Fitting F-111 wing consoles on F-14?

[Scott Kenny]

This is a really weird question, I know.

Would it be possible to bolt F-111 wings onto an F-14? This would give the resulting plane 4 extra hardpoints capable of holding Phoenixes, though it's unlikely that would be an option from a carrier. I'm mostly thinking in terms of the extra wing tanks in the Vark wings (especially FB-111 wings).

If possible, how wide would this make the resulting plane's wingspan?

 

[Archibald]

Pretty wild idea ! Could be tested on 1/72 models.

 

[BlackBat242]

The entire wing center section, including the sweep mechanisms etc are very different - including how far from the aircraft centerline the wing pivot points are located, etc.

 

[Scott Kenny]

The entire wing center section, including the sweep mechanisms etc are very different - including how far from the aircraft centerline the wing pivot points are located, etc.

Well, yes. But as long as the wing pivot bolts are the same diameter between the two, that makes the first step easy.

Then you need to fabricobble up the sweep mechanism connection points to match.

And then you'd end up with a Tomcat with a really absurdly wide wingspan. Varks have a wider wingspan but narrower distance between the pivot points, so the outer wing panels themselves are a lot longer.

 

[NMaude]

And then you'd end up with a Tomcat with a really absurdly wide wingspan. Varks have a wider wingspan but narrower distance between the pivot points, so the outer wing panels themselves are a lot longer.

That would make an F-14 with a very low takeoff and landing speeds, the F-111B may've been a turkey when it came to manoeuvring but apparently it was a pilot's dream when it came to being catapulted and especially when it was landing.

 

[Scott Kenny]

For example, the F14D has a spread wingspan of 64ft1.5in/19.545m, while the Oz F-111C has a spread wingspan of 70ft.

So there's 6ft extra wingspan even before you count the extra width through the wing box between the hinge pins. I'm thinking the total is going to be closer to 10-12ft extra wingspan.

So, how much wider was the F14 wing center box compared to the F-111?

 

[BlackBat242]

For example, the F14D has a spread wingspan of 64ft1.5in/19.545m, while the Oz F-111C has a spread wingspan of 70ft.

So there's 6ft extra wingspan even before you count the extra width through the wing box between the hinge pins. I'm thinking the total is going to be closer to 10-12ft extra wingspan.

So, how much wider was the F14 wing center box compared to the F-111?

Wingspan of a standard F-111 (in this case an F-111F) was 63'.

The RAAF's F-111Cs had the longer wings of the F-111B & FB-111A.

I don't have an actual number, but the below drawings show the F-111's pivot point even with the outer fuselage line while the F-14's is a little outside of that line - note that the F-14's fuselage is wider due to the space between the engines for missiles etc, while the F-111's engines are next to each other.

The other issue is that the F-111 wing CANNOT be swept to a different degree like the F-14's could - due to the inner ends of the wings being toothed to physically lock both together no matter what sweep angle is chosen. This results in the sings extendng inboard well past the pivot pins - while the F-14's wings end before the pivot pin location - the pivot pins fit into a narrow extension of the wing spar.

So adapting the F-111 wings would be a hard job with lots of "cut and modify to fit" work.

 

[Scott Kenny]

Wingspan of a standard F-111 (in this case an F-111F) was 63'.

The RAAF's F-111Cs had the longer wings of the F-111B & FB-111A.

I don't have an actual number, but the below drawings show the F-111's pivot point even with the outer fuselage line while the F-14's is a little outside of that line - note that the F-14's fuselage is wider due to the space between the engines for missiles etc, while the F-111's engines are next to each other.

The other issue is that the F-111 wing CANNOT be swept to a different degree like the F-14's could - due to the inner ends of the wings being toothed to physically lock both together no matter what sweep angle is chosen. This results in the sings extendng inboard well past the pivot pins - while the F-14's wings end before the pivot pin location - the pivot pins fit into a narrow extension of the wing spar.

So adapting the F-111 wings would be a hard job with lots of "cut and modify to fit" work.

Crud, I thought that was a plastic model thing, not on the real airplane! ( :mind blown: )

 

[TomS]

Crud, I thought that was a plastic model thing, not on the real airplane! ( :mind blown: )

I'm about 99.99% sure it is just a display model thing. Image below is from an article about a composite fitting used to repair cracking in RAAF F-111 wing pivots. You can see the shape is very different from the one shown above.

https://www.sciencedirect.com/topics/engineering/wing-pivot-fitting

Confirmed here. The jack screws that control wing sweep are interconnected in a way that does prevent asymmetric sweep, but nothing so crude as that toothed gear.

https://ocw.mit.edu/courses/16-885j-aircraft-systems-engineering-fall-2004/890c513e968a82107d00a7629db6b1c7_f_111_final_b_42_86.pdf

 

[aim9xray]

You'll note that the jackscrew is located in front of the F-111 WCS versus to the rear of the F-14 WCS. I believe that the MiG-23/27 implemented it that way too.

 

[aim9xray]

The TLAR distance between F-14 wing pivots is about 18 feet. For the F-111, it is about 11 feet. (Based on 1/72 models; large error bars. YMMV.)

Putting FB-111A/F-111B/F-111C outer wing panels on a F-14 (disregarding all other practicalities) would yield a wingspan of about 78-81 feet. E-2C wingspan is 81.0 feet.

Using 1/72 Hasegawa FB-111A wings and 1/72 Precise F-14A model blank.

 

[NMaude]

It has just occurred to me that this would be an interesting idea for a thread in the Alternative History and Future Speculation for a what-if thread where Grumman gets a couple of its' pre-production YF-14As and rebuilds them with F-111B/C wings in "What the Hell? Why not" type experiment and test-flies them (Call them YF-14Bs) in the 1970s.

 

[starviking]

It has just occurred to me that this would be an interesting idea for a thread in the Alternative History and Future Speculation for a what-if thread where Grumman gets a couple of its' pre-production YF-14As and rebuilds them with F-111B/C wings in "What the Hell? Why not" type experiment and test-flies them (Call them YF-14Bs) in the 1970s.

Longer wings for increased loiter time?

 

[NMaude]

Longer wings for increased loiter time?

Not to mention reduced landing and takeoff speeds too.

 

[Scott Kenny]

Hrm. Surprised that Grumman swapped which side of the box the sweep actuators are on, that seems like a non-trivial level of design change. Maybe it's related to the much wider wing box?

The TLAR distance between F-14 wing pivots is about 18 feet. For the F-111, it is about 11 feet. (Based on 1/72 models; large error bars. YMMV.)

Putting FB-111A/F-111B/F-111C outer wing panels on a F-14 (disregarding all other practicalities) would yield a wingspan of about 78-81 feet. E-2C wingspan is 81.0 feet.

Using 1/72 Hasegawa FB-111A wings and 1/72 Precise F-14A model blank.

View attachment 752563

Thank you for that!

And yes, the idea of Grumman swiping a couple of F-111B outer wings and sticking them on a YF-14 would be entertaining...

 

[isayyo2]

And yes, the idea of Grumman swiping a couple of F-111B outer wings and sticking them on a YF-14 would be entertaining...

Maybe rephrase the question as "What if the F-14 had an extended wingspan enabling swiveling hard points ala F-111/Tornado?"

I'm picturing additional bomb lugging capabilities like the F-4 with triple ejector racks and dual AIM-9 rails...

 

[Scott Kenny]

Well, I think that for carrier ops you'd need to leave off the wing glove pylons. Too much weight with 4000lbs per pylon on the wings, at least to recover easily.

But flying from land bases, say for RAF work? Oh, heck yes!

 

[aim9xray]

@Scott Kenny, you really need to review Mike Ciminera's lecture at View: https://www.youtube.com/watch?v=SsUCixAeZ0A particularly starting at about minute 11:30.

Also the F-111 inner pylons would physically conflict with the existing F-14 Station 1 and 8 multi-purpose pylons at max wing sweep.

Lastly, the actual wing pivot design greatly differs between the F-111 and the F-14; in no way are they compatible or interchangeable (wing carrythrough structure/pivot <--> outer wing panel).

But Whif away!

 

[CV12Hornet]

I do not recommend those swiveling wing pylons. They had absolutely murderous effects on drag, and thus range - an F-111B has less CAP loiter time than a Tomcat both loaded with six Phoenix, despite the Tomcat also having to deal with the drag of two drop tanks and still having less fuel in that configuration.

If you fit those wings, it's solely for the extra fuel and lift - 700 extra lbs of fuel isn't nothing.

 

[Scott Kenny]

Also the F-111 inner pylons would physically conflict with the existing F-14 Station 1 and 8 multi-purpose pylons at max wing sweep.

They're that close to the wing glove?

Crap.

Guess that makes an either-or for the inner wing pylons or the wing glove pylons.

I do not recommend those swiveling wing pylons. They had absolutely murderous effects on drag, and thus range - an F-111B has less CAP loiter time than a Tomcat both loaded with six Phoenix, despite the Tomcat also having to deal with the drag of two drop tanks and still having less fuel in that configuration.

If you fit those wings, it's solely for the extra fuel and lift - 700 extra lbs of fuel isn't nothing.

Are you sure about that? F-111B are supposed to have a 1800nmi range, about 3.5 hours flight time, with 6x Phoenix.

 

[aim9xray]

From Tailspin Turtle:

According to the F-111B SAC, when it was loaded with full internal fuel and six Phoenixes, it weighed 77,566 lbs and required 11 knots wind-over-deck on a tropical day for launch; the F-14A, not surprisingly, weighed almost 7,000 lbs less but, surprisingly, required 16 knots wind-over-deck, five knots more than the F-111B. Moreover, at its takeoff gross weight the F-111B was carrying 3,000 lbs more fuel than the F-14, making the difference in takeoff gross weight for the same amount of fuel and weapons carried only 3,866 lbs, or 5%, not exactly the amount or percentage difference that most would have guessed given all the negative publicity garnered by the “Sea Pig.” With that additional fuel, the F-111B could loiter on station for 1.5 hours with the combat fuel allowance assuming an acceleration to 1.5 Mach; the F-14A with the two external tanks of overload fuel, and with the same combat Mach number (one has to read the SACs very closely), could only loiter for 1.1 hours.

https://thanlont.blogspot.com/2011/01/f-111b-versus-f-14a-one-more-time.html

 

[Manuducati]

Don't forget that longer wings would move the center of lift significantly backwards with the 68° sweep. Not sure the flight control system and surfaces could handle that.
Its spotting factor on (and below) the deck would be augmented as well.

 

[BlackBat242]

Crud, I thought that was a plastic model thing, not on the real airplane! ( :mind blown: )

I'm about 99.99% sure it is just a display model thing. Image below is from an article about a composite fitting used to repair cracking in RAAF F-111 wing pivots. You can see the shape is very different from the one shown above.

Confirmed here. The jack screws that control wing sweep are interconnected in a way that does prevent asymmetric sweep, but nothing so crude as that toothed gear.

Thanks... the drawing I was going by is labeled as an official General Dynamics drawing, not something for models - which is Why I posted it.

Your info is much more detailed and proves my drawing to be someone's fake-up.

 

[TomS]

Thanks... the drawing I was going by is labeled as an official General Dynamics drawing, not something for models - which is Why I posted it.

Your info is much more detailed and proves my drawing to be someone's fake-up.

Glad to help.

I've seen yours before; I wonder if it might be an official drawing of the display model.

 

[TomS]

Hrm. Surprised that Grumman swapped which side of the box the sweep actuators are on, that seems like a non-trivial level of design change. Maybe it's related to the much wider wing box?

Or just a different design team chose a different option. Grumman came late to the F-111 and didn't have anything to do with designing the wings or pivot mechanism. That was GD's territory.

 

[NMaude]

So if Grumman had been serious about this and got one of its YF-14A pre-production aircraft after it had completed its required test-flights (And was therefore available) and got together with GD what structural modifications would be required to its' fuselage to enable mounting a pair of F-111B wings onto it?

 

[Arjen]

Quite a lot if Grumman had elected to fix the F-111B in the swept-forward position. It might even fly.
Integrate them to produce a working, flying swing-wing VarkTomcat hybrid, and I suspect it would end up, many many years later, looking like neither. But, why bother?

 

[NMaude]

Integrate them to produce a working, flying swing-wing VarkTomcat hybrid, and I suspect

Incomplete sentence, you suspect what?

 

[Arjen]

I inadvertently posted a reply before I had finished typing. Sorry to keep you on tenterhooks

 

[Arjen]

For my next trick, I present to you: the Sopwith Jet Camel.

 

[aim9xray]

So if Grumman had been serious about this and got one of its YF-14A pre-production aircraft after it had completed its required test-flights (And was therefore available) and got together with GD what structural modifications would be required to its' fuselage to enable mounting a pair of F-111B wings onto it?

The. Wing. Pivots. Won't. Fit.

That said, one approach is to redesign the F-111B wing to mate with the F-14 WCS box. Advantage: Double slotted flaps, more fuel per OWP, adds one outboard Phoenix Station (not two due to interference with existing Station 1 and 8). Move screwjack to interface with the aft spar of the OWP wing box. Oh, and you are going to take a drag hit because the F-111B wing has a higher thickness/chord ratio.

On the other hand, redesign the F-14 wing to be a little more F-111B-like and have greater aspect ratio, hard points and double slotted flaps?

Evaluate the F-14 WCS for increased stress loads due to greater moment arm on OWP from external Phoenix, and possible greater torque loads induced from wing in aft sweep from Center of Pressure aft travel.

Evaluate horizontal stabs for increased stress/buffeting from double slotted flaps and outboard Phoenix (at high wing sweep).

Evaluate increased fuselage loads due to increased max landing weight (PDOOMA: +4500 lbs ... you're gonna need bigger engines), with attention to existing fuselage fatigue hot spots (such as the 569 bulkhead).

And oh, the AMCS/AWG-9 can't guide more than six Phoenii at a time. So, get Hughes to mod the system you say; I say get out your checkbook and get ready to pay out some large HughesBucks checks.

All this when Grumman is teetering on the edge of bankruptcy and the Navy is looking at "Peace Dividend" outyear budgets.

If you want a real Whiffer, cancel the F-14 for a carrier-capable TSR.2. Ready, Set, Go!

 

[Scott Kenny]

So if Grumman had been serious about this and got one of its YF-14A pre-production aircraft after it had completed its required test-flights (And was therefore available) and got together with GD what structural modifications would be required to its' fuselage to enable mounting a pair of F-111B wings onto it?

I don't thing you'd need a lot of structural mods to the fuselage.

You'd need new wing pivots to put the screw drive on the aft end. I believe that's not a deal breaker, but it would be an issue.

That said, one approach is to redesign the F-111B wing to mate with the F-14 WCS box. Advantage: Double slotted flaps, more fuel per OWP, adds one outboard Phoenix Station (not two due to interference with existing Station 1 and 8). Move screwjack to interface with the aft spar of the OWP wing box. Oh, and you are going to take a drag hit because the F-111B wing has a higher thickness/chord ratio.

Huh, didn't realize that the F111B wings were thicker. That will cause some problems.

On the other hand, redesign the F-14 wing to be a little more F-111B-like and have greater aspect ratio, hard points and double slotted flaps?

That'd be the other alternative. Though I'm starting to think that the swiveling hard points aren't worth the effort. Still want the extra fuel tankage, however.

 

[aim9xray]

Huh, didn't realize that the F111B wings were thicker. That will cause some problems.

They aren't necessarily thicker in absolute terms. The chord is less. That changes the denominator in the Thickness/Chord relationship. The higher the T/C ratio, the higher the induced drag at higher speeds (all else being equal). The F-104 with a 4% T/C can go real fast; the A-10 with 16% to 14% (varies across the span), not so much, even though it has more thrust.