Super 7 GTS

[Scale-Master]

Back on 3/12/23 I had a barely street legal semi-open wheel race car styled Super 7 based concept planned out enough to start work, but I changed my mind after I realized I was discarding most of the kit to the point I might as well just scratch-build it. (I may still build that concept.)
So I came up with something else. The new design was a 180 degree change; a full bodied street car utilizing the basic Super 7 frame, engine, suspension, and proportions. The premise is the owner of this car wants something other than a “normal” Super 7, but does not want to change the mechanical layout; just an exterior cosmetic redesign with a fiberglass or other composite body. The lights and other accessories will be reused to keep some of the same theme. This will be built in 1/12th scale.



As with the first draft, I figured starting with the new wheels and tires would be as good as any place to begin with since the track will determine the width of the body.
The rim is a design I originally came up with for AFX Racing in 2022 that I enlarged, fine-tuned and added some details to. The tire is all new artwork.



I grew patterns for the tire and wheel halves. Since the tire is directional I designed it to be cast in two pieces so I could have good sidewall detail on both sides. I also designed the 3D grown parts to be post-machined for better tolerances.

To make sure the tire halves aligned correctly I machined a ring from PVC. This saved a few hours of grow time by not having it as part of one half.


Like the tire, the wheel was designed to be machined after it was grown. Because the tires are hard, the rim has to be two pieces for a proper lip/bead on both sides.
I originally grew the inner part of the wheel in 3D, but it was very fragile and I couldn't machine it to fit the main section as well as I as wanted. So I machined a new one from PVC. It and the main part of the wheel have an interlocking step-fit so they snap together.



The rotor hub was machined with the lug holes to match the wheel. The five larger holes were machined into the wheel and the hub for magnets. (I made the studs and lug nuts too.) Not shown is the aluminum outer lip that I still have to make. Now it's time for hand finishing some of the parts before the molds can be made.

[Scale-Master]

After hand finishing the wheel I added a faux sand-cast texture to it.

[Scale-Master]

Unfortunately real life things came up that required my attention later in 2023 and this project had to be put on hold at that point. I had cast some wheels and tires, but essentially it was a stalled venture.

In August of 2024 I started back up on it.
First I drew up a traditional Caterham Super 7 frame (that matches the Tamiya one) in SolidWorks to build the car around and brought in the CAD versions wheels and tires, then I began sculpting the exterior of the body to fit those dimensions also taking into account the established locations of the seats, dash, engine etc.

Once again other more important things came up and I had to set it aside. (But I kept thinking about it...)
Fast forward to April 27, 2026 and I started back up on it once again.
As of May 30, 2026 I had this designed and ready to be grown. Due to the constraints of the Caterham chassis layout, a full coupe body is going to have some interesting and arguably unconventional proportions.

[Scale-Master]

I had a good friend grow the body parts for me, my printer is way too small for something like this. He got the main body on the first print. There is still a good amount of clean up to do, but it was very fulfilling to see how well it fit the frame.

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I’ve got the hatch, roof and hood fitted to the body. A hair dryer came in handy to reshape a few areas. I had to add a little material to the leading edge of the roof and good amount of sanding to the roof and hood to get them to follow the contours of the body. I also made the hinges for the hood and hatch out of brass.

[Scale-Master]

The kit frame is for a RHD set up, I’m building a LHD car. I made a new frame section for the dash with acid etched support brackets out of brass for strength. Since there is not going to be an aluminum cowl for support, this section has to be stronger. I also made a LHD steering rack in CAD.

I made a new dash, foot box and under hood panel from sheet styrene and swapped the necessary frame parts to be LHD.

The header was also modified to allow clearance for the steering shaft. I had a leftover seat and steering wheel handy to help get everything in the proper locations. A few minor modifications were made to the main frame too.

It took a lot less time to do this than the last one, and it was very helpful to have this Scale Auto magazine article from June of 2017 to refer to as a guide.