Detailing a Tamiya 1/12th scale Lotus 72

[Mark Addleson]

Background

 

There have been some beautiful Grand Prix cars in the post-WWII era. My personal favourites include the ‘shark nose’ Ferrari 156, in which Phil Hill won the world championship in 1961, when 1.5 litres was the rule, and the only Eagle-Weslake built, which Dan Gurney drove. The Lotus 72, however, may be the most iconic Grand Prix car of this – and perhaps any – era. Someone said the 72 was basically a standard chassis for the time. Colin Chapman and Maurice Phillippe, however, changed the shape of GP cars for the next 50 years and we’ve not seen again livery as refined as the JPS design. I wonder how many different models of the 72 have been produced and how many kits Tamiya has sold of its 1/12th scale version, which it has re-released a few times. There have been 1/8th scale versions too and Pocher is soon to release its own kit in this scale.

 

I bought the Tamiya kit intending to model the R5 ‘D’ chassis driven by Fittipaldi when he won the Italian GP at Monza in September 1972, taking the world championship. In principle this might have been fairly straightforward, as the kit is based on a ‘D’ and Tamiya provides numbers and other decals for the ’72 Monza GP. The trouble, as many modelers well know, was with ‘additional detail’. I could find only a few photos with specific details of that car. Recognizing how things change from race to race and particularly from year to year, I’ve tried to be careful when inferring details based on pictures from other races, but without a complete picture some guesswork is inevitable. Another a drawback of modelling a car raced 50 years ago is that after 1972 all existing chassis were converted to ‘E’ and then later specifications, while many of the pictures you find online are of recently restored cars. Ian Wagstaff’s book, Lotus 72 Owners Workshop Manual, provided invaluable information, though in that, too, many of the photos are of rebuilt cars. The book includes Tony Matthews’ excellent cutaway drawing of an early 72D which also served as a useful guide, while Mike Oliver, who wrote the definitive book on the 72 (unfortunately I don’t have it), kindly sent me some photos with hard-to-find details.

 

With one exception – drilling 16 holes in the 1.2mm brass tubing of the rear anti-roll bar for the adjustable drop-links to the uprights – I use hand tools and a small ‘pen’-type electric drill extensively. With an adjustable chuck, it accepts PCB micro drill bits, burrs, as well as sanding and polishing bits and the carbide cutoff disks that I seem to use for almost everything.

 

Though recently completed, I’d lost track of when I started this model. My earliest photos say it was essentially five years ago. Since then, I retired and moved continents, from the USA, near Washington D.C., to the Southern Cape coast of South Africa.

 

Why additional detail?

 

Over the years I’ve made and collected all kinds of models, from railway-related ones – although I never built a layout – to household product miniatures, including – in the late 50s – some of the UK-made tiny reproductions of everything from packets of Player’s Navy Cut cigarettes to boxes of soap powder. The reason has always been the pleasure of a miniature version of something; and the more it replicates in its details the ‘look and feel’ of the prototype the more I enjoy it. If you compare some of today’s highly detailed tiny cars in HO scale – they have interiors, opening boots and bonnets, and even some engine detail – with, say, their diecastMatchbox counterparts, which I loved as a child, you get a sense of how ‘toy cars’ have improved in detail and accuracy.

 

The early 1/12th scale Formula 1 car kits weren’t the precise scale models we get today. Tamiya’s earliest kits included a small motor and batteries, so, in spite of their general quality, the manufacturer sacrificed accuracy and detail for ‘play value’. This changed over the years with improvements in manufacturing techniques, a wider variety of materials being used, more competition and, not least, modelers wanting more accuracy. Even though the detail in Tamiya kits is marvelous, big scale kits allow and even encourage detailing, which, besides replacing (remaking) parts, often means substantially modifying the parts I do use.

 

I thought I’d begin with photos of the ‘finished product’ and work backwards to earlier stages, to show the construction. That said, as I’ve not kept a careful photographic record of the construction, this will be a bit random. At the same time, I thought it might be interesting to compare details on the model against the prototype, using cropped sections of photos I’ve collected. We’ll see how it goes!

 

[Apologies if this is confusing. I've redone some of the photos because they weren't properly lit and weren't particularly clear]

 

 

 

 

 

 

 

 

 

 

 

 

Edited December 1, 2022 by Mark Addleson
redid some of the photos

[klubman01]

That looks really nice!  I remember seeing the real car in action at Brands Hatch in 1972, and then buying this kit a bit later.  The end result was OK, but nowhere as good as yours.  Looking forward to seeing more photos, especially those from the construction phase.

Trevor

[Kitkent]

Very nice! I agree with the Haynes manual too,essential reading. Chris.

[Flintstone]

Great build of the 72! I remember seeing these race at Brands Hatch in 74, such a great colour scheme.

[Mark Addleson]

Thank you to those who've posted in response to the first batch of photos.  I wish I'd had the opportunity to see the 72 in action, but for some reason I never did.  In the early 70s, when the cars were running in the South African Grand Prix at Kyalami (incidentally, that name translates as 'my house': kya=house, lami=my), I was at university on the other side of the country! A bit later, I just didn't get around to watching the Gunston and Lucky Strike sponsored local drivers in the national championship.

 

Some information regarding this first batch of photos.  The body rivets are two sizes of resin rivet from Archer in the USA.  They're relatively easy to apply and with a good decal softener the carrier film will more or less disappear.  Unfortunately, my softener which originally worked well, might have been getting old and diluted as it didn't produce the results I'd had previously.

 

For larger rivets - for example on the trailing edges and sides of wings and the Gurney flap on the nose - and other fasteners like the ones around the fuel filler on the left of the cockpit, as well as for all weld lines, I use regular, slow-setting (12 hour) J-B Weld epoxy.  I'm sure other epoxies will work just as well, but I find J-B Weld convenient to work with.  I let it stand for about 10 minutes after mixing a small amount (two little blobs of equal size) then, dragging a sharp toothpick gently over the top, you can pick up more or less as required.  Dot it into place and if you wet the end of a toothpick or a blunt large-headed pin (spit works well!) you can 'push' it into a small hemisphere, moving it into place if you need to adjust spacing.  Even with practice it takes patience.  Too much and you remove a small amount with a sharp pin.  Too little and you add a tiny bit.  But the next morning, when it's set, you have a nice row of rivets or fasteners.  It's more or less the same procedure for making weld lines, except that you want to drag your sharp pin through the epoxy to produce a thin thread behind it, then lay that down, adjust it as needed, and repeat the process until you have the weld line you want.

 

Tamiya decals are excellent but the kit doesn't provide any JPS decal. This means that instead of a tiny JPS badge for the front of the nose, there is a plain gold circle. To compensate, I used F'artifice's fill-in set.  Their quality is superb.  The details on the race-winner roundels on the wing, for example, are excellent and the gold is a good match.  They also make a complete set that duplicates the Tamiya decals too.  A web search also brings up an Italian company that currently produces a complete decal set.  For that nose badge, which is not included in the fill-in set (why?), I took a jpg file to a local business with a photo printer then removed the emulsion layer and glued it under the kit’s gold circle.  I'd like to hear other modellers' views, but It seems to me ridiculous that a model company is prevented from providing or chooses not to supply decals with the logos of a cigarette brand that is no longer available. Surely the modellers or people who see their models are not going to be encouraged to smoke by small versions of images used in sponsorship 50 years ago!

Edited January 29, 2023 by Mark Addleson

[desert falcon]

That’s a most lovely looking Lotus Mark 🥰   

[Mark Addleson]

Here are some images of the basic 'tub' with cockpit sides.  In photos of the 72’s cockpit, the ‘raw’ aluminium stands out and, as the firm that makes the ‘Bare-Metal’ range of ultra-thin foils suggests, if you want it to look like metal, use metal! So, I started by replacing the bottom of the chassis with a piece from K&S aluminium sheet stock #255 (approx. 0.4mm). In terms of added detail, the whole model owes a lot to K&S. The sides of the cockpit, rear fuel tank and a few other pieces are from their # 3625 (roughly 0.125mm, soft aluminium) glued to styrene for rigidity.  This thick foil is easy to work and holds rivet or other detail, but it also scratches easily.

 

The side pods are removable, with brass rod for the pins and, inside the shell, some thin tubing for grip.  As the fuel tank covers (interior and exterior) are also removable, there are small magnets behind black plastic sheet pieces (from a plastic bag) to hold the covers in place.  The metal additions to the rear sides and bulkhead are from thin brass sheet. 

 

 

 

I've sanded the rear of the pods to take them down to something more like scale thickness.  And later did more sanding!

 

Basic modified bulkhead and tubes visible on the cockpit floor for the fuel lines.

 

Sanding needed to make the underside uniform as the aluminium is considerably thinner than the styrene bottom provided.  I was never able to find a clear photo of the underside of an intact 72.  Mike Oliver kindly sent me one of the underside of Guy Tumner's crashed body from which some details are visible.  It looks as though there were two thin metal bars running lengthwise under the foot box (to anchor the pedal assembly?)

 

 

Cockpit sides reversed for punching rivets

 

 detail gear lever with cover

 

gear lever detail

 

gear change rod 'clip on' cover

[Malc2]

Hi Mark,

 

Good stuff, thanks for showing it.

Through your profile I found your Lotus 49 and had a look at that too.

Looking forward to the next update.

 

Malc.

[Mark Addleson]

Some photos of the cockpit in various stages of assembly

bare cockpit

With instrument panel lap and crotch belts fitted

With seat pan

Modified Tamiya instrument panel.  The 'glass' is AK's glass coat gauzy agent which makes lovely clear pieces. Also used for the JPS logo on the nose.  I use the Dime for scale because the size of the coin has been unchanged for decades

 

 

With surround and shoulder belts.  Knob at top right rear of cockpit goes to cut-off switch to which battery ground wire is attached.  Note radiator side pods removed.

 

Parts of the belts come from the Tamiya sheet with the kit, parts are from the MFH blue seat belt set (some nice etched parts) and the webbing is additional ribbon.

 

The seat is made from a textured, paper-like, thin, layered material that was used as an absorbent sheet under chocolate covered strawberries received as a gift when we were in the USA.  The maker of the chocs wouldn't give me the name of their supplier. Between my model 49 and 72, I've used it all and I've never seen the material again!  

 

Wiring and plumbing behind the cockpit  as well as seatbelt anchors.

Roll-over hoop from aluminium bar, bent on a former made from two pieces of thick styrene sheet glued and screwed, with stainless steel tubing and ballpoint ends for the cones on the ends of the hoop.

Hoop test fitted.  The panel holding the emergency cut-off switch should be silver, not black on R5 at Monza.

 

The cockpit surround provided by Tamiya must have been modelled on an earlier prototype, as the shape as well as the paint line on the Perspex surround changed over time (I'd be interested to know how often new Perspex ones were made).

 

Monza

Monza again

The other problem with the kit version is the two-part styrene moulding, which makes the screen area unrealistically thick.  So I made a 'buck' (is this the right term, it's used in the USA) from Milliput on the original, from which I made a silicone mould and a dental plaster cast (materials kindly provided by a person locally whose business is selling casting kits online). I gave the cast to a commercial business for vac-forming.

 

 

 

 

 

 

 

It required a bit of finessing to get the Tamiya striped decal pieces to fit the wider, flatter front

 

The headrest and back support piece is the Tamiya part slightly modified to fit my cockpit rear which was altered to take the aluminium sections.  The surround is pinned to the headrest piece.

 

I still want to colour the screen area pale yellow, which was the colour of the perspex used at the time.  The second Monza pic shows this best.  I think dilute veg dye mixed with a clear acrylic may be the solution, but I need to experiment on scraps of PET.

Edited December 10, 2022 by Mark Addleson
some typos corrected!

[Malc2]

Thats fantastic, what did you make the dzus fasteners for cockpit surround from?

 

Malc.

[klubman01]

More excellent stuff.  The cockpit surround looks really good.  Have you considered Tamiya X-24 (clear yellow) for the screen?  Suitably diluted, it might be just the job.

Trevor

[Mark Addleson]

Thanks for your kind remarks Trevor.  I have some X-24, which I used, diluted, on the windscreens of a Lotus 49 reasonably effectively.  With food dye and clear acrylic, I thought it might be possible to brush it on and avoid having to mask the surround again inside and out for airbrushing.  An alternative, which I'll test, is the AK 'glass coat gauzy agent' with colouring .  If you don't know it, it's intended to clear coat plane canopies, etc. and in the process eliminate scratches.  I used it to gloss coat the nose of my 49 and it worked very well.  I'd love to know what's in the bottle!  Supposed to be dipped, you can brush it on and let it run off with a paper towel to wick it.  It becomes a very thin, hard, smooth coating.

[TBC]

Very, very nice! I like what you did to correct the cockpit cowling. DMold Models had a corrected one in the works for this kit before they shut down. I'd amassed a bunch of aftermarket for my kit waiting for DMold to release their replacement which never happened. I like what you have done on your own. Lovely car.

[Vesa Jussila]

Stunting work. I like all those details.

[Mark Addleson]

TBC and Vesa thanks so much.  I appreciate your comments.  TBC, I responded a few days ago, but for some reason - as I see now - it has disappeared without showing up.  Like you, I try to line up parts before I get started and I was still in the USA (that's 4 years plus) when I contacted DMold, more than once, about their surround.  The quality of the parts they produced - mostly for aircraft - seemed really good and it's a pity that they went out of business, which is presumably why I didn't get an answer about if/when the surround was likely to be available.  That's a potential problem with websites.  They may outlive their usefulness!  As I didn't take a photo of the kit surround, I used their picture above.

Edited January 15, 2023 by Mark Addleson
corrected name. Sorry Vesa. Possibly the fault of autocorrect!

[Mark Addleson]

Here are some photos of the 'front end' along with a few of actual cars.

 

The front of the subchassis is mostly made from K&B's 1/16 brass profiles range.

 

The almost complete subchassis. Glued with cyano and JB Weld. Pins on the outside edge of the top lengthwise square tubing (just visible) are mounting points for the top end of the brake hangers, while the bracket pieces added to the front vertical square tubing will get pins for the bottom end of the brake hangers.

 

Subchassis from above.  Those Pins clearly visible.  Sides of the footbox are from a soda can.

 

A fairly recent restoration of a 72 - which is largely being rebuilt - at R&J Simpson.  As far as I can tell the 'bracing' on either side of the footbox near the bulkhead is post 72D.  I couldn't see it in any photos of 'Ds'.

 

The front torsion bars as modelled.  The rotating drilled rod between short brackets welded to each bar anchors a rod end (right side one just visible in front of the bulkhead in the photo above) which secures the torsion bar.

 

Model rod ends on left and right torsion bar brackets with dampers from aluminium tubing and stainless steel rod.  The bump stops are silicone.  All rod ends and associated nuts are from RB Motion.   Such details, in my, view make for much more 'realistic' models

 

Damper and torsion bar bracket on left side.  The pin holding the damper is temporary!

 

Footbox under construction

 

 

Upper and lower wishbones added.  These were remade using the original Tamiya parts.  Also visible are the brackets or 'stays' securing the brake callipers to the front of the subchassis and in the background the brackets on the upper wishbones for the pull rods connected to the torsion bars.

 

 

 

Wishbones and brakes from underneath

 

Detail of the bracket and pull rod on the (almost) completed model which should have been cleaned  before photographing!

 

Bottom to top: disks (with Tamiya's etched parts), brake hangers, brake hubs and CV boots

 

Assembled callipers, disks and hangers from front

 

From rear

 

A brake hub with 'universal joint' fitted

 

Completed hubs.  Modified round-head screws, intended to function as universal joints, were dropped into each.  The just visible piece of wire inside fitted a slot in the screw head.

 

Universal joints!  Unfortunately the boots for the CV joints, made from shrink tubing are too inflexible to allow the joints to function properly.

 

Front end without axles and uprights fitted

 

Remade front uprights.  'Ball joints' are small balls from Milliput drilled to take guitar string.

 

RIght upright and stub axle.  The axle is a pinned sandwich of aluminium tube (outer), section of 3mm nylon bolt, and thin steel tube probably cut from a ballpoint cartridge.  The head of a small screw is glued into this and to the CV joint fitted inside the upright.

 

Subchassis and suspension complete.  Used a silicone mould to form the tops of the clutch and brake master cylinders in epoxy to make them translucent.  Brake and clutch lines follow the prototype to the extent that I could find suitable photos.

 

'Jig' with front frame that, at this time, carried one extinguisher and served as the 'tie down' for the nose section.  Note the high-tech solution for preventing cyanoacrylate  sticking to the jig: waxed paper.  When applying cyano, I generally put a drop or two on wax paper then apply it with a pin or toothpick.

 

Frame is made from paperclip wire. In my view when closer-to-scale wire or tubing (e.g. parallel links and trailing arms) replaces the moulded parts this makes a huge difference to the 'accuracy' of models.

 

 

 

I still need to add reinforcing plates on top of each bracket the holds the front frame (see photos of actual cars below).  Note that the left disk is at an odd angle because the top of the brake hanger had come loose.

 

R5 at the Rothmans 5000 in 1972, which preceeded the Monza race.  Note the blue steering rods.  Malc2 speculates that perhaps these were the aluminium ones, painted blue to identify them as such.

 

 

Footbox in John Love's Team Gunston 72 (the team bought 72/6 and 72/7) and raced in the South African F1 Championship 

 

Fittipaldi at Watkins Glen in 1972

Edited January 29, 2023 by Mark Addleson
added some photos and corrected some typos.

[Mark Addleson]

I'll post the last batch of photos of building my 72.  These are of the engine, transaxle, rear suspension, oil tank/cooler and wing - from the rear bulkhead to the back - so I'll post them 'thematically' as far as possible starting with the rear bulkhead.

Rear bulkhead and lower radius arm brackets from what I think is Classic Team Lotus' R5 chassis when it was undergoing restoration.  Following Fittipaldi's crash, the chassis was 'stored' for many years before it's restoration.  The Tamiya kit brackets are very basic as part of rear bulkhead.

 

 

 

 

While we're looking at trailing arm brackets here are some photos of the actual and model upper trailing arm brackets attached to the valve covers.

 

It was difficult to get the model's pieces to 'hang together' - wire and tubing - so that these could be attached (with pins through the tubing) to the valve covers in a prototypical way.  Glued, with epoxy (JB Weld) for the welds, I'm pleased at the way these turned out.

 

 

 

Now on to the engine block from some early photos to the finished engine

 

Intake plenums fitted with fuel rails and some etched parts from the 72 fret produced by Thunder Valley.

 

Top of 'V' peripherals: Fuel metering unit (plus alternator and distributor) right side and top.  The small bits of guitar string are to attach the fuel lines.

 

 

Left side peripherals: water and oil pumps and oil filter

 

Right side peripherals: water and scavenge pump.  I can't remember what the coupling (clutch?) between the two is called.  Perhaps a reader/viewer knows the technical term?

 

 

Edited January 15, 2023 by Mark Addleson
correction of terminology!

[Mark Addleson]

 

Detail of throttle control bar, fuel metering unit and fuel filter

 

 

Basic block and transaxle underside

 

Construction: combined camber adjusters and torsion bar pull rod links to rear uprights

 

Rear uprights are modified Tamiya parts

 

Triangular combined camber adjusters and torsion bar pull rod links to uprights are modified Tamiya parts too.

 

Dampers from aluminium and stainless tubing

 

Fitted uprights with remade CV joints, exhaust pipe and oil tank support frame, parallel links, dampers 

 

Construction detail - right rear suspension with uprights and dampers

 

Detail - exhaust pipes

 

Engine and transaxle before fitting to chassis.  

 

right exhaust pipe Monza in '72

 

 

 

 

 

Right side of transaxle.  Note bracket for oil tank and ground wire cut-off switch with solenoid behind it.  The wrapping on the two hoses from the scavenge oil pump to the oil tank is the wrapping from round-wrapped guitar strings, with the larger diameter one (like the hose from oil tank to oil pump on the left side) from a bass guitar string.  On the left of the brake is the clutch slave cylinder and on the left of it, the gear change mechanism.  The tank was covered with talcum powder and beach sand before painting.  Although the beach sand is ultra fine, it is clearly over-scale!

 

Detail ground wire cut-off switch

 

 

Detail of ground wire cut-off switch and insulated oil pipes on R5 at Watkins Glen in 72

 

 

Detail coolant pipes and temperature sensor.  Coolant pipes made from solder wire.

 

Detail oil and coolant temperature sensors

 

 

 

Drilling the holes in the rear anti-roll bar for the drop link to the upright was a challenge - eight each side I believe.

 

If you scrolled all the way through, thank you for your interest!

Edited January 31, 2023 by Mark Addleson
added pictures