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Airfix Mercedes 280 SL

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wixwacing
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Posts: 1871
Joined: Thu Jul 10, 2008 9:22 am

Airfix Mercedes 280 SL

Post by wixwacing »

Mercedes 280 SL
Conversion


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By Phil Wicks

A year or two back I was looking to make a good NC1 powered sports car. Why? Well firstly I like building models and secondly I wanted something that would keep up with the Ninco NC1 Jag XK120 without being an XK120!! Without a doubt, the XK120’s go very well (I have the Alpen Rally version) and in the NC1 category there is very little else as stable. Cars like the AC Cobras and Ferrari 250’s and 160’s go well but when pushed to the limit just lag behind in a variety of corners. Not only that, A Ninco 166 fetches a pretty penny these days. Other solutions are conversions such as the Carrera Maserati birdcage or the Aston Martin DB3, these can get up and go if well thought out but I still wasn’t happy with them, and everything seemed to be a bit of a compromise until.....

Whilst at a friend and neighbours house, I was looking through his definitive collection of classic Scalextric cars when I noticed a couple of mint condition Mercedes 250 SL’s. These models were made by both Scalextric and SCX Spain and are a very attractive model of the classic Mercedes. These models are even dearer than the Ninco NC1 so the alternative was to find a body in a spares auction. Typing Mercedes in an eBay search brings up a lot of models and will need some refining but after doing a spares/Mercedes search I come to a lot with a poor picture and a very loose description. I down loaded the picture and fixed it up on Paintshop Pro and sure enough there was a Merc of unknown designation almost in its entirety amongst a plethora of other scraps of junk. The auction price was quite low so I put in a snipe and a couple of days later I was reading an email which was telling me I was the new owner of a box of slotcar bits.



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The box turned up ten days or so later and upon opening it, sure enough, amongst other things, there was an almost complete Airfix Mercedes 280SL. Checking it over revealed that there would be little required by way of restoration so plans were made firstly to build a running chassis and then to restore the body to its former glory. The chassis was always going to be a PCB chassis and tubular axle mounts. I have reduced simple chassis making to the very basics and these ARE versatile and simple to make (see the Lotus Cortina in the scratchbuild section).

First up was to cut the basic chassis shape and mark wheel arches and axle positions, Next was the job of making four axle mounts, simple vertical posts with 3/32 id. brass tubes passing through at right angles. With axle positions marked the chassis was drilled to take the post. The posts were assembled ‘dry’ with an axle and contrate. This allowed me to position and mark where the Ninco NC1 was going to sit. The motor opening was then cut through with a dremel type cut-off disc and cleaned up with a small hobby file. The last chassis job was to mark the position the guide tube would occupy. Again a simple task. The tube position was marked in front of the front axle and a piece of brass tube which was a snug fit over the guide swivel pin was selected and cut to size. The guide was a Ninco spring loaded guide. Nothing is soldered in place at this point as the standing height of the body hasn’t been determined. This will be done after the body has been restored to primer stage.



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Next, the body. This had already had the once over and the only body parts missing was one of the rear quarter bumpers and a tail lamp. No sweat. The body had been roughly assembled and painted and to avoid a lot of fiddley work I decided to disassemble it and start again. This was done by carefully applying liquid polystyrene cement to the glued joints with the tip of a modeller’s knife. After several applications, this has the effect of softening the bonded joint, then the joined parts can be carefully prized apart! The parts were then left for a couple of days to allow the soft faces to reharden. The bare body was primed, rubbed back, dimples filled and primed again. The driver’s tray was constructed out of some plastic card and the interior was trimmed up to the point where the driver’s tray was to be. A driver was resurrected from the spares box and some seat backs were trimmed down to finish off.



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Now, with the body in its almost final state, I offered up the chassis complete with choice of axles, wheels and tyres and trimmed the model chassis to fit at either end. Contrary to my normal practice of two mounting screws only, I decided to mount this body firmly with four screws. Some side rails were made from plastic card and screwed to the top side of the chassis. This was then held in place and liquid glue applied to the touching edges. The whole lot was left to dry for at least a week and then the PCB chassis was removed carefully. At this stage the side rails were glued at one edge only and certainly no fit for the rigours of slotcar racing. Gussets were made from thick plasticard and glued to the front and rear of the side rails at ninety degrees. They were also glued to the body sides. This gave a very rigid structure which I was more than happy with. The body mounting screw holes too had some thicker card glued over them. This would ensure there was enough mounting material for the screws to bight into without fear of stripping threads. Once the chassis position was fixed, the axle mounting tubes were moved up and down to establish the best ride height then the brass tubes were spot soldered front and rear to fix them. Lastly, once the ride height was established, the guide tube position could be set and soldered into place. I allowed for a little up and down movement with the model sitting on all four wheels. The chassis is held in by four ‘in hex’ 2 gauge screws from the local R/C shop.



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Next was more body detail. The top coat was applied. This was a mid grey to which I added a small amount of mid blue. This more resembled the blue grey colours Mercedes were fond of in the late sixties and early seventies. The grille was painted and glued. The headlight lenses had to be cleaned, painted on the inside and glue and the front bumper was painted and fixed. One of the rear quarter bumpers was missing so the remaining one was duplicated by laminating several pieces of thin plasticard and shaping. These were painted silver and a missing rear lamp lens was made from some clear sprue from another kit. The screen was intact which was amazing so all that needed was a rub down with some Tamiya fine polishing compound, painting and epoxying in place with clear epoxy.

Decals were applied and the first coat of clear was also applied. I left this to cure for a week then a second thinned coat of clear was applied. The last job was to paint the interior detail. This was left till last for one simple reason. The interior is in flat and satin textures and to avoid a tedious masking job, I left the interior to get covered in the final gloss coat and then paint the finished item. The dash was done in Matt black with facia picked out in silver. The side trims and seats were done in matt red. (A popular combination for Mercs of this era). The steering wheel was colour coordinated and glued in and finally, the driver received his paint job and after standing for a couple of days, he too was glued in place. He had been absent during the clear coat stage.




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Choice of wheels were the Cartrix Alfa Romeo wheels, simply because they were available at the time. I did have Cartrix tyres all round ly but they lacked grip on painted board surfaces and soon the rears were to be changed for SCX rally. I have found these to be an excellent tyre for board, needing little attention between race meetings. On the track from the word go this has been a great little model, It has no bad habits and with the exception of the addition of a small amount of ballast either side of the motor, there has been nothing else to do.




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Statistics

Wheelbase					74.0 mm.
Front axle width				51.5 mm.
Rear axle width			        	51.0 mm
Overall weight				        76.0 grams
Front axle load				        36.0 grams
Rear axle load				        40.0 grams
Front/Rear weight dist			        47.36% / 52.64%
Motor						Ninco NC1
Pinion						Ninco 9z
Contrate					Cartrix 27z
Final drive ratio				3 : 1
Rear Axle					3/32” Music wire
Front axle					3/32” Music wire, ‘Wixle’ configuration.
Chassis					        Blank Printed Circuit Board
Axle and guide mounts			        Selected modeller’s brass tube
Wheels						Cartrix ‘Alfa Romeo’
Front tyres					Cartrix ribbed
Rear tyres					SCX type 8
Body screws					‘Du-Bro’  3/8”x 2gauge in-hex drive.
Paint – body					Tamiya Acrylic
Paint – driver’s tray			        Humbrol plastic enamel
Decals						Patto’s white roundels and black numbers


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Since I had been admiring the Mercedes from afar as a Scalextric/SCX model, I was pleased to be able to pick up this little beauty. Not only does it look good on the track, it drives a peach! It’s possible to go deep into corners under brakes and exits smoothly with good manners ready for the next straight. I have run it successfully against the Ninco XK120 and it is every bit a match and good fun. The term ‘very forgiving’ comes to mind and all who drive it are duly impressed. It has occupied its own spot in my race box for more than a year now and will stay there for a while yet.
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When I'm not racing slotcars,
I'm out in the back yard, burning food!!

When I win, it's because of my talent, not my car or my controller!
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