Cars

Building the Bandai STP turbine Indy car 1/12 scale

by Mark Laird © Modeler Site

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For years I wanted to build the 1/12 Bandai STP Turbine car. It is very unique piece of Indianapolis history, but the price that they were bringing was just more than I was willing to spend. I was lucky enough to find a complete kit on eBay for 200 US dollars. It was a “Buy it Now”, so I purchased it, and waited for it to arrive.

 

 

Editor note: Mark is an old Modelersite's reader and supporter. I discovered his amazing Bandai model at FB and he was so kind to share with us. I really want to thanks him for all their support and nice words he said to me.


The old Bandai kit

Upon its arrival, I opened it up and the first thing I noticed was that the instructions were in Japanese. I started going through the instructions and realized that although this is a big 1/12 scale kit, it lacked detail in many areas. It has no brake calipers, no rotors, no gas or brake pedal, the steering shaft went nowhere, very limited detail to the motor, no detail to the fuel pump, the fuel control unit, no fuel manifolds or external oil lines. It is an all-wheel drive car but has no drive shafts, no differential hookups, no u joints, and the only panel that was removable was the engine cover, so lots of detail work to bring this thing up to a decent 1/12 scale model. Lots of research pics to see what needs to be done, yet so few pics to be found for referencing due to it being over 50 years old.


I think that the chassis is the highlight of the car, it is very unique with the engine on one side and the driver on the other. The model when completed per the instructions would have the body placed over the chassis and the chassis would not be able to be seen. I wanted the chassis to be seen, and for the body to be able to be put on the car and removed.


Building

First things first, I decided I wasn’t going to open the bags until I could do the things to the car I wanted to do. I was lucky enough to have some old rotors from a 1/12 scale lotus 49 that had bought as a parts kit.

 

 

I scratch built 4 calipers based on the reference pics I could find of the car.

 

 

I also wanted to remove the wheels, so I used the spindles from the Ferrari 641/2 that I had bought from Thunder Valley F1. I had to remove the plastic stud that came on the original rims that were used to support the axle, and then I used the drill bit and counter sink from the spindles kit to open the rims center hole to fit the spindles. The spindles did not just fit directly into the rotors so Evergreen tubing was used to fit into the rotors and then the spindles would fit into the tubing. The knock offs that came with the kit were not big enough to hold the nuts from the spindle kit, so I went to the parts bin and found 4 knockoffs from a Lindberg Fiat kit I had. They were drilled out to fit the nuts, and all I had to do was determine the depth the spindle would have to go into the rotor for it all to work properly.

 


With that done, I figured the rest would be fairly easy to do, so I opened the bags, and decided to build the jet engine first. I painted the parts of the engine as per reference pics I had found. I should have made a better air filter for the engine, but used the one that came with the kit. I scratch built the fuel lines, the tachometer, the external oil lines, the oil pump, the fuel manifold, and the remaining pieces that were not on the engine. The exhaust tube was painted chrome by pouring the ink out of a Molotow Chrome pen into my siphon feed airbrush, sprayed and then returned the unused ink back into the pen. I completed the remaining detail to engine, and then added the fuel line parts to the top of the chassis along with the wiring. The reference pics showed a small tank at the rear of the car that corresponded with the cap off set to the right of center at the rear of the body. It is another gas tank, I scratch built one from aluminum and styrene, and simply used white glue to attach temporarily to ensure it fit later.

 


The drive shafts needed to be added to the transmission. Using aluminum tubing, I measured where they would be placed, and realized that the chassis needed to be cut in the front to allow the driveshaft to make it to the front axle. I used plastic tubing and some parts from the parts bin to hook the drive shaft to the front axle. The rear axle was much easier to work, again using old parts from the parts bin to fabricate a rear differential. This was all my design as I could not find any reference pics to show what it really looked like. After getting the driveshaft’s how they should be, I fitted the engine to the chassis.

 

 

The oil cooler at the back of the car had slits in the backside, but no opening in the front since it would not be seen if made according to the directions. I cut openings in the front and then added radiator photoetch over the opening to give the flow through appearance. The old Modeler hose fittings were used to go between the oil cooler and the transmission.

 


The instructions show a sway bar behind the front springs and upper control arms, but it not connected per the instructions, so back to the parts bin and found some old suspensions linkages. I snipped off the heim joints drilled them out with a pin vise and added aluminum rod between the hemi joints to make end links that were then attached to the sway bar and the upper control arms via nuts and bolts from R B Motion.

 

 

The cockpit needed much work. There were no gas or brake pedals, so I scratch built the pedals and structure by which the pedals would be mounted. I could find no reference pics of the pedals, so they are of my design.

 

 

The steering shaft supplied with the kit was discarded, and Evergreen styrene rod was used, then I added a U joint from the parts bin as the shaft had to turn, go through the chassis and eventually into the back of the rack and pinion unit. The dash uses gauge faces from old decal sheets and white glue poured over top of the gauges several times to get the appearance of glass over the gauges. The seat had the seat belt impressions removed and seat belts added. The connections to the gauges are either small nuts or little metal pieces from the parts bin.

 


I started on the body by flattening the dimples they call dzuz fasteners with a file and then drilled each one out to .050 inches for location for the photo etched dzus fasteners that I will use later. I cut the panel lines, as I want to be able to take the body on and off, but not the whole way through. I thought I better put the chassis into the tub to make sure it fit, it did not! The rear tank I had made was too big, and did not allow the chassis to fit into the bottom tub. So I made a new rear tank and tried it again. It looked like it would fit, but now some of the fuel lines at the front of the engine did not fit into the tub. I made new fuel lines out of 1/32 inch aluminum, and tried to put the chassis into the tub, and it fit! I went one farther and placed the top of the body on the tub, it did not fit! All of the fuel plumbing I added to the top of the chassis was hitting the top of the body and won't allow the two to mate.

 

I thought about my options

1. Remove the plumbing from the top of the chassis

2. Display the model without ever being able to put the body on it

3. Increase the thickness of the body to allow it all to fit.

 

I chose 3. I took .040 Evergreen card stock and ran it through my paper cutter at about 1/4 in. I then glued these on to the bottom portion (tub) and made three rows for about .120 inches.

 

 

This was ground down with the Dremel tool, sanded and then sprayed with primer to see any imperfections. Then I glued the top and bottom sections of the body together at the nose, the rear of the body and in front of the engine, as these sections will remain together as panels. This made the fuel inlet holes at the rear oval instead of round. I tried to add some of the card stock into the holes, it didn't look good, so I looked around for something round that might work. I found some round pens in the house. The rear inlet measure .460, and I found a pen that was .440 around. I cut the pen and added the pieces did some sanding and re-primed to see.

 


I started cutting some of the panels off and have found places to install the magnets to hold it together when reassembled. Unfortunately I was seeing much more work that needed to be done, the rear opening on the car was incorrect, too large, so I added Evergreen card stock to fill it to the proper size. For some reason when I cut the rear off, the 2nd rear gas tank did not fit, so I made number 3.
I had to find a way to hinge and install the air brake. I made the hinges (out of paper clips) for the hydraulically activated air brake. I made the mounts for the hinges out of evergreen strip, and used strip stock, .080 in, to make a way to secure the hinges to the chassis. The cylinder for the air brake is styrene tubing and another end link from the parts box. It attaches to the actual air brake panel via a piece scratch built. Since the chassis is chrome, I just used the Molotow pen to make the styrene pieces chrome. I also had to enlarge the opening for the turbine's exhaust on the engine cover as the engine appeared to be too far forward even though the mounts for the engines went on where they should with no problem. I also made the exhaust deflector out of aluminum and set it aside for later
 

 

Now on to paint. I used Model Master Enamel Florescent red. This paint is a real pain in the butt to use, it doesn't spray well, covers terribly and you can't get a good glossy surface to save your life. The key is to get the coverage without runs or orange peel. I will shoot it at about 20 PSI. After multiple coats over several days, the paint looked very nice.

 

 

I had ordered decals from Indycals, both for the body and the tires. I tried to use the original decals until I realized that there was a spelling error on the decal sheet. It says “Oil Treatwent” instead of Oil Treatment. So I cut up all of the decals from Indycals and installed them using Solvaset to set the decals. It looked good, but it still needed to be clear coated to give it the shine it should have. I used Model Master clear gloss acrylic. Not sure what happened as it was sprayed at about 18 PSI, but it was drying before it ever touched the surface of the model. It also kept clogging the airbrush despite being thinned. Needless to say after two separate spraying sessions, the clear coat looked absolutely terrible. It was very rough, and I had to wet sand for days to bring it back to the point it looked good. But it came out OK, and I then put some Maguires 7 polish on and then a coat of wax.

 


The tires were hand painted despite buying the tire decals. In 1967 the tires were hand painted, not stenciled. My concern was the gold rings around the tires. I made a small device out of a T hinge to hold my gold fine line marker. I clamped it to my drill press table, placed the tire and rim in the chuck of the drill via a narrow nut and bolt, removed the belt to the motor and laid the marker on the tire and manually turned the chuck one rotation. Not perfect, but still better than using a decal.
I decided that I would display the model with the body and wheels off. I still think the chassis is the show piece for this engineering work of art. So I made a tire rack, supports for under the car and the body supports out of metal and airbrushed an alloy look.
I am pleased with the final product. If I ever had another one, there would be things I learned this time that I would do the next time.


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