The Dyna Sidewinder – part 2

This is part 2 of my effort to recreate the Dyna Models/AYK Sidewinder buggy from 1983.  I have been preoccupied with the Torpedo Optima build lately, but yesterday I had some time to (almost) finish the rear suspension on the Dyna Sidewinder.

As I said in part 1, the MIP blocks/pivots used for the trailing arm setup is basically impossible to find. They never come up for sale anywhere, and should they happen to be parts of a car showing up on a popular auction site, the prices are insane. I played with the thought of having some sets recreated, but the cost of having small volume steel and aluminum parts made, are too high to justify. I looked around for other solutions on how to mount the trailing arms, but I never found something that kept the basic look of the real thing.

The almost finished rear suspension setup.

After studying the pictures of the MIP parts that Mike sent me, I think I have found a solution that could work, and still be faithful to the original MIP system. The solution involves 3D printing some blocks (Shapeways), and instead of the angled-head pivots I use M4 steel bolts with some 3D printed angle cut spacers. Between the blocks and the bolts there are brass bushings that are press fit into the blocks, just like on the original MIP system. The pivot bolts are secured with nylock nuts, and there are even space on the bolt for a second nylock nut to secure the first, if anyone thinks the nut might loosen over time. Between the nut and the block there is a steel washer, and the same goes on the other side between the block and the inner spacer. The blocks themselves are secured to the mounting plate by two M3 bolts and flanged nuts. These blocks are the first prototypes, and I might add some more “flesh” to the blocks outside where the mounting holes go through. Since there are mounting holes on opposite sides, it really shouldn’t be necessary, but it’s better to be safe than sorry.

Trailing arms mounted to the 3D printed blocks.

The angle cut spacers mimics the angle-headed pivots of the original, and are adjustable in the same way. The mounting hole in the trailing arm is enlarged enough that the bolt can go through it at an angle, but not so much that the bolt is loose inside. You can actually tighten the bolt to the arm, as long as you have the outer angled spacer fitted. The tight hole, combined with the angle of the bolt and the angled spacers keeps the arm secured to the bolt in whatever position you want. I honestly believe it’s even better than the original MIP solution….

This is how the angled spacers mount to the trailing arms. One on each side of the arm.

The rear shocks mount to the trailing arms with modified original mounts. The mounts are shortened, and there are two mounting holes drilled and tapped to M3. The mounts are rather thin, and there is not much space to mount them on the arms either, so I had to be very precise when drilling the holes. I started with a 1.5mm drill bit, as it’s easier to drill accurately with those. I then drilled it to 2.5mm, and finished the process by tapping the holes with a 3mm tap bit.

Rear shock mounts cut, drilled and tapped.
The finished trailing arms.

I have also, like on the Dyna Scorpion, mounted AYK 566B wheels and tires. I have tried to get other tires (spikes) mounted on the 566B rear wheels, but the construction of those wheels/tires does not match the standards used by other manufacturers, so mounting other tires are not as straightforward as I thought it would be. I’ll just let the “Padla Trak”-lookalikes stay on for now.

The shock mount secured to the trailing arm, and the 566B wheel/tire/hub.

I have ordered a set of these Parma heavy duty rod ends for the steering rods. I’m not sure if those are the correct ones, but they were the closest I could find, and they are from the correct era.

Parmas heavy duty ball ends.

For bumper I will use this Dirt Burners! bumper, originally for the Kyosho Gallop/Progress. These bumpers were also sold through RCH.

Dirt Burners!/RCH bumper for the Kyosho Gallop/Progress.

Well, that’s it for part 2. Next up are making some drive shafts, the steering rods, mounting of the electronics, and painting the body. The body is for the Kyosho Tomahawk, but I’m still undecided if I will paint it in that yellow scheme of the original, or if I’ll try to do a version of the scheme from the Dyna Scorpion. I don’t really fancy the original body, with the Christmas tree on the roof and everything. Maybe you’ll find out what I went with in part 3?

About TomEG 46 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.

3 Comments

  1. I am a die-hard Ayk fan and your article/ website is brilliant! Thank you for a interesting reading and ideas/ Tony

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