Limitless Formula 1 body parts

[vicat70]

I've been researching Formula E Scale Racing and this picture resembles it.
I always felt that if you cold some how acquire the scale dimensions of E. cars, you benefit from the Aero as designed above. You would be successful if you follow the competing E teams designs perfectly as could be. The Teams copy each others aero design cues. ?‍
E cars have spats ahead the wheels. The Limitless is handicapped in this regard. Hence GT bodies dominating speed run with this Lim chassis. Even E cars are good for sustained speeds of 200mph. The Limitless should have better Aero than it does. Customizing them is fun, but to get real serious with speeds , Aero is usually the barrier, not the electrics. I think a body that is identical to a Formula E would be an objective.

I think formula E is an hybrid between f1 and GT. I was figuring out that maybe is possible to build something to make limitless similar. A bit tricky for me but it's a nice challange. And not only would be good looking, but covering tires will help aerodynamic too.

 

[LibertyMKiii]

Inspiring work you have there. I have played with placing weight on the Lim. body. To check shock compression. It takes some amount of weight. The 15 pounds you state make sense. Sometimes I think its also great to focus on the below chassis negative pressure to balance out top downforce.
I think having a crossweight scale also helps dial in chassis balance. Done wrong you lose negative pressure at a certain speed threshold. Gets out of shape quick. Downforce from the body can only help so much.

Yep, I had the sky rc balance scales and was planning on making a wind tunnel. I was also going to use an Eagle Tree pitot tube setup to measure air speed, and an additional scale at the rear of the car to measure drag forces. As always $$$ was the limiting factor, but I would still love to do this one day. Even the tunnel I could create wouldn't properly simulate under car ground effect, because of the ground not moving relative to the car's speed. Boundary layer airflow attached to the car, and attached to the ground would be the problem. I looked extensively into a rolling belt setup, but is almost impossible to do for speeds over 100mph. High speed air wasn't to big of an issue, I had solved that for up to 150mph air speeds through the small test box.

Aerodynamics is tricky and takes much trial and error without a wind tunnel. As you mentioned the below car venturi is very important. It can have a massive impact on the downforce. So much so that in the 70's, Formula 1 outlawed some of the concepts like sliding side skirts. For those reading this who do not know about it... Collin Chapman's Lotus team had a ground effect side skirt, which created a seal holding the low pressure and high pressure areas separate from each other. This created massive downforce and allowed higher speed cornering than had ever been seen before. The problem was during cornering the drivers would clip rumble strips or bumps on the track raising the car. The car would suddenly loose handling and in some cases result in crashes. On an RC car this would be tricky with the added friction. I had considered nylon brushes or silicone wiper blades as some possible solutions.

Then there is the fan/sucker cars like the chaparral 2J, which use a high power fan to create the low pressure area under the car. This also needs some seal under the car but less so. This would be pretty easy to replicate and one that I would like to try at some point. The idea in an RC application would be to use a body that is streamlined ignoring any need for downforce and let a EDF at the rear of the car suck the car to the ground through the body and carefully chosen paths through the chassis and front bumper area. This should create enough downforce while maintaining very low drag. Ideally this should be a very fast car.

Lots of fun ideas to keep me busy for years

Ultimately aerodynamic frontal area is the killer of speed. This is why my 1/10 4tec 2.0 will always have more potential for high speeds over the Limitless. The limiting factors are always the same between any scale RC. Power, Aerodynamics, driveline failure, heat, and TIRES!

 

[vicat70]

Aerodynamics is tricky and takes much trial and error without a wind tunnel. As you mentioned the below car venturi is very important. It can have a massive impact on the downforce. So much so that in the 70's, Formula 1 outlawed some of the concepts like sliding side skirts. For those reading this who do not know about it... Collin Chapman's Lotus team had a ground effect side skirt, which created a seal holding the low pressure and high pressure areas separate from each other. This created massive downforce and allowed higher speed cornering than had ever been seen before. The problem was during cornering the drivers would clip rumble strips or bumps on the track raising the car. The car would suddenly loose handling and in some cases result in crashes. On an RC car this would be tricky with the added friction. I had considered nylon brushes or silicone wiper blades as some possible solutions.

Yeah, side skirts were a great idea to generate the vacuum effect under the car, but they have even two important side effects.
They create more drag at high speed that is something we exactly don't want, and as you said, is difficult to reproduce.
The big fan... yeah, but does that worth to try? For the sake of knowledge probably yes, but definitely?
It would be more effective a twin turbo jet as someone already did on limitless.
That would give a nice "kick in the ass" to the car, relieving the stress the motor has to sustain alone, for the purpose of additional speed.
But we are talking about aerodynamic here and as you correctly said the problem is: " aerodynamic frontal area is the killer of speed ", that's it.
Actually this is the same issue that real f1 cars or generally open wheels cars all have.
The big step would be cover or deviate the air flow from all the front axial area, to benefit of a significant improvement.
Improvement that yourself estimated to get 10-15 mph more speed. Probably does not look a big deal, but in a competition even a couple of mph more have a huge impact after all.
By the way, covering front area would for sure improve aerodynamic but would even "denature" the f1 look of our beloved limitless.
So, I guess the challenge is pretty tricky!

 

[LibertyMKiii]

By the way, covering front area would for sure improve aerodynamic but would even "denature" the f1 look of our beloved limitless.
So, I guess the challenge is pretty tricky!

Yes this is why I'll offer multiple versions of the front nose. There will people who will cry about it saying "that is not a Limitless".

 

[SrC]

At what point does an open wheel design become a closed wheel...
@LibertyMKiii do you like doing lexan vacuum forming? Are you sculpting with clay at all?

 

[LibertyMKiii]

At what point does an open wheel design become a closed wheel...
@LibertyMKiii do you like doing lexan vacuum forming? Are you sculpting with clay at all?

Like everything I have tried the plastic forming has some unexpected challenges that make it very frustrating. Unlike composites where you have some ways to fix/repair any problem areas.... if the plastic messes up during the forming process it is done. For this reason I may never do 1/7 scale bodies in plastic given the plastic sheet costs go north of $60.00. I do thing working with smaller parts like the Limitless nose is a good option for me.

I wish I had the budget to purchase a commercial grade plastic sign forming machine. Using two 1500 watt quartz heaters is just barely enough heat and I am finding I have to use a heat gun also in the tighter radius areas. The plastic also picks up very small details that I had not expected would show.

I have worked with clay in the past. Right now I am working mostly with plaster. I do some edits/re-shaping with sheetrock mud. Ultimately this is only good for making the shape and would need to be re-created in something more flexible. My current plan is to make a mold as I have done in the past to form a carbon fiber positive. This will allow great strength, heat resistance, and flexibility to remove the plastic off the positive. I broke one of my plaster noses this past week when attempting to remove the plastic . This was its first time on the vacuum former and luckily the result was good so I can use that plastic copy to make the carbon version.

By technical definition open wheel must have 100% of the wheel/tire visible from the top view and side view.

 

[LibertyMKiii]

I had envisioned something like this for the aerodynamic version of the nose when I began the process. After working with the plastic a bit, I have learned that I'll have to add some body lines to be rigid enough. Curves like this work well in composites for strength, but not plastic.

 

[SrC]

I have never formed PC but I see some guys use an oven. How thick are your PC sheets?
Thanx for the open/closed wheel explanation. I always figured there was a spec.
The nose piece is key. Side spats strategically located might reduce side turbulance and increase topside down force if its not interrupted with the wheels.
Have you considered running in the dirty wet with a basic stock design rig to develope dirt/air channeling marks on the body for reference where to clean up air flow. It becomes a visual guide to show aero, much like a wind tunnel. You would need an expendable cheap rig for running in the wet. with a stock Lim body. I watched how F1 cars that run on wet surfaces reveal wind tracing across its body. A matte/flat black matte body might enhance the visual effects.
Do you feel Dish wheels are much better than spoked for ground effects. Spoked wheels can release negative underbody pressure and cause more side turbulance.?

 

[LibertyMKiii]

I have never formed PC but I see some guys use an oven. How thick are your PC sheets?
Thanx for the open/closed wheel explanation. I always figured there was a spec.
The nose piece is key. Side spats strategically located might reduce side turbulance and increase topside down force if its not interrupted with the wheels.
Have you considered running in the dirty wet with a basic stock design rig to develope dirt/air channeling marks on the body for reference where to clean up air flow. It becomes a visual guide to show aero, much like a wind tunnel. You would need an expendable cheap rig for running in the wet. with a stock Lim body. I watched how F1 cars that run on wet surfaces reveal wind tracing across its body. A matte/flat black matte body might enhance the visual effects.
Do you feel Dish wheels are much better than spoked for ground effects. Spoked wheels can release negative underbody pressure and cause more side turbulance.?

The sheets I have right now are 1mm and my heater is effectively getting them up around 220-250 F
The oven is an option, but I'd have to move the entire setup into the Kitchen and this hobby already has me on thin ice with the wife ?

I certainly don't have the budget for an throw away rig to run through dirt and water LOL
For air tracing I figure I could go with the string/yarn method and a GoPro to see where airflow is laminar, and also reveals turbulent airflow areas.

The best source of truth for land speed is the Bonneville cars. Most wheels like F1, which are spoked is related to brake cooling. Mercedes had some interesting engineering around heat transfer from the brake/wheel hub into the wheel that was causing issues with the tires blowing up. After modifying the airflow and increasing the cooling the tire problem went away. For RC land speed where electric motors do the braking, the flat face wheel without spokes do have some advantages. Nearly all Bonneville cars run "moon disks" or non spoked wheels.

CFD can be used, but I have not figured out how to make a rolling road under the car in Autodesk CFD.

 

[SrC]

Have you considered smoke trail with the wind method and a High speed video slowed down to capture laminar trails?

 

[LibertyMKiii]

Have you considered smoke trail with the wind method and a High speed video slowed down to capture laminar trails?

If I ever get around to building a wind tunnel that was the plan in addition to the scales taking measurements.

 

[jondilly1974]

I had envisioned something like this for the aerodynamic version of the nose when I began the process. After working with the plastic a bit, I have learned that I'll have to add some body lines to be rigid enough. Curves like this work well in composites for strength, but not plastic.

View attachment 111768

Couldn’t you just line it with drywall tape and shoe goo? Or make two and glue them together?

 

[LibertyMKiii]

Couldn’t you just line it with drywall tape and shoe goo? Or make two and glue them together?

Absolutely, but if it were just for my personal use I would probably make it out of carbon and be done with it. In this case for selling.... top concerns after lessons learned playing with composites is material costs. If I can make it strong enough with lower cost materials that would be a win win. Hopefully this is not one of those "you only get to pick 2" scenarios:
-Low cost
-High strength
-Low weight

In addition to those my other criteria is:
-Small size easy for shipping
-Low hours to produce final product
-Product people would want

Thicker plastics would likely get me further into the heater getting the plastic hot enough scenario.

 

[Luigibell78]

So cool. Good job

 

[JoshHefnerX]

Are you using vacuum in your plastic forming?

 

[LibertyMKiii]

Are you using vacuum in your plastic forming?

Yes sir!

Cannot really see it but there is a vacuum port on the right side of this box.
I also have a large vacuum table that I may use for making full bodies at some point. This small vacuum box seems to work good for making my version of the Limitless noses.