Limitless LibertyMkiii's crazy belt drive car project

[1coopgt]

I think you would need at least a 70mm fan but most likely a 90mm to hit the kind of speeds you want. I fly with 64mm fans in pretty light weight aircraft and just don't think they would have the amount of thrust your needing. I could be wrong but would be surprised.

Well that makes a lot more sense! I guess that is why I am still learning.

The Chaparral fans were powered by a snowmobile engine.

And the Brabham was Designed by Gordon Murry

Both cars were banned from their respective series CanAm and F1. Both cars drew air from under the car to suck them down closer to the ground. If you look both cars have skirts to seal the bottom off to the road . All in the name of more downforce. Both were pioneers in Ground effects .

 

[LibertyMKiii]

If anyone has been curious about cutting a carbon fiber plate, it honestly is not as hard as you might imagine.

To begin you absolutely need a good quality respirator as the CF dust created is said to be like asbestos to your lungs!
I use a 3M dual filter respirator. A quality respirator is a good thing to have around for painting and other uses such as this example.

Next I would say that you need a shop-vac to collect the extreme amount of dust created as well as a jigsaw. Using your wife's indoor vacuum may not go over well and I wouldn't want to re-use that inside my home....

For the setup to cut with, I have tried a few blades and found this Bosch ceramic cutting blade to be my favorite. It cuts like butter!

For initial setup I always cover the CF plate in white or blue painters masking tape (both sides). This helps protect the edges from the cut and is extremely useful to layout your lines needed to be cut. I also use a block of foam underneath to support the CF while cutting. This makes a huge difference!

Then just clamp it all to your work table and take it slow.

When cutting I always cut on the outside of my line leaving 1-3 mm extra. This allows me the ability to go back with a long sanding block and get those edges extremely straight and smooth. It is extra work but well worth it.

I decided to under cut what I need around the tires and slowly expand it so that I can maintain the smallest air gap possible needed.

I still need to add a larger gap in front of the front tires for turning, but so far I am very happy with how it has turned out.

There is about a 4mm rake built into the chassis design/mounts. You can sort of see how the rear is higher than the front in this shot:

And yes it does look like one of those penny board skateboards

 

[Doom!]

I was going to mention the skateboard.

 

[Jason F]

Looking forward to seeing this run.
love the updates! I have raced motorcycles on the Salt Flats, this reminds me of some of my friends building streamliners!

 

[CameronCodes]

If anyone has been curious about cutting a carbon fiber plate, it honestly is not as hard as you might imagine.

To begin you absolutely need a good quality respirator as the CF dust created is said to be like asbestos to your lungs!
I use a 3M dual filter respirator. A quality respirator is a good thing to have around for painting and other uses such as this example.

Next I would say that you need a shop-vac to collect the extreme amount of dust created as well as a jigsaw. Using your wife's indoor vacuum may not go over well and I wouldn't want to re-use that inside my home....

For the setup to cut with, I have tried a few blades and found this Bosch ceramic cutting blade to be my favorite. It cuts like butter!

View attachment 136392

For initial setup I always cover the CF plate in white or blue painters masking tape (both sides). This helps protect the edges from the cut and is extremely useful to layout your lines needed to be cut. I also use a block of foam underneath to support the CF while cutting. This makes a huge difference!

Then just clamp it all to your work table and take it slow.
View attachment 136394

When cutting I always cut on the outside of my line leaving 1-3 mm extra. This allows me the ability to go back with a long sanding block and get those edges extremely straight and smooth. It is extra work but well worth it.

I decided to under cut what I need around the tires and slowly expand it so that I can maintain the smallest air gap possible needed.

View attachment 136395

I still need to add a larger gap in front of the front tires for turning, but so far I am very happy with how it has turned out.

View attachment 136396

There is about a 4mm rake built into the chassis design/mounts. You can sort of see how the rear is higher than the front in this shot:

View attachment 136397


And yes it does look like one of those penny board skateboards

View attachment 136398

Is carbon fiber even worth it though? It's what half an ounce lighter but ten times the price.

 

[ABabyEater]

When you are looking at the top 0.1% of anything, marginal gains will be expensive. Bell curve and all that.

 

[LibertyMKiii]

Is carbon fiber even worth it though? It's what half an ounce lighter but ten times the price.

The strength and rigidity is on par with steel. This chassis is longer and more narrow than a Limitless so it needs to be very strong!
Weight is a consideration, but I am mostly looking at those other characteristics.

Plus as seen in posts above I made the carbon fiber plate myself from leftover materials.

 

[CameronCodes]

The strength and rigidity is on par with steel. This chassis is longer and more narrow than a Limitless so it needs to be very strong!
Weight is a consideration, but I am mostly looking at those other characteristics.

Plus as seen in posts above I made the carbon fiber plate myself from leftover materials.

Do you do custom work for others?
My car needs some carbon trim...

 

[LibertyMKiii]

Do you do custom work for others?
My car needs some carbon trim...

No sir.
I have our home, a demanding job, demanding wife , 2 kids, and a baby due at the end of May. I barely have time for my own project....

 

[CameronCodes]

No sir.
I have our home, a demanding job, demanding wife , 2 kids, and a baby due at the end of May. I barely have time for my own project....

Congrats on the new child

 

[LibertyMKiii]

Few days of measuring/drawing with 5 mins of cutting

Top carbon brace or upper chassis is done for now. I am holding off on cutting any openings on it till I am certain what things I may need to mount in the car. Examples would be belt guides or tensioners. I also left a little extra at the rear and front incase I might need it, which can always be cut off later.

Gears are Saga 8mm bore and have plenty of room to go larger on the pinion side
Now if TP Power would get me the TP4070 motor I ordered

Also as a side note I believe I will have to remove the carbon chassis material on the outside of the wheel/tire. It makes it nearly impossible to change tires without fully taking the car apart

 

[CameronCodes]

Few days of measuring/drawing with 5 mins of cutting

Top carbon brace or upper chassis is done for now. I am holding off on cutting any openings on it till I am certain what things I may need to mount in the car. Examples would be belt guides or tensioners. I also left a little extra at the rear and front incase I might need it, which can always be cut off later.

View attachment 137648

Gears are Saga 8mm bore and have plenty of room to go larger on the pinion side
Now if TP Power would get me the TP4070 motor I ordered

View attachment 137649

Hat are the wheels made out of? You could probably lose some weight there.

 

[jondilly1974]

Few days of measuring/drawing with 5 mins of cutting

Top carbon brace or upper chassis is done for now. I am holding off on cutting any openings on it till I am certain what things I may need to mount in the car. Examples would be belt guides or tensioners. I also left a little extra at the rear and front incase I might need it, which can always be cut off later.

View attachment 137648

Gears are Saga 8mm bore and have plenty of room to go larger on the pinion side
Now if TP Power would get me the TP4070 motor I ordered

View attachment 137649

Also as a side note I believe I will have to remove the carbon chassis material on the outside of the wheel/tire. It makes it nearly impossible to change tires without fully taking the car apart

That’s a very minor amount of material outside the tires anyways.

 

[LibertyMKiii]

That’s a very minor amount of material outside the tires anyways.

Agreed, and if I really wanted to keep the air blocked off I could always add that same blocking on the body instead.
More than anything I think it looks great from the underside of the car.

 

[jondilly1974]

Agreed, and if I really wanted to keep the air blocked off I could always add that same blocking on the body instead.
More than anything I think it looks great from the underside of the car.

I guess there is always a trade off of aesthetics vs practicality.

 

[LibertyMKiii]

I guess there is always a trade off of aesthetics vs practicality.

Hopefully I don't see the car upside down other than on my work bench!

 

[ABabyEater]

What about adding tabs to the bottom of the body shell to replace the material removed to access the wheels when the body is off?

 

[Doom!]

Right now, it looks like a really fast bookshelf! I can see how changing tires would be difficult. It's coming along nicely.

 

[LibertyMKiii]

What about adding tabs to the bottom of the body shell to replace the material removed to access the wheels when the body is off?

I had the same thought
Despite how it might look I am one of those "I'll just wing it" type of builders. After the body gets made and I can evaluate how the body fits I'll probably add some air blocking spots. If I do some sort of skirt then it may be a mute point.

 

[RC-Dad]

This build is epic and I'm not sure how I've missed it until now. Either way I'm here now and am pulling up a seat to root you on!