by Tommy H. Thomason

Sunday, October 4, 2009

Grumman F-111B

The misunderstood and much maligned Grumman F-111B has been of interest to me for many years. I've even written a monograph about it that can be purchased from an Amazon books supplier. (You could also write to me for purchase of an autographed copy along with a xerox of errata and additions.)

Thanks to David de Botton, Sam Fletcher, Craig Kaston, and Jim Rotramel among others, I've continued to acquire more information about the airplane.

I've updated this post occasionally, but also created a number of other posts on the F-111B. For a list see http://tailspintopics.blogspot.com/2015/03/the-complete-f-111b.html

Only seven F-111Bs flew. There were three different configurations, not counting paint schemes and detail differences: the first three, the middle two, and the final two. The first five had the short nose and translating cowl inlet; the final two the long nose and a blow-in door inlet. In 1/72 scale, the Hasegawa F-111C has the requisite long wing, translating cowl inlet, and boat tail for the fifth F-111B, which was used for the carrier landing trials. In 1/48, the Academy-Minicraft F-111C is the equivalent. All that's needed is the nose and decals. (Forget about the Revell kit for just the nose: the F-111B nose is one of the few inaccurate parts in that kit.) At least one aftermarket nose has been available in each scale in the past but these are out of production and hard to find, with the exception of a 1/48 nose by Custom Aeronautical Minatures that is available from John's Models.

Microscale Decal Sheet No. 72-132 provided markings for BuNo 151972, including the Phoenix Missile System logo. See http://modelingmadness.com/scotts/decals/super/72/ss72132.htm. It's long out of production but you might be able to find it on eBay.

In any event, for a time these were superseded by 1/72 and 1/48 conversion kits from Pete's Hangar, which in the past had been available from Victorian Hobby Centre in Australia. Unfortunately, they are now out of stock and Pete is no longer with us to supply more.

Pete's conversion includes the F-111B short nose, the complete launch bar nose gear in brass (1/72) or plastic (1/48) with resin wheels, F-111B main wheels, the IR detection pod, a tail hook installation, and paint/markings instructions and decals for the first five airplanes, including the big blue Phoenix Missile System log that was on the tail of 151971 and 972. The original release did not include the early knife-edge boat tail or the F-111B specific speed bumps but these parts have now been added. The quality is excellent, the nose profile looks right (although reportedly it is not accurate), and the decal sheet is much appreciated, providing complete markings for any of the first five aircraft. If the tail hook installation doesn't look correct for the specific airplane you're modeling, it's easily replaced by a scratch-built substitute.



(The parts pictured above are in the 1/72nd conversion)

Pete also produced a kit with the Phoenix test missiles and the F-111B Phoenix pylons, including decals.

The first three F-111Bs were BuNos 151970, 971, and 972. 970 had a unique paint scheme: the gray/white demarcation line on the forward fuselage was much higher up than on subsequent airplanes. The first three also had Escapac-type ejection seats rather than the crew escape module, no rotating glove slat, under-wing inlet BLC vents, an open tail hook installation, the vertical-fin-tip IR warning antenna, and a knife-edge boat tail. They also had the Air Force nose landing gear although 972 was modified to have a launch-bar nose gear during its test program at Hughes. This is 151971:

The middle two were BuNos 151973 and 974. These had escape crew modules, the launch bar nose gear, the rotating glove slat, the repositioning of the inlet BLC vents to the top of the wing, and a faired-in tail hook. The fin-tip antenna was deleted. 973 had a knife-edge boat tail while 974 had the blunt configuration. 974 was also retrofitted to have the Triple Plow I inlet configuration. It also appears that at least 974 had the landing gear raked aft to reduce the tip-back tendency.

The all important "sit" of the airplane can be established from this drawing:
The final two, BuNos 152714 and 715, had the long F-111B nose, so-called "Super Plow" inlets with two suck-in doors similar to the FB-111A Triple Plow II inlet that had three suck-in doors, an auxiliary flap added, and a different tail bumper, tail hook installation, and boat tail. The 1/72 Hasegawa 1/72 FB-111A and the 1/48 Academy-Minicraft FB-111A provide the starting point for this kit, the main problem being the creation of the longer nose. These two aircraft did not have the raised canopy, which was reportedly on aircraft number 8 and subsequent. Note that 152714 first flew with the inlet ramp and translating cowl.

These pictures illustrate the addition of the rotating glove slat and over-wing vents to the middle and final two F-111Bs.
In addition to the raised cockpit, the production airplanes after the two that were completed and flown were to have yet another inlet configuration. It's not a sure thing that they would have had the production F-111A inlet since the production F-111B might have had a slightly different one optimized for low-speed thrust for wave-off performance.

The following illustrations summarize the inlet and forward fuselage differences. (The inlet labeled Triple Plow II is an early version that only had two suck-in doors instead of three.)

Note: It turns out that the production fuselage outline shown above is slightly off. For the time being, refer to http://tailspintopics.blogspot.com/2014/01/production-f-111b-fuselage.html for one based on a Grumman lines drawing.

For a discussion of the short versus long-nose inflight refueling probe installations, see http://tailspintopics.blogspot.com/2012/01/f-111b-inflight-refueling-probe.html

The conversion kit doesn't include the knife-edge boat tail on 970/971/972/973 but it is not too hard to create:

There were four slightly different tailhook installations and boat tails among the four airplanes. (Note that the following drawings are notional, based on bits of Grumman drawings and evaluation of photographs.) There was no fairing above the tailhook on 970/1/2 and it appears to be longer than the ones on 973 and subsequent F-111Bs.


 The area above the tail hook was filled in on 973 and 974. However, 973 had the knife-edge boat tail with a fairing (possibly housing an antenna) behind the hook point.
Note that the hook may be straight rather than kinked as shown above and the fairing cut back above the hook point.

As part of the drag reduction program, 974 had a blunt boat tail not unlike the final F-111A version (note the small fairing behind the tail hook):
 Although the following picture shows the fuel dump to be recessed, it subsequently protruded as shown in the illustration above.

The production boat tail, tail skid, and tail hook on 714 and 714 were yet another configuration.  The attach point for the hook appears to have been lowered and the hook shortened:

The red turbine warning stripe was seldom seen on US Navy jet airplanes. It was a carryover from USAF practice, instituted in the early days of jets when catastrophic failure of turbine wheels turning at high RPM was not unknown. Ground crew were advised not to tarry in a zone perpendicular to the red line when the engine was running, so as to avoid the consequences of a turbine burst, unlikely as it might be.

The F-111C kits have the fin tip IR warning antenna which is appropriate for 970/1/2 but were deleted from subsequent F-111Bs. They also have the crew module, rotating glove slat, and overwing BLC air vent that weren't on 970/1/2. They don't have the "speed bumps" (that's what they were called) at the end of the fairing inboard of the stabilator that were on all the F-111Bs.
The F-111C engine inlet and boat tail are only appropriate for 974. The F-111C also had the simplified (and truncated) aft main landing gear door that was simply bolted to the landing gear trunnion; six inches was cut off the aft edge of the door, which resulted in an opening between the aft edge of the door and the aft end of the wheel well when the landing gear was retracted. On all the F-111Bs (and early F-111As, which received the simpler door beginning in late 1975/early1976), when the main landing gear extended, the door pivoted aft and down on a parallelogram mechanism driven by links to the main landing gear and fuselage and the door completely closed off the aft part of the wheel well when the gear was retracted.


Thanks to Mark Hanson, Curator at the Chanute Air Museum in Rantoul, Illinois, we now have pictures of the mechanism:

The attach point of the door leading edge idler is hidden above and shown here in a picture looking aft at the right shock strut and idler. Note how the idler is curved outboard to clear the shock strut:

The bracket on the maintenance trainer that mounts the clevis providing the upper pivot point for the idler is not representative of the aircraft. As shown here in a picture provided by Craig Kaston, the clevis was actually mounted on the side of the wheel well.

One landing gear change doesn't seem to have attracted much notice. In order to move the main landing gear wheels aft to reduce the propensity to tip back with the wings swept aft, the landing gear was rotated aft around the retraction pivot point. The difference in the pitch of the crossbeam is the visual indication of this change. (Note also that 972 is shod with the Air Force tires.)
This may have required the widening of the aft end of the wheel well by removing a triangle of fuselage skin from the rear corners of the well and adding them to the aft door:
I'm no longer sure about the aft door change. The main landing gear "shift" was implemented on 974, 714, and 715. I'm not sure about 973.

Grumman planned to move the wheels aft by eight more inches in production. See http://tailspintopics.blogspot.com/2017/02/the-f-111b-production-main-landing-gear.html

One error in the review sample from Pete's Hangar was the size of the main gear wheels. This may have been changed but here is an illustration of the size and the differences. In 1/48, the wheels were notably undersized but it's not that hard to convert the Academy wheels to the correct diameter and thickness because the hubs are the same diameter on the A and the B. It should also be noted that at least 970 and 972 were shod with F-111A wheels and tires on occasion.

The first three F-111Bs first flew with the F-111A nose gear and probably the F-111A main landing gear wheels as well. The difference is best illustrated by the red lines on the nose gear door which indicated the position of the landing gear and drag link/retraction struts when the nose landing gear was locked down. Note that the nose gear strut is angled forward.

 The F-111B nose gear strut was beefier and mounted vertically. It incorporated the nose-tow launch bar, angle of attack lights, a radar reflector for automatic approaches, etc.




One configuration anomaly is that 972 was repaired using an F-111B nose landing gear after one of its crashes. However, at some point before it was retired, an F-111A nose landing gear was substituted.

Most if not all of the F-111Bs carried a Phoenix missile at one time or another. The Phoenix were an early version with a blunt nose and no antennas on the side. These illustrations provide the details of the pylon, including position.
The test missiles had various markings, with black stripes and red fins for position reference in test drops and firings. The two wide vertical stripes on the mid section are brown, indicating a "low explosive", the rocket motor.




Although there are plenty of cockpit illustrations in my F-111B monograph, for those who don't want to go to that expense, here is a picture of the cockpit with the full right hand panel. Note that it is 151972 which had ejection seats.



The short-nose F-111Bs had a different inflight refueling probe than the production long-nose airplanes were to have. See http://tailspintopics.blogspot.com/2012/01/f-111b-inflight-refueling-probe.html

If you can find the Revell kit with the Navy option, it can be built into an accurate representation of one of the first three prototypes. It is gimmicky, with a movable wing, a removable crew module, and a retracting landing gear, all of which require some effort to make it a realistic model (as opposed to a plastic toy). As an older kit, it also features raised panel lines and minimal cockpit detail. The good news is that it does provide the shape basis for the first four prototypes (151970-973) including the original knife-edge boat tail and the speed bumps. The only shape problem is the cross section of the F-111B nose option where it joins the fuselage. For one thing, Revell assumed that the transition began in front of the windscreen and was vertical. It actually started along the forward edge of the crew module until it reached the bottom of the crew module and then went vertically down, well aft of the bottom of the Revell F-111B nose:

As a result, the cross-section where the two different noses attach is a bit too "square" and slightly too large in width and depth for the F-111B at that point:

There may be enough plastic to round it off, but it's going to be close...

If you want to create your own, this is a fairly accurate representation of the short-nose shape for 970-974:
The Revell kit is also missing the Navy tail hook/skag arrangement and the main landing gear tires are Navy in diameter and Air Force in width. Correcting those things is just modeling, like adding some bracing between the fuselage sides and joint reinforcement to avoid fit problems with the crew escape capsule. For one of the first three, as with all the other F-111 kits, you'll have to substitute ejection seats for the capsule seats. These were Douglas Escapac seats, probably Model IC. Note that they have two large pull rings for the face curtain rather than just a single one.

The top of the ejection seat actually sat under the aft edge of the canopy in order for the pilot's parachute, and therefore his body, to be properly positioned with respect to the controls; there was an additional panel behind the side hatches that came off along with the side hatches and the overhead console/canopy center frame to provide clearance for the ejection seat. Also see http://tailspintopics.blogspot.com/2016/07/f-111ab-ejection-seats.html


Finally, here is an matrix of configuration differences by BuNo with a corresponding one providing the characteristics of the production Air Force airplanes represented by kits:

17 comments:

  1. Hey Tommy. I always enjoy reading your comments and posts regarding USN aircraft. You've revealed alot of information not only on well known aircratft but also of the not so well known ones as well as the really not so well known ones. I have found your insights very informative.

    I have your monograph on the F-111B. It is the most comprehensive history of this particular variant of the F-111 series I know of. There have been many books and publications on the USAF's many F-111 versions. The USN's version meanwhile has slipped into relative obscurity. Thanks for shedding a new light on this very interesting aircraft. Not just the design but the politics also.

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  2. Hello Tommy,

    Great info for my F-111B project.

    It would be nice to see that kind of detailed info about the reworked version of the F-8 Crusader (F-8K,P,..) : type of ejection seat, wheels, layout of cockpit,...

    Marc

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  3. Mr. Thomason,

    I'd be interested in hearing your opinion of the best place to start for the final two F-111B noses. The shape of the base reminds me of the F-14 but the nose is distinctly closer to being an F/A-18 or even F-15 in styling. Also, are there any drawings, perhaps in the pilots manual, which detail the mounting hardware for the internal missiles?

    Thanks for this writeup, I have your book as well and it's comforting to know I won't have to cut and splice the forward fuselage height increase at least.

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  4. I've looked at modifying the F-111A nose that comes with the kit and while it could form the basis for the production F-111B nose if sectioned and cut down, it wouldn't be a straightforward modification. I suspect that the other noses you mention would start off being too narrow, which would again require considerable surgery. I've tried to interest a few of the conversion part manufacturers in making this nose and chosen to wait until one does so.

    With respect to mounting the Phoenix in the bomb bay, I've only seen a simple inboard profile that shows the missile in place. Due to the size of the missile, my guess is that it was dropped rather than extended on a rail, so the mounting would be a simple pylon. However, I doubt that any of the aircraft that flew had the pylons installed, since the bomb bay was probably needed for flight test instrumentation, particularly the F-111Bs that had the Phoenix Missile System installed.

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  5. Do you think the Pete's Hangers 1/48 nose will fit the HobbyBoss F-111C?
    Thanks

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  6. I haven't personally checked this but I would be surprised if it didn't. The Hobbyboss canopy and main wheel wells have been criticized but the kit is reportedly cheaper and/or more available than the Academy/Minicraft one.

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  7. For a pre-production nose in 1/72 I used a Revell Su-27 nose and looking at the measurements in your notes it's not too far out, about 1/20th of an inch short. In 1/48 I have a Quickboost Su-27 replacement resin nose to use. The Pete's Hangar set is disappointing in that the prototype nose seems too short (I used the Esoteric nose and the result is still short by about 1/6 of an inch). The wheels also seem to be exactly the same as the kit ones.That leaves the nose gear which is welcome and the decals. Pylons are easily sourced from a scrap F-18 kit with their rear edges cut back.

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  8. Hiya TT,
    just wanted to say thank you for the invaluable info you have posted, as I've been converting an Airfix 1/72 F-111E recently. It was my most ambitious project for a long while, and ended up a part scratch build due to inability to source the conversion set, but it got moderately close in the end (yes, I did up-angle the main gear, but no, I didn't put the rear door on a trapeze - too lazy for that! I also used standard AIM-54's from the Hasegawa Weapons kit - I suspect that they are C's, but otherwise I'm hoping it meets your approval.)

    I've sent a pm on another site with the actual links.

    Really - thanks again - your website was invaluable.

    James (Paveshadow)

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  9. Hello, Tommy,
    My dad left the Navy after 28 years of flying and went to work for Grumman in flight safety dept. His first job was the F-111B. I was 14 at the time and can remember getting to go down to GD in Ft. Worth and watching take offs and landings, and also seeing them fly out at Peconic. It was a grand time to be a model builder. There may still be some of his notes in storage so I wil look next time I visit. If I find anything that I think might be of use to you I will let you know. Thanks fo this little jaunt down memory lane.
    Cheers from NYC,
    Michael Scarborough

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  10. Hello Tommy,
    Great reading and wonderful information.
    My father was on the 111 program off and on from start to finish at GD Fort Worth.

    Thanks for this wonderful information.

    Scotty Battistoni

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  11. Tommy

    Thanks for bringing this info to light. I really appreciated the drawings your sent me. Like Scott Batttistoni my dad also worked for Grumman on the F-111B program At Calverton before being transferred to the Lunar Module project (Apollo 11,12 and 13).

    Again Thanks so much!

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  12. Any conversion should be of the late prototype, 'production' airframe as the amount of work that went into getting these aircraft's high lift systems ready to pass the carrier qualification testing and be deemed operationally suitable was an enormous achievement for a group that knew, going in, (Congress cancelled funding the day the tests began as I recall) that they were the red headed step child of an actively sabotaging NavAir.

    The aircraft did indeed pass the carrier suitability tests and was a much better performer around the boat than the F-14 was before DFCS (i.e. for 90% of it's service life). The longer nose and slightly upturned ogival radome are also very eye pleasing to me.

    I would add that a complete weapons bay with options for AIM-9 or AIM-54 (if it will fit) would also be welcome as the F-111B was also always a superior 'Missileer' to the Turkey with six Phoenix and 2hrs on station as a norm. Something the F-14A could simply never do with the TF30 engines and the F-14B/D only with considerable risk as the tunnel stations put the aircraft on the edge of some unpleasant CG issues.

    If you ever manage to get all this together (final prototype noses and weapons bays), please post a note on ARC and Hyperscale and I'll buy a pair of 48th sets from you.

    Thanks for a good read. KPl.

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  13. Great material here. Thanks for publishing it. Was the proposed production inlet to have a Triple Plow 1- type splitter plate but with blow in doors instead of the translating cowl?

    David W.

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  14. David,

    My short answer to the F-111B production inlet is I don't know. Since GD was responsible for inlet development, Grumman was usually at least one iteration behind in inlet configuration and playing catch-up. For example, 152714 was painted as if it originally had a splitter plate. However, both it and 715 got a version of the Triple Plow II inlet but with two suck-in doors (the cowls appear to be modified translating units so the door configuration might have been unique to these two aircraft.

    The three-view drawing in the F-111B flight manual has all the production features like the long nose (which 714 and 715 had) and higher canopy (which neither had since that required a redesign and possibly a requalification of the crew module). However, the inlet has a splitter plate and two suck-in doors, which doesn't match any of the inlets flown as far as I know.

    The F-111B might well have ended up with a somewhat unique inlet because of the need for low-speed thrust for carrier takeoffs and waveoffs. However, the way to bet is that the production airplanes would have had the production Triple Plow II inlets on the FB-111A.

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  15. Does anyone know where you can get 1/48 f111b Decals Sheet. Thanks

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  16. The only one I know of was produced by Pete's Hangar, which is long out of production. However, you might email Victorian Hobby Centre in Australia and see if they have one or can get some more: sales@victorianhobbycentre.com.au

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  17. Although it has been more than a year since anyone has commented here, I am compelled to commend you for your efforts on this subject. I have been involved in an ongoing project to kit bash the hideous and ancient Airfix F-111 into a B model (the kit does have its redeeming qualities, for instance it has the under-wing boundery layer air vents even though it was billed as an E model).

    Here's a link to my photobucket page showing my progress so far, your work has been an information bonanza for which you are to be gratefully thanked.

    http://s926.photobucket.com/user/uberdave1/library/F-111B?sort=3&page=1

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