F-111 Auxiliary Flaps

7 September 2022: Updated with pictures of the auxiliary flaps. Also see this subsequent post: https://tailspintopics.blogspot.com/2017/01/the-f-111b-auxiliary-flap.html

One of the fixes required of the F-111B for Navy acceptance was restoration of the requisite over-the-nose visibility for carrier landings. It had been accounted for, of course, in the original design.

Yes, that is an Essex-class carrier.  The A3D Skywarrior, aka the Whale, was of a similar size/weight and routinely deployed on Essex-class carriers.

However, as the overly optimistic empty-weight prediction began to be exceeded, the angle of attack on approach increased and the carrier deck began to be less and less visible to the F-111B pilot. There are three basic ways to restore the required sight picture without going faster on approach: lowering the nose/raising the cockpit, reducing the weight, and increasing lift. All were employed (weight reduction being the hardest to achieve), with the production airplanes after the first two to have a raised cockpit.

 

Most of the wing-lift changes were introduced in production with F-111A #12 and F-111B #4. (An F-111B span, five-segment flap version of the new wing was evaluated on F-111A #4.) The most obvious was the so-called rotating glove on the inboard fixed section of the wing, shown here on F-111A #4 while it was "armed" with dummy Phoenixes during aerodynamic evaluation of the new wing.

One last lift change was also reportedly introduced on the first two production F-111Bs, the six and seventh built. This was the auxiliary flap, which was located inboard of the existing flaps.

These little flaps were intended to squeeze the last bit of lift out of the existing wing planform. They were electrically driven and controlled by the flap handle. If the pilot selected more than 28 degrees of flap and the wings were swept 16 degrees or less and the wing-sweep handle was set at 16 degrees or less, then the auxiliary flaps would lower. (The 16-degree sweep limitation was driven by the need for clearance of the inboard edge of the auxiliary flap from the side of the fuselage.)

These were reportedly incorporated on the USAF  F-111s (its function is described in the F-111A flight manual) and FB-111s as well as the Australian F-111C.

 FB-111A photographed by Ron VanDerwarker

This is an inflight picture from below of an Australian F-111 with the auxiliary flap not yet extended (or perhaps locked up).

 I've never seen a picture of them on F-111Bs, not even the early production 152714 and 5, but it seems likely that they would have been incorporated on the subsequent F-111Bs along with the raised canopy.

However, on most if not all of the USAF and Australian F-111s (the FB-111A may be an exception) the auxiliary-flap function was reportedly disabled fairly early as being a maintenance burden and not being very effective from a lift standpoint for shore-based operations.

F-111B Envelope Expansion Wing

One of the remaining mysteries to me about the F-111B program was the presence of the four-segment flap wing (i.e. the F-111A wing) on F-111Bs #1 and 4. I didn't even notice it in the picture of #1 on the cover of my F-111B monograph until someone eventually pointed it out.

Note that the wings have the ferry tips so that the span is that of the F-111B.

This is the F-111B early five-segment flap wing.

Tim Lent pointed out that F-111B #4 also had a four-segment flap wing at one point.

(You can take my word for it - a lightened version of a high-resolution scan of a pretty good photograph shows that the fifth flap segment is not present.)

The reason for Tim's search for evidence of this wing on #4 was the desire to identify the third F-111B in this photo, the one with its back to the camera.

 I was pretty sure that it was #4 because it appeared to have the rotating glove flap on the fixed portion of the wing and did not have the pod on the fin tip. However, Tim noted that it had a four-segment flap with the ferry tip.

My speculation is that this set of wings was specifically instrumented for high-speed envelope expansion and the use of the ferry tips allowed it to be used by both General Dynamics on an F-111A and Grumman on an F-111B. In fact, #4 was used for flutter/envelope expansion in late 1966 and early 1967. After its crash, #1 was used for flutter/envelope expansion at Edwards in the fall of 1967, which is likely when the monograph cover picture was taken.

North American FJ-3 Redux

One of the topics of conversation at the excellent IPMS National (U.S.) Convention this year, at least among the folks I talk with, was the ongoing lack of a good injection-molded 1/72 (or any scale, for that matter) FJ-3. Note: I have provided material on it whenever asked and a previous post, http://tailspintopics.blogspot.com/2011/04/fj23-fury-redux.html, illustrates a lot of the detail differences in its configuration over time.

Since there is a pretty good 1/72 F-86H kit available and it has a bigger inlet like the FJ-3 (it had a more powerful engine), there has recently been a discussion as to whether it would be a suitable basis for conversion. Suitable, of course, varies by individual, ranging from minor alterations to, as the late, great Bondo said, "practice bleeding".

Herewith an illustration of the basic differences (the F-86H has the wing-tip extension and many detail differences but that's no hill for a stepper; the basic empennage is pretty close):

So far, so good. A comparison of the North American drawings illustrates some of the shape and size differences in profile. The FJ-3 lines are in general less dark; I didn't bother to determine if either drawing needed to be resized vertically for accuracy. However, it's pretty clear that the F-86H has a deeper fuselage in addition to being longer.

Vertical fin overlay:

Wing root overlay:

Windscreen overlay:

The consensus was that if you just had to have an FJ-3 now, the Falcon conversion (which is still available) is the better bet; it consists of fuselage halves and a pretty good canopy but no decals. This R.J. Tucker's build combining it with an Academy F-86. Note that the F-86 horizontal tail might be too small. See more photos and a summary of the build here:http://www.arcair.com/Gal1/101-200/gal142-FJ3M-Fury-Tucker/00.shtm

Print Scale put a couple of FJ-3 schemes on an FJ-4 sheet: http://www.internetmodeler.com/scalemodels/nraviation/Print-Scale-1-72-FJ-Fury-Decals.php

As of this writing, the Falcon conversion is available from Hannants and Falcon (click HERE). I couldn't find it on the Squadron or Sprue Brothers website.

The best single reference is Ginter's monograph Naval Fighters Number Eight-Eight:

Draft Tailhook Topics

In addition to this blog and one on Naval Aviation History (http://thanlont.blogspot.com/), I also occasionally post articles on my Draft Tailhook Topics blog (http://tailhooktopics.blogspot.com/). My original intention was to create articles there and then when they were ready for prime time, post them here. It didn't work out that way. For one thing, copying and pasting into Blogger using a Mac sometimes (often?) resulted in a string of format instructions, visible only in HTML, that caused Windows operating systems to hang at that point, a condition that I would be unaware of until one of my more diligent readers brought it to my attention. As a result, I usually just link to a post there when it provides more information about the subject of a post here.

So if you find interesting things here, you might find more there. In some cases, it was just a convenient place to post answers to questions that were raised on modeling websites, like F9F Panther and Cougar ejection seats, http://tailhooktopics.blogspot.com/2014/07/grumman-f9ff-9-panther-and-cougar.html.

Things Under Wings - Training Wheels

A question was raised about the unusual store under the wing of a distressed F8F Bearcat in the prior post.

It is a Mk 47 practice bomb dispenser. For more on it and other U.S. Navy armament training devices circa World War II, see http://thanlont.blogspot.com/2014/07/things-under-wings-training-wheels.html

F8F Bearcat Wheels and Wheel Wells

 28 August 2025: Added tail wheel information

I've seen a couple of questions on the modeling blogs recently about F8F Bearcat wheel well color, which suggested a post on the subject. Since what I have is not all that conclusive, I thought I'd add wheel hub configuration to the discussion.

It appears that the F8F wheel wells were painted the same color as the exterior with the exception of some hardware located in the well (there was apparently no specific requirement as to wheel well color until they were to be painted white in the mid 1950s).

Although these are grey-scale pictures (the second one has been lightened considerably) and the color pictures I have aren't conclusive because the wells are in shadow, that's the way to bet.

However, some of the very early F8Fs had the accessory section (viewed from the inboard wheel well) painted with either a metallic color or zinc chromate.

And there are pictures of F8Fs at Grumman with non-blue wheel wells so it may be that the wheel wells became blue at the first Navy overhaul.

The two different wheel hubs are distinctive. The early ones had "spokes" and might be either blue, "black" (cosmoline?) or metallic (in this case, on the drop test article, probably unpainted).

The brake pucks were initially located on the lower forward area of the brake disc.

These were subsequently relocated to be at right angles to the strut.

The later wheel hubs were forged, possibly introduced with the F8F-2 and similar to the hubs on the F9F Panther.

 

They were usually a metallic color.

 The tail-wheel fairing was two piece, an upper/forward fairing that was attached to the strut and a lower/aft one that was attached to the full-swiveling tail-wheel fork that kept a pendant from hanging up on the tail wheel.

 

 

The tail wheel retracted into an opening in the bottom of the fuselage so the wheel was barely visible if at all from the side.

 Note the strakes on the bottom of the fuselage ahead of and behind the wheel well.

For some other of my posts on the F8F, see

http://thanlont.blogspot.com/2011/02/conception-of-f8f-bearcat.html

http://thanlont.blogspot.com/2012/10/f8f-safety-tipsit-seemed-like-good-idea.html
(also includes a plug for the excellent Meyer/Ginter monograph on the F8F)

http://tailspintopics.blogspot.com/2010/12/f8f-bearcat-1-vs-2.html

http://tailhooktopics.blogspot.com/2013/02/f8f-formation-lights.html

Grumman F9F-8T/TF-9J

Chinese plastic kit manufacturer Kitty Hawk has just released a 1/48th scale kit of the Grumman F9F-8T/TF-9J. (For my earlier notes on this airplane, see http://tailspintopics.blogspot.com/2011/02/f8f-8t-cougar.html)

This is very welcome since it is one of a handful of U.S. Navy airplanes that have gone unrepresented as an injection molded kit. A built model looks pretty good:

 

It's clear that the length of the nose-gear strut on this model is representative of the TF-9J on display at the Pima Air&Space Museum in Tucson, Arizona rather than a flyable airplane. (It may have been fixed in the kits as produced.) The "sit" should be more like this:

There are few other detail discrepancies notable in the model built. See http://tailhooktopics.blogspot.com/2014/06/grumman-f8f-8ttf-9j-notes.html for some notes and illustrations. Darren Roberts is providing a excellent and informative progressive build review here: http://www.arcforums.com/forums/air/index.php?showtopic=277195&st=0 and a summary of the build here: http://www.zone-five.net/showthread.php?p=286534#post286534 Before you buy it and for sure before you build one, you should take a look at his posts.

Another very helpful and illustrated build review: http://www.themodellingnews.com/2014/07/review-build-nic-cougar-tamer-takes-on.html. Note that the builder did not encounter the problem with gluing the plastic that the kit is made from but did note a couple of detail errors. (Others have noted the "Marines" marking on the upper right wing is incorrect; it should be the aircraft number and the tail code.)

One configuration option provided in the kit is the ejection seat. The first two-seat Cougars were delivered with Grumman ejection seats. These were soon replaced with Martin-Baker seats. See http://thanlont.blogspot.com/2011/02/transition-to-martin-baker-ejection.html. The Grumman seats were used in the model above, but Martin-Baker seats had been standard long before the Marines began to use the TF-9J as a Fast FAC (Forward Air Control) as the model is marked.

As usual, the single best reference on a Navy airplane is available from Steve Ginter. See http://www.ginterbooks.com/NAVAL/NF68.htm

Darren Tamanaha put some excellent detail pictures of the Pima TF-9J HERE. Note that the shock struts are bottomed instead of being inflated as it was for a flyable airplane.