Limitless LibertyMkiii's crazy belt drive car project

[Doom!]

She is going to be one sleek machine!

 

[CameronCodes]

Question,
Wouldn't it be better to give it a more teardrop like body due to the high speed aerodynamics?

 

[1coopgt]

Have you looked to anything like this . https://www.rockwestcomposites.com/...z8Z7qwL07yf0w9AMLxjEh8Xwn0X5DzvBoC9joQAvD_BwE

You could use this for some of the chassis structure possibly. I don't know what all size panels they make . But ya never know.

 

[LibertyMKiii]

Question,
Wouldn't it be better to give it a more teardrop like body due to the high speed aerodynamics?

If reducing drag was the only goal then yes that would be best. The only tire material that can handle high speeds is foam. Due to this foam tire I need extra downforce to retain grip through the run. The key is to design in downforce in a slippery way

Have you looked to anything like this . https://www.rockwestcomposites.com/...z8Z7qwL07yf0w9AMLxjEh8Xwn0X5DzvBoC9joQAvD_BwE

You could use this for some of the chassis structure possibly. I don't know what all size panels they make . But ya never know.

I thought about it but I only need 3mm total thickness. A honey comb laminate is not ideal for the size I need. They are incredibly strong and light. In a past life I went to school for aviation maintenance and played with materials like that.

 

[CameronCodes]

If reducing drag was the only goal then yes that would be best. The only tire material that can handle high speeds is foam. Due to this foam tire I need extra downforce to retain grip through the run. The key is to design in downforce in a slippery way

I thought about it but I only need 3mm total thickness. A honey comb laminate is not ideal for the size I need. They are incredibly strong and light. In a past life I went to school for aviation maintenance and played with materials like that.

So your joining the big Wang gang?

 

[LibertyMKiii]

So your joining the big Wang gang?

It will likely have a small airfoil on the rear vertical stabilizer.

 

[Notoriousone]

If reducing drag was the only goal then yes that would be best. The only tire material that can handle high speeds is foam. Due to this foam tire I need extra downforce to retain grip through the run. The key is to design in downforce in a slippery way

I thought about it but I only need 3mm total thickness. A honey comb laminate is not ideal for the size I need. They are incredibly strong and light. In a past life I went to school for aviation maintenance and played with materials like that.

You said it, it’s all about getting a shape that’s slippery but still generates some downforce.. I wish someone like Delta Plastik or Protoform would do what your doing, but with the resources they have. Spend the money, Invest in R&D using a wind tunnel, and come up with 3mm Lexan bodies that have a good aero balance so they can achieve high speeds without running wings, or minimal wings.
The cost of these bodies would be high at first, but speedrunning is so popular now that they would sell anyway, and eventually they would sell for less as they made more of them. Delta Plastik is usually sold out of 1/7 Arrma bodies at a hundred bucks each, the demand is there

 

[LibertyMKiii]

You said it, it’s all about getting a shape that’s slippery but still generates some downforce.. I wish someone like Delta Plastik or Protoform would do what your doing, but with the resources they have. Spend the money, Invest in R&D using a wind tunnel, and come up with 3mm Lexan bodies that have a good aero balance so they can achieve high speeds without running wings, or minimal wings.
The cost of these bodies would be high at first, but speedrunning is so popular now that they would sell anyway, and eventually they would sell for less as they made more of them. Delta Plastik is usually sold out of 1/7 Arrma bodies at a hundred bucks each, the demand is there

I was playing with vacuum forming plastic with the idea of selling bodies. Ultimately it takes some special equipment beyond what I can afford.
I also found that you cannot use a smooth flat design when dealing with plastic. It requires hard body lines and many contours to retain rigidity in the plastic.
It would be a tricky thing to balance the design to have smooth airflow characteristics like this body while having all the body lines needed to give the plastic the strength needed.

I imagine they will get there one day. For the 200mm 1/10 scale there are pretty close with the delta plastiks phantom x-1 body.
(I am quite shocked I have not seen anyone speed run this body yet)

 

[Jason F]

I’m getting ready to. Just finishing the design of the bottom.

 

[LibertyMKiii]

To further reduce drag and improve this car's aerodynamics, it will have a tail.
You can see in this simulation the vacuum that is formed behind the car. This region is pretty large and is slowing the car down.

To combat this I have built a bolt-on "boat tail" and integrated diffuser. FYI diffusers should be less than 10 degrees angle and the 1/7 Arrma cars have a 30 degree angle Beyond 10 degrees you get air flow separation and the function does not work as well, air gets turbulent, and other fun stuff...

This tail needed to be a bolt-on design because the car is freaking long! One nice thing is that because the tail sees very little force at the rear of the car I can use it in 3D printed form as more of a disposable part on the car.

Ignore the air gap between the tail/diffuser and the chassis. I will be modifying the rear chassis design to fill in that gap.

Top view:

Zoooom Zoooom

 

[CameronCodes]

To further reduce drag and improve this car's aerodynamics, it will have a tail.
You can see in this simulation the vacuum that is formed behind the car. This region is pretty large and is laterally slowing the car down.

View attachment 134667

Combat this I have built a bolt-on tail and integrated diffuser. FYI diffusers should be less than 10 degrees angle and the 1/7 Arrma cars have a 30 degree angle Beyond 10 degrees you get air flow separation and the function does not work as well, air gets turbulent, and other fun stuff...

This tail needed to be a bolt-on design because the car is freaking long! One nice thing is that because the tail sees very little force at the rear of the car I can use it in 3D printed form as more of a disposable part on the car.

View attachment 134668

Ignore the air gap between the tail/diffuser and the chassis. I will be modifying the rear chassis design to fill in that gap.

View attachment 134669

Top view:
View attachment 134670

Wait. Do you have actuall equipment for this aero stuff?

 

[jondilly1974]

To further reduce drag and improve this car's aerodynamics, it will have a tail.
You can see in this simulation the vacuum that is formed behind the car. This region is pretty large and is slowing the car down.

View attachment 134667

To combat this I have built a bolt-on "boat tail" and integrated diffuser. FYI diffusers should be less than 10 degrees angle and the 1/7 Arrma cars have a 30 degree angle Beyond 10 degrees you get air flow separation and the function does not work as well, air gets turbulent, and other fun stuff...

This tail needed to be a bolt-on design because the car is freaking long! One nice thing is that because the tail sees very little force at the rear of the car I can use it in 3D printed form as more of a disposable part on the car.

View attachment 134668

Ignore the air gap between the tail/diffuser and the chassis. I will be modifying the rear chassis design to fill in that gap.

View attachment 134669

Top view:
View attachment 134670

I’m just gonna cut some golf balls in half and glue them on the rear

 

[LibertyMKiii]

Wait. Do you have actuall equipment for this aero stuff?

What do you mean by equipment? It is all CFD software...

I’m just gonna cut some golf balls in half and glue them on the rear

"What is the worst that could happen"

 

[CameronCodes]

What do you mean by equipment? It is all CFD software...



"What is the worst that could happen"

Why do I feel like you have a wind tunnel?

 

[LibertyMKiii]

Why do I feel like you have a wind tunnel?

I almost built one at one point. The issue is the rolling road setup to correctly measure ground effect.
I don't have the budget to do it right. If the effects and data are not right, then its all worthless.

 

[CameronCodes]

I almost built one at one point. The issue is the rolling road setup to correctly measure ground effect.
I don't have the budget to do it right. If the effects and data are not right, then its all worthless.

If you want down force shouldn't you do something like this?

 

[LibertyMKiii]

If you want down force shouldn't you do something like this?

Road race cars like Le Mans and F1 have WAAAAAY to much downforce. It is a tricky balance to get it right.
For reference I don't know that I have it right either. Only a high quality wind tunnel could tell me that, but I think I am getting close to the ideal design...

The center channel in the middle of the body will generate a nice amount of downforce without being overkill. This clear side view of the car with dashed red lines illustrates it.
The diffuser and rear tail are not picture on this one but will also add downforce under the car directed at the rear axle. This means I may not need the airfoil on the vertical stabilizer further reducing the drag.

 

[CameronCodes]

View attachment 134674
If you want down force shouldn't you do something like this? Or maybe an f

Road race cars like Le Mans and F1 have WAAAAAY to much downforce. It is a tricky balance to get it right.
For reference I don't know that I have it right either. Only a high quality wind tunnel could tell me that, but I think I am getting close to the ideal design...

So you want a more train lIke shape in this scenario?

 

[LibertyMKiii]

So you want a more train lIke shape in this scenario?

As mentioned before you want something very similar to a Bonneville land speed car. (just not the jet or rocket powered ones)

 

[CameronCodes]

As mentioned before you want something very similar to a Bonneville land speed car. (just not the jet or rocket powered ones)

View attachment 134679

... what in the American freedom is that glorious thing?