MAZ 537: Rolling chassis complete

I made some progress on the MAZ 537, completing the chassis and installing all the assorted differentials and suspension bits. The chassis can now take wheels to test for stance.



Judging by online photos, the kit drivetrain is not entirely accurate, but I'll let it go. As it is, there are 4 final drive units, each presumably with a differential, and a fifth differential splitting between front and rear pairs.




The suspension consists of 8 independently sprung wheels, so there are 16 A-arms, 8 hubs and 8 halfshafts, not to mention 5 additional driveshafts joining it all to the motor. (The actual vehicle would have had seven driveshafts apart from the halfshafts, according to one Interweb source.)



The engine in the picture is a spare Cummins NHC-250 from AMT's White Freightliner kit. This 14 litre inline 6 makes a measly 240 hp, but a sturdy 685 lbf-ft of torque. This is a bit down on the WWII tank engine in the MAZ (the 39 litre Karkhiv V2 is a V12 making 525 hp and 1591 lbf-ft), a gap which I propose to rectify by the addition of a turbocharger or two. Of course, putting a 1/25 engine of 14 litre displacement in a 1/35 chassis is the equivalent of a 1/35 motor of 38.4 litres, so in actual fact it's all fine, but hey, a turbo never hurt anyone. (See math below).



Next will be deciding what to cut to make the White cab and Cummins engine fit. So far I have built up the MAZ completely stock. As a result, the option remains to buy a resin motor for it and continue with a stock 1/35 build. The picture shows the motor in the chassis, which is resting of 4 of its 8 wheels, with both MAZ (1/35) and White (1/25) bodies. The tires are humongous, filling the White fender wells even though the scale is way off. I foolishly didn't make a note of the tire sizes on the MAN in Iceland, but they were easily 4 to 5 feet in diameter.



Stay tuned!

Appendix A: for the math nerds.

Displacement D is number of cylinders, N, times cylinder volume V. In turn V is piston area A times stroke S. Finally piston area is πb²/4, where b is bore. Assuming bore and stroke are both equal to d, we have D = 0.25πNd³.

So an engine at 1/35 scale would have displacement D = 0.25πN(d/35)³. For one at 1/25, D = 0.25πN(d/25)³. 

So the ratio of the two scale engines, assuming the same 1/1 dimensions and number of cylinders, wold be (25/35)³, or 0.364. Put another way, a 1/35 model of an engine of 10 litres displacement, put into a 1/25 kit, is equivalent to a motor of only 3.64 litres; conversely a 1/25 model of that same 10 litre engine, dropped into a 1/35 chassis, is the equivalent of a 27.4 litre motor.

MAZ 537: And now for something completely different...

A number of years ago, I had the opportunity to ride in a converted NATO missile launcher in Iceland. The truck had been converted to a bus, with seats for about 40, and was intended to crawl up to a glacier research station. Great fun, and I immediately wanted to build a kit of one.



The ultimate off-road vehicle -- the big MAN Diesel makes over 400 horsepower, according to the tour guides, but torque is off the charts. One neat feature is the ability to deflate or inflate tire pressures on the fly.



 This 8X8 chassis is also used for mobile cranes, and Revell has a kit in 1/24 of the Simba airport fire truck which is both expensive and hard to come by.



So there aren't many options at 1/24, but lots of similar vehicles at 1/35. However, having decided to stick (mostly) to one scale, 1/35 isn't really on the radar.



Also some time ago I built a 1/24 sidewalk snow plow, with blown Pontiac 421 power, using a 1/35 light tank kit and pretending. So then I figured, why not do the same again -- build a 1/35 8X8, pretend it's 1/24, and put on a cab and engine from the spares bin.



This is where the Trumpeter kit of the MAZ 537, a Russian heavy hauler, comes into the picture. You should look it up: it's a real brute, with WWII tank motor and buckets of torque. The kit has well-detailed independent suspension and internal drivetrain components, although I will have to locate a 1/24 engine for it as the WWII tank engine (39 litre V12 Diesel) is not included.



The Trumpeter kit is very detailed with a huge amount of bits. I am tempted by a resin kit adding an engine to this, which means I stick with 1/35.



A quick scan through the parts bin turned up Jimmy Flintstone's White COE which just needs the fenders trimmed back slightly to fit the width of the MAZ. Next will be to find an engine and decide on a payload.



Stay tuned!

Lotus Elan S3: Chassis and drivetrain ready for display

Colin's little masterpiece is ready for display, and I hope I did it justice.



The Gunze Sangyo High Tech kit, with photo etched and white metal parts, is challenging but detailed, and very nice once complete.



 Not much to be said here except that the minimalist design is brilliant. Of course, it was designed for a 1.6 litre motor making about 100 horsepower, and given Chapman's razor-thin design margins, probably wouldn't survive installation of a 110 hp motor.



Torsional loads due to suspension deflection will twist this sheet metal structure pretty easily, but the fibreglass floor pan and body shell will contribute to reducing this substantially.



With torsional stiffness taken by the body shell, the beam-like structure is visible here.



The rubber donuts were perfect for 100 hp at wide open throttle, but my recollection is they led to a bit of a rubber band effect if you tried to drive it gently. But why would you buy one of these if you were going to drive it gently?



Modifications performed by owners over the years include much heavier but torsionally stiffer constant velocity joints in the driveshafts, but it is my understanding that the associated dynamic loads tend to want to fracture the chassis; a new chassis then becomes necessary, and it is possible to find pictures on the Interweb of new tube frames with CV joints and A-arms, instead of the so-called Chapman strut, essentially a MacPherson strut for the rear.



Next step is the body shell, which will take the chassis stolen from the regular Gunze Sangyo kit of this car. That kit, completed many years ago, is curbside and was built up pretty poorly by yours truly, so I am quite happy to volunteer it as donor.



Stay tuned!

Lotus Elan S3: Body, floorpan, dashboard

The donor chassis from the curbside kit has a blank bit closing off the chassis and mimicking the underside of the motor. In order for it to be worthwhile detailing the underhood area of the new Elan, I decided to cut out the fake engine and tidy up the chassis so it will look good when seen through an open hood, if not from underneath -- the car will be posed with the engine removed. Minor damage to the chassis will be fixed.







Next was paint: Tamiya TS-16 Yellow and TS-9 British Green over white Tamiya primer did the trick. The roof and windows are molded in one part, made of clear plastic, so there was some trepidation here, but quick shots of TS-13 Clear before putting the yellow on the roof, and before moving to the green, minimised bleed through and the glass, while a bit scratched, is fine.



I used the same technique as outlined in the rattle can primer click here and here), and I am happy with the level of gloss. There are some photoetched script and trim pieces to put on once it all hardens, then I'll put on some clear before polishing.



Finally the dash is made up of two photo-etched bits. The dials are very well done and a thinned Testor's flat black settled nicely into the background, leaving the raised needles and markers nice and clean. Cleaning up required only a light sanding with 4000 grit. I need to work at making the redline on the tach a little tidier... it is too bad this is a FHC because a lot of this will not be visible.



You can almost read the mileage on the odometer... The outer piece of the dash is painted in Tamiya NATO brown, XF-68, as a proxy for wood. Here again a light sanding brought out the raised nuts around the toggle switches and the bezels around the dials.



The raised square panel in the middle of the console needs cleaning up, then it will be time to put in the teensie-weensie toggle switches. This could be challenging. The instructions suggest inserting a thin layer of clear acetate between the two PE pieces, which I intend to do.

Stay tuned!

Lotus Elan S3: Body

Given the desire to exhibit Chapman's gem of a chassis, and given I put on the carbs too soon so the chassis can't be installed even if I wanted to, the chassis from this glue-bomb, curbside S3 (also from Gunze Sangyo) has been recovered with only minimal damage and will be used for the new body.







The body in turn will have a yellow stripe on BRG background. The yellow went on nicely and I hope the paint doesn't bleed under the tape and onto the glass, which is of a piece with the roof and window frame. There is no real way to find out without waiting for the yellow to set properly, a week at least, before taping up the stripe for the green. Hopefully the quick coat of clear did the trick.





Stay tuned! Other projects are percolating in the background.

Lotus Elan S3: Engine

The engine is in, and it's a squeeze. It just needs a bit of touch-up paint and the radiator, and it's done.



On the left side, the generator and exhaust system are tight fits, and the exhaust needs to be hard up against the engine block in order for it all to fit. Be sure to trial fit this before gluing the header in.



Here is the oil filter and "distributor", with the fuel pump barely visible behind, all lurking below the carbs. (A bit of touch-up paint is needed, then it's done).



The Twin Cam is a converted Cortina pushrod engine, and the old cam is still in the side of the block running oil and fuel pumps as well as the distributor. This was not a problem in the original engine which had the carb and exhaust on the same side (as in Tamiya's Seven), but I well recall the challenges in changing points and setting timing on Elans since the distributor is essentially buried under the carbs.



The distributor is simply a piece of brass tube with four wires stuck in it, and pushed into a hole drilled in the block. There is no coil wire, but if you don't tell anyone, I won't either.





And now the problem: The instructions didn't actually say to put the carbs on now ... because they won't fit through the chassis, and need to be put on once the chassis is in the car. This is not really a problem as I was planning to exhibit the chassis separately, and steal a chassis out of a glue-bomb curbside Elan (also from Gunze Sangyo) for the body; but be aware of this step if you plan on assembling chassis to body.



This photo compares the backbone chassis from Monogram's Esprit 300, with the newer turbocharged twin-cam four that Lotus developed with Vauxhall. This mid-engine chassis was developed from the Europa, and was further modified to take the rear-mounted Peugeot/Renault/Volvo 2.7 litre V6 in the Delorean. The Delorean, by the way, was a real piece of crap, with lots of flaws that should have been sorted out in the pre-production stage; I remember a colleague commenting at the time that perhaps they would have fixed all the issues if Delorean had actually managed to allegedly complete the alleged drug deal he was allegedly pursuing (yes, I am watching over my shoulder for lawyers). But I digress.



Overall it is a lovely little kit of a lovely little car! Stay tuned as I move on to paint. BRG with a yellow stripe, I think.

Lotus Elan S3: Chassis complete

The rear suspension went together reasonably well. The cross member/shock towers, made of white metal, attaches to the PE frame with 1 mm rivets. These appear to be tapered as they start easily but require a good push from a pair of pliers to get them seated, so be sure you have this right before putting them in, you might not get it apart afterwards.



The hand brake cables and the two diagonal rods from the A-arm platform to the crossmember are bent from 0.6 and 1.0 nickel steel rod, respectively. The instructions suggest using more 0.6 mm rod for the hydraulic brake lines, but as this is 0.567" at scale, it's really too big. I've got some 0.020" brass (0.472"), which is still too big but is workable and this might serve.



Classic simplicity! There are lots of replacement chassis available today that are made of welded tube, and are probably stronger; the main reason for doing this is if you were going to put in a much more powerful motor. Chapman balanced things very carefully and the chassis was no doubt well matched to the 1600 cc Twin Cam, but never intended to take much more power.



On to the front which includes photo-etched shock towers and rack mounts, all attached with rivets.



This was considerably more fiddly, and I discovered that the rivets will indeed pull out if you work them back and forth enough, after which they will be loose. CA glue to the rescue, and overall it is possible to get this to look OK, but the issue is that the pieces are really too small.



The PE structure makes it accurate in terms of scale but requires careful fiddling.



Complete! the big pins pushed through the uprights serve as axles, and the backs had to be ground down so they wouldn't interfere with the springs. The tie rod ends are pinned into the uprights with rivets and this is a bit scary given how thin the walls around the holes in the uprights are.



Just missing the disk brakes. The A-arms are pinned to the shock towers with long, 0.6 mm diameter pins with very sharp ends, which are cut off short once inserted; fortunately this step only led to minor injuries and blood loss was minimal.



On to the Twin Cam. Stay tuned!