Modeling and Advanced Physics

Modeling and advanced physics

By Professor Neurus, U.N.T.

As many modelers have noticed, resin detail parts have a tendency not to fit where they are supposed to. Particularly annoying are cockpit and wheel wells inserts which invariably are bigger than the space they should occupy, in flagrant contradiction with the dictum that states that two bodies can't occupy the same space at the same time.

A strange phenomena has been observed for years, but just very recently clarified and given a name by a modeler from Rancho Palos Verdes, California: the Sanding Event Horizon. This denomination applies to that particular instance that is reached at certain point during the sanding procedure: you measure the part and it is too big, therefore you sand a bit, still the part won't fit; you sand more, still far from ideal; you keep very carefully sanding quantum amounts of resin (or sometimes plastic, or wood, or whatever you use in your modelling endeavors) and after innumerable repetitions and dry-fittings, you try once more and the part is still too big. At this time, aware of the known and proven treacherous and unpredictable behavior of modeling components, materials, tools and the like, you carefully sand away a few more molecules, or even atoms. At this point, something strange happens at the level of sub-atomic particles and suddenly you reach the Sanding Event Horizon, and  the part is inexplicably too small, therefore is now rattling around instead of snuggly fitting in the space where it should go, exactly the same way matter, in reaching the event horizon of a black hole, is irreversibly sucked in and can't go back. The scholars are now turning their attention to related phenomena, like the (self explanatory) Glue Amount Event Horizon and the I Should Push a Bit Harder Event Horizon -that caused so many fingers to be temporarily immolated on the altar of Styrene, the Greek Goddess of Model-making-.

Corsair F2G racer - Special Hobby, 1/72nd scale multimedia kit

 

(The completed model is here:)
http://wingsofintent.blogspot.com/2014/05/special-hobby-172-f2g-supercorsair.html

That manufacturers and modelers alike seem to enjoy the incomprehensible frenzy of glorifying war machines is something that completely puzzles me. This notable behavior is especially true in the aviation field, therefore I really enjoy and applaud every time a manufacturer ventures beyond the frontiers of killing machines and presents something refreshing. In this case, Special Hobby offering started nevertheless as a war bird, as you can tell for the machine-gun holes and other clues. This exact molds were first released as such. But then, in a welcome turn of inspiration, Special Hobby went for the racers to which many of this military machines were converted after the war. The decal sheet offers no less than four choices!

The complete kit package is constituted by multiple resin parts nicely and cleanly cast, a small photoetched fret, a piece of printed film for the instrument panel, extensive decals as said before, two (!) vacuformed canopies and several pages of instructions. All of the items are neatly bagged and therefore protected, only to put them in one of those self-squashing, end-opening boxes. The model is not new now (2014) but it is still available for a reasonable price.

The price is reasonable, sure, because the moldings show the effects of a lesser molding technology, with no locating pins, thick gates and prominent seem lines. Very little flash is present, but to get out some of the parts is not easy, and I broke two -that I promptly repaired- even when I was extra careful and, err, have been doing this for a little while.

The surface detail is very good, and dry trials showed a not too precise fit, although not bad either. The masters for these parts were superb, but the technology for the fabrication of the kit traded low cost for some loss of quality. So be it.

This subject is a tad outside my usual choices' envelope, but I am building it for a friend. The machine he wants is the one portrayed in the box art, but bear in mind that the contemporary machine you see on the Net is not exactly like the original machine that participated in the races in the late 40's. You get parts for both, as well as others to cater for some little differences between the other subjects in the decal sheet.

There are a few tiny mistakes here and there in the instructions, we'll deal with them hopefully as we go, as well as additional comments regarding fit and such.

Beware that in spite the abundant decals some areas still have to be painted, in this case white at the front of the nose and the vertical stabilizer tip.

Always study your photos (NOT drawings) and compare, then take notes and proceed.

As supplementary reading you can check a review (dated 2004) of the military release (same exact kit minus some resin bits and decals pertinent to the racer) by PugetMeister Jim Schubert, who just recently had his 2,445,566th birthday. Congrats again, Jim!

http://internetmodeler.com/2004/april/first-looks/SH_F2G.php

He mentions in his review he got an incorrect 9-cyl row engine, but the kit I am building has a 7-cyl row that came with later -corrected- releases, although it still has three magnetos instead of the seven needed.

And so it begins:

As soon as I compared the "corrected" resin engine with the real thing I noticed that if it was true that the cylinder count was now correct, the cylinders themselves were not; being the shape, pushrods, configuration, all not accurate. So I ordered and Engine & Things P&W R-4360 aftermarket engine and to hell with the kit's one.

Then I turned my attention to the resin bits. There are three things I don't like about resin parts:

1) When they are bad (NOT this case)

2) When they do not have a good fit (more on this)

3) When they are ridden with flash, pinholes, bubbles, etc ( again, NOT this case)

4) When the pouring blocks are not intelligently or practically connected to the parts themselves (more on that)

5) That they are made of resin (more on that too)

Sorry, did I say I didn't like three things about resin parts? I guess they were more.

The resin parts as said are good, well detailed, and mine had no blemishes whatsoever. While most came out obediently from their pouring blocks, the wheel wells were cast in a way that made very difficult to remove the excess resin, and this is critical because these parts are trapped between the wing halves, and of course, like every other resin cockpit and wheel well in the universe, they do not fit, being too thick (point 2). But if you sand too much, you will come through the wheel well roof , ruining the part, so WHY was the pouring block located there (point 4)? Anyway, you will have to sand too the wing parts to allow for the part to fit. As you sand the resin parts you produce an interesting amount of harmful resin dust, a health hazard. So the more you have to sand away those pouring blocks and the parts for them to fit the more crap you generate. I use a mask and do it partially under running water, but the stuff surely gets somewhere else too (point 5).

The resin exhaust stubs are correct for the original racer (the two top on the sides being larger and the two lower ones shorter). The contemporary rebuilt plane has all four side stubs of the same length. The kit manufacturer omitted the ones that run underneath the fuselage, another three pairs of them, that you will have to scratch and add. 

The prop is too small for this variant, so see photos bellow for correction.

Another glitch that keeps you in "step 0" fixing things and thus unable to proceed with the building itself. It is good that the overall quality of this kit is so high, and that's a strong motivation to persist.
All these minor issues are not something terrible, and are relatively easily taken care off.

But I have one complaint: the fuselage is split in two halves as usual vertically, but all the way up to the front; no separate cowl, no separate lip. This for me is a mistake, because you trap the engine as you join the fuselage, therefore corrections on the joints inside the cowl's lip are very difficult. A separate front lip was all that was required, and as it is, is reminiscent of bad and old kits. I was tempted to cut the cowl off and assemble it separately, or at least cut the lips off and join them apart, but decided against it in order not to mount even more corrections and tidying ups, so I'll deal with it as it is.

 

 Cleanly molded nice resin parts:

 Grateful for the two canopies:

 Comprehensive instructions:

 The decals look very nice, will see how they behave and fit:

 Riddle me this, Batman: how to extricate that blob from the middle of the part:

 Parts are separated:

 Very nice surface detail, although the dark past of the military version has to be dealt with erasing those machine gun moldings:

 Nice detail of the fabric-covered areas too:

The resin parts now sawed-off their pouring blocks, sanded and washed. The incorrect "corrected" engine as said will be replaced. There will be surplus resin parts not shown on this shot :

 The prop, as found by other modelers, is too small. The spares bin provided longer blades

 The replacement blades are shaped, sanded, their washout corrected, cut off, and given locating pins:

One of the parts that was damaged taking it out from the sprue is drilled and given a new metal locating pin:

In order to be able to allow for the inserts, you will have to engage in a lot of careful sanding of both wings inner surfaces and the inserts themselves:

 You will have to go to the very edge, otherwise they won't fit, praying not to go through the parts' roof:

 Same for the plastic in the wings, where you can see how I almost screwed it:

 The machine guns chutes and rocket launchers' locating holes must be blanked:

Some photoetched parts are painted, as well as the backing plate for the instrument panel:

 The film is glued on the backing part, the cockpit is already painted:

 One exhaust stub was lost in translation, so a new one was made drilling a styrene rod and cutting the tip diagonally to match the others. I glued it to the same base in order not to lose it and to facilitate painting:

The cockpit is assembled and painted. The photoetched parts are superb:

The sidewalls of the cockpit are now in place too. The cockpit parts were a very good fit and the overall quality and effect is excellent. The resin wheel wells are glued in place and a bead of white glue is applied to seal any cracks or gaps. The fit of those nicely detailed wells is, as I said before, horrid, and this is so far the worst part of the assembly:

The upper wing halves are glued uneventfully:

 The resin inserts for the intakes are a very good fit:

To correct the absence of the three pairs of exhaust stubs underneath the fuselage, the cowl flaps are cut off and a plastic strip is glued to the wing. The area will need more work later on:

The modifications/additions continue to correctly represent that area:

The fit is checked and the cowl flaps are prepared:

 Tube ends are sanded to a slant and then cut to size to later represent the exhausts:

Don't forget to add the part that supports the tailwheel assemble:

 While I wait for the replacement engine smaller parts are prepared:

 The structure that supports the headrest seems not be an accurate depiction of the two tubes, slightly oblong in section, seen in photos. The part will be either refined or two styrene rods will be used. In any case these are better added once the fuselage has been dealt with, to avoid knocking them off:

The engine arrived! The resin aftermarket engine needed to correct the wrong one in the kit (wrong in all issues of these kit, by the way) from Engines & Things in Canada came in the mail today; now building can proceed:

The engine is cleaned up, washed, painted and mounted. The detail on top of the cylinders will have to be sanded away if your are not opening the cowl -as in this case- to make it fit inside the kit's fuselage. The third and forth banks, and the accessories and carb section at the end can be left aside, since they will interfere with a closed fuselage approach:

The fuselage halves are closed locking the engine, but the cockpit can be added later through the wing opening. The unfortunate decision by Special Hobby of rendering the cowl as part of the fuselage sides and not including a separate lip for it, leaves us with the annoying chore of cleaning up all the joints -especially those at the front- with the engine painted and already inside the cowl:

The fit of the fuselage leaves a bit to be desired. As said before, the short run process gives no locating devices, and you can not sand flat the mating surfaces because you will deform the cross section (i.e. your round cowl will be oval). The mating plastic has uneven thickness in some areas. Therefore you have to glue what you can, may be put some reinforcements from inside later on, and out with the putty to fill the gaps. One more area where you will be paying the Special Hobby trade off of lower cost for low quality molding technology. I really get annoyed when I see beautifully crafted masters marred by a so-so industrial process. What's the point of all that really nice surface detail if you have to file, fill, sand, scrap, putty, reinforce, shim, etc?

 On the fuselage upper front you have only to correct the lip, since the joint will be obscured by the intake (here only dry-fitted):

 The seams are puttied and the wing fit is tried. Some little putty will be needed there too:

The putty has been sanded off. The little triangular bump behind the canopy that annoyingly lies in the middle of the seam you have to clean up, is erased and supplanted by a scratched part. The canopy rail is also glued:

The air scoop and cockpit are glued in place:

The wing and stab halves are glued:

 "Mind the Gap" as the British say. It is the same on the other side:

One of the two clear canopies is carefully trimmed to fit. The fact that there are two is something I am really grateful to Special Hobby for, since it takes a lot of pressure off the process of cutting it. They are also sturdy, well molded and very clear. You can also see the styrene shims applied to the wing-to-fuselage gap:

 A part is added aft the tailwheel bay. There are some options and you should match with the adequate parts the version you are building:

A view of the ongoing projects in parallel with the Supercorsair, the Junkers K-16 and the Potez 62.1 airliners:

The wing/fuselage joint is masked following panel lines:

 Liquid putty is applied:

 The Pitot tube is fabricated and added:

Painting begins with a white coat over all assemblies and loose parts. Part of that white will be masked before applying the red color:

The coat of paint revealed as usual a few faults, which were treated with liquid putty:

 Then sanded:

 In preparation for another few coats:

Then some masking and the red color is airbrushed:

 Whilst other parts are readied:

Masks removed, general view. Still a long long way to Tipperary, in spite of the deceiving appearances:

Fiddly landing gear with not really clear instructions regarding the actual precise contact point of the parts:

 The chamfered metal tubes I prepared for the exhausts underneath the model -omitted by the kit- were a tad large, so new ones were made from solder:

The decals, extensive and seemingly well printed, had lots and lots of carrier film, though, never good news. 

My strategy will be "trimming the fat" as much as possible from them. This will of course make application much more difficult and somewhat tricky, but hopefully cleaner results may be achieved this way. The landing gear doors have individual decals for each of them (six), be careful during application, since the diagrams are there, but not really in an unequivocal way:

 The resin part for the head piece is discarded and styrene rod used:

Decaling begins. As said, many subjects are covered by them, which is a truly appreciated bonus.

There are good news, not so good news, and bad news.

The good news: the register is extremely good, which is very difficult to obtain in large markings, my sincere congrats for that. The white is really opaque, thus covering neatly and not allowing bleeding of the underlying color, a common problem with white decals. On all that, well done AVIPRINT. The not so good news: they are very, very thin. This is on one hand good, because they will adapt more easily to the surface, but on the other hand that makes then very fragile, and that has to do also with the necessary amount of white, which perhaps cakes a bit hindering flexibility. I would like to clearly stress the term "very". I broke many, even being extra careful. The bad news: some individual subjects came pre-marred, most likely by particles during the printing process -see image-. Some decal numbers are wrong, don't be fooled and check everything before committing; examples: the stabilizer "sunburst" decals are either two 13 or two 14, not one 13 and one 14 as instructed; the Sohio decals should be 32, not 34. The "ray" underneath the wing that is more externally located is too long. The larger subjects will have to go over many bumps, so you may help those areas cutting small slits with a very sharp blade.

 As said, some factory boo-boos, but also notice the excellent register:

The decals adapted nicely to the surface details. I used Micro Sol, not sure if it is really needed, but just in case. Beware, because the decals really freak out when you apply it, and look absolutely awful for a while, before setting:

The LG covers decals are applied. They are a little oversize, helping you position them:

The three flaps that cover the bottom exhausts are painted.  The decals also include very thin black trim lines as a border for the white areas that the modeler has to paint him/herself: the tip of the vertical stabilizer and the nose lip. They are very helpful and thoughtful, but again extremely fragile, and tend to shatter:

The quality of the graphics is superb, and the way they conform to surface detail is truly amazing, but they are a pain in the neck and shatter a lot. I would suggest that the individual "rays" on the wings should be separated and applied one by one, checking very carefully their position. The compound curvature of the wing, especially on the top side, makes the decals wrinkle if you don't slice them, plus if you apply the wing decals as they are -which I did not- you get a lot of ugly carrier and a headache as you push and pull. By the way, the manufacturer forgot to include in the instructions the registration on the top view -the decals are there, though-.

Fantastic decals, and totally nerve-wrecking to deal with: