F-104 with AIM-9C?

[Scott Kenny]

I think a mix of AIM-9C and AIM-9B is more likely. While AIM-9D is better than AIM-9B, it's not that better that export customer - who already brought a large supply of AIM-9B - would be compelled to buy AIM-9D in numbers.

Advantage of shifting to -D is that it uses the same rocket as the -C, Hercules Mk36.

So I suspect that a European SARH Sidewinder would either get the -B rocket (Thiokol Mk17, which did show up back on the -E and FGW.2/-F) or they'd go to giving their IR Sidewinders the Hercules Mk36.

Note that the USN did keep their Sidewinders post -C/-D (the -G/-H/-K variants) on the Hercules Mk36, while the USAF stuck with the Mk17 in their Sidewinders (-E/-J/-P). USN and USAF having separate Sidewinder variants till the all-aspect Lima version.​

​

Unless I am missing a big advantage for the faster burn rate for tail chasing IR seekers?

 

[Dilandu]

So I suspect that a European SARH Sidewinder would either get the -B rocket (Thiokol Mk17, which did show up back on the -E and FGW.2/-F) or they'd go to giving their IR Sidewinders the Hercules Mk36.

Hm. But engine is the low-maintenance part of missile. What could be gained from buying the SARH missile with older motor? Or you means production lines commonality for local AIM-9C production?

 

[Scott Kenny]

Hm. But engine is the low-maintenance part of missile. What could be gained from buying the SARH missile with older motor? Or you means production lines commonality for local AIM-9C production?

Production commonality. Though with several thousand SARH missiles it may be worth the two separate rocket production lines.

 

[Rule of cool]

Note that the USN did keep their Sidewinders post -C/-D (the -G/-H/-K variants) on the Hercules Mk36, while the USAF stuck with the Mk17 in their Sidewinders (-E/-J/-P). USN and USAF having separate Sidewinder variants till the all-aspect Lima version.

I think this reflects the tactical ideas of these two arms; they do things differently. For example, the USAF did much more with the Sparrow in Vietnam than the USN did.

Procurement has an inertia all of its own. Going with the 9C, and perhaps with the associated 9D, means abandoning whatever portion of some 15,000 9Bs that are virtually brand new and subject to a large and therefore good value major update program. Maybe the head on capability is worth it, but that's not a given.

 

[Rule of cool]

Yeah... but their results weren't exactly satisfactory, and Navy didn't exactly view AIM-9C as anything more than situational weapon, to gave F-8 Crusader at least some head-on capability. This weapon was, let's be frank, primitive:

* It have pulse-based guidance (because its tiny antenna would not be able to receive CW echo good enough to track), without any ability to discriminate ground clutter;

* It have terrible angular resolution, due to antenna being very small;

* It could be very easily confused by chaffs or ground clutter;

So essentially - it was not a dogfight weapon, and it was not a BVR weapon. It was a weapon for short-range head-on attacks. But short-range head-on attacks weren't exactly Crusader speciality.


Essentially yes, because frankly, it's the niche where AIM-9C would work the best.

I wouldn't get too hung up on the sophistication of the 9Cs guidance, I don't think it's too out of place in the era. IIUC the Matra R530 had pulse guidance, the British looked at it for the 'radar Red Top'' and didn't like it for the reasons you state about the 9C and preferred CW. However, I think CW was a significant step in the early 60s, perhaps a step too far and the 9C is a 'take it or leave it' proposition.

 

[MadRat]

Maybe the head on capability is worth it, but that's not a given.

The point of a SARH head on Sidewinder is to force the approaching opponent to turn. Countermeasures against a SARH missile are energy driven or trailing chaff, neither of which nullifies AIM-9C completely. Few Russian fighters had any resemblance of a SPJ let alone RWR in this timeframe. Most of the Russian fighters had short legs and to force a pre-merge turn dictated the initial contact up to a point.

 

[Rule of cool]

The point of a SARH head on Sidewinder is to force the approaching opponent to turn. Countermeasures against a SARH missile are energy driven or trailing chaff, neither of which nullifies AIM-9C completely. Few Russian fighters had any resemblance of a SPJ let alone RWR in this timeframe. Most of the Russian fighters had short legs and to force a pre-merge turn dictated the initial contact up to a point.

Turn or get shot down.

I think at best 60s fighters might have some chaff packed in behind their airbrakes, like Sea Harriers did in 1982. Even that's pushing things given how prevalent gun fighters still were back then.

In any case, I'm not talking about the capability in isolation, but if Air Forces would see that capability as worth chasing if there was no extra money allocated to it as a distinct project. If it's seen as more or less a general missile upgrade, then finding the money and resources at the expense of the 9B FGW.2 is a tough sell.

 

[Scott Kenny]

In any case, I'm not talking about the capability in isolation, but if Air Forces would see that capability as worth chasing if there was no extra money allocated to it as a distinct project. If it's seen as more or less a general missile upgrade, then finding the money and resources at the expense of the 9B FGW.2 is a tough sell.

Thing is, at most you'd be looking at a production run of about half the the size (USN ordered 1000 -C and 1000 -D). But we're talking about all of Europe here, and a historical 15k production run. So a 7500 unit run of -Cs wouldn't be a problem.

Moreover, I wouldn't expect a 50-50 split in production. Obviously there would be some Sidewinders produced for countries not operating F-104Gs, and I wouldn't expect every country operating F-104mods to buy -Cs to begin with. After all, the USN ordered ~1200 Crusaders while also only ordering 1000 AIM-9Cs.

Moreover, less than 300 AIM-9Cs were expended (or lost), as there were enough -C seekers left in the early 1980s to make into ~700 AGM-122 Sidearms.

Even assuming that every F-104G was modified** to be able to use AIM-9Cs, the total production run of F-104Gs was ~1200 (plus another 210 F-104Js that would definitely want head-on and all-weather interception capabilities. And the -Js were -Gs with the air-to-ground capabilities deleted). So further assuming that all F-104Gs and -Js were ordered with a pair of AIM-9Cs and nobody got into a shooting war to expend lots of them in a hurry, you'd be looking at an additional production run of about 3000x AIM-9Cs. Japan might prefer their ~500 to come from the US, which would make the European production ~2500.

You'd still have over 10,000 AIM-9Bs to upgrade to FGW.2!

** Couldn't be designed in, the F-104G was designed in 1959, while the AIM-9C was designed in 1963. Bummer for Lockheed, it'd be a very simple option to include during the design phase!

 

[Dilandu]

Production commonality. Though with several thousand SARH missiles it may be worth the two separate rocket production lines.

If AIM-9C production would be localized in Europe - yes, it make sence to use existing motors.

Procurement has an inertia all of its own. Going with the 9C, and perhaps with the associated 9D, means abandoning whatever portion of some 15,000 9Bs that are virtually brand new and subject to a large and therefore good value major update program. Maybe the head on capability is worth it, but that's not a given.

That's why I think that AIM-9C in Europe would be mainly paired with AIM-9B, and not AIM-9D.

 

[Dilandu]

The point of a SARH head on Sidewinder is to force the approaching opponent to turn. Countermeasures against a SARH missile are energy driven or trailing chaff, neither of which nullifies AIM-9C completely. Few Russian fighters had any resemblance of a SPJ let alone RWR in this timeframe. Most of the Russian fighters had short legs and to force a pre-merge turn dictated the initial contact up to a point.

The first Soviet fighter that got automatic chaffs disperser was Mig-21R (recon version) in mid-1960s. The frontline fighters, like Mig-21M, Mig-21FM and Mig-21bis were equipped with SPS-41 "Siren" self-defense pod (which included range deception jammer, azimuth deception jammer and speed deception jammer, as well as chaff dispersers) since early 1970s.

I wouldn't get too hung up on the sophistication of the 9Cs guidance, I don't think it's too out of place in the era. IIUC the Matra R530 had pulse guidance, the British looked at it for the 'radar Red Top'' and didn't like it for the reasons you state about the 9C and preferred CW. However, I think CW was a significant step in the early 60s, perhaps a step too far and the 9C is a 'take it or leave it' proposition.

Essentially yes, true.

 

[NMaude]

For example, the USAF did much more with the Sparrow in Vietnam than the USN did.

Well that was due to the AIM-9E being a crap design.

The first Soviet fighter that got automatic chaffs disperser was Mig-21R (recon version) in mid-1960s.

MiG-21R.

 

[Scott Kenny]

If AIM-9C production would be localized in Europe - yes, it make sence to use existing motors.


That's why I think that AIM-9C in Europe would be mainly paired with AIM-9B, and not AIM-9D.

After looking at the likely production numbers, I think that Europe would build a whole lot** of AIM-9Bs, while the US would build -Cs/-Ds (and just sell a whole lot more -Cs if not -Ds).

** At least 10,000, maybe 12,000.

 

[Dilandu]

So let's work out the timeline:

* It stand to reason that "Lockheed" - with its connections in industry and military - would get a notion about Navy working on SARH version of Sidewinder somewhere around the first testing. Which, AFAIK, started about 1958-1959, with first sucsessfull test in 1959;

* Assuming that Kelly Johnson got interested and suggested adding AIM-9C on F-104 as head-on capability, we could expect "Lockheed" starting to look about required radar modifications somewhere around 1960-1962;

* The full-scale testing of AIM-9C started around 1965, so it left about three years (1962-1965) for "Autonetics" to develope a NASARR F15A-41B version (NASARR F15A-41C ?) adapted to work with AIM-9C seeker;

* The AIM-9C missile was adopted into USN service somewhere between 1965 and 1967 (exact data is a bit unclear), so it stand to reason that "Lockheed" would start to promote the F-104G with head-on attack capability upgrade starting from 1965;

* Assuming "Lockheed" typical agressive promoting, and European interest, we could except modernization orders starting from 1966-1968. It's a quite good moment for "Lockheed", because it's American production of F-104 was just finished, and it have a lot of experienced personnel and equipped facilities capable of handling a refit of large number of planes;

* It's reasonable to expect a major interest from Canada, Japan and Spain (who are most interested in interception capabilities of F-104), later Denmark, Belgium and Netherlands, somewhat more limited interest from Germany and Norway (who are more interested in strike capabilities). Italy would likely pass, preferring to wait till the F-104S would be available;

* The first deliveries of both modified planes and newly-ordered AIM-9C missiles could be expected in 1968-1970 timeframe. Around the same time, "Autonetic" and "Motorola" would likely start to look into ways of improving the missile for futher sales. And likely would start to work on dual-beam version;

* It could be reasonably suggested that F-104 with AIM-9C upgrade could have their first combat in Indo-Pakistan War of 1972 (Jordan managed to smuggle some units to Pakistan, despite embargo). If it would be sucsessfull (a few more Mig-21 downed in head-on attacks), we could expect more interest to the weapon, especially toward the proposed low-altitude upgrade;

* The low-altitude version of AIM-9C (AIM-9C Block 2? AIM-10 maybe?) could be expected in 1973-1975 timeframe. Since it would face competition from AIM-7 Sparrow-equipped F-104S (from Fiat) and F-4 Phantom II (which started to saturate the market), it would most likely be of interest mainly for the nations that buy second-hand F-104 from Europe. Still, an interest from Spain, Japan, Turkey, Taiwan and Greece could be expected;

* By late 1970s, the limited possibilities of further improvement and competition from improved, all-aspect IR-guided Sidewinder's would likely cause SARH-guided Sidewinders to fell out of favor. Still, due to large supplies produced and abundance of second-hand F-104 on market, the dual-beam versions would likely stay till the end of Cold War.

 

[NMaude]

* By late 1970s, the limited possibilities of further improvement and competition from improved, all-aspect IR-guided Sidewinder's would likely cause SARH-guided Sidewinders to fell out of favor. Still, due to large supplies produced and abundance of second-hand F-104 on market, the dual-beam versions would likely stay till the end of Cold War.

By the late 70s radar-seeker technology would've had significant advances enabling a fairly sophisticated 5" diameter SARH-seeker to be designed, built and tested.

 

[Rule of cool]

I wouldn't over egg this pudding.

Firstly, I think the customer base is pretty small in those F104 operators who in the early-mid 60s have a particular interest in interception rather than (or in addition to) air superiority, I think posts have identified these quite well.

Secondly, if the USN F8 loadout is any guide, and I think it is, the 9C will be used alongside the IR 9B/FGW.2 on the same mission, maybe 1:1, 2:2 or 3:1 rather than a wholly a 9C load. This would further limit the number of missiles purchased and as a result the resources invested into this project. The customers will still want the vast majority of the 9Bs and FGW.2s and the 9Cs will be seen as an addition to that.

Personally, I like the idea but think if a consortium of 3-4 F104 customers managed to buy ~1,000 9Cs that would be about the extent of the programme. Perhaps this would come at the expense of maybe 2,000 9B to FGW.2 conversions, leaving 12-13,000 still converted.

Or am I deluding myself?

 

[NMaude]

Is the FGW.2's tri-services designation the AIM-9F?

 

[Rule of cool]

Is the FGW.2's tri-services designation the AIM-9F?

Yes, its european rebuild of european built 9Bs. USAF 9Es are also rebuilds, but were a touch earlier and have a different front end.

 

[Scott Kenny]

* Assuming "Lockheed" typical agressive promoting, and European interest, we could except modernization orders starting from 1966-1968. It's a quite good moment for "Lockheed", because it's American production of F-104 was just finished, and it have a lot of experienced personnel and equipped facilities capable of handling a refit of large number of planes;

* It's reasonable to expect a major interest from Canada, Japan and Spain (who are most interested in interception capabilities of F-104), later Denmark, Belgium and Netherlands, somewhat more limited interest from Germany and Norway (who are more interested in strike capabilities). Italy would likely pass, preferring to wait till the F-104S would be available;

Best part is that this would be a relatively small modification without the dual-beam radar. More or less half of whatever wiring harness the F-8 had in and running to the cheek pylons. (unless you want to get crazy and add Y pylons to the F-104 cheeks, to carry 4x AIM-9s on the cheeks and 2x on the wingtips?)

So it'd be a trivial upgrade to aircraft-yet-to-be-completed, and something that the end user could probably do in regularly scheduled depot maintenance to aircraft-already-in-service. Once the bribery scandal hits the media, further sales are going to be unlikely so refits are the plan of the day instead of early selling-off of any airframes built before the SARHwinder was standard equipment for the F-104G.

* The low-altitude version of AIM-9C (AIM-9C Block 2? AIM-10 maybe?) could be expected in 1973-1975 timeframe. Since it would face competition from AIM-7 Sparrow-equipped F-104S (from Fiat) and F-4 Phantom II (which started to saturate the market), it would most likely be of interest mainly for the nations that buy second-hand F-104 from Europe. Still, an interest from Spain, Japan, Turkey, Taiwan and Greece could be expected;

It'd probably be AIM-9C-1, the CIM-10 was BOMARC.

Or maybe FGW.3, since I don't believe the US would be using any of these. US designation place-holder might be AIM-9K in this case.

Personally, I like the idea but think if a consortium of 3-4 F104 customers managed to buy ~1,000 9Cs that would be about the extent of the programme. Perhaps this would come at the expense of maybe 2,000 9B to FGW.2 conversions, leaving 12-13,000 still converted.

With as relatively easy as the backfit would be, I think there's good cause for every F-104G to eventually be fitted with the SARHwinder capability. Then it's just a matter of the various national air forces wanting to buy any missiles.

As we've thought it out, adding a head-on shot capability would be a pretty good option for just about everyone, even Germany and Norway. Not to mention an all-weather potential in European winter (which would speak to running the wiring out to the wingtips despite the weight penalty)! And even Germany operated two full wings of F-104Gs as interceptors, so there's at least 300 missiles for them.

Is the FGW.2's tri-services designation the AIM-9F?

Yes.

 

[Dilandu]

By the late 70s radar-seeker technology would've had significant advances enabling a fairly sophisticated 5" diameter SARH-seeker to be designed, built and tested.

But I doubt that pulse-doppler seeker could be implemented on such small missile before 1980s. And by late 1970s there would be IR-guided all-aspect missiles in service. So the niche for SARH-Sidewinder would be even more limited.

 

[Dilandu]

Best part is that this would be a relatively small modification without the dual-beam radar. More or less half of whatever wiring harness the F-8 had in and running to the cheek pylons. (unless you want to get crazy and add Y pylons to the F-104 cheeks, to carry 4x AIM-9s on the cheeks and 2x on the wingtips?)

So it'd be a trivial upgrade to aircraft-yet-to-be-completed, and something that the end user could probably do in regularly scheduled depot maintenance to aircraft-already-in-service. Once the bribery scandal hits the media, further sales are going to be unlikely so refits are the plan of the day instead of early selling-off of any airframes built before the SARHwinder was standard equipment for the F-104G.

Logical - while SOME additional production is possible, it would likely not be significant, and mostly would be relegated to Canadian or European producers.

It'd probably be AIM-9C-1, the CIM-10 was BOMARC.

Or maybe FGW.3, since I don't believe the US would be using any of these. US designation place-holder might be AIM-9K in this case.

Hm, an argument.

With as relatively easy as the backfit would be, I think there's good cause for every F-104G to eventually be fitted with the SARHwinder capability. Then it's just a matter of the various national air forces wanting to buy any missiles.

As we've thought it out, adding a head-on shot capability would be a pretty good option for just about everyone, even Germany and Norway. Not to mention an all-weather potential in European winter (which would speak to running the wiring out to the wingtips despite the weight penalty)! And even Germany operated two full wings of F-104Gs as interceptors, so there's at least 300 missiles for them.

Exactly my thought. Didn't knew that Germans operated two wings as dedicated interceptors, thanks for the data!

 

[Dilandu]

It'd probably be AIM-9C-1, the CIM-10 was BOMARC.

Or maybe FGW.3, since I don't believe the US would be using any of these. US designation place-holder might be AIM-9K

There are two non-assigned numbers, 82 and 83. The AIM-82, IRRC, was planned to be assigned to 1970 project of next generation AAM, that didn't go further than paper. So in theory it could be re-used for dual-beam AIM-9C-1 version.

 

[Scott Kenny]

There are two non-assigned numbers, 82 and 83. The AIM-82, IRRC, was planned to be assigned to 1970 project of next generation AAM, that didn't go further than paper. So in theory it could be re-used for dual-beam AIM-9C-1 version.

Because it'd still be a development out of the AIM-9 program, I think it would stick with that number series.

Again, assuming that the US used any. I really think it'd just have a place-holder equivalent like the FGW.2 aka AIM-9F.

 

[Dilandu]

Because it'd still be a development out of the AIM-9 program, I think it would stick with that number series.

Again, assuming that the US used any. I really think it'd just have a place-holder equivalent like the FGW.2 aka AIM-9F.

Some export name, like Radwinder (Radar Sidewinder) could be used, I think.

 

[Dilandu]

Again, assuming that the US used any.

A point. Since by late 1969 the F-104 are leaving the USAF service, they might not get AIM-9C refit.

On the other hand, the National Guard have four squadron with F-104, specifically dedicated to interceptor duty. So they might get some refitted F-104 and AIM-9C - if Lockheed would be willing to do the work at reduced price (since having no US F-104 equipped with missiles that Lockheed marketed would be bad for buisness).

 

[Archibald]

Could this help F-104C in Vietnam ?

 

[Dilandu]

Could this help F-104C in Vietnam ?

I seriously doubt that - by the time F-104 upgrade with AIM-9C would be available (1966-1967), the Starfighters would already be slated for replacement. And I'm not sure that USAF would be willing to spend any more money on refitting the planes, that would be removed from service in just few years.

More importantly, USAF would likely not be interested in AIM-9C at all. They have SARH Falcon's (both AIM-4 and AIM-26) and AIM-7 Sparrow to fit the role. Each of those missiles is more advanced and capable than AIM-9C. They have no real motivation to even try it.

The only possibility I see if that Lockheed would push for USAF's AIM-9C upgrade - mainly because promoting the weapon that wasn't adopted into service isn't good for foreign sales. It's possible, that some number of F-104C might be refitted for "field testing" of AIM-9C, and sent to Vietnam. But generally, I doubt USAF would have much use for them. National Guard, on the other hand, would likely be interested in cheap but capable upgrade, so they could order such during fighter's transfer preparation overhaul.

 

[pathology_doc]

At the same time as you're pushing the SARH seeker head for Starfighter users, you can be pushing it for Chaparral and Sea Chaparral users...

 

[Dilandu]

At the same time as you're pushing the SARH seeker head for Starfighter users, you can be pushing it for Chaparral and Sea Chaparral users...

True. While the original AIM-9C would not be very efficient due to seriously limited low-altitude performance, it would still provide Chaparral with head-on and crossing shot capability for the cost of one primitive illumination radar (of pulse-doppler variery) and 15-Kw generator; both could easily fit on original chassis.

And the dual-beam version would be a MAJOR step forward, especially for Sea Chaparral. Low-altitude performance would be basically as good as for RIM-24 "Tartar". Worse than RIM-7 "Sea Sparrow", of course - can't beat Doppler CW seeker - but it would be much more compact system, capable of fitting on even small warships (like FRAM's, Knox-class and Pegasus-class).

 

[NMaude]

But I doubt that pulse-doppler seeker could be implemented on such small missile before 1980s.

I suspect that such a seeker would be possible in the late 70s (1978/79). Keep in mind that when the AIM-9C project started in 1958 the integrated circuit had just been invented and when the AIM-9C entered service (IIRC the AIM-9C seeker used discrete transistor circuitry) semiconductor ICs were still a very expensive niche-item. But by the time the 1970s ended ICs were not only in mass-production but both advanced analogue and digital ICs were available (The AGM-122A Sidearm conversion of the AIM-9C IIRC used early 80s tech).​

 

[Dilandu]

I suspect that such a seeker would be possible in the late 70s (1978/79). Keep in mind that when the AIM-9C project started in 1958 the integrated circuit had just been invented and when the AIM-9C entered service (IIRC the AIM-9C seeker used discrete transistor circuitry) semiconductor ICs were still a very expensive niche-item. But by the time the 1970s ended ICs were not only in mass-production but both advanced analogue and digital ICs were available (The AGM-122A Sidearm conversion of the AIM-9C IIRC used early 80s tech).​

Hm. Maybe I was too skeptical about late 1970s electronics...

 

[NMaude]

Hm. Maybe I was too skeptical about late 1970s electronics...

For example in the 1970s Fairchild Semiconductor* was the Intel of analogue-electronics especially when it came to operational-amplifier (Op-Amps) ICs, they were the creator of the groundbreaking uA741 Op-Amp IC (Which is still in generic mass-production).

*It held this position for a long time.

 

[Dilandu]

For example in the 1970s Fairchild Semiconductor* was the Intel of analogue-electronics especially when it came to operational-amplifier (Op-Amps) ICs, they were the creator of the groundbreaking uA741 Op-Amp IC (Which is still in generic mass-production).

*It held this position for a long time.

Yes, but I'm still not sure that you could fit multiple narrow-band filters into Sidewinder body on 1970s tech.

 

[NMaude]

Yes, but I'm still not sure that you could fit multiple narrow-band filters into Sidewinder body on 1970s tech.

Are you referring to the AGM-122A's seeker electronics or the AIM-9C's?

 

[Archibald]

Some export name, like Radwinder (Radar Sidewinder) could be used, I think.

Perfect !

 

[NMaude]

Some export name, like Radwinder (Radar Sidewinder) could be used, I think.

What about Raywinder?

 

[Dilandu]

Are you referring to the AGM-122A's seeker electronics or the AIM-9C's?

The AIM-9C ones. The AGM-122A electronic solved much simpler problem - homing on enemy radar. It wasn't concerned about sidelobe echo, or ground clutter at all; the enemy radar pulses were so much stronger than the echo, that a very simple filters could completely remove clutter & other stuff.

Making the AIM-9C seeker capable of pulse-doppler scanning would be much more complex. It would require a large set of filters, capable of creating ambiguous range intervals. I'm still not sure, that required 1970s electronic would fit(

 

[Dilandu]

Perfect !

Thanks)

What about Raywinder?

Sounds good, too)

 

[Dilandu]

Okay, let's try timeline for land/sea based version?

* About 1965, US Army would likely notice the AIM-9C being actively promoted by Lockheed. The year is important; around 1965, the US Army finally gave up on Mauler and cancelled the program. The MIM-72 Chaparral, instead of temporary measure, became the backbone of US Army air defense for foreseeable future;

* The idea of fitting AIM-9C on Chaparral - with a simple illumination radar, slaved to radar sight - came into mind of someone from Chaparral development team. While the Army in general weren't much interested, the Navy liked the concept enough, to propose cooperation in "head-on capable Chaparral" development;

* The first version of "Improved Chaparral" is tested somewhere around 1967-1968. It's basically the same Chaparral, with the addition of 16-kw pulse-doppler illumination radar (the doppler mode is for aiming, so the radar could discriminate ground clutter) and additional diesel generator on same M730 chassis. The radar is slaved to optical sight (a primitive scope is added to make it possible to use radar as sight also), and provided with large 1-meter dish to make beam as tight as possible;

* In general, the "Improved Chaparral" (I-Chap) is not very impressive. While system demonstrated head-on and cross-shot interception capability, the ground clutter made it impossible to use AIM-9C missiles against target lower than 500 meters overland (somewhat better over sea). Still, it worked better - and have radar for nighttime and poor visibility - so Army started to deploy I-Chap's in 1969, as OTL, instead of basic model;

* The Army is generally satisfied with Improved Chaparral system, and mainly worked on making it's radar capable of search & scan for target. The Navy, though, is not satisfied with Improved Sea Chaparral performance. While system is fit on several FRAM destroyers, Knox-class frigates and small ships (like landing ships and minesweepers), its poor low-altitude performance preclude from it's wider deployment;

* So in 1970s, the Navy started to seek for solution, and came with a two-beam version. Since the illumination radar of I-SeaChap is much simpler than aircraft radar, it didn't took much time to work out the solution;

* In 1972-1973, Navy and Army deploy a Super Chaparral system - with a two-beam illumination radar, and low-altitude AIM-9C-2 missile. It's now capable of intercepting targets as low as 150-200 meters overland, and 30-50 meters over sea. The Army version also have radar dish capable of separate search & scan mode, so the system could now be called fully all-weather;

* The low-altitude model is mainly used as additional armament for small ships, as plug-in armament for refitted ships and auxilarities. Iowa's would likely got them in addition to Vulcan cannons;

* In 1975, Navy, finally fed up with multiple confusing designations for the SARH Sidewinders (the official designation is AIM-9C, but the export designation is Radwinder, the surface-launched version is MIM/RIM-72C, and there are subtypes, like European version with AIM-9B motor!) officially pushed for AIM/MIM/RIM-82 Radwinder designation, re-using the old unused number;

* Due to large number of Radwinder missiles in service and continued production, the Navy in late 1970s decided to invest into developing a pulse-doppler version, hoping that progress in digital electronic would overcame technical limitations;

* In mid-1970s, USMC - who didn't like the idea of having separate MIM-72 Super Chaparral SAM and M163 Tracked Vulcan gun - put at effort to develope the "common turret", which combine the Vulcan gun mount and Super Chaparral radar and missile rails. The resulting system, called Vulparal (Vulcan-Chaparral) is deployed in limited numbers on LTV7 chassis as LTVAA system;

* In early 1980s, US Army, worried about the problems with "Sergeant York" SPAAG, desided to adapt USMC's Vulparal turret as "intermediate" solution. To solve the problem of basic Vulcan gun - which is now considered as not powerful enough - the 25-mm GAU-12/U Equalizer cannon is fitted instead;

* So when in 1984-1985 the numerous problems with "Sergeant York" became obvious to public, the Army just shrugged and pushed Vulparal as "proven solution that we, of course, always have as fallback option". Renamed "Vulpine" to sound better, the system is deployed on M2 Bradley chassis;

* In early 1980s, the Navy pulse-doppler Radwinder enter service also, finally solving the ground clutter problem completely;

 

[Scott Kenny]

I'm not sure the Army would go for radar-Chaparral, as it would require a fighter-sized targeting radar to be installed on the mount, along with the 400hz generator to power said radar. Even as a generator-on-a-trailer, that's asking for a lot of extra fuel and load.

 

[Dilandu]

I'm not sure the Army would go for radar-Chaparral, as it would require a fighter-sized targeting radar to be installed on the mount, along with the 400hz generator to power said radar. Even as a generator-on-a-trailer, that's asking for a lot of extra fuel and load.

Well, the M730 chassis is rated for six-ton payload, and Chaparral mount is about two tons at most. So there are reserves to fit the generator and radar.

And the radar is not exactly targeting. It's illumination only radar; it's slaved to the optical sight, with no independent capability to search or track (at least initially). Basically the radar is only illuminating the target tracked by optical sight. A much simpler system than any kind of proper tracking radar.