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1/72 Republic XP-47B Prototype Conversion


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Having just finished up on the 1/72 XP-72 Super Thunderbolt, I am trying to stay on a roll by starting on a model that I have always wanted, but heretofore could not figure how get.  I THINK that I have finally figured out how to do it, because I'm just tired of waiting for all you lazy people out there to do it for me!  So, with great hope, and no guarantee, here we go...

 

First up, the famous bird, the very first of the actual P-47 line to be built, the XP-47B.  Both the proposed XP-47 and the XP-47A proposals were never built, as they would have been under powered and totally unsuited for war. Here is what the beast looked like:

 

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Among the most notable differences between the XP-47B and the later XP-47D variants were: (1) 8" shorter nose section (2) totally different rear side view windows, and (3) the fewer cooling flaps on the cowling.  These are all obstacles to be overcome if we are to model this variant.

 

The kit I chose to hack up was this one:

 

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the Academy 1/72 Razorback kit.  I have the slightly better Tamiya kit on hand, but as I don't have a razorback "D" in the collection yet, I will save the Tamiya kit for it's intended use.  I also have several of the old Hasegawa kit (parts of which were used in the XP-72 build, mentioned earlier) but they didn't meet the simple criteria that the rear-view glass on either side fit snugly into the window cutout.  This kit does, and we will eventually see why this is important.  While the Academy kit has a decent cockpit, I will use the True Details P-47D-M set instead.

 

We begin by holding the two kit fuselage halves together, and gluing ONLY the two rear cockpit join lines indicated by the arrows, below:

 

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Middle above, the rear cockpit interior is cut away from the fuselage halves, using a razor saw, the thinnest one I could find.  Next, above right, the rear canopy molding is taped along the rear vertical panel lines and scribed a few times, in preparation for cutting the rear parts off:

 

Next, after adding some .005" plastic card to make up for the razor saw kerf, the rear side windows are glued to the fuselage halves:

 

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Above right, after drying the entire front of the turtle-deck, including the rear side windows, is then sawn from the fuselage halves, as shown.

 

OOPS -- BEFORE that, the door part of the left fuselage side was cut out and glued to the center part of the kit canopy, shown loosely setting in position, below:

 

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Above right, the white plastic card spacer is cut down flush to the inside and outside of the canopy, and the whole thing is sanded very smooth, including areas of filler, shown in red.  More sanding, filling and a couple of dips into the old bottle of Future will hopefully yield masters suitable for making new clear parts with casting resin.  WE will see how that turn out.

 

More later.  Stay tuned for more butchery, and possibly, foul language, suitably blanked out...

 

Ed

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I look forward to this one, Ed!

 

Once you know what to look for the extra bit spliced into the Thunderbolt nose is easy to spot.  I think the Academy kit will do just fine for this backdating endeavour.

 

If a Lindberg P-47B kit falls in my lap I think I'd be tempted to do it as Zemke's bird.  The colours, irregular demarcation between OD and NG, and the Medium Green mottling are just too tasty.

 

As it is, I'm quite excited to watch you build the experimental prototype.

 

 

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Hello again!

 

Last time. we were just getting the canopy parts ready for casting.  I created a mold from Ooo-M00 30 and some old Legos, and prepped the masters and shot some resin into the molds.  Rather than repeat all those steps here, I'll just refer you to the article on how I did it for the YF-105A,  Clear Cast Resin Canopies 

 

If you check out that discussion, be sure to either read all the way through, or skip ahead and start reading from the 2nd attempt, as the first attempt was not successful!

 

While all that's drying in the molds for the next two days or so, we'll move on the the next obstacle in our build, removing the 8" that were added to the P-47D in real life, so that, of course, must be removed here.

 

I started by laying out the correct 8" distance back from the chosen panel line, and then first scribing, then sawing the vertical lines with a razor saw.  Note that in the following photo, I took care NOT to saw through the wing fairings, only the fuselage sides:

 

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Next, above right, the rest of the fuselage front was removed from either fuselage half by sawing down the line of the wing fairing to the fuselage, taking care to preserve the wing fairing, as much as possible.

 

Next, the painted and detailed resin cockpit was glued to one fuselage side with a couple of drops of CA adhesive, just to check the fit and center up the cockpit.  When that was done, the cockpit was given more CA, and then two bits of plastic rod scrap were glued to the fuselage sides, to provide a "ledge" to glue the rear deck area onto later:

 

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In the center photo, above, the "W" shows where white canopy glue was added to re-enforce the cockpit-to-fuselage join.  I have explained elsewhere the reasons for this -- neglect this step at your own peril!

 

Lastly, in the third photo, above, the "P" marking show the pieces of scrap plastic card added here and there, to re-enforce the joint when the front fuselage is later re-attached.

 

I'll be back later on, after some glue had dried, to continue to flounder my way through this build!

 

Ed

 

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Hello again...

 

Next, the front fuselage part is re-glued to the rear fuselage:

 

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Above right, the new join line is masked with tape about 1/8" (or less) from the line, on either side.  This allows the 3M acrylic putty to be slathered on, without covering very much engraved detail.

 

When that's all dry and sanded, more putty is applied to the wing fillet, on the leading edge area:

 

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Above right, after some filing and sanding, it's starting to shape up! 

 

Next, after painting and detailing the engine and the inside of the cowl area, the cowl cooling fins are sawed in between, and bent out just a bit, to give a better representation of slightly-opened cooling flaps:

 

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Above, the two lower cooling flaps on either side (marked "X") will needed to be sanded down, as they were not present on early P-47's.

 

See you next time,

 

Ed

 

 

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Thanks all,

 

Sorry for the lack of recent updates.  I had a rather minor surgery, and it took a little longer to bounce bask than I thought it would.  I guess being 76 is starting to show...

 

Anyway, when last we met I was awaiting the outcome of the molding of the new canopy parts.  Well, they are done, but things didn't work out as well as I'd hoped!  The molded parts looked like this:

 

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When I took the parts out of the mold, the forward canopy part (main canopy broke in two while I was sawing it from the pour block, and the new rear part of the canopy was not smooth enough to use, due to the fact that the original rear windows and the original rear turtle-deck were of different thicknesses.  I knew this, but just didn't sand them down enough, and you could see the join of the original parts (arrow).

 

So, back to the drawing board.  I cut two pieces of regular thick plastic, around 40 thou, I think, and built a new turtle-deck.  In case I hadn't mentioned it before, the ultimate goal is to have a completely clear turtle-deck, upon which I can simply mask the new rear window shapes. Anyway, I glued two pieces together, and to the fuselage:

 

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Above center, the new plastic will be sanded to follow the shape of the fuselage in the rear, to a more or less flat surface on the front sides, using the shaped sanding tool with sandpaper wrapped around.  (An appropriately-shaped dowel would also work!)

 

Above right, the finally -shaped turtle-deck is shown.  This was then sawn from the fuselage with a fine razor saw, along the back and lower edges.  The arrow shows where the two un-needed lower cowl flaps were sanded and filled.

 

When sawn free of the fuselage, a thin piece, "A" to allow for the saw kerf, and a thicker piece "B" for a pour reservoir, piece of plastic were added to the new rear turtle-deck as shown below:

 

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Eventually, I used this master to make a new mold for the turtle-deck part, but I was in a hurry, and did not "cure" the silicone mold in the oven for 4 hours at 150 degrees F.  Thus, the part came out a little fuzzy or blurry, requiring fine sanding to clean up the clarity.  As we speak, the silicone mold is in the oven, in case I have to take another shot at it!  The main canopy original (cured) mold worked fine, and I took care not to break the brittle resin part this time!

 

*** EDIT *** After completing the model, it dawned on me that the rear area could have been easier to build, by simply

using two pieces of thick enough clear flat plastic sheet, perhaps that used as storage bin divider panels, to mahe the rear cockpit area.  Since this area is mostly painted, these could have been glued to the model, sanded to shape, then been sawn off... duh!

 

Below, both pieces of the new canopy are shown just set roughly into place on the fuselage, so you can get an idea of what I'm trying to do:

 

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The center part will eventually be cut apart, to form the door, as well as the right side of the center canopy, which is stationary.  I reality, they booth look better than the photo, but we shall see how everything turns out in the end. Either way, it will be better than the XP-47B that I had before....

 

Now to figure out the actual shape of the part behind the pilot's headrest, underneath the rear windows.  More later on.  As I am scheduled for a week's vacation at the end of next week, I probably won't have a lot done before I get back, but I'll try for at least one more update before I go away.  Thanks for looking in!

 

Ed

 

 

 

 

 

 

 

Edited by TheRealMrEd
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Back again, with the last update before a few days Holiday..

 

After the new resin canopy castings were made (they turned out good), the clear part of the turtle-deck was attached to the fuselage with CA.  Note the white plastic card shim to get everything to fit together:

 

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Above center and right, a little filler here and there...

 

Next, after carefully sawing off what will become the door (consisting of the left center canopy area, as well as the upper curved portion of the center canopy, and of course, the door sill), the right side center canopy window was installed.  This was after dry-fitting the kit front canopy section, to assure the correct location for the right-side windows.  The, the right side windows were glued i with CA, and the front windscreen was attached with liquid plastic cement, in this case, Weld-On #3:

 

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Not shown in these pictures is the fact that I masked the clear glass areas with tape, before sanding, to protect those areas. Below, everything is in place except the new door, shown laying on the table beneath the fuselage:

 

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Note that the door includes the upper curved part of the canopy.

 

Well more sanding, polishing and scribing when I get back, and then we can attach the wings and move on down the line...

 

Ed

 

 

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  • 2 weeks later...

Hello everyone,

 

Back from a rainy but otherwise relaxing holiday!  Next up, the wings for the XP-47B, which had no wing guns mounted, so the gun tubes will have to be removed from the Academy wings, and the spent shell ejection chutes must be filled on the bottom as well. 

 

The wingtip lights, for any newbies who may be tuning in, are just clear plastic bits, with tiny holes drilled in, after which the holes are filled with the appropriately-colored paints --  in this case, red and green MM clear acrylic colors.  Then the clear plastic bits (blocks in this case) are glued to the wing-tips, after the needed areas of the win were sawn off with a razor saw.  In this case, I used old plastic bin dividers from a screw, etc. storage cabinet, so I could simply glue them on with liquid glue -- in my case, Weld-ON #3 which can be had in large quantities on Amazon for a relatively cheap price, vs the cost of individual little bottles of cement.  In the past, I have also used clear acrylic sheet for these lenses, which require CA or epoxy to glue them onto plastic.  In cases where the whole light lens itself is colored, vs just a colored bulb, my go-to's are old-style Lite-Brite pegs, or cheapie colored translucent toothbrushes, which last a long time for this purpose in 1/72 scale!

 

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Above left, the spent shell ejection chute areas are masked with tape, then the holes are filled with putty.  "A" and "A" show the rough clear light lenses glued to the wing tips, with the pant-filled bulbs oriented correctly.  The gun barrels have also been sanded off; they will be sanded smooth later.

 

Above right, stretched sprue is used to fill the bomb pylon holes, which are not needed on the XP-47B.  The sprue will be nipped off flush and sanded after the glue dries.

 

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Above, all sanded and ready for attachment!

 

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Wings on, now ready for some tricky masking before adding the horizontal stabilizers..

 

Later,

 

Ed

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Back again.

 

This time, I'll start by showing the rudder trim tab, which on the prototype (at least early on) was painting some kind of yellow (possibly yellow primer?), but the photo I have in color does not allow for a distinction to be made, at least by me.  Also, the fabric-covered rudder itself was painted some dark color, probably a dark O.D., or possibly black.  I will go with the O.D., later on:

 

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Perhaps they just covered the trim tape with Tamiya tape...?

 

Next up is masking the cockpit, particularly the new rear windows.  To start, I scaled the XP-47B drawing to 1/72 scale, at least on my computer.  Your mileage may vary:

 

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Next, I cut out the new rear window portion from the printed drawing, shown above right.

 

Next, a piece of tape is attached to the edge of the front side if the cutout drawing, to enable me to hold it and spray one coat of contact adhesive, on the paper pattern, on the WRONG side of the drawing, and attached two pieces of Tamiya tape to BOTH sides of a piece of thin card, although you could use a piece of plastic from a bubble-wrapped package, etc.  The idea is to attach the drawing over the plastic part that has been taped on BOTH sides, so that eventually, when the drawing is trimmed to shape, you will have a thin piece of plastic sandwiched between the two pieces of tape, giving you a tape pattern piece for each side of the model:

 

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Above right, the drawing has been cut out of the plastic/tape/paper drawing sandwich, right.  The left view shows the reverse side of the sandwich, so hopefully, you get the idea. You can use a sharp #11 blade for this; I used a sharp pair of small scissors, something like cuticle scissors, or sewing thread scissors (like in your wife's sewing machine...?).

 

Next, the paper drawing is peeled off the sandwich, hence the need for only a single coat of contact cement on the back of the paper drawing.  Anyway, we are eventually left with a thin piece of plastic pattern, with tape on both sides.  The edges can be sanded gently or trimmed to final shape:

 

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This part being done, we proceed to mask the model:

 

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After figuring all this out, I took a dive and used a set of Eduard CX-110 masks for the rest of the canopy.  I almost bought the wrong set for the Academy P-47D, as Eduard also makes a set for the bubble-top P-47D.  Last, an old bloch of foam that I had lying about provided a cube of foam to mask the canopy innards:

 

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Did I mention that I NEVER throw anything away, as almost everything is grist for the modelling mill...

 

After adding the masks to the wheels, everything is ready for the paint booth.  Back in a few days, stay tuned...

 

Ed

 

 

 

 

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  • 2 weeks later...

Back again!

 

After surviving the rigors of the paint booth (black Krylon glossy primer, sand, more black, sand, more black, coat of Alclad II Alclad finish, sand, etc...), it finally looks like this:

 

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Above, the vertical tail surface is wrapped with Parafilm M, along the rudder hinge line and forward, with the rudder hinge areas masked off with tiny strips of Tamiya tape, cut to width.  A better view of this process is shown below, where "A" shows the Parafilm M more clearly, and the arrow indicates the tape strips:

 

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This solves a lot of nasty masking problems.  For these tape strips, and getting consistent tape (or decal) widths, this is the best tool I've found yet, the Infini Easy cutting Jig Type A, which is marked off enabling strips, squares, rectangles, etc. to be marked off quickly and evenly.  Just slap on your tape, use a sharp blade run along the grooves, and suddenly, Bob's once again in your mother's life!

 

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The only markings on this aircraft, at least in the early part of testing, were the "U.S." and "ARMY" markings on the lower wing, and the propeller decals.  This made for a very not-colorful bird, except that they had the kindness to paint the rudder itself in what is simply called "Army camouflage", which I interpreted to be, in that era, Olive Drab 41, for which I used White Ensign (now Colourcoats #ACUS15.

 

I also used their ACUS23 zinc chromate yellow here and there on the model to add a little bit of color, but all the areas could very well be just plain aluminum, which is probably the more likely choice.  However, artistic license and all that, plus, I have no photos to prove either...:

 

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On sort of the same note, above right, I painted the elevators the same OD41 as the rudder, as I have photos showing various stages of paint on the rudder, and a couple which seem to show the same paint on the elevators.  This is my best guess, as I simply don't know.  Later on, and just before it's flight-ending crash, it was panted OD over Neutral Grey, with stars with red centers, so there is a little variety to be found in color schemes.  Interestingly, the crash was caused by the fact that on the fatal final flight, they chose to fly around with the landing gear left down, and the heat from the turbocharger exhaust, which exits right in front of the rear wheel well, caught the rear tire afire, which then spread to the fabric-covered rear control surfaces, with resultant complete loss of control!

 

Since I like to do prototypes in fairly early schemes (roll-out is my favorite), this is what I chose.

 

Well, it's back to the paint booth to tone down the shine a bit, and then we'll be rounding the final turn, I hope!

 

Later folks,

 

Ed

 

 

 

 

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Loving your work and the interesting tid-bits of historical information about the subject aircraft.

I prefer the Razorback Thunderbolt to the Bubbletop - don’t know why - probably because I’ve only built the Razorback. 
I’ll have to get a bubbletop sometime to accompany the one I’ve got.

 

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Thanks Brigbeale,

 

You've got to do a bubble-top to get the D, M, N or versions anyway, so you might as well get on with it!

 

Back with just a brief update, due to a rather stupid mistake on my part!  After toning down the shine a bit with some Alclad II Klear Kote Light Sheen AC111,  I noticed finally that I'd forgotten to fill the hole for the location of the original antenna, which needs to be shortened and moved forward for the XP-47B:

 

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and the other side:

 

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I glued in a scrap piece of stretched sprue, and after that's trimmed and sanded, it back to the paint booth for some touch-up... rats!  Oh well, as we're all going to learn, sooner or later, you can't legislate away stupidity!

 

Back later,

 

Ed

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