Miles M.52 Scratchbuild 1/48th WIP

[Gremlin807]

 

As requested, here is a WIP report relating to the M.52 I posted on RFI yesterday.

 

Apologies that I did not keep an account of everything as I progressed with the build.  The following is therefore more a historical recount of the build rather than a real WIP.

 

At 1/48th scale the model was going to be about 200mm long, excluding the pitot probe, so using Visio and the 3 view drawing I had schemed up, I worked up what the cross-sections would be for every 10mm down the length of the aircraft.  The plan was to build the skeleton out of 20thou (0.5mm) plasticard, so the ‘noggins’ between sections would be 9.5mm.  The wings, tailfin and tailplanes were just upper and lower skins so they were much simpler to fabricate.  The cockpit was going to be somewhat awkward even though it is basically a conical shape (the real thing was ogival, but that gets pretty complicated to produce on this scale).  The large canopy and the need to provide details inside meant the structure would be mainly hollow so sections and noggins were not an option.

 

The section plans are shown below. 

 

The skin for the main part of the fuselage was a wrap of 20thou plasticard (simple rectangular shape), and the elliptically tapered rear fuselage section was made up using long, thin, triangular strips of 20thou running from behind the wings to the exhaust hole.  I’d already decided the model was to be displayed flying so I didn’t need to worry about designing/building the undercarriage and internal support structures.  Also, I decided not to build the Power Jets W2-700 engine and thrust augmenter into the model.  The engine is very interesting in its own right so I may just decide to build this one day as an after project.

After working out the major components in Visio, I transferred them to a new Visio drawing where they were all laid out next to each other and the file saved as a .svg so I could transfer the file to a Cricut Explorer Air cutting machine.  (My wife bought this cutter beastie a year or two ago ‘cos she does paper cutting as a hobby.  Brilliant piece of kit: a computer-controlled cutting machine.  It will happily cut through 10thou plasticard but will only deep-score 20thou – which is more than acceptable for what I need.  The real benefit is that I can cut say 50 awkward shapes into a piece of plasticard with say 0.1mm accuracy in a matter of a couple of minutes rather than having to manually draw each item on the plasticard and then manually cut out each shape with a scalpel.  And if I make an error, OK I lose some plasticard, but I can make a correction in Visio, transfer the file to the cutter and have a new single item cut in seconds.)

The 20thou cut sheet looked like this:

 

 

And the 10thou cut sheet was based on these three components:

 

After cutting the 20thou sheet and cleaning up the bits I had a sandwich box full of some 65 actual kit parts and loads of noggins (the rows of small rectangles on the cut sheet).  Now all I had to do was glue all the bits together!

 

The next piccie show the main sections with the noggins glued on.  Looks like one was in need of some encouragement to stand up

 

The noggins ensured each section was correctly separated from the next.  To ensure correct orientation there was a small notch cut in most of the sections at what is the bottom of the section.  These were all lined up using a length of 20thou cut as a guide keel, and I used the 9.5mm hole through the majority of the sections as another guide to ensure all sections were in alignment.  Rather than rely just on the thin keel piece to hold the sections in the correct place, I decided to thread the sections onto a 10mm knitting needle.  This provided plenty of stiffness to the assembly while I glued it all together.

 

When I threaded the sections onto the knitting needle, I found that the keel piece just wouldn’t stay in position, and because it had no longitudinal stability it was a pain to try to keep it straight and fully engaged into the sections.  Simple answer was to mount it on a piece of 20thou so I had a ‘T’ arrangement piece – much more rigid – and the 20thou strip then acted as a length of skin piece for the underside of the craft.

 

Once the rigid keel was offered up to the sections, it was then just a matter of one by one gluing the sections together and to the keel.  Hey presto, one solid skeleton to work on.

 

Now, my original plan for the air intake section of the fuselage was to use the three thin circular profile sections and glue a whole host of carefully shaped very fine noggin pieces between them.  This proved a nightmare, trying to keep the sections concentric and the thin noggin pieces glued correctly.  In the end I gave up, the whole assembly was too flimsy and wasn’t concentric enough.  My plan B was to recut the sections, fit them on an oversized version of the knitting needle to keep them concentric and repeat the build.  However I could not find a ‘knitting needle’ with even vaguely a profile of 23.5mm diameter at one end and 25.5mm diameter at the other, over a distance of 20.3mm.

In the end I decided to use a completely different tack.  As drawn I had a lovely elliptical change in diameter of the annular intake from the intake lip to the font of the engine.  In practice all but the first 5mm or so would be invisible once the cockpit cone was installed, so why not make things a bit simpler, so I drew up a simple truncated cone shape with straight sides.  Again the problem of how to make it.  At work we have an excellent Stores department with a plethora of electronic goodies and a smattering of mechanical items too.  One of which was a cylindrical aluminium handle, about 100mm long and 25mm diameter.  Hmm.  If I could fashion down the one end to provide the shape of my truncated cone, I could use this as a former to build the air intake section on.  After a brief chat with the Stores manager, he took the aluminium cylinder off me and asked for a drawing of what I was after and he would ‘see what he could do’.

 

The drawing I gave him was this:

 

And two days later I was handed a shiny piece of turned down aluminium.  Perfect.

 

The diameter of the hole down the middle ring any bells?  It’s the same as the knitting needle, and so, once the intake section had been built around this former, I could slide the whole assembly onto the knitting needle to mate concentrically with the main fuselage portion.  Simples!

 

The aluminium former was the inside of the intake, so I still had to make the actual plastic part.  The cut from 25.4mm diameter down to 22.75mm is straight, so first up I fashioned a truncated cone out of 20thou card and slid this over the former.  The excess was carefully cut off so that the truncated cone matched the 20.5mm height required.

Instead of cutting noggins to be skinned over, I decided on a simpler of building a solid structure using wraps of 10thou, 20thou and 40thou plasticard around the circumference of the truncated cone until the correct overall external diameters and shape was achieved.  For some daft reason I started this process at what is the front of the intake where I had nothing to use as a reference to hold the wrap straight around the circumference.  No matter.  I persevered using loads of wraps and fill in pieces until I had a solid structure, slightly oversized in diameter.  It didn’t look pretty but all I needed to do is carefully sand away the excess plastic so that I was left with a lovely contoured air intake piece.

 

Sanding down such a beastie presented its own problems.  The shape needed to end up completely circular and centred on the centre of the former, otherwise it would not mate correctly to the rest of the fuselage.  A few plans fell by the wayside and I ended up just sanding down manually and by eye.

 

For the body wrap I took the rectangular piece and used various stages of hot water baths to ‘encourage’ the plastic to take on a curl until I had rolled it into a tube of the right diameter.  The photo below shows my first attempt on the right – using a hot air gun to melt the plastic – not good! – and the final wrap on the left – much better.

 

The photo below shows the final stage of making the fuselage wrap – I had gone slightly too tight and it needed opening up.  Luckily a Barocca tube was the right diameter.  As you can see the wrap is now nicely round and the outer diameter of the Barocca tube was just about right.  The 5mm or so gap in the circumference of the wrap matched the 5mm strengthener I added to the keel.

 

When I fitted the wrap over the skeleton, it fitted like a glove.

 

(Here’s where I failed to take photos of my work, so you will just have to bear with me.)

The wing, tail plane and tail fin pieces were simply glued together with spacers placed at the centre chord points to provide more of an aerofoil shape. These spacers stuck out to provide tabs to be used when attaching the parts to the fuselage.  The 20thou wing etc. pieces obviously left 40thou leading and trailing edges when glued together.  These were slowly thinned down using various grades of wet and dry.

 

The rear section of the fuselage is a tapering ellipse shape.  To cover it I used the long triangular pieces of 20thou card, gluing each to the cross-sections and then to eachother.  This didn’t go perfectly and I ended up having to apply a second wrap at right angles to the first.  This second wrap was made up of 5mm wide strips that were curved in shape to account for the elliptical overall shape of the rear fuselage.  The cut sheet for these wraps is shown below.

 

This second layer of wraps made the rear fuselage thicker than the main fuselage, so I had a problem in how to meld the two bits of fuselage together.  The problem was solved when I re-ran my calculations for the diameter of the main fuselage and uncovered a double accounting error.  The real aircraft is 5ft overall diameter.  This equates to 30.9mm diameter at 1/48th scale.  For some reason I had taken 1mm off all round for the thickness of the 20thou skin, not 1mm total.  This meant all I had to do was make up and fit another main fuselage wrap out of 20thou and the problem went away.  (That problem took rather more than 5 minutes to realise and almost had me thinking I would have to remove and then completely rebuild the rear section with new correct diameter cross-sections and taper skins.)  

 

You can imagine the sight.  For several days there was me at lunchtime conversing with colleagues while holding this white phalanx shaped article, gently caressing it with wet and dry as I sanded back the tapers to give a smooth surface.  Yes there were several comments!                              

Anyway.  That got the main fuselage done.

 

Before attaching the annular intake to the fuselage, I drew up what would be the front face of the W2/700 engine, printed it out and stuck it on the front of the fuselage.  A bit of a waste really because you cannot see it at all with the depth of the annular intake.  But Hey Ho, I know it’s there!

 

The next big task was the cockpit.  I wanted this to be at least reasonable, but it took several attempts to make one that was strong enough hold together.  The large canopy area meant that my initial attempts at a nice circular cone shape just failed and flopped around ‘cos of the lack of plastic support.  My breakthrough was to use a small diameter piece of keyring wire, cut to size and dropped down into the cone so that it sat at the same position as the start of the front canopy arch.  I then used a second larger diameter keyring wire circle at the front/rear canopy frame location and then a third ring at the widest part of the cone, i.e. at the rear of the rear canopy section.  These three metal inserts, held in with CA did the trick.  I had a cone with a circular cross-section that was actually quite strong.  The downside of this was that I then had to fit the clear canopy as two separate pieces, and as you can see from the photos they fitted nicely at the rear but tuck in at the fronts due to the metal rings.

The inside of the cockpit has a central instrument panel with a bulge aft of it where the front wheel would have retracted into.  This undercarriage bulge would have been a pain in the real aircraft with the pilot having to fit his legs either side to reach the rudder pedals.  I took a fair bit of time trying to work out how old Winkle Brown (my pilot figure from the Mosquito) was going to be fitted into this cockpit.  I ended up having to split him at the hips and then separate his legs so they went around the bulge, and then I had to chop his legs off at mid-calf.  This cockpit was definitely designed to only accommodate a small height pilot!  For a seat I designed/built one based on a Spitfire seat – fitting but probably not very accurate. 

 

Once I had the instrument panel and undercart bulge in place and the pilot figure fitted I was able to close up the rear of the cockpit cone, using the other two parts from the cockpit cut sheet above.  All in all it was a very tight fit.

 

To fit the cockpit cone to the main fuselage, the Flight International cutaway drawing I had come across indicated the use of 8 tubular struts set as 4 pairs of two sides of triangles.  These I duly made from 0.5mm square section strip.  Even before I fitted these I knew they would not be strong enough to hold the cockpit to the fuselage, so I cheated.  The cockpit was held to the fuselage using a column made from 3off 5mm diameter lengths of sprue glued together.  At the fuselage end I had to rip off the central part of my W2/700 drawing to attach the column to a blanking plate fitted across the 10mm hole in the forward fuselage cross-section.  The rear flat plate of the cockpit cone was then simply glued to the end of the column.  You can’t see any of this (luckily).

The wings, tail planes and fin were all fitted to the main fuselage by cutting slots into which the tabs were inserted and then the junction between wing etc. and fuselage glued.  The tail planes are horizontal.  The wings have a 2 degree dihedral and in theory have a 1 degree angle of attack.  The latter being necessary on the real aircraft because of the symmetrical biconvex aerofoil shape.

 

You might have noticed that there are very few panel lines on the model.  I have only done the ailerons/flaps/rudder and undercarriage doors, and a token ring around the annular intake.  My logic was as follows.  Based on testing performed on Spitfires/Hurricanes during the war (I can’t remember which) the use of recessed flat head rivets in place of the previously used proud rivets gave some 25mph speed advantage.  This aircraft was designed to travel very very fast, so any surface irregularities that could increase friction would have been avoided.  The leading edges of the wings were so sharp in order to minimise friction that they had to be protected during manufacture to prevent injury!  Thus the model is pretty well ‘clean’. 

 

Painting is one thing I still need a lot more practice with.  The model was painted in two parts – cockpit and built up fuselage.  Both were sprayed with Halfords Grey Primer (surprise!) to look for any obvious errors.  This was then sanded back gently.  I did toy with the idea of a Natural Metal Finish using Humbrol Metalcote, but I wimped out and just used Humbrol Acrylic Silver spray instead.  This doesn’t polish up very well at all, but it will have to do.  I did add a bit of NMF around the tailcone in the form of aluminium kitchen foil held on with thinned PVA.  It actually worked better than I expected!

 

The decals are another spoiler.  In hindsight I should have invested in a set of ‘P’s from Xtradecal and roundels and fin flashes likewise.  But no, I took it upon myself to make my own.  Attempt number 1 was using Mr Decal Paper Dry Rub off paper.  I must have got this completely wrong ‘cos I had a real fight trying to get the decals to rub off and sit in the right place.  This was then made worse when I sealed the decals down using Holloway House Quick Shine (poor man’s Future/Klear).  When the shine was dry it had curled up the edges of the decals and they looked awful!

 

At this point I almost gave up ‘cos removing Quick Shine is known to be a real pain.  In the end I just attached the rub-ons / Shine with a very sharp curved edge scalpel and managed to remove them and their immediate area of Shine without destroying everything.  The rub-on glue just wouldn’t fully come off so I researched using the Google thingie and found that WD40 is a really cheap way of removing sticky adhesive stuff.  I was worried about what WD40 might do the Shine, so I ran a quick test.  I painted a section of an old model with Shine.  Waited an hour for it to dry and then dabbed on WD40.  I waited another hour then rubbed off the WD40 with loo roll.  No effect on the Shine!  Given the results of the test, I bit the bullet and dabbed WD40 onto the remaining decal adhesive on the model, waited a few seconds and then carefully wiped with a bit of loo roll.  Ta Dah!  Adhesive gone!

 

My 2nd attempt at decals was to use Lazertran Inkjet Waterslide Decals.  These (like the Rub ons) printed off lovely, but are relatively thick compared to normal kit decals – and they dry with a white background.  I used MicroSet/Sol to try to get the decals to sit better on the model (I’ve found in the past that the Lazertran water triggered adhesive is very weak and the decals peel on non-flat surfaces).  The MicroSet/Sol helped, but not nearly as much as it does on normal kit decals.  To get rid of the white decal background I used decanted PlastiKote Clear Super Matt varnish (stinky stuff!). (You have to use an oil-based varnish, Acrylic won’t work.)  Boy does that stuff dry quickly!  Before it did I tucked a little of the varnish under the edges of the decals as a glue and then used the paintbrush to push the decal edge down to set the decal against the model surface.  The result, although nowhere near perfect, was better than the MiscroSet/Sol had achieved.  The upside of this process – no white decal background.  The downside was a smearing effect where I has brushed on the PlastiKote.  For some reason this only occurred on the upper wing decals (typical!!).  Unfortunately this has had to stay because I had reached the point of just wanting to finish the model.  A quick overcoat of Shine and the paint job was done.

 

The last jobs were to mate the cockpit cone to the main fuselage and add the Pitot tube (a bulk standard embroidery needle nicked off the wife when she wasn’t looking, cut to size and CA glued into a receiving hole drilled in the tip of the cone!)

 

All in all this was an interesting build.  Being a Scratch everything has to be thought about, everything has to be made and resolved.  Much more challenging and rewarding than just a simple Build Out Of the Box.  My OCD got in the way at several points and probably caused me more grief than ANOther more laid back builder might have suffered.  The Cricut Explore Air cutter is a real game changer.  No more careful transcribing of individual shapes to a piece of plastic and labouring with a scalpel.  If you like the idea of Scratching but have been put off by the legwork, or can’t commit that amount of time, go buy a Cricut.  (Other similar tools are of course available from other vendors blah, blah.)

 

All the design, build work and filling/sanding was done in my lunch hours.  The painting and decalling was done at home (I’m not sure work would have appreciated me paint spraying at my desk!  And did I say that PlastiKote ponged?) 

 

All I’ve got to do now is package the little beastie up in a Sandwich container and take it back to work so it can hold prize position on my desk.

Done!

[Space Ranger]

Words fail me.

[Vultures1]

Wow.  Just ... wow!

[AdrianMF]

Very nice! That certainly puts the Hi into Tech and a great result! Some of us actually quite like bodging things with a scalpel and making a mess, you know  Although there have been times where being able to say "scan that, cut this" would be awfully nice!

 

Regards,

Adrian

 

[qn30jEkPz7]

Very, very nice - I've made a start on doing the same in 1/72 but using 3d printing. I'll be pillaging this thread for ideas and tips

[Gremlin807]

Space Ranger and Vultures 1 - Thanks for all the comments.

LostCosmonauts - Pillage away!  That's what this site is all about - helping each other to solve problems.

AdrianMF - I totally understand your sentiments.  Using a cutter made this model so much easier, but I really do respect those who can do all this by hand - there is  the REAL skill.  I think it is like anything, there is always more than one way to skin a cat.  Hard manual graft, resin aftermarket bits, PE bits, scan and cut bits and bringing it right up to date 3D printing.  I think its something we humans have been working on for a while - evolution.