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Radical ultima

Posted: Sun Jan 25, 2015 6:43 pm
by Mr. ED
I've done a couple ultimas with the battery mounted along the length before. Not using shorties but full size packs and old Ni-xxx sticks.
So when I started this built with a shorty, I did not want it to be just that... I wanted to use the extra space to mount every last bit of electronic as low as I could get it.

And this what came out of that idea:
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To get it all in there I used a low profile servo pushed as forward as it could go without hitting the belcranks, and the RX next to it on its side.
The AMB sits on the servo, right below the handmade front topdeck.
The center topdeck keeps the battery down and is made such that I can also use it with my low profile shorty should I wish to.
The ESC sits right behind the battery; Big heavy and high... glad I don't have to stickit on top of the battery!
Picking a smaller sized ESC (and RX) would have made things easier. But I wanted to try this first.
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A couple more improvements: better belcranksystem with better servo saver built in, widened front and rear, doubled up front and rear shocktowers, hot trick front axles, CVD's and a B4 wing mount
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IMG_9370-web.jpg (81.88 KiB) Viewed 1752 times
IMG_9370-web.jpg
IMG_9370-web.jpg (81.88 KiB) Viewed 1752 times

The body is a stripped and repainted radicator item. Tape and many different colours spraycans... pretty proud of the result.
The wider front allows me to hide the wiring to the RX and the bellcrank part sticking out of the chassis.
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Still need to mount the motor, put a brace on the front inner hinge-pins and build a spare tranny by friday. Then it's test and practise time. And hopefully she'll do well on the race saturday and sunday after that 8)

Re: Radical ultima

Posted: Sun Jan 25, 2015 6:57 pm
by RichieRich
I like this! The laminate shock tower is a great idea too. What wheels and tires are those?

Re: Radical ultima

Posted: Sun Jan 25, 2015 7:02 pm
by SFC K
That looks great with everything tucked neatly into that narrow chassis. I like the washer idea for strengthening the rear shock mounts too! Hopefully it will perform as good as it looks this coming weekend!

Re: Radical ultima

Posted: Sun Jan 25, 2015 7:03 pm
by Mr. ED
Drastic tires, and tamiya/carson wheels for the fighter series.
Those are just place holders as the race organisation obliges us to run Jconcepts dirt webs all around.
I'm expecting the tires tomorrow just need to find innerfoams still

Re: Radical ultima

Posted: Mon Jan 26, 2015 1:19 pm
by Returning_Jim
That Radicator body looks pretty cool on there.

Re: Radical ultima

Posted: Mon Jan 26, 2015 1:48 pm
by Coelacanth
Great job shoe-horning everything onto the ground floor! Kind of what I did with OptiMutt, but you went one step--a very challenging step--further, by getting a battery in there longitudinally. I just couldn't make that work with a SWB Mid chassis. I bet that has a really nice, low center of gravity.

Re: Radical ultima

Posted: Mon Jan 26, 2015 3:05 pm
by Mr. ED
Thanks guys

A little word on the wheels: I don't recommend using them.
Their offset is minimal, they are brittle and the inner reinforcements on the rear weels easily interfere with any type of arm that reaches deep into the wheel.
(I trimmed those for an earlier build already)

Dirt webs came in today and apparently come with foams; one less thing to worry about. Gonna check which diameter front wheel they fit ... after this post ;)

Re: Radical ultima

Posted: Mon Jan 26, 2015 3:42 pm
by DennisM
Cool Build Mr. ED

Re: Radical ultima

Posted: Mon Jan 26, 2015 5:31 pm
by Mr. ED
Thanks Dennis.

The 2WD front dirt web tires are way too wide and too big to fit any of the wheels I thought of using :?
I have some other tamiya wheels sitting in acetone now, which will hopefully match the tires better.
(I think those red ones would just melt in acetone)

If worse comes to worse I'll have to keep this car for later in the season and get something else ready for Friday.

Re: Radical ultima

Posted: Mon Jan 26, 2015 9:48 pm
by 1300GT
Really nicely done "Radima" Mr Ed. 8) Hope you do well with it.

Re: Radical ultima

Posted: Mon Jan 26, 2015 9:49 pm
by Returning_Jim
1300GT wrote:Really nicely done "Radima" Mr Ed. 8) Hope you do well with it.
"Ultimator"

Re: Radical ultima

Posted: Tue Jan 27, 2015 1:30 am
by Mr. ED
More like the 'de-ultimator' :wink:
Originallly I started this project with the idea of using the original body and maintaining most of the original look. But the it's top-heavier and doesn't cover RX and steering well

Re: Radical ultima

Posted: Thu Jan 29, 2015 8:39 pm
by SMOKE-DOG
Nice work. Love these types of builds.

Re: Radical ultima

Posted: Fri Jan 30, 2015 6:50 am
by Hcp22
I like this Ed 8)

Re: Radical ultima

Posted: Fri Jan 30, 2015 5:23 pm
by Mr. ED
SMOKE-DOG wrote:Nice work. Love these types of builds.
Me too ;)

I went to the the free practise today and it didn't go all that well unfortunately.
The track has been redone from last year and now has hard clay instead of astro turf. This change had me struggling a lot more than expected.
I couldn't get the car to do what Iwant. It would spin in cornersand was difficult on the straights too.
Tires are spec, and most other cars seemed to do well,so it's probably my shock setup. Hopefully I get it right before I hit something real hard

On top of that the freshly repainted body turned out to be quite brittle and was clearly not going to make it through the 2 coming days.
And , of course, the tranny broke down. I shouldn't have used the robinson racing 48 pitch outer gears I guess. I already noticed long ago the gears weren't centered well and for sure one's got some teeth kicked out today.
Luckily I had a standard gearbox along as backup, and for the body I put some extra holes in the old 'black-dog' project body. So now the ultima looks somewhat like a baldre :roll: It will have to do for the weekend.