If the F-111 never happened... Done!

[Weaver]

I think a strike-F-4 would be fast enough, but the RAF found that doing the low-level role for a few years before they shifted to air-defence (after the Jaguar came in) absolutely ate the airframe life, which was one of the time factors leading into the Tornado F.3 decision. If you were building a strike F-4 from scratch with a USAF budget, one of the things I think you'd need to do is some serious structural strengthening to absorb that. Of course, that adds more weight, which in turn adds to fuel burn, which is a bad thing, but on the other hand, it makes wing-loading higher which is an actual advantage in low-level flight.

Something I've often thought of, not neccessarily for a strike F-4 but just for F-4s in general, is that they could have made specialized air-to-ground stores for it that fitted in the Sparrow bays. The advantage would be lower drag and not sterilising wet pylons that could then be used for fuel. Air-to-ground Sparrows, perhaps with a Maverick seeker, would be the obvious option. Another might be cluster bombs consisting of 8" diameter "cans" stacked nose-to-tail, ejecting from the aircraft as a single store but then splitting up after a time delay.

A Sparrow is 12ft long with an 8"diameter and weighs 500lb.

[Charlie_c67]

Isn't the AGM-45 Shrike pretty much the same size? Instant Wild Weasel.

[Spino]

First of @Spino great work as always. I bow to your 3D prowess 

The core question of cancelling the F-111 really depends on timing. If it was early in the program say early 60's then the USAF would probably just start a new program. It it was later in the program, then the options become more interesting. The only real contemporary to the F-111 at that time was the TSR.2. For both their primary mission was fly real-low, real-fast, drop whatever fun sticks they had and run like hell, in all kinds of weather. The only other thing by late 60's that kinda fits that would be the Mirage IV but there's no way the USAF would consider a French aircraft. The Vigilante was too far out of production by that point but maybe some kind of new de-navalized, just for USAF, derivative could be an option. A "strike" centered F-4 could be possible but the issue would be range and on the deck speed. While you could find a different engine to help (Spey or maybe some derivative of the TF-30 assuming it had gotten far enough along) I'm not sure how well the F-4 could really do at true nap-of-the-earth mission profiles.

I mentioned on @Spino F-8 build but if they were looking for something really intermediate, Vought had a couple of supersonic attack Crusader ideas they had been kicking around in the 60s. Something like what would become the YA-7F but with an afterburner and de-navalized could be an option. Say combine it with the Spey-Sader proposal they did there might be something there. 

Lots of juicy ideas in this. 

Indeed.  I believe the YA-7F did actually have an afterburner, and that it was part of the reason that the YA-7F got a lengthened fuselage.  I don't think any fighter-sized jet engine at that time could make enough power to make a plane like that supercruise.  The sources I have found say that it had an F100-220 with afterburner.  An F-8 derivative would make for an interesting option for sure, maybe make it a bit bigger and either twin-engined or a single F101 or something.

[Weaver]

Isn't the AGM-45 Shrike pretty much the same size? Instant Wild Weasel.

I know I've read somewhere that there's a reason why you can't fire Shrikes from an AIM-7 bay, but I'm damned if I can remember what it is...    

[Charlie_c67]

Probably something to do with the seeker head not acquiring or some such. Easily whiffed out with a RIO/WSO on board...

[Weaver]

First of @Spino great work as always. I bow to your 3D prowess 

The core question of cancelling the F-111 really depends on timing. If it was early in the program say early 60's then the USAF would probably just start a new program. It it was later in the program, then the options become more interesting. The only real contemporary to the F-111 at that time was the TSR.2. For both their primary mission was fly real-low, real-fast, drop whatever fun sticks they had and run like hell, in all kinds of weather. The only other thing by late 60's that kinda fits that would be the Mirage IV but there's no way the USAF would consider a French aircraft. The Vigilante was too far out of production by that point but maybe some kind of new de-navalized, just for USAF, derivative could be an option. A "strike" centered F-4 could be possible but the issue would be range and on the deck speed. While you could find a different engine to help (Spey or maybe some derivative of the TF-30 assuming it had gotten far enough along) I'm not sure how well the F-4 could really do at true nap-of-the-earth mission profiles.

I mentioned on @Spino F-8 build but if they were looking for something really intermediate, Vought had a couple of supersonic attack Crusader ideas they had been kicking around in the 60s. Something like what would become the YA-7F but with an afterburner and de-navalized could be an option. Say combine it with the Spey-Sader proposal they did there might be something there. 

Lots of juicy ideas in this. 

Indeed.  I believe the YA-7F did actually have an afterburner, and that it was part of the reason that the YA-7F got a lengthened fuselage.  I don't think any fighter-sized jet engine at that time could make enough power to make a plane like that supercruise.  The sources I have found say that it had an F100-220 with afterburner.  An F-8 derivative would make for an interesting option for sure, maybe make it a bit bigger and either twin-engined or a single F101 or something.

During development of the YA-7F, LTV experimented with putting the F100-PW-220's afterburner on the existing TF41. This produced 26,000lb thrust rather than the 23,770lb of the standard F100-PW-220. However the two prototypes used the latter, probably because it was immediately available as a non-developmental item.

Having said that, it's important to remember that the A-7 was NOT just a short F-8, so the YA-7F wasn't a "near F-8" either. It's non-VI wing had greater span, greater thickness and less sweep than the F-8's, so even with more power it still wasn't very supersonic (Mach 1.2). It also had a much bigger intake than the F-8, and in fact, there were very few common structural components between the two aircraft at all.

The A-7 had a very advanced nav-attack system for it's day. You could easily see it becoming the basis for a strike F-4 variant. When various "super Phantoms" were being looked at in the 1980s, some truly huge conformal tanks were proposed. You could easily evisage similar tanks being developed in the late 1960s for a Spey-powered strike F-4.

[Weaver]

Probably something to do with the seeker head not acquiring or some such. Easily whiffed out with a RIO/WSO on board...

Well I thought that, but then the Sparrow seeker has to acquire the target too, and it's only detecting echos from an AI radar not outgoing signals from a large, ground-based AD radar.