F-104 with AIM-9C?

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Let's consider the possibility of two not very sucsessfull projects - F-104 Starfighter and AIM-9C radar-homing Sidewinder - meeting each other?

In 1960s, the F-104 capabilities as fighter and/or interceptor were seriously limited by its light armament. Essentially, F-104 was limited to tail-only attacks with Sidewinders and Vulcan cannon. Essentially no head-on attack capability of any kind till much later.

Alternative: in first half of 1960s, Lockheed, seeking ways to sell even more Starfighters, notice the Navy work on radar-guided Sidewinder version, the AIM-9C. The missile was generally unimpressive even on paper, but it was as compact as usual IR-guided Sidewinder. What's more important, its seeker was X-band and purely pulse-based (thr only way to make echo from target visible enough for tiny 4-inch antenna dish was to send powerful pulses). Insidentally, the NASARR F-15 radar, that equipped nost of F-104 fleet, was also X-band and purely pulse.

So apparently it wouldn't be exactly hard to mate F-104 with AIM-9C. The radar would require re-wiring to make its impulses readable for missile, of course. But not the complete redesign, merely a modification. The same with hardpoints - they would need additional connections to make them compatible with AIM-9C (which required tuning with radar before locking on target), but would generally remain the same type.

Sure, the efficiency of small NASARR radar & limited AIM-9C missile combo would likely be pretty poor. But on paper (which is important for sales) the combination would looks pretty attractive - adding head-on engagement capability to F-104 for a rather moderate price. And at least till Vietnam War experience, the AIM-9C problems with low altitude targets (pulse seeker has a lot of troubles with ground clutter) would not be considered serious. And as high-altitude jnterceptor, F-104 would clearly fare better than as low-altitude figher-bomber.
 
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The 9C/D had a lower thrust, longer burn motor than 9B/E so could probably get a decent engagement range with a head on shot.
Yep. And NASARR F15A-41B (from F-104G) is more powerful than AN/APQ-83 (from F-8). So we could expect somewhat better lock-on range from F-104G than from F-8. About 11-12 km versus 9 km - not much, but still better.
 
What the idea then begs is also an answer to, "How many missiles would be carried?" You need to add rails attachments which is unique to Navy versions. If you only have two AIM-9Cs then do you fire one or two at a target? I would assume in mixed carriage they would be firing two missiles at a time, so in a headon engagement this probably means two AIM-9C. In a chase would you elect one AIM-9C and one AIM-9E, or two Es?

And would this modification come at the expense of the Vulcan cannon?
 
What the idea then begs is also an answer to, "How many missiles would be carried?" You need to add rails attachments which is unique to Navy versions. If you only have two AIM-9Cs then do you fire one or two at a target? I would assume in mixed carriage they would be firing two missiles at a time, so in a headon engagement this probably means two AIM-9C. In a chase would you elect one AIM-9C and one AIM-9E, or two Es?

And would this modification come at the expense of the Vulcan cannon?
Well, the F-104G have four hardpoints for Sidewinders - two wingtip and two side rails - so a combo of two AIM-9C and two AIM-9E could be carried.

And no, it would likely not require Vulcan cannon removal. The radar modification is limited to aligning its pulses with AIM-9C working mode. Not a major redesign.
 
Just a word on the earliest Sidewinder variants and numbers for context.

9B 1958-62, 80,000 produced
9C 1965-69, 1,000 produced
9D 1965-69, 1,000 produced
9E 1968-, 5,000+ rebuilt 9Bs
9B FGW.2 1969-76, 15,000 rebuilt NATO 9Bs

In the same period the USAF (primarily) was also building AIM4 Falcons, if not in direct competition they at least were utilizing similar procurement budgets.

4C IR 1958-, ~13,000 produced
4E SARH 1958, 300 produced
4F SARH 1960, 2,700 produced
4G IR 1960, 3,400 produced
4D IR 1963, 4,000 produced + thousands more converted from 4A (SARH) & 4C (IR)

The F104 user, or more likely consortium of users, wanting to get a SARH AAM in the mid 60s would have to get in on the small USN 9C effort, rejecting the larger USAF SARH Aim4F program already being exported to Sweden and Switzerland while buying 9Bs and planning to rebuild these 9Bs into FGW.2s. Seems like a big ask, assuming it's technically easy.
 
The F104 user, or more likely consortium of users, wanting to get a SARH AAM in the mid 60s would have to get in on the small USN 9C effort, rejecting the larger USAF SARH Aim4F program already being exported to Sweden and Switzerland while buying 9Bs and planning to rebuild these 9Bs into FGW.2s. Seems like a big ask, assuming it's technically easy.
There weren't much problems with producing more AIM-9C in 1960s. Their only difference from AIM-9D was the seeker, everything else was literally the same. So if Europeans place more orders, factories would crunch out thousands more.
 
Interesting idea, compared to OTL F-104S. Which crammed SARH into the F-104 through AIM-7 Sparrow, a far bigger system. What fits into a Crusader smallish nose cone should fits inside a F-104.

Btw the Crusader got another SARH missile: the Matra R530.
 
Interesting idea, compared to OTL F-104S. Which crammed SARH into the F-104 through AIM-7 Sparrow, a far bigger system. What fits into a Crusader smallish nose cone should fits inside a F-104.
Yep. And while AIM-9C is far less capable than Sparrow, its also far smaller and better fit Starfighter's sleek aerodynamic. For high- and medium-altitude interceptions - espcially in boom & zoom mode - the AIM-9C likely would work fine. It's low altitudes where it got into troubles due to very poor clutter discrimination and antenna large angle.
 
Yep. And NASARR F15A-41B (from F-104G) is more powerful than AN/APQ-83 (from F-8). So we could expect somewhat better lock-on range from F-104G than from F-8. About 11-12 km versus 9 km - not much, but still better.
Also, from what I've read, Autonetics NASARR F15A-41B was considered somewhat more reliable than the Magnavox AN/APQ-83.

Regards
Pioneer
 
There weren't much problems with producing more AIM-9C in 1960s. Their only difference from AIM-9D was the seeker, everything else was literally the same. So if Europeans place more orders, factories would crunch out thousands more.

Sure, but it won't happen before 1965 and will be in an environment of other large Sidewinder programs.
 
Sure, but it won't happen before 1965 and will be in an environment of other large Sidewinder programs.
Well, it would basically run parallel to AIM-9D program, with the only limitation is seeker production. So it would hardly create any bottlenecks. Both AIM-9C/D production per year is much smaller than AIM-9B was just a few years before anyway. So there are industrial reserves that could be used to support additional AIM-9C procurement.
 
The main problem of the whole concept is that AIM-9C is rather hard to improve significantly in 1970s timeframe. We can't put a CW seeker on her (the antenna is too small, and would require extremely powerful CW illuminator to reliably get the echo), we can't switch on pulse-doppler (the missile body is too small for 1970s processing electronic to fit). Basically it would be the same AIM-9C till early 1980s at least.

There is one idea that just might work, though... We could try to split the illumination radar beam into two frequency-divided beams, slightly offset, one at top of another. The overlapping zone of two beams would be centered on target. The idea is, that only the target (being in overlapping zone) would produce roughly similar echo on both frequences within the range gate. Any ground clutter would not have such equality of both beams - at least within the range gate. The AIM-9C could be relatively easy modified to extract both frequences from the return signal - using a pair of filters - and compare them by amplitude, letting only the roughly similar signals pass.

It won't be as good as Doppler, of course. But it could allow AIM-9C to work reliably on altitudes about 200-500 meters over land and 30-50 meters over sea. And it could actually fit into the AIM-9C limited size.
 
Well, it would basically run parallel to AIM-9D program, with the only limitation is seeker production. So it would hardly create any bottlenecks. Both AIM-9C/D production per year is much smaller than AIM-9B was just a few years before anyway. So there are industrial reserves that could be used to support additional AIM-9C procurement.

I have no doubt that the US could supply the 9Cs to a customer or consortium of customers, if the numbers are to be believed they built 15-20,000 9Bs a year 1958-62. The US forces are so vast that the US runs a continuous production run of missiles (and aircraft) so they just switch from making one variant to the next, or run old 9Bs back through the factory to emerge as 9Es. This is why I mention both AIM 9 and AIM 4 earlier.

What I'm musing is how smaller forces buy their things. The RAAF bought a batch of 9Bs for their CAC Sabres and kept them in service through the Mirages until replaced by the Matra Magic 2 in the early 80s, similarly the batch of R30 acquired in the early 60s with the Mirages were retained until 1986 or so. IIUC Britain built 2,500 Red Tops in the 2nd half of the 60s, 2,000 for the RAF and 500 for the RN, and kept these until the Lightning left service, with no extra production or 9B to 9E or FGW.2 style conversion.

In the European F104 context AIM9B started production in Germany in 1961 and ended in 1965, these missiles than were cycled back through the production line to be converted to FGW.2 spec 1969-76. I suppose that does leave a convenient 9C/9D shaped hole in European F104 consortium missile acquisition that someone could use. However I suspect F104 customers' Politicians would be looking at their big 9B stocks and the FGW.2 programme as the way forward, a user wanting 9Cs would have to make a pretty good case.
 
What I'm musing is how smaller forces buy their things. The RAAF bought a batch of 9Bs for their CAC Sabres and kept them in service through the Mirages until replaced by the Matra Magic 2 in the early 80s, similarly the batch of R30 acquired in the early 60s with the Mirages were retained until 1986 or so. IIUC Britain built 2,500 Red Tops in the 2nd half of the 60s, 2,000 for the RAF and 500 for the RN, and kept these until the Lightning left service, with no extra production or 9B to 9E or FGW.2 style conversion.

In the European F104 context AIM9B started production in Germany in 1961 and ended in 1965, these missiles than were cycled back through the production line to be converted to FGW.2 spec 1969-76. I suppose that does leave a convenient 9C/9D shaped hole in European F104 consortium missile acquisition that someone could use. However I suspect F104 customers' Politicians would be looking at their big 9B stocks and the FGW.2 programme as the way forward, a user wanting 9Cs would have to make a pretty good case.
In general I agree, but the AIM-9C in such scenario is marketed as a new capability - not merely an improved version of existing one. For hte majority of European F-104 operators, the additon of head-on attack weapon is a highly desired capability. Especially if it could be achieved relatively cheap, by rather limited modernization of existing planes.

So while Europeans were reluctant to buy more advanced Sidewinders in 1960s - because, while better than AIM-9B, they only improved the already existing capability, not providing anything new - the AIM-9C would likely be a different thing. Because it provides a new, highly desired capability, and for moderate price.

I fully agree, that this logic isn't flawless, but it workable enough) With a good marketing, of course.
 
In general I agree, but the AIM-9C in such scenario is marketed as a new capability - not merely an improved version of existing one. For hte majority of European F-104 operators, the additon of head-on attack weapon is a highly desired capability. Especially if it could be achieved relatively cheap, by rather limited modernization of existing planes.

So while Europeans were reluctant to buy more advanced Sidewinders in 1960s - because, while better than AIM-9B, they only improved the already existing capability, not providing anything new - the AIM-9C would likely be a different thing. Because it provides a new, highly desired capability, and for moderate price.

I fully agree, that this logic isn't flawless, but it workable enough) With a good marketing, of course.

Who do you think would be likely customers in the mid 60s? I don't think West Germany wouldn't be much of a candidate, being on the front line of WW3 its task would be air superiority against Frontal Aviation and head-on attacks would be more suited to the bombers used by DA and AVMF. Japan and Norway might find head-on attacks at longer range a useful capability for their F104s, possibly Italy with its long, exposed eastern coastline.
 
SARH has more advantages over IR method than just head-on:
- pursuit shots when target drops flares
- pursuit shot when target escapes to approx. direction of sun (IR erroneously locks on on the sun within ~10° of it)
- shots through clouds (not impossible with IR, but less issues with SARH)

I lack knowledge about how long the AIM-9C's lock-on time was, though - certainly relevant for pursuit shots against targets trying to disengage.
 
SARH has more advantages over IR method than just head-on:
- pursuit shots when target drops flares
- pursuit shot when target escapes to approx. direction of sun (IR erroneously locks on on the sun within ~10° of it)
- shots through clouds (not impossible with IR, but less issues with SARH)

I lack knowledge about how long the AIM-9C's lock-on time was, though - certainly relevant for pursuit shots against targets trying to disengage.
Agree lastdingo, and considering the weather conditions in Europe (including West Germany), I would think "being on the front line of WW3 its task would be air superiority against" everything and anything that crossed its boarder on day one would be a high priority threat - be it fighter, ground attack, reconnaissance, bomber or transport aircraft/helicopter.

Regards
Pioneer
 
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Agree lastdingo, and considering the weather conditions in Europe (including West Germany, I would think "being on the front line of WW3 its task would be air superiority against" everything and anything that crossed its boarder on day one would be a high priority threat - be it fighter, ground attack, reconnaissance, bomber or transport aircraft/helicopter.

Regards
Pioneer

The Aim9C, in common with all SARH missiles, has to illuminate the target for the entire flight of the engagement. While this is fine for a deliberately set up, CGI engagement, I don't know how appropriate it would be over West Germany lousy with hundreds of Mig 19s, Mig 21s, Su7s and Il28s as well as a similar number of friendly arcraft. I think such an environment guns and fire-and-forget IR missiles would be more appropriate compared to an area with less aircraft, more tactical space that would allow more time consuming SARH missile engagements.
 
Who do you think would be likely customers in the mid 60s? I don't think West Germany wouldn't be much of a candidate, being on the front line of WW3 its task would be air superiority against Frontal Aviation and head-on attacks would be more suited to the bombers used by DA and AVMF. Japan and Norway might find head-on attacks at longer range a useful capability for their F104s, possibly Italy with its long, exposed eastern coastline.
I think Norway, Spain, Japan and Canada as most likely candidates. For them F-104 was firstly a fighter, then bomber. Italy is possible, too, albeit they might decide to wait for Sparrow integration.

SARH has more advantages over IR method than just head-on:
- pursuit shots when target drops flares
- pursuit shot when target escapes to approx. direction of sun (IR erroneously locks on on the sun within ~10° of it)
- shots through clouds (not impossible with IR, but less issues with SARH)
True, my point was that head-on attack capability was fundamental advantage.

The Aim9C, in common with all SARH missiles, has to illuminate the target for the entire flight of the engagement. While this is fine for a deliberately set up, CGI engagement, I don't know how appropriate it would be over West Germany lousy with hundreds of Mig 19s, Mig 21s, Su7s and Il28s as well as a similar number of friendly arcraft. I think such an environment guns and fire-and-forget IR missiles would be more appropriate compared to an area with less aircraft, more tactical space that would allow more time consuming SARH missile engagements.
Well, don't forget - it's a short-range missile. It did not have much of BVR capability. It's engagement time is measured in seconds. It's main use would likely be exactly the head-on attacks on high speed (in which F-104 excels), launching from relatively short distance.
 
Well, don't forget - it's a short-range missile. It did not have much of BVR capability. It's engagement time is measured in seconds. It's main use would likely be exactly the head-on attacks on high speed (in which F-104 excels), launching from relatively short distance.

The 9B/E/FGW.2 had a high thrust rocket with a 2.2 second burn time, the 9C/D had about half the thrust and a 5 second burn time. Holding the target in radar lock for 5 seconds is an eternity compared to firing the IR ones and turning away. This is why I focus on the head-on engagement, as it gives time to run the SARH flight profile.
 
The 9B/E/FGW.2 had a high thrust rocket with a 2.2 second burn time, the 9C/D had about half the thrust and a 5 second burn time. Holding the target in radar lock for 5 seconds is an eternity compared to firing the IR ones and turning away. This is why I focus on the head-on engagement, as it gives time to run the SARH flight profile.
I agree, and this is additional reason, why I specify the head-on engagement as main "marketing point" of F-104 & AIM-9C combo.
 
About potential low-altitude version with two-beam scheme (AIM-9C2 ?). It would require several modernizations of both NASARR radar, and missile.

On radar side:

* A dual feed horn (one above other) oriented in such way to produce a narrow beam overlap zone directly at antenna boresight;
* A coaxial magnetron with travelling wave tube on exit, capable of very fast switching between two frequences;
* A two-way diplexer waveguide, dividing the output by frequency between feed horns;

The result would be two beams - one above other, both slightly offset from boresight - with the narrow overlap zone directly on boresight. Only the targets in overlap zone would give roughly equival echo on both frequences; targets outside the overlap zone would give noticeable greater one or other component.

On missile side:

* A high-pass diplexer to divide the incoming signal by frequency;
* A second amplifier channel to boost second frequency;
* A transistor-based amplitude comparator, to compare both frequences;
* A logical circuit that would "let through" only the signals with roughly equival frequency components (i.e. echo from the target set in narrow overlap zone);

Such modernization - theoretically! - could lower minimal interception altitude to about 50-300 meters (depending on surface - over sea results would be better than over land - and interception geometry - look-up would give sugnificantly better results than look-down). Worse, than Doppler; better, than nothing.

Would likely not cause much interest from NATO customers - who would already be switching on either F-4 or F-104S with Sparrow integration by early 1970s - but could be very attractive to second-hand F-104 buyers, like Turkey or Pakistan.
 
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The Aim9C, in common with all SARH missiles, has to illuminate the target for the entire flight of the engagement. While this is fine for a deliberately set up, CGI engagement, I don't know how appropriate it would be over West Germany lousy with hundreds of Mig 19s, Mig 21s, Su7s and Il28s as well as a similar number of friendly arcraft. I think such an environment guns and fire-and-forget IR missiles would be more appropriate compared to an area with less aircraft, more tactical space that would allow more time consuming SARH missile engagements.
Thank you Rule of cool, for your valid analogy.

Regards
Pioneer
 
Thank you Rule of cool, for your valid analogy.
Sounds logical - so it stand to reason, that main interest in AIM-9C equipped Starfighters might came from "second echelon" NATO nations, such as Norway, Spain, Netherlands and Belgium. Higlhy likely, Canada and Japan would want such refit too; they have money and a serious need of interceptors.

And the upgraded, dual-beam version might also be of interest to such countries as Greece, Turkey, Pakistan, Jordan. Might be possible, that more non-aligned nations would show interest in buying second-hand F-104 with AIM-9C dual-beam upgrade; it would basically be next best thing to F-4 Phantom (and Phantom was expensive!)
 
Very interesting thought experiment.

Aside from Kelly Johnson's mostly-rational hatred for dealing with the USN, I think telling him that there was a SARH Sidewinder that could be mounted onto the F-104 would get his attention.

Side note, to minimize weight gain I'd put the AIM-9Cs on the side rails, not the wingtips. Minimal extra wire length getting added. If the extra wiring wasn't too heavy I'd wire all 4 pylons for AIM-9Cs.
But I think the better arming mix would be a pair of SARH and a pair of IR, so you could save some wiring weight in the wings that way.

A 10-12km head-on lockon and shoot would see the AIM-9C powered almost all the way to impact, depending on closing speeds. Sidewinders doing M2.5-3, plus whatever the target is doing, likely means a 1.5km/s closing speed.


I fully agree, that this logic isn't flawless, but it workable enough) With a good marketing, of course.
If it is Lockheed's marketing department, just add a few more millions in "client entertainment expenses" aka hookers, blow and bribes; problem solved.


On missile side:

* A high-pass diplexer to divide the incoming signal by frequency;
* A second amplifier channel to boost second frequency;
* A transistor-based amplitude comparator, to compare both frequences;
* A logical circuit that would "let through" only the signals with roughly equival frequency components (i.e. echo from the target set in narrow overlap zone);

Such modernization - theoretically! - could lower minimal interception altitude to about 50-300 meters (depending on surface - over sea results would be better than over land - and interception geometry - look-up would give sugnificantly better results than look-down). Worse, than Doppler; better, than nothing.

Would likely not cause much interest from NATO customers - who would already be switching on either F-4 or F-104S with Sparrow integration by early 1970s - but could be very attractive to second-hand F-104 buyers, like Turkey or Pakistan.
Could you pack all that stuff into the 5" Sidewinder airframe early on? Or is this something that would have to wait till the 1970s?
 
Very interesting thought experiment.
Thank you)

Side note, to minimize weight gain I'd put the AIM-9Cs on the side rails, not the wingtips. Minimal extra wire length getting added. If the extra wiring wasn't too heavy I'd wire all 4 pylons for AIM-9Cs.
Yes, basically what I proposed; AIM-9C on side rails, and AIM-9B/D on wingtips. A perfect combo for high-speed engagement. Which is what F-104 do best)
A 10-12km head-on lockon and shoot would see the AIM-9C powered almost all the way to impact, depending on closing speeds. Sidewinders doing M2.5-3, plus whatever the target is doing, likely means a 1.5km/s closing speed.
Exactly. Which means, it would be quite good weapon for fast head-on attacks from near-visual range. The whole engagement would be fast, so maintaining the radar lock would be required for just several seconds.

If it is Lockheed's marketing department, just add a few more millions in "client entertainment expenses" aka hookers, blow and bribes; problem solved.
Ahahah, true)

Could you pack all that stuff into the 5" Sidewinder airframe early on? Or is this something that would have to wait till the 1970s?
As far as I know, it's doable. All this equipment is pretty well-known and miniaturized by late 1960s. The missile would likely become a bit heavier and (maybe) slightly longer, but we are talking about percents, not orders of magnitude.
 
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Did the Crusader ever carry both Cs and Ds in the same mission?
Just thought - F-8 Crusaders were highly maneuverable planes, so it stand to reason that their pilots preferred IR-guided AIM-9D (they were sure that they could out-turn the target and get on its tail).

F-104 Starfighter, on the other hand, isn't exactly maneuverable. It is designed for high-speed attacks. So for F-104, the balanced armament of AIM-9C and AIM-9D make much more sence; make head-on pass, launch SARH AIM-9C during fast approach. If missiles missed, then accelrate, break the distance, turn and make another pass from behind, now with IR AIM-9D.
 
Let's talk about wing areas. I've checked, Crusader was 35 m2. F-104 was barely half of that, 18 m2. Just for the sake of comparison a Mirage F1 had 25 m2.
 
Just thought - F-8 Crusaders were highly maneuverable planes, so it stand to reason that their pilots preferred IR-guided AIM-9D (they were sure that they could out-turn the target and get on its tail).
Also, since Crusaders were the last fighters designed with guns as their primary weapon system, their pilots were trained to dogfight first.

IMO the SARH Sidewinders were a way to get the Navy's Best (day) Fighter some night/all-weather capabilites.


F-104 Starfighter, on the other hand, isn't exactly maneuverable. It is designed for high-speed attacks. So for F-104, the balanced armament of AIM-9C and AIM-9D make much more sence; make head-on pass, launch SARH AIM-9C during fast approach. If missiles missed, then accelrate, break the distance, turn and make another pass from behind, now with IR AIM-9D.
Boom and zoom with longer-ranged weapons.
 
IMO the SARH Sidewinders were a way to get the Navy's Best (day) Fighter some night/all-weather capabilites.
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.

Boom and zoom with longer-ranged weapons.
Essentially yes, because frankly, it's the niche where AIM-9C would work the best.
 
Would a customer going down the 9C path also be compelled to buy the 9D or could they have a mix of 9C and 9B FGW.2?
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.

On the other hand, AIM-9C provide a new capability (head-on interception), and this capability is highly desired. So I think more likely AIM-9C would be brought to supplement the existing supply of AIM-9B.
 

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