Project: Kyosho Optima

Aktualisiert: 20. Dez 2018

One of my early racing buggies was the Kyosho Turbo Optima. I bought a used Optima from a friend and updated this car with the belt drive conversion and front one-way as differential, what worked excellent on the slippery dirt tracks we had at that time. At that time I just started my education as precision mechanic and I decided to make a new chassis with a lower plate to use saddle pack batteries. There was several reasons to do it. The lower center of gravity and the more forward position of the battery packs helped a lot to improve handling. The Optima was more ballanced and faster in the corners. And at this time everybody started to use single resistors for each battery cell for discharging the good old Sanyo NiCd cells. So with a saddle pack configuration it was much easier to install the resistors with crocodile clamps. The outline of the new lower chassis plate has the same, as the Pro Optima body I used and it was good to keep the dirt outside of the car.

Because the lack of money I raced this Optima in a time, when the Optima Mid came out. But my Optima was so fast, that there never was a problem to drive against more modern buggies into many A-finals. On some very bumpy racks, there was indeed a little advantage against the mid ship cars. The rear motor settled the whole car through the bumps. And some will remember, those bumps was huge back in time!

As the re-release Optima came out some years ago, it was clear to go back to the roots and build another Optima with some old ideas and some new ones.

The main idea was, to increase the wheelbase and to improve the weight distribution. Apart of the new battery holder to use low profile shorty lipo batteries, most things was exactly the same stuff I did more than 30 years ago.

So I started the project as always. Taking dimensions from the original parts, making an assenbly group and then modify parts. From the first look, it is the same layout that I used many years ago. I removed the radio plate and all the stuff around. Some modifications on the side plates and a new lower chassis plate.

The decided to increase the wheelbase by 21mm. Sounds like a huge step. But the standard wheelbase was always a little bit on the short side. I made clamps for the battery, inspired by the old Schumacher stick battery clamps, what I really liked. The battery is mounted pretty forward as counterweight of the rear motor. I knew, with this lightweight lipo battery, the Optima will go too light anyway. So I made the new chassis rails from brass meterial to get some more weight on the elegant way. The fit the longer wheelbase I had to print new tunnels for the belt.

The rear view of the CAD assembly. I made some little adjustments on the shock towers as well. I optimized the shock positions and also the positions for the inner suspension linkages.

I made all plates from carbon fibre, apart of the motor plate. So this works well es heat sink.

The Optima Pro body was always my favorite! Okay, I installed it a little lower.

No front bumper there. The little nose is the modified kit gear guard plate. You also can notice the new position of the outer ball stud of the upper suspension linkage. It is mounted directly above the king pin bushings. The original geometry has always too short upper links, what resulted too much camber gain. On this way now, the camber gain is much better with the longer upper linkage.

The overall look is pretty much the same as from my old Optima.

Chassis without body. I use JConcepts 2WD rims. Front and rear. The total width is 240mm now, what is okay for me. Schumacher 2WD Staggered tires at the front and Dart on the rear. Some may say it looks strange, but I like the look and the handling with those wheels.

Front View. The shocks are not original Kyosho Option House shocks. That are 100% copies, what you can order from a HK company named "Mayonnaise-RC" - no jokes! The quality is pretty good. I also ordered there the CVD Driveshafts and they are great! You find more informations on their Facebook Page. I use Team Associated RC10 shock spring clamps. I did this 30 years ago - why not today. I like a little mix.

The sleek chassis. Yokomo wing mounts. RC10 Worlds Car wing with large end plates.

For this project I use a LRP Phaser FM reciever, a LRP IPC Speedo and a Highest Low Profile Servo.

Yes, it is still an Optima! Really!

There is a Reedy Titanium 13x3 in the rear. Too much power? Yes, but it makes fun!

What I really like from the re-release Optima kit are the adjustable rear hubs to change toe-in. Today we know, why it was so difficult to drive on slippery tracks, with zero toe-in. One of the biggest differences between the manufacturers 30 years ago was the know-how of designing a good suspension geometry. Maybe the Kyosho cars was overall well designed. Has great quality and durability and attention to the details. But they simply did not understand how to make a good geometry. Yokomo, Schumacher and Team Associated was lightyears ahead with proper geometry, like anti-dive, toe-in settings, or caster/camber settings. And I am sure, this was the reason, why Kyosho lost so many titles.

As always, I use the great and timeless Lunsford turnbuckles. I hope, you can´t see the Xray pivot balls and ball ends, what I use in all of my Kyosho vintage projects at the moment. But they are so much better, than anything else today. And the look fit a Kyoshe very well.

How does it drive?

First of all: The re-release Optima is loud! Because the use of a complete metal gear drivetrain, instead of plastic gears from the past, the Optima makes siginficantly noises. I tested the Optima on an un-loved EOS carpet track near Hamburg/Germany. Super high grip. Again, Vintage cars belongs on dirt! But there was no other chance to test that beast. And what can I tell? It ran crazy good! The handling is neutral and the boost of the Reedy 13x3 brushed motor was crazy! I managed to make some crashes, but we talk about a Kyosho! It´s very robust. So no breaks. Nothing. Some weeks later there was the VOREM2017 Vintage race in Langenfeld/Germany. And I started in 5 different classes. A little advise from first hand: never start 5 classes in only 1 race! It was pure stress. In the practice runs my Optima rocked the bumpy Langenfeld track super smooth and predictable. On the jumps you instantly got remembered, that this is a rear motor car! Thanks god, we had no jumps back in time! But the overall performance was amazing! Unfortunatelly i was totally overcharged to handle 5 classes. It was a literally jump & run game. So I decided to run only 3 classes for the finals and my Optima had to stay at the pit.

But the old feelings came back with this car. The way it drives and the look and the familiar wrenching on the car - like an old friend you missed so much time.

As addition - I found some old RC Car magazines from 1989 with some of my race results.

My personal RC god and inspirator was a young man from Kiel/Germany with the name Lars Eytz. His Turbo Optima on the picture changed my mind. So my project is a little tribute to his style and perfection. Thanks, Lars!

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