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1/72 Spitfire Mk.XII -the early Griffon Spit


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Notwithstanding the fact that I'm building (or butchering should I say?) a couple of Hurricanes, I could not resist starting this new work.

First of all I have to say thank you to two benefactors who supported me with a lot of material for this conversion work. Thank you gentlemen (you know who you are!).

Last week I was evaluating what will I build with these new assets and now I have a plan.

I would like to model a Seafire Mk.46: although a rare bird, I think it is so beautiful with its low-back, huge fin, and contra-prop...

I would also like to model a Pr. Mk XIX because I rate it the most elegant Spitfire ever.

But first of all I want to model a Mk XII.
Some people like this variant the most among the Griffon-engined ones; I like better the long-nose (more appropiately the two-stage-compressor-engined) ones but this variant has a particular charm in being a sort of a "hybrid", being a "rare bird" and even for its war record being employed as a stop-gap against the Fw-190 low-raiders and V1 missiles...
...Thinking about it I feel the same fascination for the very early F Mk.IX which had a similar origin and operational history, or the Mk. VI and VII.

 

There's no perfect Mk.XII kit on the market (that I'm aware of, at least) so add the fashion of a modelling challenge to the above mentioned reasons to build one!
Publicly available documents about this variant seem scarce and photo coverage is not abundant too.
There are no preserved original Mk.XIIs, and the closest relatives available today as a reference are Seafire Mk XVs which are quite different in many detail.
The general shape of the aircraft is well undestood but there are differences in detail between the early-build airframes and later ones; moreover Mk XII has some peculiar elements like the carburettor intake and the magneto hump which are unique in the Spitfire lineage.
Fortunately the few existing photographs show rather well these particulars and allow for an accurate reconstruction.


Here is the recipe I have in mind for the ultimate 1/72 Mk.XII:

Base kit: Eduard

Engine cowling and propeller blades: modified Airfix Mk.22

Spinner: modified Airfix

Underwing oil radiator: Tamiya or Sword

Scale plans: Jumpei Tenma's

A lot of work, a little scratch-building


The base kit is well known; Eduard's 1/72 Spitfire is a scaled down version of Eduard's 1/48 Spitfire which in turn is a scaled down version of .....(it can't be said openly) which is a 1/32 reproduction of a full-size Spitfire.
All of the main features are dimensionally very very close to the data reported in the monumental "Spitfire engineered" book by Montforton; it is the only real "Spitfire looking" 1/72 Spitfire model I'm aware of, together with Airfix Mk.22 incidentally.
That 2012 kit still has the best Griffon nose ever produced in 1/72 and is the perfect donor for a conversion work, as many modellers before me discovered.  
To be honest, both Airfix Mk.22 and Airfix Pr.Mk XIX have a correctly-shaped engine cowling; both kits have small defects in the shape of the cylinder bank fairings: the Mk.22 has them too short at the back, Pr.Mk XIX has an incorrect shape in front (due to the simplified moulding process chosen by Airfix for this kit) AND too short fairings.
Correcting the Mk.XIX cowling is much more difficult than adjusting the Mk.22's so the last is a better choice.
When asserting that this is the best choice for a Griffon nose in 1/72 I mean the following verified facts:
-the profile is accurate within 0,1-0,2mm (or can be easily done so after the careful removal of the moulding burrs)
-the width in plan is accurate, and the cross section is just about right (I'll try to have a better look at this in the building process)
-the position, shape and angle relative to the thrust line of the cylinder covers appear to be accurate (whitin my measurement capabilities) except for the length in the back.
I checked also Sword and Special Hobby products but simply  they are not accurate, in particular regarding the shape and position of the cylinder humps and exausts (Sword) or overall cowling shape (SH).
The propeller is a very good base for the Mk.XII were not for the fact that it has five blades instead of four...

The Spinner assembly results slightly excessive in length (0,4mm) and the baseplate has some peripheral burr so that its diameter is about 10,2mm instead of 9,9mm.

This mismatch is easily addressed by some reshaping of the spinner assembly on a lathe.


If normally I can't decide which livery put on a particular a/c variant the Mk.XII requires yet another choice from the beginning: fixed tailwheel or retractable tailwheel?

I resolved my quandaries choosing the retractable tailwheel variant (although at this moment I've not choosen a particular a/c to represent)

Let's begin.
The Griffon cowling is separated from the fuselage and compared to a scaled down version of J.Tenma's plans of the Seafire Mk.XVII (he did not trace plans for the Mk.XII or Mk.XV although you can find colorized profiles for them in his website)

 

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If your printer does allow just integer percentage scaling of the original (like mine), you can get perfect results by scaling with Inkscape, Photoshop or similar software.

 

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Please notice in the photograph above how well the Airfix nose matches the profile; it can be further improved by gentle bending of the upper arch, but this is not necessary for the Mk.XII because of the magneto bulb in that position.

The cut is refined until reaching the perfect size, and the process is repeated for the other side.

 

According to this quoted drawing for the Seafire Mk.XV

 

seafire15_nose.jpg

 

(which is supposedly based on Supermarine data and matches J.T. plans), the "measurable" (I mean with a caliper) lenght of the section is calculated with some easy math:
from fuselage datum point to the front of the cowling, at propeller axis: 76,2 inches
from fuselage datum point to the upper cowling panel line: 1,28" (source "Spitfire engineered")
the front cowling section is a disk, reportedly 28" diameter, inclined 2° to the cowling panel line. This adds 14" x tan(2°) =0,49" to the measurable length so:
measurable lenght= 76,2"-1,28"+0,49"=75,41" which in 1/72 converts to 26,60 mm.

 

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My result is pretty good!...and was obtained matching the plans, and taking some progressive measurement of the part.
One of the key points in getting a precise cut is adjusting the final tenths of mm with the right tool.

I use 400-grit sandpaper glued to the side of a square aluminum block, and lay both the nose part and the aluminum block on the same plane, so that the sandpaper results perpendicular to it.

 

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Both halves are finished.

 

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And now... there's no return! Two perfectly good Eduard Spitfire Mk.VIII fuselages are horribly mutilated!

 

Edited by steh2o
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Some progress...

I filled in the lower cowling panel line because the Mk XII has a different one and different fasteners.

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I used stretched sprue and CA as it  is immediately workable after curing of the CA

 

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Sanding done and ready for rescribing. The rear part of the panel line is not filled because the wing fillet will extend over it

 

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The Mk.XII has less cowling fasteners than the Mk.XIV and later variants. Moreover, the fasteners have a different spacing. To eliminate the surplus ones, I choose to drill a 0,5mm hole and fill it with 0,5mm styrene rod.

 

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Here the fasteners are filled and a rough outline of the wingroot is marked.

 

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After a first rough sanding, I started rectifying the too short cylinder fairing. I choose to create a mask with kabuki masking tape, then build up some dissolved plastic (sprue bits+MEK) trying to keep it inside the masked profile. After some minutes I removed the mask and adjusted the profile of the added material. After a 24h wait for the mix to fully cure, I was able to sand it to the right shape

 

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Here two pics with a comparison to the original (too short) shape

 

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Now I marked the position of the small step in the side cowling panel using a block to align the upper line of the two elements...

 

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...And I check the two parts together for the first time

 

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Thank you for the comments!

I'm working in parallel on the Mk XIV (more about it later) Mk XII and Hurricane Mk Is, it's a nice experience because I feel that I'm using my time intensively!

The Mk.XII cowling is far from finished yet but I wanted to check the propeller+spinner assembly (being one of the most characteristic aspects of the Mk.XII)

Good news!!

The Sword Mk XVII propeller that I planned to use is actually -unusable-

 

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Here's a comparison photograph with the Airfix Mk.22 one.

I took my time in measuring both. Airfix is fairly shaped, but is slightly too long (about 12mm overall, should be 11,39 or 32,3" scaled) and the diameter of the baseplate seems excessive (10,2mm instead of 9,87mm or 28" scaled) but the excess is mainly due to some moulding burr. When I built the Mk XIVe I did not correct the spinner length (don't know why) so I decided to do it now (this work will be described in the Mk.XIV WIP page). Talking about the shape, the Airfix spinner is not totally right either having too slight a curvature  up to the tip, were the curvature  becomes accentuated giving a rather blunt tip. The real item has more constant curvature and an almost pointy tip. I noticed this problem now that my Mk.XIV is nearly finished and I spent some time analyzing it.

The Sword item seems better in terms of profile/curvature but.... it is too short (problem) has too large a diameter (small problem) has too large blade apertures (problem) has a too thick baseplate (biggest problem). Even correcting diameter and length, the blades result too much forward.

Considering the amount of work required to correct the Sword spinner, I choose to modify the  Airfix one... ok it has five blades but who will notice?

Just kidding....

First of all, I removed the blades from the ring support, they will be modified and used (four of them) at a later stage.

 

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Looking at the assembled Mk.XIV, I noticed that the Airfix blades seem a tad narrow;  I will measure again, but it seems they have a maximum chord of about 3,4mm they should be 3,6mm and the difference , although small, is visible.

 

Here are all the components before starting the real fun!

 

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The  first part: creating a workable baseplate.

Airfix provides a baseplate part with a countersunk hole in the back having a diameter of 1,5mm. With a 1,5mm drill, I deepened the hole until passing through the other side. Then, I inserted a 1,5mm brass tube section checking it to be perfectly perpendicular to the baseplate and glued it with CA and CA+flour

 

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With everything rock-solid, I added the blades ring to the baseplate (the blades will be glued to it and it provides a pressure-lock for the spinner part.

Now that niggling problem... five blade apertures and I need just four of them... After a brief thinking I resorted to this method (I do not have an indexing head for producing accurate angularly spaced holes, this would produce the ideally perfect result). I choose one of the apertures of the spinner. Diametrally opposite to it I opened a 1mm hole on the solid wall between two apertures (I do not have a precise dimension for the blade apertures but I hypotized a diameter of about 1,4-1,5mm). I reshaped the first aperture with the same diameter. Then I filled the four un-used  apertures with  some plastic bits cut  off the unused instrument panel of the Mk 22, glued with MEK and reinforced with CA

 

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In the photograph you can see the two opposing holes and the four patched-up apertures

 

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Here I trimmed the plastic plugs level with the baseplate plane

 

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And here I trimmed level the side. Visible are the two new blade holes finished with their right dimensions and positions.  A word about this procedure. Initially, the two holes have a smaller-that-nominal diameter, about 1mm. They are progressively enlarged until reaching the desired size-while enlarging them, I modify not only the diameter but also adjust their longitudinal and tangential placement. For the two first holes the placement is rather precise because the second hole is positioned at the mid distance between the two opposite holes of the five-blade configuration. To be really accurate, I use a kind of "tape measurement". First of all, I need the spinner to be round so I proceed in sanding away the burrs while turning it on the lathe (here the prop axis previously installed comes handy). Then I take a length of thin kabuki tape and put it  along the spinner circumference on the blade holes line. Trimming it at the hole sides, I remove the two sections and check them to have the same length. If there is a discrepancy, I adjust slightly the tangential hole position while enlarging it.

With the two "reference" holes finished, I proceeded in placing the other two. Again using the kabuki tape, I find the midpoint and mark it with a sharp tip.

 

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I place back the tape between the two reference holes and scribe the position of the third and fourth holes with a pointy tip, then proceed in opening a small "pilot" hole and enlarge it while adjusting its position like before. This adjustement is a simpler operation, because the tangential position relative to the adiacent "reference" holes can be directly measured with the  fork of my digital caliper.

 

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Four blade holes

 

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And a first look at the rough shape of the spinner.

It now has the correct blade openings, equally spaced (to the best of my capabilities, the four caliper measurements (from side to side) of two adiacent holes vary within +/- 0,02mm which is good enough!)

 

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...and a photo to show there are now just four of them!

The spinner still needs a global reshaping (length, diameter) and for that a lathe is mandatory.

I bought one of those extra-cheap mini-lathes for sale on e-bay. They can be found at under 30 euros, they are not high-tech but offer a ball-bearing mounted three-clawed spindle which is almost all you need to get very good accuracy.

More of it in the next post

 

 

 

 

 

 

Edited by steh2o
many typos!
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I'm quite impressed about the clean work you show here in such a small scale (well, for 1/48 modellers like me at least). Always a fan of conversions which include a good portion of "old school" modelling... :)

 

Cheers

Markus

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Thank you Paramedic and Markus!

the Mk XII seems to me even more interesting than the Mk XIV! Let's see if I manage to get a decent result!

Cheers

Stefano

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Another step forward

As written above, after modifying the spinner assembly for hosting four blades instead of five, it is time to adjust the diameter, length and shape of the spinner.

Having carefully positioned the the spinner axle I was able to shape the spinner turning it on a lathe.

 

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The main instruments for this operation are the sandpaper and a scalpel.

The spinner is shortened to measure using the scalpel blade; the baseplate as well is reduced to its proper diameter using the same instrument, Periodical check with the caliper allows for an ideal result.

 The profile is progressively adjusted with sand paper, starting with coarse (400) grit

 

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the profile must be checked with the drawings: as a guide I cut a template from J. Tenma drawings

After using a finer (600) grit the result is this

 

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the surface is rather rough so it can be smoothened with finer and finer grits (1000 or lower).

At the end, I polished the spinner with my faithful Mk.1 Woolen Jumper

 

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The profile seems quite good even if it could be a little blunt-tipped... I have many hours before "freezing" this shape.

 

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Diameter: 9,85 +/-0,02mm, should be 9,87mm

 

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Length 11,36mm should be 11,39mm

 

And here's a photograph of the Mk XII embryo-nose

 

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  • 3 weeks later...

Hello again!

And thanks Cookie, thanks for your support!

I had some weeks of slow-down with my modelling activities. Most of my time went in the modification of the Mk.XIVe propeller

 

and some small progress with the Hurricane Mk I rag-wing

reforming the finished Spit  propeller was really unnerving- when I feel something is wrong in my models I become really psycho... but I discovered that being  so nit-picky  in modelling avoids me being so in real , every-day life!

Let's discuss some progress now.

I'm a bit stalled on the nose because I want to add more detail as possible before gluing the new cowling to the fuselage. In the past few days I adjusted the exhaust opening height and some panel line. To proceed in tracing the lower cowling panel line, I need to know exactly the postion of the wing leading edge. So basically I need to place the wing-fuselage leading edge fillet before having a fuselage ready! I did this  before with Mk XIVe, here's the way:

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Dry-assembly of fuselage and wings: it has to be done with great precision. As described earlier I used a Mk.VIII fuselage (so, retractable tailwheel, MB- serialled a/c) and I'm gonna use a Mk. IX late wing (narrow gun blisters) upper and lower part. It would be wise to use an early Mk.IX lower wing part, but  I want to save those for future builds so I'll convert the carburettor intake panel to an earlier configuration.... after all this seems downhill if compared to the rest of the conversion work

 

Now the choice of the wing root leading edge parts: it is rather clear from period photographs that the Mk.XII had no blisters there neither left nor right so I choose parts I7 and I8, and glued them to the fuselage halves paying attention to get a perfect alignement. When happy, I freezed everything with CA

 

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Now I can trim the cowling parts to fit the fuselage and thereafter proceed in tracing the last cowling lines, rivets and fasteners.

 

Meanwhile, I decided to have a go at the left wing oil radiator transplant.

Allright my dear reader (if I have readers at all!!) here's the truth about it: this is a nightmare!!!

Perhaps I did something wrong but at some point I feared not to make it.

My original brilliant and cunning plan was this one:

"explant the oil radiator panel of the Tamiya Mk.Vb , and transplant it in a suitably-cut recess in the Eduard wing".

In the photograph I have outlined the donor part

 

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...so I proceed and cut away the whole part from the Tamiya wing (Tamiya Vb is not that great and there is a great probability that Eduard will produce a short-nose Merlin in the  next few decades) but a doubt occurs to me: what is the correct placement for it on the Eduard wing? the only  gudelines are the flap line, the diagonal root line, and the wheel well opening but.... Tamiya and Eduard don't match at all! OMG! I have at hand an underside view of the the Mk.I by Jumpei Tenma and try  to understand who's right. No match. Total panic.

Moreover, I check the oil radiator: it is not deep enough and the intake is rather oddly-shaped. So I have an oddly shaped radiator mounted on  a oddly  shaped panel.

Here is the moment for a leap of faith. I will plug the Eduard radiator area with a suitable flat plate, fill the gaps with liquid plastic, re-scribe new panel lines and remove the ones in excess, add a new oil radiator baseplate and use a Sword's oil radiator instead of Tamiya's

As for the panel lines, I will check Eduard's with Monforton's drawings. It is wholly possible that they are wrong; It is possible that J.T. plans are wrong. It is possible that those lines are different from Mk.Vb to Mk.IX (I don't think so).

So it starts the "wing plug" work.

I choose to cut away the left radiator housing with sharp wire cutters then scrape the original radiator's flange flush with the wing undersurface

 

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The same scraping operation has to be done with the slightly raised inlet and outlet ramps.

Then I progressively opened a "radiator shape" hole using the scalpel blade

 

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In doing so, you have to respect the reinforcing ribs on the inside surface or the wing will probably  suffer some deformation in profile when gluing top and bottom parts. The forward cut is the most difficult one due to the closeness of the landing chassis well. Obviously I managed to cut cleanly through the forward corner and had to repair it before proceeding further.

For the new panel I used a giant sprue tab found in the Airfix Spitfire 22.

 

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It was cut in half and glued again together to get almost correct dimensions, then slowly shaped with scalpel and files

 

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The shape of the panel and the hole were progressively adapted to each other. When nearing thee right dimension, I curved the panel surface diagonally to follow the contour of the wing root. Then followed an endless sequence of trimming the panel and the hole until they adapted fairly well.

The panel was squeezed in place and glued: keeping the corner nearest to the wheel well leveled to the wing undersurface, I applied CA from the interior and freezed it with flour. Then repeated this operation with the adjacent corner near the flap. Then applied MEK from the interior between the  two CA areas (this to provide a first filling effect. Then repeated the operation with the two remaining corners, every time filling  with MEK.

The end result (28/V/2021) is this

 

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...and thanks to the careful shaping and positioning of the plug requires very little in terms of filling and sanding.

The downside is that it took me five panic-filled hours to get there!

 

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Thanks Cookie!

In the last couple of weeks I purchased and received two Spitfire books that have some interest for this work.

In the Mk.XIVe WIP I observed that the Mk XIV has two different kinds of spinner fasteners, while the Mk XII/MkXV/MkXVII share the same spinner shape but has a different underlying structure and no evident fixture to fasten the spinner to the baseplate.

Troy suggested that this propeller assembly could share the same fastening method used in some Hurricanes; at that moment though I wasn't able to detect some evidence of this fastening device.

Well Troy was absolutely right!

As I learned from the recent Walkaround-Spitfire Merlin variants the fastening method of key+slot was adopted before in the Spitfire lineage (at least in the Mk.V)

here below I report a photograph of one of the photographs in the Walkaround book: please note the slot shape and the stencilled caution wording

 

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Once you know what you are looking for, it becomes easier to find it elsewhere;

here a Mk.XV spinner (image by www.thescale.info for discussion purposes only)

 

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The tiny slot is plainly visible. In the Mk.XII/XV/XVII it is framed by an oval-shaped panel (in the above photograph it is barely evident).

Seafire Mk.XVII SX137 has it too but is well hidden in the black baseplate!

 

8db57fbb-e61c-4fd1-a59e-71d302dbf478.jpg

 

The final evidence comes from Squadron! n.5 about Spitfire Mk.XII units. A to-me-unknown-before photograph (I photographed a detail of it for the sake of discussion)

reveals this particular on the Mk XII too:

 

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The  slot, the oval panel, as well as the caution wording (identical to the Mk.V warbird's above) are well evident.

 

 

 

 

Edited by steh2o
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A small update regarding the work on the cowling parts.

 

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The basic Airfix Spitfire Mk.22 cowling has been shortened to the correct size, verifying that its profile and section matches well the drawings. The quarter-turn fasteners in excess have been removed and the panel lines have been filled.

In the photograph above, I have rescribed the main panel lines:

-the line between the upper cowling panel and side panel has been slightly moved upwards (about 0,1-0,2mm) according to the drawings; the exhausts opening has been reduced in height adding two 0,1mm styrene stripes top and bottom

-there is a very faint panel line behind the cylinder heads blister, it was scribed. According to some sources, there should be an equivalent line in front of the blister but I can't fine evidence of it in the known Mk.XII photographs, just a possible hint in the photograph at p.17 of Squadrons! N.5, above the second fastener of the upper cowling panel, I'm evaluating to add it after some cross-check with Seafire cowling photographs.

-the line separating the side- and lower cowling panel has been  scribed in  with  a sharp point. You can make out the original Mk.22 filled in panel line and note that the new line follows an entirely different path: it is almost straight and is approximately 1.1mm higher at the propeller, and 1,6mm lower than the original to join the wing leading edge line.

I added the quarter turn fasteners characteristic of the Mk XII (and of the Mk.XII only, because the Seafires had denser fasteners matching the Mk.XIV and later pattern)

For this I used a #3 beading tool

 

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The end result is as follows:

 

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The two photographs show the position and quantity of all the fasteners (I will probably add a hole in the middle of each to match the look of the original).

Regarding the fasteners: I spent my time looking at the few available photographs and at the end I'm fairly certain about quantity and position of the fasteners exception made for the row on the front upper cowling. I found just one photograph that shows some evidence (again in Squadrons! N.5 p.9), and I'm 90% sure that there are six fasteners equally spaced on the front panel. They have almost the same pitch of the four in the front lower cowling, while the front side panels have three more  closely spaced. The Seafire Mk.XV and XVII have a different arrangement here (more and densely spaced).

Now I have to scribe in some more detail then proceed to mate the cowling to the fuselage. I'm still unresolved about the best way to add the magneto blister, but this will be done when the fuselage is closed.

Ciao!

Stefano

 

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  • 3 weeks later...

Progress is particularly slow this month; my laziness seems directly proportional to the external temperature.

I concentrated my (scarce) attention on the lower wing element. I choose to modify a "late style" c-wing which  includes the fairing of the carburettor air filter and actually has different panel lines in that area, too. Retrospectively, I would now choose the early style part that Eduard provides in the F.Mk IX boxing but I have just two of them (perhaps overtrees are available? I will check).

Anyway... I started with a very simple silicon mould (done with inexpensive white silicon) of the "early style" wing part

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I did the same with the large cannon blisters of the early c-wing just to try the concept...

 

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The silicon moulds received a layer of liquified sprue parts, reinforced with CA+flour

 

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...and got  an acceptable result

 

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the general idea is getting a copy that can be glued with MEK instead than CA; as I discovered too late, the thin surface layer is nice, but is very very thin and easily damaged in subsequent operations. Anyway, I proceeded

 

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the best copy (right) was trimmed at the panel line so that I can insert it in place of the late carburettor fairing area.

 

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Here I carved the right shape in the lower wing part and removed the panel lines just behind the carburettor intake (they are different)

 

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The insert is glued in place; looks horrible because it's unevenly tinted but the result is not so bad. I had to replace some lost rivet to match the original part.

 

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I glued the two halves of the Mk.IX short carburettor intake.

Initially I thought that the Mk.XII carburettor intake duct was different from the Mk.IX's but checking again and again with photographs convinced me they are exactly the same part. I couldn't find much reference for this particular element; while the overall shape of the Eduard parts seems correct, I had doubt about the intake shape and presence of a mesh screen/filter of some kind.

But wait! At least one preserved aircraft has this same type of intake!

It is.......

EN474 at NASM! The shape of the inlet is now well understood to me, and it seems like no mesh screen was present inside of it.

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I will thin down the intake (even if it will be scarcely visible with the external mesh screen applied)

 

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So today (22-VI) the wing looks this way:

- I added the new carburettor intake and relevant panel (red arrow)

-I modified the panel lines just behind, restoring the proper rivet lines (orange arrow)

-filled the lefthand radiator area and rescribed some of the panel lines and rivets (blue arrow)

The small blisters behind the chassis legs are well evident in the  photograph of MB882 from below (thinking about it, they are related to the augmented forward rake of the chassis legs in the "c" wing) as are all of the  blisters for cannons and guns.

The thin red lines point to a panel line which is suspect.

-Mk.Vc seem not to have it

-Some Mk.IXs seem to have it

-Mk VIIIs seem to have it

Monforton suggests that this panel line is present in early-build Mk.IX but he's uncertain if this is factory fitted or sort of a re-work of the original skin.

The photograph of MB882 from below doesn't show clearly the situation. A dark line is evident there but is probably due to dirt accumulating on the double-line of rivets present there.

At first look preserved Mk.Vcs do not have a panel line there, just a double staggered rivet line.

Delete or not delete?

Stefano

 

 

 

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  • 1 month later...

Work on the Spitfire is languishing mostly due to the hot season.

Though, I have overcome one of the most unnerving parts of the conversion work, that is building ex-novo the oil cooler area.

I have found little in terms of photographs or documents regarding this area but I think I've managed to get a decent result.

What I understood about the Mk.XII's radiators:

Mk.XII used the tropical housings as fitted to the late Mk.Vc, that is the enlarged radiator fairing which was adopted by the  Mk VII-VIII-IX series and the oil raditor fairing with the "fishtail" exhaust.

About the radiators themselves, I think they were different units with respect to those installed in the Mk.Vc (due do the different power rating of the Griffon) but I have collected no clear evidence until now.

One small difference with other Marks is that the fuel vent pipe at the radiator inlet was supported by a small angled brace

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at least in MB882, that is. If I'm not wrong this brace is not present in other Marks.

On with the work, let's talk about the oil cooler first.

I used the Sword Mk.Vc oil cooler, slightly modified

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These are the original parts matched to the faithful Tenma plans

 

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the plan view is OK, and the depth too (Tamiya is shallow) but the "fishtail" is not well represented. It is also slightly short.

So I sliced the terminal and modified it with small plastic wedges

 

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Liberal use of melted plastic as putty

 

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The exhaust part has been reshaped and the intake part has been added with a spacer to lenghten the whole assembly; dissolved plastic again is used as putty. After curing, the external shape was adjusted with sandpaper. The intake was hollowed out with a ball mill, as well as the internal cavity that houses....

 

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...this! the oil radiator is a sprue cylinder with fine steel mesh, copper and silver wire.

 

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Here the two elements in a near-finished state; the inlet and outlet were painted MSG at this stage

 

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The oil cooler seen from the thinned intake; the cooler is part-wise sunk in the wing undersurface, let's modify it.

 

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The oil radiator flange is copied from the 1/72 JT plans (for the Spitfire Mk.Vb, assuming they are right!).

The flange thickness is 0,1mm; I have traced a centerline with a pencil.  I then measured the distance from the a/c centerline to the housing centerline on the plans and used my caliper to position and align the flange. Then it was glued with small drops of MEK.

In the photograph you can see the restored surface detail: I deleted the panel lines present in Eduard's c-wing and replaced them with the correct rivet patterns, single and double rows. I'm rather happy with my choice, the modified Eduard wing is superior in detail to the Airfix Mk.Vc one which at some point I tought to use instead.

 

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the rough outline of the oil radiator is pencilled on the flange, then drilled out and refined with files and sandpaper to re-create the inlet and outlet ramps....

 

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...and the radiator housing finally fits in its place

 

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I'll add panel lines and fasteners after the whole assembly will be glued to the wing.

Next is the coolant radiator+housing, and wheel wells.

Stefano

 

 

 

 

 

 

 

 

 

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Lovely work,may i ask,have you slowed down the lathe you used on the spinner,if so what did you use to slow it down,i have a similar set up but even on its slowest setting i find its too fast and the plastic heats up and melts.

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Hello and thank you for the comment.

This lathe has variable speed and I'm using it at its slowest. I noticed that there is a bigger risk of melting the plastic the lower is the grade of sandpaper so that I'm using 400 for rough reshaping and 600 for finer re-contouring. Another help comes from wetting the sandpaper.

Hope this helps,

Stefano

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Blimey, there's some lovely work. When I made a Spitfire XII I just kit-bashed a Sword Seafire XV with AZ wings, rudder and elevators with some spare bits from an AZ Vb... that tells you all you need to know about the difference between our attitude to modelling.

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7 hours ago, steh2o said:

Hello and thank you for the comment.

This lathe has variable speed and I'm using it at its slowest. I noticed that there is a bigger risk of melting the plastic the lower is the grade of sandpaper so that I'm using 400 for rough reshaping and 600 for finer re-contouring. Another help comes from wetting the sandpaper.

Hope this helps,

Stefano

Thanks Stefano,i will give that a try 1🙂👍

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I'm not doing 1:72(anymore), and I don't have much interest in Griffon Spits ( I do like their shape though).

Yet I've read through all of your stream. It's absolutely fantastic with the way you lay out, and proof your concepts!

One reads "build stuff logs", and some things just happened (magic) 😉

Your posts are helpful, superb and inspiring! Best of BM 4 me!

Zig

 

 

 

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Thank you all guys for the positive comments;

Beard : sadly (from my point of view) my approach to modelling is too speculative and progress is very slow. I'm now in the middle of building the landing gear wells, I will post something in the next few days hopefully.

These days I'm considering other builds as well -currently I'm evaluating a new "hybrid" that is building "gelb 10" the Fw190D-13 from Hasegawa+AZ+Eduard parts... perhaps its better if I keep focused on the MkXII instead!

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Thank you Zig- I have to say that when I post something the worst part of it is just gone and everything looks simple and straightforward- but in the process I made mishaps and disasters or just plainly make errors and I have to throw some part in the trash bin and start again.... so my reports are kind of edulcorated...

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