MR ED 's ultima hop-ups

[Mr. ED]

As some of you may have picked up from another tread on the board: I' ve recently made a design for 3d printed arms for the YZ10 works 91-92 (and 93?)
While waiting for the protoypes I'm getting started on some designs for the Ultima too.

If you guys have some ideas, feel free to throw them in here.

The first part I want to do is the front bulkhead. Ofcourse I'm not going to just copy them; here're some ideas I want to implement:
- design adapted to the differnt production method and material
- perfectly compatible with the stock chassis and top decks, shock towers, stabilzer, ...
- hingepin holes for the arms moved a little further outwards:
- for more meat around the mounting screws
- to give the front some extra width with the stock arms (the wider Andy's arms are getting too hard to find and too expensive)
- MR ED logo incorporated

Subscribe to this topic and be the first to see the renderings soon.

[alien3t]

An idea for the 93 arms. Only difference i know for 93 specific arms was a hole in the rear arms for a sway bar.

[Mr. ED]

An idea for the 93 arms. Only difference i know for 93 specific arms was a hole in the rear arms for a sway bar.

Ok, thanks. I incorporated that hole. So those arms will work for the 91-92-93 works and hot-dog cars. And with the right parts for most, if not all, of the YR-4 series and 870C.


Back to the Ultima since this is the kyosho section:

The holes in the front will let you screw a brace over the front of the hingepins. But yoy would need longer hingepins for that; so it's optional.

The width is only 6mm more than original, so even with some wider wheels you should be well within the legal limits of today.

[EvolutionRevolution]

Nice.

Maybe add some holes to lock the hinge pins in place with set screws (like on the Ultima RB)?

[Mr. ED]

Thanks for the compliment and suggestion.
I actually thought about that earlier and then just forgot about it. I'll add a little boss and make it an M4 grub screw. M3 would be too easy to strip the tread of the plastic.

[Mr. ED]

I inclined the hole slightly outward so the grubscrew would be easier to reach with an allen key. But now, well, I'm not sure if this won't hinder the upward movement of the arms. Also, I'm not sure if it helped much as I think the grubsrew is now in line with the ball-link on the shocktower .


I also have to check if the stabilizer can pass the thickened shocktower mount.
The prototype will tell I guess... if I can find an original stabilizer. Then again, if I do I can also model it up a and check on the CAD data.
I guees I'll know what to do tomorrow evening after work

[RichieRich]

Oh, this is nice. I'm trying to think of the problems I had when I raced. Definitely more meat for the four main bulkhead screws. I like the idea of a hinge pin brace. Which one were you thinking of using?

I think your grubscrew location might be right under the shock tower or at least hard to get to with the shock tower mounted. Either way, this looks pretty darn good.

[EvolutionRevolution]

On the Ultima RB the grubscrew location is halfway the hinge pin hole and accessible from the bottom, no boss. Whether it strips or not depends on the material used and how you screw it down - I usually counterrotate screws that go into plastic parts until they "step" down (finds the previous thread) and then screw them down.

[Mr. ED]

@RR
Glad you like it. The hinge pin brace will just be a flat strip with 4 holes in it. Easy enough to make your own, but I can ask Orb Design if they are willing to add that as an option once these parts become available from them. Ifnot I'll just draw it out and put the dimesnioned drawing here for anyone to see.
The grub screw is right behind the tower and angled 15° to make it reachable, but I did notice just after my post last night: the shock tower hits the extra meat around the grubscrew. So my last thought before I fell asleep was: let's move that grubscrew to the bottomside: flush with the chassis bottom and behind the bumper.

@ER
I like it a little further back because the front takes more of the leverage upon frontal collisions. But closer to the bumper is better protected... to decide. The thing with most grubscrews is : they only have a few winds, and when you tighten them up itti's easy to strip the tread in the part.
That's good practise but to prevent stripping I also want the heavier M4 thread, and option to use a little longer grubscrew (and M4 is longer than M3 already).

I'm heading home now and will work on it more tonight. IF you guys have ideas for other ultima parts, feel free to PM me or post here.
The next I have in mind are new C-carriers for the front: adding a little more width, And offset axle carriers for the back: adding wheelbase and moving the motor a little closer to the rear wheels.

[Mr. ED]

PS: if anyone wants to measure up a front stabilizer, please do

[Mr. ED]

Found the stabilizer and it 'just' fits fine.
While I was test fitting that up on the original bulkhead I discovered I had made a miscalculation on the brace mounts height.
So here's version 3 with the grubscrews out of sight and a lot easier to get to, and shallower bumps up front.

[Mr. ED]

I decided to model up some rough copies of the original front arms. These are not modeled up for production but to help verify the front bulkhead and as reference for the new C-carriers I want to do next.

As you see I also added the front brace for reference. A good thing as the bumps on the front of the bulkhead were still not the right height: too shallow this time.
Here's the corrected bulkhead:

[DennisM]

Looking good Mr. ED -

[Mr. ED]

Thanks Mr. D


The new C-carriers: for now:

I won't know for sure if this is the final shape for prototypes untill I've modeled the steeringknuckles.
The steeringknuckles will be original, but I need to model them to verify the C-carrier design.

The upper link point is moved 3mm inward: to compensate for the 3mm the lower arm is moved outwards. That way the top link will keep its original length. The steering knuckle is moved out 2.5mm. So, together with the wider bulkhead your car will get a total extra width of 11mm with the stock arms.
The steering links will need to be about 5mm longer than stock, unless you use a wider linkplate on the steering side. I might design one, but let's wait till I have a prototype bulkhead and carriers. If 5mm longer steering links are fine, I'll leave it at that.

[Mr. ED]

I'm a little distressed today, so I stuck to some basic parts to help on the design of the actual parts to produce later... till I found some issues with the fitment of the front bulkhead.

The chassis angle is 20° on both the the turbo ulitma and ultima2 right?
I hope so, 'cause I got a lot of little adjustments done based on that assumption: the top shaved, top holes relocated, and shocktower dropped... all to make it fit the ultima2 top plate - and Turbo chassis dimensions.

And from the bottom:

You can see how the bosses for the grubscrews are nicely tucked away but wel accessable.

And I just remeber I want to add grubscrews to the C-carriers also. Will be for tomorrow..nearing 1 AM here.