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Austin Healey Sprite I was walking along the front lot earlier looking for sections that still needed raking, when I heard the rumble of an antique motorcycle engine coming around the corner. I turned around and found that it was a tiny bright red Austin Healey Sprite. I remembered that I probably have one of those packed away somewhere in the basement, possibly even in the right scale. I eventually took a look and found a Healey 3000, as well as a 32’nd scale Sprite. It was a nice AirFix box of the 1958-1961 Sprite MkI. (1997 re-box of 1961 tooling). However, the contents weren’t so nice and I recalled that I had set it aside deciding that it wasn’t worth spending time on it. But seeing the real thing drive by, gave me renewed motivation. Fig. 1: You can’t judge a book by its cover – you can’t judge a kit by its box-art ! I had built many model cars when I was a kid, but never a 1/32 scale, and this one looks like the tiniest of the tiny. (I use two large magnifying glasses while doing intricate work, but here I could make use of a microscope!) I started work on it and found that the tooling, moulding, casting were even worse than I had initially thought. The front fender pontoons were lumpy. The three sections making up the front end of the car did not fit properly. The hood seam in front of the windshield was scored different thicknesses from one segment to the next. Door seams were irregular. Rocker panel seams were different heights and shapes between left to right side. Other body features that were supposed to be the same, were different sizes and shapes from each-other, and not symmetrically positioned on the left and right sides. The headlight lenses are nice but the dome sockets they are to fit into on top of the hood are not smooth and semi-circular but are instead elongated leaving excess at the top and a gap at the bottom. There are other inconsistencies that I won’t bother listing, plus more I’m sure to discover. (Once again, it seems that I’ve stumbled into an overly difficult model to work with.) But I decided to stick with it anyway. One of the problems for me in this smaller scale, has been motivation, so I decided now that I have a bit, I should make use of it. Fig. 2: Sprite in another of the many standard colours, ‘Mint Green’. I assembled the front end body sections, and started the prep by sanding down those seams and all the lumps on the curved surfaces. I’ve never used body putty on a motorized car, fearing that it may crack under flex during competition, but here I couldn’t avoid it and decided to take the chance. I filled in the top hood seam and the small body-fit gaps in the front, as a start. Fig. 3: Kit contents. There is something else about the body that doesn’t seem quite right. I almost bought a 3000 Mk III when I was a youngster, but I don’t know much about the Sprite, so I started searching the references to learn a bit about the car. If I’m going to the trouble of building it, I want to do it right. I couldn’t find matching wheels in my collection, so I tried the body onto a ‘Carrera Go’ chassis, and even at that 1/43 scale, the chassis was too large for this tiny body ( ~10.5 cm x 4 cm; ~4” x 1 ½” ) . With the kit wheels in place, the body looked very high off the tech block. I thought the problem may be that the wheels were out of scale too large. Doing a search and some arithmetic, I found that the kit tires are properly scaled and do correspond to the vintage Sprite tires, “Cross-ply 5.20-13 tyres”, which are apparently 23.1” or 587mm overall diameter (on nominal 13” rims). The kit wheels have a Rim diam = 11mm, Tire diam = 18mm, giving a Track clearance = 7mm with tires touching the inside of the fenders, and that already appears far too high for the tiny sportscar. Adding a 2 mm tire/fender clearance on the model, (which would be more realistic and would be needed to allow for minimum body roll), gives 9 mm track clearance, and would convert to 288mm, or 11.3” road clearance on the real car. (That 2mm tire/fender scale clearance converts to only 2 ½ ” tire/inside fender clearance available to the real car, still far too small.) I don’t own a sports car, but the road clearance from the bottom of the rocker panel of my mini-van is only 8 ½” ; the other cars in the garage are lower. Since the wheels are to correct scale, the only conclusion I can draw from this analysis is that the model is out of scale too shallow. As a result, they had to cut the wheel arches too close to the top of the body. The shallow body also gives very little clearance for the tires inside the fenders thus the whole body is raised far too high off the track. All of this is even apparent from photos of the real car. (Exterior photos, as well as photos under the bonnet show that there is plenty of space, and structure, between the top of the tire and top of the fender.) Fig’s. 4 & 5: Body proportions of the kit and the real car. It’s very obvious from comparison of these two photos, that the model body is out of scale too shallow, streamlined. (Compare the heights of the door panels, the heights of the fenders above the cut-outs, and the space from top of tire to top of fender.) Unfortunately, it’s an effect that can’t be corrected on this model without major surgery. On the other hand, using smaller wheels helps with the body height and track clearance, but makes the wheel cut-outs on the model look even larger . (I may have to do what I see done on my Ninco XK120 and many other sportscar models - build a step drop between the body and chassis. Even on the real car, some chassis components show below the bottom edge of the body. However, such a step will limit my chassis design and it’s dynamics.) This thing has given me so much trouble; Looks like my initial assessment was correct and I should have just left it in the box! In any case, now it’s become a challenge! So I have been searching for correctly scaled rims and tires. I have worked out four possible chassis designs to fit this tiny body, but until I have the wheels in hand I can’t finalize the adjustments on the body or the detailed dimensions of the chassis. I’m looking for rims 13” nominal which usually work out of be 13mm diameter at the centre ridge and 11.5 mm diameter at the outside edge, depending on the manufacturer. I need 5mm wide for the front pair and 7mm for the rear. Corresponding tires would be 18mm diam before truing. It's going to be difficult to compensate for the shallow body; I may have to do other adjustments, but I want to get the best balance possible. I am always doing what I cannot do yet, in order to learn how to do it. Vincent Van Gogh
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in: Scratch Built Models
- 6
- 20
- 2 years ago
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Taking Apart Scalextric GP When the Scalextric Legends series became available, I recall people saying that they had a hard time taking them apart to remove the magnets, as needed for participation in proxy races on plastic track. Of the Lotus49 versions, the Lotus72 versions, the Eagle T1G Weslake, and the Tyrrell 002/003, it turns out that the Tyrrell is the most difficult to open and take apart. This is because of the ‘clamshell body’ as well as the way the rear suspension is built, both factors being different from the other models in the series. I needed to take apart my Tyrrell in order to see what was causing the irregular power loss, and repair it. I also wanted to convert to a regular guide keel. I later found that the left rear rim is wobbling slightly, and the gear mesh is rough from 8.5V all the way past 15V. Since the other models in the series are easier to take apart, a description for the Tyrrell should cover those as well. [ I will outline some of the differences as they arise in the discussion, and provide some suggestions. ] Besides repair, it’s also useful to open these cars first if you are considering a scratch-built chassis. Two items to note: Even within a particular model, the cementing of the connection joints may be different from one sample to another and therefore may separate at a different junction. Because of the nature of these bodies and the intricate suspensions, in order to take them apart certain cemented joints may have to be broken apart and the tabs may break in the process. A. I would remove the rear wing and all tires, since they obstruct some of the joints you will be working on. The first main stage in opening these bodies starts with removing the 5 screws under the base plate. In the case of the Tyrell, this will loosen the seam between the top and bottom sections of the clamshell body. Now, slowly and carefully lift the front cowling, (top half, in front of the engine). This should eventually loosen and lift off. That's the easy stage, completed. As shown in the photo, you now have the driver, cockpit, guide keel, and front suspension open. This will allow replacement or repair of the guide keel, and you can re-assemble the car if no other work is needed. (I could now see that my red lead wire was frayed and must have finally broken; very fine wires, with little flex.) B. If you decide to go further, the second main stage of separation starts with holding both front rims in one hand; twist the front assembly slightly. Try to identify the seam joints in the front suspension – see which joints are cemented and which are just dry contact. In the case of the Tyrrell, there is U-shaped tab joint on the bottom of the front suspension assembly. That joint is cemented and must be carefully loosened by twisting, prying, making a partial cut through it, wedging with a tiny chisel blade (one of the optional Exacto knife blades), or by any other careful means that comes to mind. If it is strongly cemented together, you may have to do a partial cut then break the seam – it can be easily cemented back together at re-assembly. (In my sample, the cemented seam separated quite well using the above methods, and it stayed intact for re-assembly. The tops of the springs were in dry contact.) Once those bottom joints are loosened, the whole front assembly, rims, axles, top half of the suspension, link-plate to the instrument cluster and steering wheel, can all be lifted up off the car. [ After a grueling race, you may need to carefully pry the driver’s hands off the steering wheel! ] As shown in the photo, unlike the other cars in the series, the Tyrrell has stub axles, so you would have to take things apart up to this stage if you were to change the plastic front rims to aluminum ones. [ Comparison with the other models: Judging from the joint seams on the other cars, it appears that: In the case of the Lotus49, the whole front suspension assembly would lift off of the chassis plate, and remain intact with the body. In the case of the Eagle and the Lotus72, the whole front suspension assembly would stay intact with the chassis plate. (As mentioned, it’s possible that this may still vary from one sample to another, depending on which seams are more strongly cemented.) ] C. The third and last stage in the work is a bit more tricky, but necessary if you want to repair or replace any parts related to the motor or rear axle assembly. There are two general ways to approach this stage. Option-A involves breaking the seams at the bottom of the rear suspension uprights, and results in the top half of the engine-transmission housing, top half of the rear suspension assembly, and the full rear axle assembly, all lifting up off the rest, leaving the motor and bottom half of the suspension to remain with the chassis. Option-B involves separating off the top half of the engine-transmission housing, lifting it upwards, and results in both the upper and lower suspension components, and the full rear axle assembly, remaining on the chassis along with the motor (basically as it would in a regular chassis). I tried the first approach and found that, on my sample, the seams at the bottom of the rear suspension uprights were hard to get at, and were strongly cemented, and there didn’t seem to be any other advantage to that option. On the other hand, I found (at least in my sample) that option-B would allow me to separate the key components at dry-fit joints. With either approach, the first two steps in the work of this stage are the same. The rear oil tank/exhaust support covers the back seam of the transmission housing, and must be removed. It can be pried loose with a tiny chisel or flat-head screw driver. (In my sample, it snapped off clean without breaking the tab or socket.) You will now find that the horizontal seam all around in between the upper and lower half of the Cosworth engine and transmission housing, is loose. But don’t try to separate it yet. There are left and right tie rods coming up from the bottom rear corners of the suspension, linking to stabilizing arms that cross the top of the transmission housing. I found that I could flex the top arms downward and slide and flex the tie rods backward, enough to separate the two. The rear suspension springs contact the lower assembly by dry-fit and will separate away attached to the top half. Now the top half of the engine-transmission housing, along with the attached driver, can be carefully separated and lifted up off of the bottom half. The reason I say carefully, is that the left coolant pipe winds its way from the front radiator, along the side of the body, over the exhaust headers, and up over the top of the transmission cover. Fortunately it’s a flexible pipe and is dry-fitted, so it can be slowly flexed away as you remove engine-transmission. This step completes the last stage of the separation work, and gives access to the motor and rear axle assembly, allowing changes in motor, pinion, axle, crown gear, bushings/bearings and rims. [ Comparison with the other models: I’ve described how taking apart the other cars in this series affects their front suspensions. The Lotus49, Eagle, and Lotus72 models also have rear suspension constructions that are easier to take apart than the Tyrrell 002/003. The models other than the Tyrrell have rear uprights that have an inverted U-shaped opening with two pegs at the bottom that fit into holes in a plate in the bottom A-arm. This connection is either a dry-fit, or a minimal glue surface connection in the samples I’ve seen. There are two advantages stemming from this geometry; there is either little or no glue seam to break at the bottom, and the U-shaped opening allows the whole rear axle assembly to be lifted off of the rear suspension and a new one dropped in its place. Whereas, on the Tyrrell, even after fully separated, there is still a cylinder surrounding the axle at the outer end of the suspension, even if other parts were cut away. This means that, in order to change the crown gear or the bushings, you must pull the axle through those disc surrounds that are moulded extensions of the uprights. The only way to do so is to pull the rims off of the axle, and force the crown gear off the axle over what I would assume would be a knurled section. This, all the while the axle and crown gear are being housed in a structure of flimsy plastic. The way these cars are designed, I can only conclude that they are not intended to have parts repaired or upgraded! (Finding aluminum rims correctly sized to match, is another matter!) ] I hope this description is of some use to anyone considering a replacement of internal parts, or design of a scratch-built chassis for these GP cars. Felix.
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in: How To – Tune It
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- 4
- 2 years ago
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Airfix 1933 MG K3 Magnette Hi Gents: I have been interested in this car for its appearance and its history. I’ve had the Airfix kit in my eBay shopping cart for a while, but have decided that I can’t afford it. I’m posting it here in case someone else may be interested in it. It’s the Airfix 8204, 1933 MG K3 Magnette. It is listed at $35 usd, but it’s shipped through eBay’s ‘Global Shipping Program’. This redirects the package from the seller, to a third party facility in Erlanger, KY (often in the opposite direction to the purchaser’s destination), apparently re-packages it then ships it to the purchaser. They also tack on an import charge ‘to cover duties’. In fact, model kits, diecast models, slotcars are all categorized as toys by the Canada Border Services Agency and do not require duties or excise fees, (though they can trigger GST, usually collected by Canada Post). There have also been many complaints from sellers and buyers regarding poor handling, damaged and missing packages at the Erlanger facility. It’s basically another scheme to allow eBay to skim off more money from the purchaser. I have always refused, on principle, to buy anything shipped through their GSP. It looks like a nice kit for our pre-war series, but I don’t know the quality. I have found some of the Airfix kits made in England to be excellent, whereas some others have been terrible in terms of moulding and casting. (This one is made in Texas by USAirfix, and is the 1980 re-box edition.) It is listed at $35 usd (C$50), plus $10.50 ship to Canada, but when you go to buy it, there is an additional $10.50 that shows up as ‘import fees’. That brings the total to $56 usd, or C$82 with the added PayPal exchange surcharge. That’s more than twice my limit for a 32’nd scale model kit. However, someone else in the group may have a higher cost threshold, or may have a US shipping address set up through their business, or through a relative. But even with that, it may still be overpriced. (I’ll still buy one if I can find a fair price.) https://www.ebay.com/itm/USAirfix-Kit-8204-K3-Magnette-MG-1-32-Scale-USAirfix-Plastic-Model-SEALED-NIB/324101968737
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in: Scratch Built Models
- 4
- 4
- 3 years ago
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Symmetric Masking Patterns for painting a car body. (This is a generalized and expanded version of some suggestions I made to a member who had said he had experienced some difficulties with masking work. Another member later asked me to place my ideas in this How-To forum.) Finishing a car body often entails some curvilinear shapes that need to be replicated symmetrically between left and right sides of the body. These can range from fairly simple to very complex curves, as shown by various photos below. Lola T70 Can-Am; Dan Gurney and John Surtees. (1966 Bridgehampton won by Gurney, the only Can-Am race won by a Ford engine. Surtees won the first race in this inaugural season, three of the six races in total, as well as the series championship.) Mercedes Benz 300 SL; Factory car, Carrera Pan Americana Ford Daytona Prototype Porsche 917K; Psychedelic/ Hippie In terms of the masking, these symmetric patterns are very difficult to replicate from left to right. I’m not an expert, but I’ve had some success with this approach; you may want to try it on your next finishing job. Buy a few widths of Tamiya masking tape, thin and flexible. Testors also makes a version that you may find useful. Before doing any painting, stick the tape over the areas – on one side of the body, that you want to remain as the light colour. Take a pencil, pen, or marker and draw as smooth an outline of the perimeter shapes you want to achieve. (Doesn’t need to be perfect at this stage.) Find a piece of Lexan (clear plastic sheet) from a container of some sort. Remove the sections of masking tape that you have scribed from one side of the body. Stick those scribed sections of tape spread out onto the Lexan sheet. On the back of the Lexan sheet, stick new strips of tape to coincide with the ones on the front. I have also used wax paper, instead of Lexan, as the middle layer and it also seems to work well. Remember, your original scribing did not have to be perfect; now the next step does have to be perfect! Find a sharp large pair of scissors. Carefully cut a smooth line (through the three layers) along the scribe marks you had made while the tape was on the car body. You now have sections of flexible masking tape back-to-back in symmetric mirror images. Save these until later. You can now start the first stage of painting. Prepare the body with sanding and washes as you see fit. Apply your choice of primer, possibly Tamiya fine grade white, if you intend on using light coloured regions on the body. Do any follow-up smoothing and further preparation; a second coat of primer may be needed. After curing, apply your light colour finish coat. Let cure fully then do any follow-up smoothing. Now, carefully peal the tape pieces from both sides of the Lexan and place them at the corresponding positions on the car body. Make sure they are stretched properly and that the edges are smooth and tightly adhered to the body. You are ready to start spraying the first coat of your second colour (the darker colour). Mist the dark colour over the taped pattern and the rest of the body. Do the appropriate follow-up spray steps. Let the final coat cure partly but not to a full hard shell. Carefully remove the tape masks after the final paint is dry to the touch, but still has a bit of flex. Do any follow-up refinements. You may want to clear-coat at this stage. I should mention that I have not yet applied this method to finishing any 1/32’nd scale bodies. ( I used to use it - with limited precision and success as a ten year old kid, on my IMC and MPC 25’th scale LM bodies. ) With new improvements in tape, I’ve used the method more recently on 24’th scale track bodies. The 32’nd scale bodies are 1/3 smaller than 24’th, therefore the compound curvatures will be higher. If I encounter an adhesion or wrinkle problem with the mask due to increased surface curvature, I intend to use a band of the narrowest masking tape ( a couple of mm wide) and stretch it around the perimeter to smooth out any problem areas. This method is not limited to making mirrored shapes between left and right sides of the body. It can be applied to central shapes that need to be symmetric, such as waterfalls patterns. Scribe your pattern near the centre on one side of the body, mark an axis of symmetry, remove the scribed mask from the body, place your line of symmetry along the straight edge of your Lexan sheet, then wrap your scribed masking tape around the front and back of the Lexan. You are now ready to move to the smooth cutting step. You will end up with a mask that is symmetric but is this time, a single pattern to be applied along the centreline of the body. Lotus 49, Ford/Cosworth; Team Lotus. Jim Clark, pole sitter of 1967 Italian Grand Prix, fell to 3’rd due to a faulty fuel pump on the last lap. Hope this works well for you; I’m no expert. You should be able to improve on the method. Felix. I used to be one of the sharpest tools in the shed; now I’m just a slot-head !
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in: How To – Paint It
- 3
- 3
- 3 years ago
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Salivary Exchange at the Track ! That’s a very strange title! But, a relevant one in our era of viral epidemics. Hello gentlemen racers, and fellow ‘slot addictos’. (I posted this on the weekend; it was listed for a while then disappeared.) Saliva, secreted by the salivary glands inside the mouth, is primarily water but holds a very large collection of cells, molecules and compounds, including white blood cells, epithelial cells, enzymes such as salivary amylase for the initial breakdown of carbohydrates, and many other components. Apparently, one millilitre of saliva contains up to 8 million human cells and 500 million bacterial cells. So what has this to do with scale racing? Well, a popular method of cleaning tires for the track is to put a layer of saliva on one’s thumb and rub it along, through, and into the tire contact surface. It seems to be effective in gaining traction! Of course, a good proportion of the contents of that first person’s saliva is transferred from his tires into the track. Another person’s car later runs on the same lane and his tires pick up the salivary components left by the first person’s tires. When that second person cleans his tires by the same technique, repeatedly putting thumb to mouth, the second person now has a good number of cells and molecules from the first person’s saliva. I know we are all friends, but I don’t think we all want to be that friendly! (No need to further expand on the health consequences generated by this practice.) Now, coming from sponge tire use, I’ve never had occasion to practice this method of improving traction, nor had I any inclination to apply it previously, when I was using urethane tires. For those, I usually carried a small bottle of water and applied a drop to my tires. The first track of Arts that I saw was a few years ago, the MVL track. He had invited me to the Friday track cleaning and prep session before the scheduled Saturday race. (I couldn’t attend the race day because I had a 24’th scale one already scheduled for the same day, and I was doing the tech inspection of all the cars.) To that Friday pre-race session, I brought along a couple of 32’nd scale cars, and my 24’th scale Porsche 962 Lowenbrau, as well as a tire cleaning kit I had constructed. I cleaned each of the rear tires with my kit, before running them on the track. The previous night, I had already removed my sponge-tire rear wheels from the 24’th scale car and replace them with a set of rims with urethane tires, wheels that I had sitting in a pill vile for the previous five years. (The chassis was brass base-plate and phenolic suspension-plate that I had designed.) Art let me run the car when no one else was on the track. I could not believe it; I had never seen such good traction on that car, with any tire - sponge or urethane, on any track surface - treated or untreated! (Those urethane tires had been cleaned only with water.) Photo of my 24’th scale Porsche 962 on MVL track; (body a bit beat up from years of racing, but I bought a spare when they were still available). The tire cleaning kit I built is a fairly simple design, not my invention; I just made a few improvements to one I had seen long ago. It’s made from a small plastic food storage bin in which I cut a slot into the lid and attached brass conducting strips to contact the car brushes. The bin itself stores a sponge wetted with water, a transformer-rectifier wall plug, a 9V dry cell, all the wiring and connectors. I set it up so I could use it on the bench with the wall plug, or use it portable at trackside with the optional dry cell. That allows quick cleaning of the rear tires in between heats, if the ruleset permits. It’s very simple and easy, and works better than spit ! Photo of my cleaning kit as would be used; ( I’ve thrown in a few other cars to compare 32’nd, 24’th and 18’th scales. ) Hope you find this a bit useful. Felix. I used to be one of the sharpest tools in the shed; now I’m just a slot-head !
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in: Local Slot Car Groups
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- 4 years ago
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1934 Aston Martin Ulster kit for the Pre-War GP series in S32 (This is my very first post to any forum or website, so please excuse any peculiarities!) I have always been interested in cars from this era. I have the 1/24’th scale Heller kits of the 1930 Bentley 4.5 Blower, the 1932 Alfa Romeo 1750cc Zagato, the 1927 Bugatti T35B, the 1930 Bugatti T50, the 1936 Mercedes Benz 540K, and a few others. I have not built them yet because there has been no track to run them on, and the people racing 24’th scale don’t seem interested in vintage cars. So I was glad to find that S32 was considering a series for them. I recently bought three Matchbox 1/32’nd scale kits: the 1934-36 Aston Martin Ulster, the 1936-41 Jaguar SS (Swallow Sidecars)/100, and the 1933-34 Bugatti T59 GP. I am also inquiring on the shipping cost for a 1933 Alfa Romeo 8C; it’s an old MPC kit, so no chrome parts and no rubber tires. Here’s my Aston Martin Ulster kit: Having never built a 32’nd scale model, I did a dry-fit build of most of the parts, to test the fit and do some measurements. It has a ride height/track clearance of 7.5 mm at the Rr axle and slopes upward to the front. The finely detailed chrome two-piece spoke rims have a diameter of 14.8 mm. It has rubber/vinyl tires, well cast tread detail, with a total diameter of 23.0 mm installed on rim, and a width of 4.8 mm. The wheelbase is 81.0 mm and the Rr track is 53.3 mm without the wing nuts, same at front. The width of the body/chassis plate just in front of the Rr axle is 30 mm. I hope to use the kit’s spoke rims as detailed wheel inserts on the scale racer, as well as the front tires. (Unfortunately I may not be able to devote enough time to the hobby for the next few months, a few of my other projects have been set aside for too long.) Thanks; hope to see you at the races. Felix.
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in: Scratch Built Models
- 5
- 20
- 4 years ago
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