After 4-yrs...my '91 Stealth has begun

[jbmeyer13]

After working with Fred on this project off and on across the past four years the final build has begun. I've collected 95% of the parts I need but am trying to track down the last few pieces.


Aside from Fred and his tireless approach to getting the suspension right a big thank you goes to Steve and Curtis Husting for their help in providing photographs and answering questions. I'm very happy with how this project has turned out and could never have made this as accurate without your help.

I started by drafting the chassis to scale on paper. After having a solid baseline I had my brother draft up the 2D model in AutoCAD. After he left his engineering firm I started learning to use AutoCAD to continue what seemed like a never ending series of tweaks to get both the visual and wheelbase parameters accurate. The first mock ups were done using acrylic and eventually that gave way to 30 degre CF blanks. More than once a CF chassis was cut that turned out to be slightly off the mark. While it cost quite a bit to conduct R&D in this manner there are always subtle details which couldn't be fully captured in a computer model and required real world testing.

These are some select shots throughout the process:

[XLR8]

Awesome, Justin, simply awesome! Can't wait to see this one come together.
Are you planning to color your printed parts or leave them white?
Either way, it's gonna be COOL!

[mikea96]

Looks great nice job!

[jbmeyer13]

Awesome, Justin, simply awesome! Can't wait to see this one come together.
Are you planning to color your printed parts or leave them white?
Either way, it's gonna be COOL!

Funny you should ask. Below is a photo of a 4-yr old printed part, a vintage battery cup and vintage hub. Seems that the Shapeways parts will yellow with time. To me that looks like a perfect match and I'm not sure if dye or tea will work that well. Right now I'm test fitting and grinding where necessary to make everything look as close to original as possible.

[XLR8]

Hey, I think you're right. It makes sense, doesn't it. Okay, that settles it, I'm not dying my parts.
I'll just let them develop a patina over time. Thanks Justin.
Then, in 10 years, I'll be pulling the car apart and soaking the parts in hydrogen peroxide to make them look new again.
So, what's next? Based upon the Yoke parts you have, it looks like you going for a Masami replica? Me too.

[jbmeyer13]

So, what's next? Based upon the Yoke parts you have, it looks like you going for a Masami replica? Me too.

Well the yoke parts were standard on all the '91 cars (copper springs, tires, wheels, etc.) and the only thing I think that was unique to Masami's car was the wing mounts. So my goal is to make a team issue car but not a masami replica. Your paint job is very similar to one of my viper bodies from that era which I'll likely do a variation on again.

[XLR8]

Hmm, I didn't know that. I'd just assumed the collection of Yokomo parts on Masami's car was his choice. I'd love to know why AE would look to Yokomo to provide parts they already had on hand. I recall seeing an interview recently where Cliff explains the gentlemen's agreement between the two companies; AE would supply their drivers 2wd cars while Yokomo would supply 4wd cars. Maybe there was some performance advantage to running Yoke wheels and tires?
Do you know if all the '91 cars used a YZ10 undertray or was the body choice (+ wing, undertray, gear cover) left to the drivers?

[scr8p]

Most guys ran RCPS bodies. Either the Mirage SS or Turbo Mirage.

Not everyone ran the copper springs. There are a few pics of Rick Howart's car and he has silvers on it.

[jbmeyer13]

Hmm, I didn't know that. I'd just assumed the collection of Yokomo parts on Masami's car was his choice. I'd love to know why AE would look to Yokomo to provide parts they already had on hand. I recall seeing an interview recently where Cliff explains the gentlemen's agreement between the two companies; AE would supply their drivers 2wd cars while Yokomo would supply 4wd cars. Maybe there was some performance advantage to running Yoke wheels and tires?
Do you know if all the '91 cars used a YZ10 undertray or was the body choice (+ wing, undertray, gear cover) left to the drivers?

What I had read and or heard via podcast was that when there was a preworlds event a prototype stealth smoked the track but when they arrived that had trouble getting it to behave ideally. Cliff came up with the idea of having groups of drivers test only one parameter (shocks, tires, etc.) and then after comparing notes did they find the ideal set up. So while there are photos of Howart's and Kinwald's cars we don't know when they were taken and it could have been during testing. There's also a shot out there of Cliff's car as well but not sure when during the event it was. He lost his top time because he was late for turn martialing (for signing an autograph for a kid;-)) so I think he was running a pretty good set up.

On a funny note; been looking for a set of rear copper springs for 4-yrs with no luck. I just realized yesterday that my Works '93 has a set. So now if I could find any Yokomo rear springs I could swap it out.

[XLR8]

That's some great information, Justin.
I've noticed that photos of Stealth cars are pretty scarce. I think Masami's car is by far the best documented of all the cars so that's why I choose to try and replicate his car. Anyway, it seems reasonable to assume that the team's component choices weren't static; they tried different configurations depending upon previous testing and race results. I also recall reading somewhere that Yoke wheels flex and that this might be beneficial for rougher tracks. In fact, Masami's wheels were drilled to increase flex.

Aren't the Yoke springs just copper plated? I don't have any actual Yoke springs so I was considering copper plating some AE ones instead.

[jwscab]

Yes you could copper plate a set of springs pretty easily. They are just slightly different rate than the associated silvers.

[XLR8]

Fantastic, thanks Joe.
I bought equipment necessary to do zinc plating back when I was restoring old motorcycles. I think I can substitute the sacrificial zinc plate for a piece of copper (and perhaps adjust the current) and it will work. Anyway, it might be worth a try.

[jbmeyer13]

Fantastic, thanks Joe.
I bought equipment necessary to do zinc plating back when I was restoring old motorcycles. I think I can substitute the sacrificial zinc plate for a piece of copper (and perhaps adjust the current) and it will work. Anyway, it might be worth a try.

Can you also anodize aluminum shock caps?

[jwscab]

Anodizing shock caps is actually quite doable for the home shop since they are small. The problem is dye that lasts is expensive and there are minimum qtys. If you wanted natural color you can just seal after anodizing.

[XLR8]

I have no clue, I've only ever used it for zinc plating since nothing on my bikes was anodized. It sounds like Joe has researched this topic so I'd trust his opinion over mine.
This is what I have, except that I got the upgraded power supply:

https://www.caswellplating.com/electroplating-anodizing/zinc-plating-kits.html

I'ts been years since I last used the system. I just notice when I located their website that this company also sells an anodizing kit. Can you compare the contents of both kits and determine what items are different? Maybe its a simple matter to switch from plating to anodizing.