missile compatibility is the other major factor in determining transitter power requirements. On earlier aircraft (F-4) this compatibility was provided by the addition of a separate CW illuminator. The F-15 proved the feasibility of providing SPARROW compatibility using the high PRF pulse doppler waveform negating the need for a
separate transmitter with its inherent reduction in system reliability. This concept has been adopted on the F/A-18.


I think AI.24 Foxhunter is probably using similar techniques as AN/APG-63 and AN/APG-65.
https://www.forecastinternational.com/a ... RC_ID=1613

Here are good pictures about AWG-9 and AN/APG-71 along with other good info about them: viewtopic.php?t=56604&p=434329
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Unread post27 Apr 2020, 13:32

This is a very good overview of the F2/F3 (horror) story from someone who had various inside roles - a bit techy in places.

Tornado F3: A Navigator's Eye on Britain's Last Interceptor by David Gledhill

https://www.amazon.com/Tornado-F3-Navig ... B00TM7A80E
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Unread post28 Apr 2020, 01:03

I agree one antenna in the picture. One CW feedhorn, and one main feedhorm all sharing the antenna dish. Flood is its own antenna, which is not included in the picture. It is not necessary to use such a large antenna for flood. CW and main feedhorms create independent signal lobes AFAICT. And you also have eight IFF antenna also sharing that one dish. CW is the normal guidance mode for all AIM-7 variants. F-15C could target using pulse doppler guidance mode instead, and F-14 was fully capable of the same. AIM-7E was a CW dependent missile whereas newer missiles supported pulse doppler, too. I believe flood kicks in automatically when in boresight mode if the system loses its target return.

The main dish capability is the biggest unknown here. Can it tune more than two targets in at a time, or does it use the main dish and flood simultaneously to target the two targets?
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Unread post28 Apr 2020, 07:11

madrat wrote:The main dish capability is the biggest unknown here. Can it tune more than two targets in at a time, or does it use the main dish and flood simultaneously to target the two targets?


My understanding of the subject is that the main radar and CW operate independently from each other. The main radar transmits pulse or pulse-doppler signals and listen to those signals. CW system just transmits the CW signal and in earlier versions used separate receivers to listen to those signals and tunes the AIM-7 missiles before launch. AFAIK the newer versions didn't have any receive functionality but rather used the main radar and missile seekers themselves to achieve the same effect. Since the main radar and CW use the same frequency range and have the same dish, they also always look at the same direction and have same beam width. Because they use totally different waveforms, they do not affect each other.

I think since CW is continuous wave (transmitting all or most of the time), it has to operate simultaneously with the main radar system. Since the missile needs continuous illumination in final approach, the main radar is tracking the target and CW system simultaneously illuminates it with CW signal. If there happens to be two targets within the beamwidth, it will illuminate both but signal processing is required to filter them out as separate targets. The beamwidth is usually 2-4 degrees in fighter aircraft depending on antenna size, type and quality. So if the distance to target is say 20 nmi, then two targets need to be within few thousand feet from each other or so to be within same beamwidth (the beam is likely centered on one target).
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