Limitless Liberty's "Unlimited" dream speed build - Stretched Arrma Limitless

[LibertyMKiii]

Just including this incase someone wants to follow this sort of idea for making a body.
The primary concern is.... do you have some extra room for tire expansion, and room for the front to turn. (consider suspension travel if your car will have suspension)

After getting the shape the way I liked it, I did some investigatory holes to see where the tire was. (honestly impossible to tell at this point) You can see the tire there in the picture just barely behind the surface (not enough room for steering). Sooooooooo I needed to build up the material further where the wheels are to provide enough space. Back to adding layers and sanding....

 

[Will89]

Very professional build!

 

[LibertyMKiii]

Small update...
Still adding material and getting the shape perfect. More than anything I need everything to be ballanced for aerodynamic reasons.
Making proper holes now, and using measurement calipers to determime exact measurements from the tires.
I set it up with extra 10mm room above the tires for expansion, and 20mm extra space on the side of the front tires for steering. U-turns at either end of the run will be a 3 point turn most likely, but should be do-able.

I need to shape the balsa tail (which will be fiberglassed.) After that will be a primer and mold release wax to make the mold.
Getting so so so so much closer!

-Liberty

 

[LibertyMKiii]

When I started this project I didn't want to copy Nic Case's 202mph bullet. While my build is certainly not belt drive or 1/10 scale, it ended up almost exactly like his design. (Sorry Nic)
This build was an evolution of design, and we both ended up in nearly the same design shape. As I have added material and refined the shape to reduce lift and drag, it ended up very similar to his. My car is certainly wider and will be utilizing more smoothed surfaces versus some hard lines he had on his, but overall it is strikingly similar. Given the size difference my car may not have the ability to go as fast as his, but certainly has the potential to be the fastest Arrma or 1/8 scale.

If you are interested in reading more about his car, there is a PDF "Inside the world's fastest RC Car" that gives great detail.
Or this link has a video of his run https://www.rccaraction.com/blog/20...c-case-breaks-the-200mph-barrier/#outer-popup

 

[LibertyMKiii]

Body shape is nearly completed, just making last few adjustments. Taking my time and reviewing it over the course of a few days to be sure I am 100% happy with it and ready to move on to building the mold.

I went ahead and started on the tail. The wood used is balsa and will house the antenna inside to give a nice vertical extension of the antenna without being an aerodynamic slug. It should also act as a rudder helping me keep the car tracking straight (Assuming no extreme cross wind.)

 

[LibertyMKiii]

2 part epoxy primer was sprayed. More of the same from before.... sand spray, fill, sand spray, sand spray.....

Finally at the wet sanding step and nearly ready for the mold release wax!
The primer is all wet after a rinse (does not shine like that normally) She looks fast!

-Liberty

 

[GMballistic]

Looking good Liberty.

 

[cootertwo]

Dat's a lot of work there!

 

[Notorious J]

Can't wait to see it done. Should be super slick!

 

[Pfaulk54271]

Definitely following this one, amazing work!

 

[BashingBrian]

Getting there...??

Good job your in Texas you have the weather on your side, over here in the UK its gone to ? no painting no bashing..???

 

[LibertyMKiii]

Getting there...??

Good job your in Texas you have the weather on your side, over here in the UK its gone to ? no painting no bashing..???

Fall in Texas is probably our best season.
I have a business trip this week and a very busy weekend when I return so there will be more waiting...

I have waxed the plug 5x and the gelcoat arrives this week. I should be ready to make the mold once I have some time.

-Liberty

 

[Notoriousone]

Wow, amazing work.. Looking forward to seeing the end result of this!

 

[LibertyMKiii]

Warm days are running short so I jumped on the next steps for making this mold.

After 6 coats of wax I applied the gelcoat. (2 coats)

After fully cured, this was followed by chopped mat fiberglass:

Possibly not needed, but I also made a support frame to support the middle section from bending.

I plan to let this fully cure and keeping my fingers crossed that it will release from the plug successfully!

-Liberty

 

[LibertyMKiii]

Not a deal breaker problem but certainly a delay causing more labor.
The primer didn't stick very well to the sheetrock compound. So...… don't use that stuff if you are building a plug for a mold.

Now the process is just chipping this stuff out of the mold and then carefully peeling off the primer from the gelcoat. (it is quite easy to do because it has 6 coats of wax on it.) In the red circle is an area where I have peeled the primer off and revealed the smooth gelcoat which will be the final mold surface.

Fun Fun Fun, if you want to see a video of it with more images and detail I posted one last night. I have to say I am so happy to see the rolling chassis out of the mold again!:

-Liberty

 

[jondilly1974]

This may be a non starter, but have you tried to drop the mold and see what falls out on it's own?

 

[LibertyMKiii]

This may be a non starter, but have you tried to drop the mold and see what falls out on it's own?

I'll give that a shot when I get home from work. That is a good idea!
I did bang it around a bit and lots of flexing the sides. Last night I was just excited to get the chassis out of there. I am itching to drive it!!!

I had tried 110psi compressed air and some other tricks that all failed me.

 

[BashingBrian]

Fingers crossed you get it out all good..?? can't wait to see it out the mold ?

 

[phildogg]

This is amazing work. I love the design and if it works like Nic's then you are on to something..

 

[LibertyMKiii]

This is amazing work. I love the design and if it works like Nic's then you are on to something..

Thanks Phillip!
Knowing the physics around speed and aerodynamic resistance, I have no doubts it will improve performance over the Limitless/Infraction body, and even the average Delta Plastics GT body. I doubt it is fully on par with Nic's car, simply because he used a 1/10 scale that is significantly smaller. The coefficient of drag area is much larger on a 1/8 car. It will be quite interesting to see what it can do!

The mold is about 90% ready. I just need to wet sand and polish to make sure the final body shell releases from the mold well. It was a busy weekend and I didn't get as much garage time as I was hoping for.

I am thinking about testing it out on a senton 6s or another SCT sized 1/8 GT setup initially. The shape and design would all be the same only would have to cut the back end shorter to fit that vehicle. I don't have the balls to drive that "stretched" carbon fiber chassis at high speeds until I prove the body has stability and reliable function etc...

-Liberty