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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51969

Note: This build log is excerpted from my web site . You can check there for larger versions of every photo or further reading.

The original 58016 Sand Scorcher was released in 1979 based on the SRB (Special Racing Buggy) chassis introduced the same year. It was re-released in 2010 as 58452, the version I have. The SRB is really something special. Not only is the first RC buggy chassis ever, but it is virtually all made from metal. The bottom plate is fiber reinforced plastic (FRP), but all the suspension and gearbox components appear to be cast aluminum. The wheels are an innovative 3-piece beadlock design. The hard body was originally styrene, but the updated version is ABS. The model includes a driver and a simulated engine exhaust for detail. The electronics are all sealed in a clear plastic case which sits centered on the chassis. This is a rear wheel drive buggy without any differential so handling can be exciting. The front suspension is independent trailing arm type and the rear is independent swing arm. This means the rear camber changes with suspension travel. This is actually how the real original Volkswagen Beetle suspension worked. The shocks are oil filled, a first at the time. Unlike most Tamiya kits it does not use a 6-cell stick battery pack but a smaller, almost square pack. I had to get creative to find something that would fit.

This is an old design and can't be expected to compete with anything modern in terms of performance, but in terms of innovation and appearance it still stacks up very well. It looks amazing with that two-tone paint job and hard shell, and the tires look just like something you might see bouncing along the beech. I did a few things to make it even better. On the box it shows a metal tube front bumper but what actually comes in the box is a straight bar. I found a box art style bumper at Rcchannel.com and they had some other goodies too like a conversion to a real double wishbone rear suspension. To top it all off I added some 3D printed parts from Knight Customs. These include a highly detailed engine and a driver figure printed in full color from sandstone. I love the result.

This thing is fun to drive. It handles like a pig and bounces all over the place, but that's just perfect for an old Beetle beach buggy. The only problem is that it's so nice I have to be careful not to roll it over. There is no need for any hopped up motor in this one, the silver can 540 is just right.

The Sand Scorcher comes in a really large box. This is partly because of the large hard body, but also due to the very careful packaging and presentation. Just take a look at the contents! There is a blister pack on either side of the body that really shows off the majority of the metal components. Underneath are the hardware bags, the plastic trees, and the instructions. This box is so nice I will probably save the cover and hang it on the wall later.
Here are all the parts laid out on my building table. The first thing I notice is how few plastic parts there are. Typically a kit would be packed with a dozen or so plastic parts trees, but not this kit. Almost everything is metal. The few things that are not I'll probably be replacing with metal later. The build starts with the gearbox. You can see that the upper gear is brass but the lower two are nylon. The lowest of the gears takes the place of a differential but is just a solid spool. At least we don't have to worry about any fragile bevel gears breaking. You can't see it from this angle, but the axle for the top gear protrudes out the back of the gearbox and will hold the spur gear later. The kit includes full ball bearings throughout.
This shows the gearbox closed up with the universal joint outdrives attached. In the right hand image I've attached the rear suspension swing arms. (I was going to say lower arms but there are no upper arms.) The model uses torsion bar suspension. The long wire you see leaving the image to the left is connected to each swing arm, and in front they are connected together to prevent rotation. This results in a very soft, springy suspension. I love it.
Now we install the motor. This is a standard silver can 540 which is all you need for this model. This gear mesh is not adjustable. There is only a single pinion which works with a given spur and the motor mount is keyed to make it fit correctly. The kit comes with two pinion and spur combinations: a high speed and a low speed. I find the low speed to be better because it gives you more torque in the grass and still has plenty of top end. The motor cover is plastic and is intended to keep water splashes out with little clear flexible grommets around the wires. On the other side of the gearbox you can see the clear gear cover which allows you to see the gear mesh. Here the axle shafts are also installed and connected to the u-joints. This completes the rear suspension assembly.

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51970

The order in which the shocks are built is a little strange. You start by attaching everything to the rod including the brass rod end, the rod cap, some spacers, a rod seal, and the piston. This entire assembly is then inserted into the one piece cylinder which includes the head end cap. A rubber grommet is placed in the lug on either end in place of a ball joint to allow some rotation. There is very little fluid volume here, but these shocks still provide some nice damping for this light vehicle.
Now the shocks can be attached to the rear suspension. At the upper end they attach to the metal roll bar which in turn connects to a one piece plastic rear bumper. The bumper also incorporates a mount for the antenna. In the original release this would have been a functional AM antenna. That is no longer needed with 2.4GHz, but it still looks good on a beach buggy. The roll bar also serves as a body mount. The right hand image shows the installation of the chassis plate. This single member must carry all bending loads between the front and rear.
Time to start building the front suspension. This system uses a four-bar linkage, but it is mounted longitudinally instead of laterally making it a trailing arm type. Between the right and left sides are 3 metal bars to keep everything square. The hub spindles look a little thin, but I've had no trouble so far. The kingpins are ball joints which snap into soft plastic sockets. I suspect these will wear out and need to be replaced sooner or later. The front springs are torsional coils which lock into the upper arms. The dampers complete the assembly which is self-contained apart from the chassis.
Now here's a different kind of servo saver. The two steering tie rods connect in the center to a plate which uses a C-shaped wire for connection to the steering crank. If too much torque is applied the wire will open up. Above this is the post which will serve as the forward body mount. Finally, the front suspension is attached to the chassis plate which completes the rolling chassis.

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51971

The wheels are a 3-piece plastic design which lock the bead of the tire. This makes the wheels and tires unique and they cannot be easily shared with other buggies. On the right we see the simple electronic system: battery, ESC, receiver, servo, and motor. The battery shown will not actually fit in the model though.
Here is the rolling chassis with and without the electronics box. Enclosing everything in a semi-waterproof box makes a certain amount of sense, but it doesn't really look very good. I actually prefer the picture on the left. The right hand image shows the smallish space for the battery surrounded by a foam protector. I used a 2s 1300mAh LiPo.
Here is the electronics box. It does serve to keep everything very neat and self contained. It can also be easily removed if you want to clean the mechanical components. Access to the inside of the box is via four spring loaded 1/4 turn fasteners.
It is not an easy task to paint this model properly. I started out with a base coat of white, then I masked off all the areas to stay white as shown in the left hand image. The ellipses on the hood are the hardest to get right. Should the vertical parts of the recesses be blue or white? Can I mask well enough to control that? No. The right hand image shows all the French Blue applied. I really like this color which I had never used for anything else.

With the masking off the paint is done. The small thumbnail image looks OK, but if you zoom in on the full size you can see that the hood looks pretty bad. My tape lines on the roof worked OK. Next I went in with a silver paint pen and highlighted the rain gutters and door handles. Finally, I attached the side mirrors and the driver figure. The image on the right shows the final model in stock form.

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51972

I probably wouldn't have made any upgrades to this chassis if I hadn't happened upon RC Channel.com and Knight Customs Shapeways store. They just had too much good stuff to resist. I bought the RC Channel "metal rear suspension" without even realizing that the stock suspension is already metal. What this really is is a conversion kit to change from swing arm to double wishbone suspension while retaining the stock look of the original metal parts. The right hand image shows the high quality contents of some of the bags. I also got a bunch of 3D printed parts to add a scale engine and a better driver figure.
We'll start with the front bumper. Although the bumper which comes in the box is a pretty nice aluminum bar embedded in a plastic shell, it does not match the nice tube bumper shown on the box art. The new bumper looks exactly like it should. The cost of that new good looking is the loss of protection for the front wheels in the event of an impact.
Let's do the same thing for the rear bumper. The roll bar is metal but the cage is plastic. We'll replace the cage with tube stock and also remove the plastic exhaust which will be replaced later. You can see the metal links hanging down behind the roll bar which will become the supports for the new upper suspension links.
High on the list of unnecessary upgrades is the replacement of the stock plastic motor cover with a metal cover. Does nothing for you but looks good. It actually does add a little bit of clearance around one of the bolt which will help with the new suspension.

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51973

Now we can do the same thing to the clear gear cover on the other side. This metal cover doesn't protect any better but seems a little more "serious".
The installation of the new rear suspension is a serious project. You have to remove the entire rear assembly, pull off the u-joints and axles, remove the lower arms and torsion bars, and then rebuild with the new parts. The finished suspension is shown on the right. At first glance you might not even realize I changed anything because the design matches so well, but the geometry is totally different than stock. Now we have an upper arm and a separate hub along with new axle shafts with rubber boots. The upper and lower links are not the same links which means there is still some camber change with suspension travel, but much less than stock. The tires sit perpendicular to the ground at rest. Even though this a huge upgrade with respect to suspension performance, I'm not sure how much noticeable difference it makes at the speeds this thing actually runs. I like it anyway though.
The completed rear suspension before and after. Look closely to spot the differences. They may not look like much but they are vast.
Here are all the old parts I replaced. Because this is a historic, collectible model I will hold onto them in case I ever want to make it stock again.
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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51974

Now let's get to work on that 3D printed engine. The picture on the left shows the individual parts dry fit together for this boxer style 4-cylinder. The exhaust looks more or less like stock, but now we have cylinder blocks and heads, air cleaners, a belt system, and an oil sump. The right hand image shows my paint scheme. Most is steel colored, but I did the valve covers in red and the coil in blue. The filter elements are black and so is the belt. I added some rust colored wash to the exhaust.
Here I've installed the engine. It is actually quite hidden behind the bumper unless you look closely. The lower cross member on my metal rear bumper is not in the same place as stock and it interfered with the engine so I had to remove it. Doesn't seem to weaken the assembly appreciably. Most of this engine can't be seen once the body is on, but I know it is there are it looks good. It fits over the gearbox quite tightly and is only secured with one screw on the left side.
Here is the engine with the body installed. If you get down low it shows up quite nicely and makes the buggy looks super realistic (in my opinion). It would be better if those tail lights had clear lenses which is something I may still need to do. On the right you can see the stock driver which I painted compared to the 3D printed sandstone driver. I did no painting on him, he comes out of the machine like that. I have no idea how that technology works, but it looks incredible.

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51975

This is a very photogenic model. Looks great from any angle with that paint. The first two pictures show the difference before and after the upgrades. The front bumper is the most obvious, but you can also see the difference in rear wheel camber and the driver figure. In the pictures from the rear you can clearly see the upgraded faux engine and rear tube bumper.

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51977

This custom is awesome. I have to put mine inside my monqter beetle. :p

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Blakbird's 58452 Sand Scorcher Build 5 years 6 months ago #51978

This custom is awesome. I have to put mine inside my monqter beetle. :p

I presume you are referring to the printed driver figure? The other upgrades would not work with a MB.

I've been doing some more research on the original VW Beetle suspension and found some interesting titbits. The front suspension, as seen below, is a nearly exactly replicated by the SRB. The primary difference is that the lateral bars were torsion bars in the real thing while the SRB uses torsional coil springs instead. This leaves little doubt that the SRB was designed with the Beetle in mind even though the Sand Scorcher was not the first model to use this chassis. However, it followed only a month after the Rough Rider.


The rear suspension is another story. Although the axle matches pretty well, the real Beetle used the axle housing itself for a support and had no lower arm. What looks like a trailing arm is actually a torsion bar support. The Monster Beetle is actually a somewhat close match for the real thing. Again though, the MB was not the first to use the chassis, it started with the Blackfoot and a real Ford truck suspension is nothing like this. Again, it seems like the design had the Beetle in mind. On the other hand, the chassis is based off the ORV which uses the same rear suspension and was around for years before the MB came out. Finally, the MB rear wheels do not change camber with travel while the real Beetle did, so the SRB is a close match in suspension motion if not exact execution.
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