The secret files of Akira Kogawa – Part I – The Scorpion

Please Take Notice

This is not a webshop, and beside what’s listed under the “FOR SALE” tab in the menu, nothing presented here is for sale, so please don’t ask. If I have anything I would like to sell, I’ll post it in the “FOR SALE” section.

I’m very excited to reveal that the Maestro himself, Akira Kogawa, has given me rare access to some of his early files with concepts and technical drawings of a few of his early designs. I have been allowed to share some of those with you, and I’ll be starting with the 1982 Scorpion. These files are stored at the Auto Model office in Tokyo (JP), and from the moment I became aware of their existence, I have been dreaming of being allowed to take a look inside those files and folders. During his work with the Legendary Series of re-releases, he made several visits to his old Auto Model offices to make copies of the drawings, and it’s some of these drawings I can present today.

The Scorpion was first introduced as a kit by Kyosho in 1982. In some parts of Europe it was distributed as the Graupner Scorpion, while Cox Hobbies secured the market rights for the US. The american Cox Scorpions came pre-built, as opposed to the rest of the world where the Scorpion was sold as kits. The Scorpion was designed by the young, up and coming Japanese designer, Akira Kogawa. The design included individual suspension and oil filled shock absorbers with coil-over springs in all four corners. The Scorpion was designed as a full out racer, to take on the Tamiya SRBs and the AYK 566Bs that dominated the market and race tracks. Using the same type of aluminum rail chassis as the AYK, as well as a nearly identical trailing arm rear suspension, the Scorpion was a formidable contender in the 1/10 electric market. The solid radio tub, that doubled as the bottom part of the body, made the Scorpion both lightweight and sturdy, and quickly became a favorite with both racers and after market hop-up tuners. The Scorpion was the first buggy in the Scorpion chassis series, that later would include the Beetle, Tomahawk, Turbo Scorpion, Sidewinder (by Cox in the US, only) and the gas powered Advance and Assault. The chassis is commonly, but wrongly, called the Circuit 1000 chassis, but the Circuit 1000 name only refers to the gas powered models in the Scorpion series, as well as a few other models with a completely different chassis.

Early sketch of the 1982 Scorpion. Copyright Akira Kogawa/Auto Model.

Unlike today, when all models are designed with 3D CAD software, and prototypes can be 3D printed or quickly milled in a CNC, all the drawings for the 1982 Scorpion was done by hand. I will now show you some of the drawings related to the original Scorpion and Turbo Scorpion.

Early drawing that shows how the front suspension trailing arm could have looked like. Copyright Akira Kogawa/Auto Model.

One of the Scorpions biggest flaws is the front suspension. When properly locked, and set, the suspension works very well. The problem is that the trailing arm axle very easily can be turned out of position if the car hits a bump hard. That can twist the whole front suspension and steering out of alignment. A commonly used remedy was to arrange for a set screw to be placed on the clamps that holds the axle onto the chassis rails.

Later drawings of the front suspension trailing arm, that is closer to how the final part turned out. Copyright Akira Kogawa/Auto Model.

The original Scorpion had a wing that was mounted with spring wires onto to the rear cage, but in 1985 when the updated Turbo Scorpion was released, the wing was mounted on a more solid aluminum mount, that was bolted on to the top of the gear box. For the re-release, this wing mount was made of plastic, instead of aluminum.

Drawings of the aluminum wing mount of the 1985 Turbo Scorpion. Copyright Akira Kogawa/Auto Model.
More drawings of the wing/wing mount concept for the Turbo Scorpion. Copyright Akira Kogawa/Auto Model.

Even the decals had to be hand drawn back then.

Early sketches of what should be the decal sheet for the original Scorpion.

And here is how it ended up.

The final decal sheet for the 1982 Scorpion.

Today, the decals are of course drawn using computer software.

Here we can see the decals for the Turbo Scorpion 2016 being worked on. Never mind the “no photo” sign on the monitor….

When Akira san started the design of the 2014 Scorpion, he had moved on from pen and paper, so the new model was drawn on a PC workstation using Solid Works 3D CAD software. Luckily the original drawings still were on file at his old workplace, Auto Model, and having access to his old drawings must have helped a lot in the re-design.

My original 1982 Scorpion at the top, and my 2014 Scorpion at the bottom. Amazing that one was designed using pen and paper, while the other was designed in Solid Works 3D CAD.

Here are a couple of 3D renderings of the re-designed Scorpion 2014, taken directly from the 3D CAD software on Akira san’s workstation.

Copyright Akira Kogawa.

And here is another rendering of the gear box and drive train.

Copyright Akira Kogawa.

That concludes the first part of this glimpse into the secret files of Akira Kogawa. Again I must thank the Man himself for giving me access to this material. It would have been much easier for him to just say no. I think it shows that he takes us “fans” seriously, and understands how much his work has meant for us who grew up in the 80’s. In part two I will have a look at the most iconic 4WD buggy of all time, the mighty Optima. Stay tuned!

Please Take Notice

This is not a webshop, and beside what’s listed under the “FOR SALE” tab in the menu, nothing presented here is for sale, so please don’t ask. If I have anything I would like to sell, I’ll post it in the “FOR SALE” section.

About TomEG 72 Articles
I have been into RC cars since the beginning of the 80's, but have really never been much of a racer. I competed in some local races and some "Tamiya Cups", and actually came 6th in the Tamiya Cup Norwegian Nationals in 1987. My main interest has always been building and modifying, and that's where I still am today. Through the years I have been able to build a solid network of contacts around the world, consisting of both former and current members of the industry, as well as quite a few of the former top drivers. I have a genuine interest for the history of the 1/10 scale off-road buggies from the 80's.


  1. Rc-history that really is important and interesting to read about. And what a fantastic engineering by Mr.Akira Kogawa, i am fan of his work.

Leave a Reply

Your email address will not be published.