A-Main Bullet Fwd 4ws RC10 conversion Tribute build

[GoMachV]

You didn't think I tracked down the manual just for the fun if it, did you?

Here is the goal:










This will be a slow process, the rear was pretty simple so I knocked it out today. Just a different order of build from stock with a unique shock tower and kyosho ball joints. It also shows Delta shocks being used, I don't have that budget so it is getting Associated shocks. The tower was built out of cardboard, tested and tweaked, and transferred to G10. Once the car is built I MAY do carbon fiber. There is NO bump steer with two flat nuts under the bellcrank. The biggest challenge will be the chassis, as it has a very shallow kickup like a 4wd. Nowhere near the material I have or can easily get. I may build it flat and use caster shims from Cheetah- if I can even locate those

One last thing. This is NOT how I would build a fwd. this is how THEY built it. I know the geometry looks funny, I agree and it's all I can do not to change it. However, I am trying to keep this a true tribute car, so it will be built AS THEY DID.

Anyway, here is the start of the build.

[Phin]

Looking very nice.

Your bellcrank is upside down though. Well really it's right side up, but the Bullet manual shows that they flipped it and mounted it upside down.

Building on a flat chassis shouldn't lose you any points but Cheetah caster shims aren't going to work since the front arm mounts are going to be flipped around. The Cheetah shims would give you a negative angle. Options instead would be to chop an old pair of front arm mounts into a reversed version of the Cheetah shims, or just shim the back two holes of the arm mounts with washers/fiberglass.


How are you set on front wheels? If you're looking for some I got a pair of skinny Proline 4wd fronts I'd like to donate to the build. They look like the wheels from the manual except they're the same width as a typical pair of 2wd fronts.

[GoMachV]

I noticed that servo saver problem last night while going over the build but didn't take the time to flip it yet. It was just for mockup, its broken quite badly. I had it down to zero bump steer too lol. Did you notice they screw it together? Kind of odd. There are a few things that need to change like the inline rear axles need to get swapped out for trailing (leading). I haven't got too far thinking about wheels but those sound perfect

[Phin]

Nope didn't notice the screw in the servo saver. My guess is it serves the same function as zip tying, to remove slop?


It just occurred to me while looking at the servo saver that you can get a pretty close approximation of the chassis dimensions by counting the weave in the carbon fiber. I counted ~34 squares across the chassis at the rear of the chassis in the Bullet manual, which should be the same width as a RC10 buggy front kick-up. The buggy front kick-up is 68mm across so each square (black and gold) in the carbon fiber is 2mm.

So the chassis's twill pattern in the manual can basically be used as a 2x2 grid to lay everything out.

[Coelacanth]

Interesting front-end setup. I know you're trying to keep it original, but I have to agree with you about the less-than-ideal geometry. I think that steering setup will have issues with bump-steer. I experienced similar issues with builds that had the tie-rod angles significantly different from the control arm angles. Looks like a cool project, though...a FWD RC10? Looking forward to this.

[GoMachV]

Ahh that's a great idea. To get the rear dimensions I first built the components and the upper rods to the manuals measurement. By guessing that they retained the camber link height, I plotted the holes for them and them projected the lines up to shock mount lengths. Visually it is close, apart from the fact that I'm using associated lengths and I have no idea what length Delta they used. The bolt pattern for the arm mounts is identical to a stock nose plate

For the front I plan to lay out the same way, and figure out where the trans and suspension need to be to work. It's narrower than the rear by a bit. Once I have the front module made, I planned to build the linkages to the manual and that should give me the chassis length, however I like your idea better and with that redundancy it should be very close.

[GoMachV]

Interesting front-end setup. I know you're trying to keep it original, but I have to agree with you about the less-than-ideal geometry. I think that steering setup will have issues with bump-steer. I experienced similar issues with builds that had the tie-rod angles significantly different from the control arm angles. Looks like a cool project, though...a FWD RC10? Looking forward to this.

You would think it would have terrible bump steer but it has zero, despite being assembled incorrectly lol. The biggest issue would be if used as a front end, the Ackerman would be terrible and the bump steer while steering could be bad- havent checked. but...this being the rear suspension it will have very little movement, a few degrees I suspect. It will be interesting. I would like to build a freestyle version later on to clean up things I don't like about this but keeping with the spirit of the traditional style setup instead of the radical trailing arm fwd cars that came later

[Phin]

Interesting front-end setup.

As Gomachv pointed out that's the rear-end not the front.

Here's the manual for the A-Main Bullet in the scans section: http://www.rc10talk.com/viewtopic.php?f=82&t=32179

...and here's the RCCA ad from back in '88: http://www.rc10talk.com/viewtopic.php?p=326166#p326166

[Coelacanth]

Interesting front-end setup.

As Gomachv pointed out that's the rear-end not the front.

Ahh right you are, I missed the "4WS" completely. Makes more sense now.

[Phin]

Played around with counting the weave pattern and drew it out using Google Sketchup. I haven't gone threw and rechecked it yet but so far I think it's pretty close for a first run through. Even if it passes a recheck I'd mock it up with cardboard or wood to test fit everything first.

Left out most of the rear suspension holes since I figure with the two that are there you could mount a buggy kick-up and use it as a drill template. Also it doesn't have the servo mounting holes.

EDIT: See post on pg. 2.

[GoMachV]

You just put me on the fast track to getting this project going that's awesome, thank you! I will recheck a few things too, and the front plate will be like the rear until I can prove the dogbone lengths and such, then I can overlay it onto that beautiful chassis the more I think about it, since this is to be a tribute, I MAY make the chassis of aluminum and paint it to look like carbon fiber

Now If only I knew a designer with access to a waterjet.....

[Phin]

Front end of the chassis will definitely have to be narrower because the Optima uprights and knuckles are wider than RC10 caster blocks and knuckles.

Also the front wheels I'm sending you don't have much of an offset.

[LTO_Dave]

I'm sure I'm not the only person who would be interested in one of these conversions if you decide to make and sell them as a kit.

[klavy69]

I'm sure I'm not the only person who would be interested in one of these conversions if you decide to make and sell them as a kit.

I can verify that statement

[GoMachV]

As mentioned before, Mr Graphite is going on the body