Delta Super-J electric 1/8 project
Posted: Sat Oct 23, 2021 8:06 am
Some people may know my love for Delta cars.
I always dreamed about driving a Delta Super-J at a race track but it had to be electric, because I gave up on gas engines long ago.
Around one year ago I started to brainstorm about the project and it was no easy task at all.
Delta actually released a Super-J electric version around 1979 or 1980 but I couldn´t go from there.
They used a fix gear ratio which didn´t work for me and I didn´t wanted to use the old Astro motor.
Also the saddlepack batteries and the mechanical speed control were mounted to the same original radio tray for the gas cars. This also didn´t work for my project.
One of the main problems was, the rear bulkhead was not any intended for use of an electric motor. This means the electric motor had to be mounted different.
I went with an add-on plate to the bulkhead. But the shape of the original bulkhead was reduced to the minimum for saving weight, so it was quite difficult to find a solution and needed a lot of brainstorming, testing, redesigning ...
The design of the add-on motorplate also was dependend of the motor. So I had to choose the 'right' motor and calculate what gear ratio or rollout would be needed.
I was used to 4268 motors and 4S setup at 1/8 scale 4WD cars but I thought that would be power overkill and maybe damage the balldiff. Also the size of those motors are too large. So I went with a HW3660 and 2S setup which also reduced overall weight by around 400g.
The next problem was, I couldn´t mount a pinion to the motor because the spur gear is located very close to the bulkhead. There is no room for the hex driver to fix the pinion to the motor shaft. So I had to design an adapter to move the spur gear around 3mm, at the ball diff.
The original Super-J was made to withstand the strong barriers of the Midwest race tracks. And the quite stiff chassis was intended for high grip levels.
My friends and me think such stiff car won´t really work on low to medium grip tracks, especially not with the high power and torque of modern brushless electric motors. So I designed a new chassis. I wanted to use a shape what looks close to the original chassis from a distance. So the change had to made different. Well if someone remembers the old RC12i ...
The radio tray also had to be redesigned. The cutouts for tank, throttle servo and receiver battery were not needed anymore. But had to be replaced for the 2S Lipo and ESC. The servo position was slightly changed and optimized also.
The overall shape is very close to the original first generation radio tray but looks a bit different of course.
And there is one major difference which could be noticed only by people who really know the original Super-J car.
I would like to know who may find that detail.
Another problem was the lack of front wheels. And I wanted to try different front end setups which couldn´t use the original wheels.
So the idea was to use modern 1/8 scale wheels. But how to convert the 3/16" wheel axles to take 12mm wheels?
This was one of the most complicated parts to design. In the end I went with a design which came with my old Schumacher C-Car 1/12.
Live axles which carry internal very small bearings. And a quickchange system for the front wheels at the same time.
But those aluminium parts were very difficult to make. Big thank you have go to my friend W. who did an excellent job in making these adapters and some other aluminium parts for this car.
Unfortunately I had no Kydex plates, and not in the Delta style blue color. So I decided to go for grey PVC plates for the radio tray and bumper.
Overall there are a lot of details which had to be noted and thought of when making this car. And the journey is not over. This is an experimental car for the moment and might be modified later.
Rollout had been held lately and it was great fun.
I always dreamed about driving a Delta Super-J at a race track but it had to be electric, because I gave up on gas engines long ago.
Around one year ago I started to brainstorm about the project and it was no easy task at all.
Delta actually released a Super-J electric version around 1979 or 1980 but I couldn´t go from there.
They used a fix gear ratio which didn´t work for me and I didn´t wanted to use the old Astro motor.
Also the saddlepack batteries and the mechanical speed control were mounted to the same original radio tray for the gas cars. This also didn´t work for my project.
One of the main problems was, the rear bulkhead was not any intended for use of an electric motor. This means the electric motor had to be mounted different.
I went with an add-on plate to the bulkhead. But the shape of the original bulkhead was reduced to the minimum for saving weight, so it was quite difficult to find a solution and needed a lot of brainstorming, testing, redesigning ...
The design of the add-on motorplate also was dependend of the motor. So I had to choose the 'right' motor and calculate what gear ratio or rollout would be needed.
I was used to 4268 motors and 4S setup at 1/8 scale 4WD cars but I thought that would be power overkill and maybe damage the balldiff. Also the size of those motors are too large. So I went with a HW3660 and 2S setup which also reduced overall weight by around 400g.
The next problem was, I couldn´t mount a pinion to the motor because the spur gear is located very close to the bulkhead. There is no room for the hex driver to fix the pinion to the motor shaft. So I had to design an adapter to move the spur gear around 3mm, at the ball diff.
The original Super-J was made to withstand the strong barriers of the Midwest race tracks. And the quite stiff chassis was intended for high grip levels.
My friends and me think such stiff car won´t really work on low to medium grip tracks, especially not with the high power and torque of modern brushless electric motors. So I designed a new chassis. I wanted to use a shape what looks close to the original chassis from a distance. So the change had to made different. Well if someone remembers the old RC12i ...
The radio tray also had to be redesigned. The cutouts for tank, throttle servo and receiver battery were not needed anymore. But had to be replaced for the 2S Lipo and ESC. The servo position was slightly changed and optimized also.
The overall shape is very close to the original first generation radio tray but looks a bit different of course.
And there is one major difference which could be noticed only by people who really know the original Super-J car.
I would like to know who may find that detail.
Another problem was the lack of front wheels. And I wanted to try different front end setups which couldn´t use the original wheels.
So the idea was to use modern 1/8 scale wheels. But how to convert the 3/16" wheel axles to take 12mm wheels?
This was one of the most complicated parts to design. In the end I went with a design which came with my old Schumacher C-Car 1/12.
Live axles which carry internal very small bearings. And a quickchange system for the front wheels at the same time.
But those aluminium parts were very difficult to make. Big thank you have go to my friend W. who did an excellent job in making these adapters and some other aluminium parts for this car.
Unfortunately I had no Kydex plates, and not in the Delta style blue color. So I decided to go for grey PVC plates for the radio tray and bumper.
Overall there are a lot of details which had to be noted and thought of when making this car. And the journey is not over. This is an experimental car for the moment and might be modified later.
Rollout had been held lately and it was great fun.