Turbo Optima build - Project Barney: Finished

[Coelacanth]

I got some suspension tweaking done tonight, it's more or less just as I was hoping to accomplish. Barney now has full-size front shocks like all the OTHER race cars out there! One weakness of the Optima series that I wanted to address were the aluminum shock towers, which are notorious for bending all to hell after some rough roof-top landings, especially the rear one. As mentioned before, the stock front tower (if you can call it a tower) was backed by a proper 3mm thick CF tower.

I had to figure out a way to fabricate a rear shock tower brace (of sorts), something just a bit wider, just a bit longer, and mounted directly behind the stock aluminum tower, to hopefully strengthen it. I used a piece of 2.5mm CF cut from a scrap I bought from eBay (carbonfibersuperstore, I think)...that arrived only gloss-finished on one side. (I positioned that side towards the stock tower so you can't see it.)

The CF towers themselves were finished by blacking the edges with a Sharpie marker before applying CA glue to prevent delamination. I had to use screws that were about 2 - 3mm longer than the manual-recommended screws to properly mount the CF towers (perhaps obvious but worth mentioning).

Some test-drops from 2' high onto a table, and 3' high onto my carpeted floor both with the car horizontal and dropping at weird angles seems to indicate the suspension is working great--not even a hint of rebound. I'll have to adjust some things once the chassis is complete and weighs quite a bit more, of course. Steering & suspension all seem free of any binding, at this time anyway.

[Coelacanth]

Why does it seem that with every project I work on, I run into the "missing part(s) roadblock"? I'm getting close to finishing off the chassis and--hardly surprising--I can't install the steering servo because the Optima's little square servo mount with the 4 posts has gone missing. Happens every single time!

Rather than spend hours of time searching for one, paying exhorbitantly for it, and waste time waiting for it to arrive, I figured I would try to fabricate my own from some carbon fiber scraps. We'll see how that turns out tonight.

[Mr. ED]

curious: I may have to copy that 'cause my optima seems to miss this part too...meaning I have no clue how and whre to mount a servo in the stock shape the car is momentarily still in

[Coelacanth]

curious: I may have to copy that 'cause my optima seems to miss this part too...meaning I have no clue how and whre to mount a servo in the stock shape the car is momentarily still in

I fabricated one from 2mm thick carbon fiber. 3mm thick would make drilling countersunk holes a bit easier. The dimensions of the stock piece are about 32mm by 30mm, and the hole spacing is approximately 28mm by 26mm. The original part has 4 screw standoffs. I figured 4 spacers approximately 5mm long would be an ideal switch...this was important as the servo mount also functions to affix the upper chain-guide to the radio plate. I'll update tomorrow with some pics, the custom mount installed great & with the purple alloy spacers, looks better than the original.

The only thing I don't care for is I had to use 4-40 flat-head screws & nuts, the screws threading up from the bottom through the servo mount, spacers & radio plate. The nuts on top kind of stand out and take away from the sleek look, they look a tad clunky compared to all the RCScrewz everywhere else on top. Nothing mounts there anyway so functionally it's not a problem, it just takes away from the aesthetics, IMHO.

[Jay Dub]

You could use threaded stand offs. Short screws from the top and bottom- That would look SWEET. -Jeff

[Jay Dub]

Plus it would make taking out the servo really easy...

[Coelacanth]

You could use threaded stand offs. Short screws from the top and bottom- That would look SWEET. -Jeff

Great idea, Jeff. Now I need to find some green or purple threaded 3mm rods!

[Asso_man!]

Awesome and very original project, I can't imagine how much time you spent srutinizing about which part should be purple or green. I guess you almost had nightmares before figuring it out. Very nice, keep up the good work!

[Coelacanth]

Awesome and very original project, I can't imagine how much time you spent srutinizing about which part should be purple or green. I guess you almost had nightmares before figuring it out. Very nice, keep up the good work!

Thank you! Actually, it didn't take too long...the basic idea was to have all the middle, longitudinal parts colored purple, and do the lateral cross-pieces, like the shock towers, knuckles, spanners, motor guard in green. I didn't want for it to have a completely random look.

[Coelacanth]

Here's a mock-up of the servo mount I made from a scrap piece of carbon fiber and 5mm thick spacers. I like Jay Dub's suggestion to use flat-head 3mm screws on bottom and normal 3mm screws on top running through 5mm thick threaded aluminum posts, that will help me lose the unsightly nuts on top.

There won't be much thread for the 3mm screws to grab onto, but hopefully 2 - 2.5mm each (for top & bottom screws) with some threadlock should be enough...now to wait for the needed bits & pieces I ordered to arrive. More delays...

[Mr. ED]

So it's just double-sided tape which holds the servo onto this late?

[Coelacanth]

So it's just double-sided tape which holds the servo onto this late?

Yes, double-sided tape and a plastic zip-tie just for good measure--as per the manual. I spent so much time focusing on the suspension that I never took a great pic of it with my CYANide car, but you can pretty much see how it works here.

[Coelacanth]

One thing I wish the Optima series had is a Lexan undertray to protect the bottom of the car. I guess the belly skid-plate does that, but many Optimas lacked this part, and when one anodizes it--I guess one wants to protect the anodizing. Doh! Anyway, it seemed to me that it couldn't be all that hard to design something, so here's the design I came up with. It couldn't have been done without ROH73's expert help with forming the Lexan, thanks Robert!

It protects part of the chin undertray, the entire bottom of the skid-plate and even the underside of the rear gearbox. Getting all the screw-holes lined up was the biggest challenge. It fits a bit flat and there's some space along the sides between where the front 4 and rear 4 screws mount it to the chassis due to that middle chain-guide valley. Ideally I'd wish the tray could be vacu-formed to fit that under-tray snugly, maybe someone can help with that--send me a PM. (Imagine how many guys who run their Optimas would love to have one of these?!)

Anyway, I resolved the space issue by sticking thin strips of sponge tape to the Lexan undertray so that it mostly fits snug against the frame rails, and will prevent dirt and crap from getting caught beneath the undertray.

[Coelacanth]

Here are some of the electrics planned for Barney; some Gens Ace vintage-shaped stick-pack LiPos and a Tacon 11T 3200kV to bring on the brushless.

Shoot, I just noticed the motor's currently on sale at HobbyPartz.com for $24.09, about $10 less than I paid for it 2 weeks ago!

[Coelacanth]

I'm pretty much finished building the chassis...a bit of tweaking here and there still needs to be done, but here's Barney, in the nude.

2 of these pics will have to suffice for my MMV 1/10 Buggy Build-Off entry, I don't have time to even mount my back-up body and haven't even trimmed & painted Barney's Lexan birthday suit, but it's coming along...