"Stretched Sluff" - LTV's YA-7F Corsair II

[TheRealMrEd]

Hi all,

 

Have been contemplating my navel (as well as my next modeling project), and have come up with a rather hairy idea! (Pardon the pun).

 

I have decided to do a project that has been on the back burner for many years, and has occasionally been mentioned by others on-line, The Ling-Tempco-Vought YA-7F, "strectched sluff", as it was called by the first modeler on record to do this conversion, Mr Tom Black, in the March, 1997 issue of FineScale Modeler. Alas, this issue is out-of-print, but can still be accessed through digital subscription, or better yet, by purchasing their first 25 year's DVD collection, which I heartily recommend!. I have a copy of the DVD, and in addition have been around long enough to own every issue of FSM magazine anyway. It has been an interesting 35-year journey. (How I wish the original Airfix Magazine and Replica In Scale had gone the distance!)

 

Here is a picture of the aircraft in question, in it's maiden voyage livery:

 

 

The easiest was to do this model is probably with a copy of the magazine on hand. Since everyone can't do that, I will try and fill in the blanks, while trying to tread on the fine line of not infringing upon another modeler's rights, nor those of FSM, whom I regard highly. Apologies in advance, if I stray to close to the boundaries, as that IS NOT my intent.

 

Mr Black thoughtfully provided drawings of the fuselage of your favorite A-7 kit to work with. (He recommended the Fujimi A-7D, as the A-7D was the aircraft modified, and at the time (and probably still) the Fujimi A-7D if the best thing out there in 1/72 scale, which of course, as we all know, is really THE ONLY scale for gentlemen!), and so, that is the kit I used.

 

I regret to inform however, that this will not be a compete W.I.P., as I am cheating and starting out with any assembled fuselage of said Fujimi A-7D, which I put together years ago, and completed to the point of painting the fuselage, where I go to lazy, and put the whole shebang on the shelf-of-you-know-what.

 

However being recently re-energized in my dotage, I drug the old thing out, and decided it wasn't what I would do if I did it today. So, while being no longer good enough for a today's A-7D, it will do just fine for a YA-7F conversion. So, here we go.

 

Since I can't re-print the original magazine drawings legally, I will do the next best thing. I will trace around the actual Fujimi kit outline, to show you where I made my cuts, but you'll have to settle for a side-view photo of the extended fuse, as I have no practical way to reproduce same:

 

 

Three things to notice here: 1) I was kind enough to provide a scale at the upper left of the drawing. If you blow or shrink (as needed) until the scale measure 3 honest-to-God 3 US of A scale inches, then you'll have full size 1/72 scale drawing also (crude 'though they be), and 2) the "chin" of the drawings is missing because the Fujimi kits are pretty much the same fuselage, with the chins swapped out from kit-to-kit, depending upon the guns for each aircraft type, and 3) the rear cut line on the top drawing will result in a 4.5 degree upward tilt to the tail section, which is what we desire.

 

An aside here for fellow modelers -- I am starting a 1-man crusade to ask every modeler who post drawings that might need to be scaled, to enclose a scale at the upper left-hand corner of each document. That was, when you are using a printer to scale up the drawing, you can just print out the first part of page one (in case the drawing will span several pages). Then you can stop the printing, check the output with a ruler, and either abort the printing if it's wrong, or start over if it's right. This way sames time and ink, printing over and over until you get it right!

 

Let me end for know, and we'll get on with it soon.

 

Any questions will cheerfully be answered as the build progresses, if I fail to give needed dimensions, or if other things aren't clear.

 

Later,

Ed

 

[Hamden]

 

Another great project mind if I take a seat at the back and watch you turn this into another masterpiece?

 

  Roger

[Corsairfoxfouruncle]

Watching with interest  Anything Corsair usually gets my attention. 

[HOUSTON]

Ed..

 

 

Oooh I am SO going to enjoy this

 

Rock On!

[Vultures1]

Great project!

[TheRealMrEd]

Hello all,

 

Back at it.

 

In the FSM article Tom Black gave dimensions for a wooden plug to build of wood (he used pine) to make a vac u-formed master for the tailpipe outlet. He have the length as .61", the outer diameter as .76", and the inner diameter of the tailpipe section as .065". His way was to vacuform the master, then add a couple of layers of thin clear epoxy to stiffen it up. For me, this was way too much work, so I scrounged around in the super-deep spares box (I NEVER throw anything away that came in a model box!), and found an old tailpipe assembly from a 1/48 scale Monogram F-106A. It was within a half-millimeter of being the correct diameter, and had the added benefit of already having some inner rib detail. So, I sawed the appropriate length out of the center:

 

Ribbing shown below:

 

 

Disregard the incorrect tip on the vertical stabilizer for now, but note that you can just see the white plastic "bulkhead" glued onto the front of the F-102 part, before it was glued to the A-7D rear fuselage. This bulkhead has a pre-sized hole to fit the afterburner can from whatever the selected F-15 afterburner will be. The difference between the tailpipe diameter and the original A-7  rear fuse is shown here filled with fine white Milliput, and later touched up with spot putty. Note also that the elevator slots in the fuselage have been filled.

 

The next view shows some of the additions or mods needed to convert an A-7D to a YA-7F:

 

 

Figures (A) show the ECS and air-oil heat exchange inlets. These card be made up from plastic card, but I used the intakes from an Academy F-8E Crusader, which is awaiting completion as a modded F-8A (F8U-1), using Muroc Models conversion kit. Since the Crusader "A" model didn't yet have these, they were available from the kit, needing only to be shortened and slightly reshaped for use here.

 

Figure (B) show an oval pipe (thr air-oil heat exchanger exhaust). I used a piece of correctly sized plastic soda straw or cocktail stirrer, following the dimensions given by Tom Black, this was .11" wide, and .055" tall, and the front of the pipe tapers from protruding .021" out from the fuse at the front, tapering to flush with the fuse at the back end. Mine is a little short on the .021". I made mine by boring a hole a hair less than .055" and the center of the desired location, and then filing it into an oval shape with a small rat-tail file. At the end, I glued in the straw and cut if off on a slant.

 

Figure (C) shows a small NACA duct carved into the fuse on either side, using a sharp #11 blade, removing very tiny splinters at a time.

 

Figure (D) shows the a fore-mentioned filled elevator slots, while (E) should be ignored, as it is incorrectly shaped.

 

Next, the underside:

 

 

Figure (A) is from the A-7 kit.

 

Figure (B) is a Doppler radar fairing. My copy was from the Fujimi A-7E kit, made with an RTV silicone mold and a resin casting.

 

Figure (C) is another piece of the same soda straw used earlier It is called the JFS exhaust, and Tom gave the measurement of .13".

 

Figure (D) shows the layers of plastic card used to make a box around the tail hook, which then will sit submerged within the fuse, but still visible. The cavity is tail-hook shaped, and is smoothed flush with the filled fuselage Milliput filling.

 

Next, the other side:

 

 

Figure (A) is the ECS (environment control system) exhaust. Tom gives the dimensions as .069" diameter, and the highest point of the protruding part sticks  out .083" from the fuse.  Tom made his from an A-6 cooling scoop, but for once, the spares box came up short. Fortuitously however, I found a rather thick piece of sprue that had an elbow bend that I was able to chop off and sand down to a reasonable facsimile. It does, however, still need some kind of shroud on the front edge, which I may later add from aluminum foil or the like. We'll see.

 

Note that there should be another NACA duct on this side in the same position as the other side, but it appears to have been filled in. I'll have to re-do it. For what all these bits actually look like and where they should actually go, I recommend a trip over to the excellent Prime Portal walk around of the YA-7F:  YA-7F Link

 

Next, another view of the bottom side:

 

 

Well, that's it for this time. Again, I highly recommend trying to find the mag article, but if not, I'll try to answer questions as to how I'm doing it. At least I can promise you that unless Fotki goes belly up,

these picture will be around for another four years or so, longer if I make it that far!

 

Ed

 

 

[janneman36]

Here a linky to a nice pic at Edwards https://en.m.wikipedia.org/wiki/Vought_YA-7F#/media/File%3A445th_Flight_Test_Squadron_YA-7F_Corsair_IIs_with_ED_A-7D.jpg

 

Enjoy your build!

 

Cheers, Jan

[Killingholme]

Surely a stretched A-7 is just basically a F-8? 

[Gene K]

3 hours ago, Killingholme said:

Surely a stretched A-7 is just basically a F-8? 

Well, "basically" yes -- with a different fuselage, wings, engine(s), and electronics, among other things. 

 

Would have been a great operational aircraft, being both very capable and also relatively inexpensive. However, it had two main factors that went against it: first, the base fleet for the conversion, the A-7D, was found to have structural problems with the wings ... which was discovered after a wing came off an airplane on a bombing range mission; and secondly (and more responsible), the airplane was snuffed by the Tactical Air Command F-16 Mafia that was enamoured with that less capable and more expensive airframe. 

 

Outstanding conversion, Ed!

 

Gene K

[Cookenbacher]

Fantastic work on a fascinating project Ed.

 

I remember reading an article about the YA-7F in the 80's, and Vought responding to questions about the viability of a stretched, afterburning A-7, with the reply, "Well, we've already built a thousand of them."

[TheRealMrEd]

Thanks guys!

 

I remember them talking about this aircraft also and thinking how great it would be for it's intended purpose. But then, I also looked forward to the proposed turbofan B-57 Canberras that never happened either. I doubt that we well rarely ever see any "purpose built" aircraft in the future, as Robert McNamara poisoned the well with his "all things to all men" aircraft design mandates. Wouldn't be surprised to hear about a new F-35D anti naval strike fighter, with torpedoes hanging under each wing!

 

Ed

[TheRealMrEd]

A bit more for today...

 

First I cut two 4mm square pieces of plastic sheet (around .015"), and drilled small, wire-sized holes in the dead center. These were then glued to the fuse sides (A), with the holes aligned to the center of the elevator "fill-in" plugs (sanded smooth) that had been installed earlier. Note that to my eye, these blocks were perpendicular to a line running through the new tail structure (4.5-degrees), rather than perpendicular to the original fuse center or datum line.

 

Note here also that I'm sawing off the elevator mounting tabs (B), as eventually a small cut-out will need to be made to clear these new "blocks" where the elevator attaches. More on that later:

 

 

We'll lay those aside for now, and enter what I consider to be the hardest  part of this conversion -- the chaff/flare dispensers and the wing leading edge strake.

 

First, the CFD. I began by laminating together three strips of plastic each, making up two basic chunks of plastic card (around .030") each. Tom Black, in the FSM article, gives the finished dimensions on these as .965" long, .126" wide and .055" deep. I made mine a little oversize, to allow for final sanding to shape:

 

 

Note that both pieces need a longitudinal center line, and a perpendicular line about 1/3 of the way from one end.

 

Next, I cut the pieces to their rough shape, as seen from underneath:

 

 

As you an see here, the center line helps keep the sides equal, while the shorter line help define the beginning of the rear taper:

 

 

Next, we're getting to the "tricky"art. I needed to taper each piece from side-to-side, making the pieces one layer of plastic thick on the inner edge, or more-or-less three layers thick on the outer edge:

 

 

As you can see, the piece of the left is marked to illustrate  my intent, and the piece on the right has already been sanded on the taper, with the sanded area still flat. This flat side will eventually need to be addressed with a round file or whatever to better conform to the fuselage sides.

 

Another view:

 

 

These desired taper from the bottom to the top is more-or-less shown here, but with the proviso that the front edge should be more rounded or curved than shown by the line:

 

 

Be aware that there is one of these oneach side of the fuselage, and they are symmetrically opposite. Here is what one of mine looks like on the model, before really final-final-final sanding!:

 

 

Note that the rear edge of these fairings is almost in line with the center mounting holes for the elevator. Also note that smaller fairings of .010" card have been added, behind the elevator mounting blocks. They are a hair longer than the rear half of the elevator or horizontal stabilizer, if you prefer. They are also a hair taller (top-to-bottom) than the thickness of the elevator.

 

Here are both mounted on my model, but the lower one is way out of alignment. They should parallel the rear fuselage center line, and the flat bottoms should actually BE on the bottom. I'll have to saw off that bad boy and re-position it!

 

 

In this view, the CFD needs to be rotated inward, so that both bottoms are "flat" with the fuselage bottom:

 

 

The next two pictures show how the real aircraft looks:

 

 

 

Anyone happen to have a picture of what the dispensers originally looked like from beneath? Were there holes for the flares, etc? If I cant't find out, I'll just leave 'em off, and not detract from the model. I try to model only what I can justify, rather than faking it, wherever possible.

 

Well, having sort of survived this milestone, tht's it for today.

 

Ed

 

[Cookenbacher]

Wow, that's some fine plastic carving there Ed.

[TheRealMrEd]

Thanks Cookie!

 

To continue:

 

The next item on the agenda are the YA-7F's added wing strakes. In the FSM article, Tom Black gives the dimensions as .87" long, .10" wide (before any sanding), and .060" thick. They are shaped like this:

 

 

The inner edge, which fits against the fuse is angled to set  flat against the fuselage, where the entire strake then is horizontal to the fuse. Next, the strake tapers from small at the front, to the widest part, about 1/3 the way back. Lastly, the rear of the strake curves slightly away from the fuse on the inside edge, and yet toward the fuse from the outer edge. The whole thing is the curved at the rear end underside of the strake, to allow the forward slats to deploy. The strakes ARE NOT fastened to the wing, only to the fuselage:

 

 

Note that my strakes are wrong, being mounted parallel to the wing,  whereas they should be mounted more in line with the cure of the wing's upper surface (red line), as can be seen in the first picture in the article, of the real aircraft. . I don't know whether I'll correct mine or not.

 

For now, moving along the the sketchiest item, the unique decals for the YA-7F prototype. I printed my own on my Epsom Workforce 635 Inkjet printers, using the system and materials for inkjet printing from Papilio:  Papilio.com

As far as I'm concerned the difference is made up by their Decal Film spray topcoat (much better than spray acryics, etc.), and their Ink Freeze, a dry powder, re-usable, which is used to soak up any excess ink right after printing. I've used this system twice for custom decals, on my Mach2 B-45A, a few models back, and now here. Once on clear paper and once on white. No worries!  (I have no financial interest, yada...yada...yada).

 

 

I printed three copies, just in case, and for some strange reason, the middle one printed lighter than the other two. Oh well, that's why a wise man takes precautions! I'll be glad to post the print file for these if anyway needs them. Otherwise, Tom Black provided some masters in the FSM article. Those will need to be re-scaled.

 

The prototype nose probe is a piece of stretched sprue, sanded to shape and cut to length, which Tom Black gave as 1.7" L.O.A., and .040" diameter at the root. This was re-enforced with a piece of music wire inserted into holes drilled in the appropriate places:

 

 

The production pitot tube, was donated from he Trumpeter F-100C kit built here earlier, on which I used the upright or "stowed" tube, leaving the straight "in action" pitot for this project. It was cut to length (L.O.A. including base = 1.10"), and re-shaped:

 

 

Next (and I apologize for the not-very-edifying photo!), we approach the flap augmenter fairings. In the article, Tom says to scribe "a line .07" forward and parallel to the kit's flap hinge line". However, when looking at photos, it seems like the line should be at the REAR edge of the flaps, and that the rod end of the actuators attach there. Here's the pic:

 

 

Opinions and further information would be most welcome!

 

Anyway, Tom gave the dimensions for the fairings as .20" long, .17" wide, and .015" thick. I tried to make mine to those specs, but to me they appear to wide from side-to-side, based on the photo. If you build this model, you might drop back to maybe .14" width instead:

 

 

Note that the scribe line should be on the top AND the bottom of each flap.

 

While pondering imponderables, I often have brought to mind a scene from Clint Eastwood's movie, "The Outlaw Josie Wales". In one scene the classic American Indian actor, the late Chief Dan George, talks about a time when the Indian leaders were invited to the White House, to talk to "The Great White Father" about peace. The Chief said (more-or-less, memory dims) " We told the Great White Father about the problems of the Indians.  After a moment, The Great White Father said 'Endeavor to persevere'.  After this we went back to our home and thought about this. After we thought, we declared war on the White Man!"

 

Have a brilliant day!

 

Ed

 

 

[TheRealMrEd]

Hi guys,

 

Just wanted to set up a link to some great Edwards AFB YA-7F photos, by The Old Viper Tester, Sven:   Edwards YA-7F's

 

Ed

Edited December 3, 2017 by TheRealMrEd
typo

[Col.]

Good work so far Ed. I recall reading an article about this machine in Flight International back when it first flew but didn't realise there was two prototypes built. You're certainly doing a more comprehensive job on the conversion than I did then with a Monogram 48th scale kit that hung on my mate's ceiling for many years afterwards.

[TheRealMrEd]

Thanks for the kind comments, folks.

 

Next up, the paint booth gets a work-out..

 

I first attached the wings, then glued the windscreen into place. Next, I added the main canopy, temporarily gluing it down with white glue. Then the canopy was masked, using a combination of tape and Parafilm-M. Normally, I shoot the main body colors first, then add the other colors, such as anti-glare black at the end. This time, because it would be easier to mask the  lack bits after they were painted, I chose to paint them first. Here is shown the rather crude, hurried, and un-masked black bits:

 

 

Next, I shot the inside of the tailpipe housing with semi-flat aluminum. I have no idea what color this area really was, perhaps primer...

 

 

The arrow in the above photo was apparently intended to call attention to something about the wing strake -- but I've forgotten what!

 

Anyway, in the next photo, I've masked the black areas and shot the lighter color of the two main colors , FS-36270, or good old Neutral Grey. Technically, this color should be the mid-sheen variant, or FS 26270. But, since this flat paint has to have a layer of gloss before decals and light weathering can be applied, I'll settle it all with a semi-gloss topcoat later. Note that this paint is simply sprayed on, taking car that the color will end up where it needs to be. I'll mask the final, darker color FS-36118 (26118) Gunship Gray, when it goes on later:

 

 

The next two pics are the masking images, which are simply the paint scheme shown in the FSM article blown up to a hair oversize (so that there's a little spare excess to tape the masks together, when going around the fuselage, etc.). There is a scale on each one, and if you scale these to where the scale is exactly  3", you will have the same size as I used:

 

 

 

I use these masks in conjunction with a masking scheme advocated by Metodi Metodiev, over on ARC:  Masking Method

 

I used this with pretty good sucess on my A-37B thread earlier this year. He explains it better there than I could here. One part went like this:

 

 

After peeling off all but the canopy masking, it now looks like this:

 

 

After a topcoat of Pledge MSF  (Future), I started applying the few decals required.  The decals used on this bird are a combination of home-printed, as discussed earlier, the Fujimi A-7D kit, and the spares box. With most of the decals added, it looks like this:

 

 

 

 

 

It was at this point that I discovered that I had failed to remove the intake trunk masking foam! The intakes should have been painted the darker camo color all the way in!  Tom black had mentioned this, I had just forgot!  However, a little more masking with Parafilm-M and paper towel, and this problem was fixed.

 

As other goodies are now baking away in the paint booth, we'll end this session here. Hoping to "get 'er done" by Christmas, or maybe sooner.

 

Thanks for tagging along,

 

Ed

 

[MVW]

Hello,

Congratulations for this splendid conversion. A small addendum from my side: Decals for the YA-7F are available from Wollfpack: 72-094. See:

 

http://www.fantasyprintshop.co.uk/Shaken-Stirred_A217MW.aspx?nh=121825

 

Regards,

Martin

 

[TheRealMrEd]

Right, Martin. NOW  you tell me!

 

BTW, they mention a conversion kit for this aircraft. I know there used to be some in 1/72. Does anyone know whether one exists today?

 

Ed

[TheRealMrEd]

Hi all,

 

Got a little more done. These days, I'm spending more time cleaning the airbrush than gluing plastic!

 

But, after the major paint job, come the details:

 

 

In the above photo, figure "A" shows where the drilled hole for the tail planes has been cleaned up, and a piece of Bare Metal Foil has been added to either side of the fuse, ahead of the red "pivot block" (?), I guess as a "rub plate" for the fuse...

 

Figure "B" shows the painted tail planes and the small wires to attach them to the fuselage. They each have been bent slightly downwards to set the 5.5-degrees anhedral of the tail planes.

 

In the next pic, the control stick has been added to the long-ago-completed stock Fujimi A-7D cockpit, along with some painted foil belts, which hardly show here:

 

 

Next, the tail planes have been glued on, at a tilted angle to show the "bleed down" effects of the parked aircraft:

 

 

Next the landing gears and doors have been added. Hope I remember to add some more detail to the main gear doors later! Also, the wash looks a little heavy on the main wheels:

 

 

Next, I'll start on a little ordinance:

 

 

In the above photo, 6 Mk 82 bombs have been selected from a Hasegawa #1 weapons set. Even though they are molded in one piece, they have a mold line on either side of each piece. I had already painted them blue, when I decided to spend a little more effort to clean them up, and make proper practice bombs of them.

The bottom left foreground shows the mounting lugs, sprue attachment points and the seam. All must go!

 

The four on the right side have been scraped, then sanded with a fine sanding twig (greatest thing since sliced bread, those guys!), awaiting repaint. Also, the nose fuses have been removed.

 

Next, the finished practice bombs:

 

 

Here the bodies have been painted blue, with the after sections done up in O.D., as is common practice. The one photo I have of the YA-7F loaded has the bombs in the shade of the wings. I think the aft section MIGHT be gray, but since I can't tell for certain, back to the old standard for concrete-filled bombs.

 

The nose fuses have been replaced by tiny discs of plastic, painted steel (approx. 1.5mm dia.), to replicate the pieces put on the fronts, to close off the area where the fuse would be on live ordinance.

 

I'm still working on some drop tanks, and a turkey-feathered tailpipe. Hope I'll be finished with this build within the next week. We'll see.

 

Later,

Ed

[Cookenbacher]

That's really looking the business Ed, fantastic project.

[TheRealMrEd]

Thanks, Cookie!

 

Ed

[Hamden]

 

More great work that cockpit looks stunning as does the ordinance! 

 

  Roger

[RidgeRunner]

Nice one, Ed

Edited December 10, 2017 by RidgeRunner

[TheRealMrEd]

Thanks, Martin!

 

Here we go with a little more -- the TER's mounted to the A-7D's outboard pylons:

 

 

Next, the practice bombs attached to the TERS, with the whole shebang attached to the wing:

 

 

Moving along to the engine. I grabbed one of the engine assemblies out of a Hasegawa F-15A "Air National Guard"  box, to use on this YA-7F. I ordered an updated engine set for the F-15A kit, but as this one is only stuck into a hole, I can swap it out later, if need be.

 

There are two forward parts for the engine, and then 5 "petals" that glue together to make the afterburner nozzle:

 

 

They are a bit fiddly to install, so I used a small alligator clip to help out.

 

When glued together, the petals have gaps between them, which I filled with Perfect Plastic Putty and the wiped down with a wet q-tip, just to leave the filler in only the cracks. Too much flash on this photo hides the fact that the petals are painted white inside, and have been treated with a black wash:

 

 

The picture on the right shows the 15 afterburner actuating rods that have been glued into place. Then the nozzle was painted metal, followed by another black wash on the outside.

 

The next two pics show that most of the outer detail can't be seen once the engine is mounted, but it was the only way I could find to get the detail on the inside of the afterburner. Plus, I think it looks kind of cool...

 

 

 

 

Hmmm... got carried away wit the wash; Ill have to clean that up a bit.

 

For some reason, this a/c had a red-orange oval on it's nose. I had fits trying to duplicate that color. Finally found an old Airfix PP-39Q/P-400 decal. It was thick, but the decal film still cracked, so I had to put a coat of Micro decal film on it. You can see, it took several tries to get one I could use:

 

 

Last for now, the arresting hook meets it's custom-constructed home:

 

 

That;s all for now. Later,

 

Ed