Big Rock Nero // Custom Carbon Fiber chassis plates

[Tex Koder]

Just curious..

Would there be any actual interest in carbon fiber chassis plates to replace the aluminum ones on the Nero / Big Rock?

 

[MrTitanium]

I would consider it, but it depends on the price and quality.

 

[Tex Koder]

I would consider it, but it depends on the price and quality.

Would you know the OEM thickness of the chassis?

How thick would you think the CF plate need to be to equal its stock stiffness?

(I don't have a Nero in my hands to verify...)

 

[MrTitanium]

Factory chassis is 3mm thick.

A few facts for you:

The tensile strength of carbon fiber is approximately 4% great than of aluminum.

When using the same thickness, CF is 50% lighter than aluminum.

CF cracks. Aluminum bends (for the most part, anyways).

Where you thinking of extending the plates or keeping factory dimensions?

 

[Tex Koder]

Factory chassis is 3mm thick.

A few facts for you:

The tensile strength of carbon fiber is approximately 4% great than of aluminum.

When using the same thickness, CF is 50% lighter than aluminum.

CF cracks. Aluminum bends (for the most part, anyways).

Where you thinking of extending the plates or keeping factory dimensions?

View attachment 319246

3mm
Got it.

Thank you for the verification specs and your feedback.

I'd imagine I would first create ones with factory dimensions and mounting points..
Once I get more familiar with the original plates and where I think I can "extend" ,then perhaps I'll create XLWB versions...

 

[MrTitanium]

Careful if you are thinking of extending as the center shafts must accommodate the added length.

 

[Tex Koder]

Careful if you are thinking of extending as the center shafts must accommodate the added length.

So looking at some photos online..
The center driveshafts looks to be ribbed telescoping..
Can the driveshafts on the suspension arms be used in their place?
Are they interchangeable ,in any way??

Or, do you know if there are compatible shafts from other brands that would be suitable replacements (That happens to be longer too. Perhaps)

 

[MrTitanium]

Yes. All six driveshafts on the Nero-style platforms are splined (ribbed), not just the center units. Although the center units are fixed and do not require any travel (telescoping effect).

Are you asking if the wheel axle stubs (male portion) can be used in the center? It all depends how much you are looking to extend the chassis. Are you looking into extending the rear only? The front? Both? There's some math to do as I wouldn't want to scraping CF sheets. You would first have to decide if you are going to extend the chassis plates. Think of the chassis as two separate portion:

(1) Center to front section,
(2) Center to rear section.

IMO, the best way to do this is strip out a Nero. Install the center transmission and front and rear diffs on just one plate. Install the factory driveshafts and see how much travel you have with the stock set-up. As a rule of thumb, the minimum amount of engagement must be the diameter of the shaft. Then there's a safety factor of 1.5x to take into consideration too.

What does this mean? Simple. If a male shaft has an OD of 6mm, it must engage into the female part a minimum depth of 6mm (or 9mm with safety factor of 1.5x). If not, expect problems to occur.

Follow? If not, let me know and I approach it an different way

 

[Tex Koder]

Yes. All six driveshafts on the Nero-style platforms are splined (ribbed), not just the center units. Although the center units are fixed and do not require any travel (telescoping effect).

That's what kind of confused me.

If the center driveshafts Doesn't require any telescoping effect.. and are completely fix distance to their respective diffs...
Why not simply use dogbones instead?

Are you asking if the wheel axle stubs (male portion) can be used in the center? It all depends how much you are looking to extend the chassis. Are you looking into extending the rear only? The front? Both? There's some math to do as I wouldn't want to scraping CF sheets. You would first have to decide if you are going to extend the chassis plates. Think of the chassis as two separate portion:

(1) Center to front section,
(2) Center to rear section.

Good question.
I don't know at the moment.

So here's another thought-
Since those distances/lengths are fixed for the center driveshafts , could I just replace them with standard CVDs off any of the current models and just Design & Create the custom CF chassis plates to accommodate those lengths , whatever they may be?

IMO, the best way to do this is strip out a Nero. Install the center transmission and front and rear diffs on just one plate. Install the factory driveshafts and see how much travel you have with the stock set-up. As a rule of thumb, the minimum amount of engagement must be the diameter of the shaft. Then there's a safety factor of 1.5x to take into consideration too.

What does this mean? Simple. If a male shaft has an OD of 6mm, it must engage into the female part a minimum depth of 6mm (or 9mm with safety factor of 1.5x). If not, expect problems to occur.

Follow? If not, let me know and I approach it an different way

I follow what you saying.

Trying to think up a simpler solutions to make all this possible..




.
And, I'll Definitely try to avoid wasting carbon fiber plates while attempting to come up with the proper shape/lengths for this project..
Will be printing the prototypes at first ,then perhaps have some near-final versions made in acrylic... Before trying to get the designs made in CF..

 

[Surchaufeur]

That's what kind of confused me.

If the center driveshafts Doesn't require any telescoping effect.. and are completely fix distance to their respective diffs...
Why not simply use dogbones instead?




Good question.
I don't know at the moment.

So here's another thought-
Since those distances/lengths are fixed for the center driveshafts , could I just replace them with standard CVDs off any of the current models and just Design & Create the custom CF chassis plates to accommodate those lengths , whatever they may be?



I follow what you saying.

Trying to think up a simpler solutions to make all this possible..




.
And, I'll Definitely try to avoid wasting carbon fiber plates while attempting to come up with the proper shape/lengths for this project..
Will be printing the prototypes at first ,then perhaps have some near-final versions made in acrylic... Before trying to get the designs made in CF..

The center shafts are telescopic from the manual. They all only use one pin under hidden by the shaft boot to keep the shaft togueter. You pull them to get them put of the outdrives, dogbones would require to remove the whole front or rear of the vehicle to get them back in. It also prevents them from bending like dogbones would

The part that extends and retracts is the one who connects to the rear and front diffs. I believe it has been done for convenience of maintenance if you ask me. Its better in general than dogbones

 

[Tex Koder]

The center shafts are telescopic from the manual. They all only use one pin under hidden by the shaft boot to keep the shaft togueter. You pull them to get them put of the outdrives, dogbones would require to remove the whole front or rear of the vehicle to get them back in. It also prevents them from bending like dogbones would
View attachment 320526
The part that extends and retracts is the one who connects to the rear and front diffs. I believe it has been done for convenience of maintenance if you ask me. Its better in general than dogbones

So there's really nothing else to prevent the chassis plates from being Longer other than those center shafts..
Correct?

 

[Surchaufeur]

So there's really nothing else to prevent the chassis plates from being Longer other than those center shafts..
Correct?

Correct unless im forgetting something.

 

[MrTitanium]

So there's really nothing else to prevent the chassis plates from being Longer other than those center shafts..
Correct?

There is the two battery trays to take into consideration… and body would require to have new holes drilled for new post locations.

It isn’t complicated. Just takes some time to calculate and do. If you’re an experienced CAD user, this would be a nice project. With a simple caliper, some trig , and common sense, it’s very doable. Keep in mind that the Nero platform is considered a relic so if you’re planning to sell these units in hopes of retiring early, I would reconsider it altogether.

There was a fellow who was selling them on eBay at one point, but titanium. I never bothered with it as it looked botched. Pics of holes wouldn’t match up. A real hack job. Hope the guy doesn’t work in aviation.

Dogbones are prone to drive pins and/or cups wearing out as pins (usually hardened) dig into the cups. Plus they’re exposed to the elements. Sliders (Nero) share the twisting load around the full circumference and are sealed. I’d take sliders any day over a dogbone design.

 

[Tex Koder]

There is the two battery trays to take into consideration… and body would require to have new holes drilled for new post locations.

It isn’t complicated. Just takes some time to calculate and do. If you’re an experienced CAD user, this would be a nice project. With a simple caliper, some trig , and common sense, it’s very doable. Keep in mind that the Nero platform is considered a relic so if you’re planning to sell these units in hopes of retiring early, I would reconsider it altogether.

There was a fellow who was selling them on eBay at one point, but titanium. I never bothered with it as it looked botched. Pics of holes wouldn’t match up. A real hack job. Hope the guy doesn’t work in aviation.

Dogbones are prone to drive pins and/or cups wearing out as pins (usually hardened) dig into the cups. Plus they’re exposed to the elements. Sliders (Nero) share the twisting load around the full circumference and are sealed. I’d take sliders any day over a dogbone design.

Understood.
Thank you very much for all your feedback and insight to the matter.

I'm not doing this in hopes of being able to retire from any proceeds from these parts ,more like trying to "restore" a vintage vehicle with newer materials/enhanced parts (especially since I miss the opportunity when the Nero first came out)

Just like how there's specialized companies out there who -design/produce- aftermarket parts for classic cars.
This is sort of my way of doing it -for RCs...

 

[#ARRMArcfanboy4life]

I am trying to make these in aluminum.

I have been working on the stretched chassis idea for 3 weeks (1 day, 3 weeks ago, last time I wasn't burried in school). Going to a hard school for a hard degree is hard.

 

[#ARRMArcfanboy4life]

I got some measurements down. I am going to 3d print it in sections to make sure they all fit on right and then I will work on a stretched one.

 

[#ARRMArcfanboy4life]

Almost done with the regular design.
Next up, stretched.

@Tex Koder can you get these dimensions for me? I got a rough estimate, but I would like better and I left the nero home.
From center of rear UJ to edge where chassis starts (picture for reference)

And from center of UJ on back part of center diff to edge where chassis starts (again, picture for reference).

If I do actually stretch the chassis, I will probably try and do a build thread.

 

[#ARRMArcfanboy4life]

Something went mildly wrong forcing me to restart. Luckily I still had all the measurements.

 

[#ARRMArcfanboy4life]

I have finished the first prototype of the model. @Tex Koder can you get those measurements for me?

 

[Tex Koder]

I have finished the first prototype of the model. @Tex Koder can you get those measurements for me?
View attachment 358109

You just need me to confirm the measurements that you showed in post#17 ?