Limitless Project Downforce for VTe2 and Limitless

[Lennart]

I have not found many downforce builds here, so I will post my vte2 build on which I aim for over 5kg downforce @120kmh with less than 6kg of weight. For now, I have only done some simulations and just finished the rear wing. Let's see if downforce is worth it....

Also in the last driving session my 1717 1650kv reached 49k rpm, does that mean my kevlar wrap is ok? Or at what rpms do they explode if they are faulty?

If you have some downforce-related projects feel free to post them here.

I guess from my CFDs that this wing will create 2-3kg downforce @120kmh. Now the front wing is missing.

Some time ago I made a limitless model with maximum flaps (only from photos so inaccurate). Results: 1.63kg Downforce and 1.98kg drag @120kmh. Lift Efficiency of only 0.83 so I will try and do better than that.

 

[Dan B.]

Cool project! What kind of software are you using? Looks like a virtual wind tunnel!

 

[Tex Koder]

Very nice!
I've sub'd to see More of this

What filament are you printing your wing with?
And, is that OpenFOAM program?

This is a project Mr @LibertyMKiii would be interested in ,I'm sure.

 

[rotauq]

My main question is, do you really want that much downforce?

Also in the last driving session my 1717 1650kv reached 49k rpm, does that mean my kevlar wrap is ok? Or at what rpms do they explode if they are faulty?

The 1717 can deal with 56k based on specs. A few short runs above will likely not harm the motor either. Non chinese companies mostly are cautious with their specs and could potentially take a lot more abuse.

 

[LibertyMKiii]

I have not found many downforce builds here, so I will post my vte2 build on which I aim for over 5kg downforce @120kmh with less than 6kg of weight. For now, I have only done some simulations and just finished the rear wing. Let's see if downforce is worth it....

Also in the last driving session my 1717 1650kv reached 49k rpm, does that mean my kevlar wrap is ok? Or at what rpms do they explode if they are faulty?

If you have some downforce-related projects feel free to post them here.

View attachment 257834

I guess from my CFDs that this wing will create 2-3kg downforce @120kmh. Now the front wing is missing.
View attachment 257835
Some time ago I made a limitless model with maximum flaps (only from photos so inaccurate). Results: 1.63kg Downforce and 1.98kg drag @120kmh. Lift Efficiency of only 0.83 so I will try and do better than that.

I love what you are doing here. Swan necks are more efficient, but only if they are strong enough.

My main concern would be that if the swan neck flexes, then your wing AOA will be off and creating lift instead. I think for small scale like our RCs you will likely need to make the wing held up by the end plates.

This was one I made for a guy in FL.
3D printed core with twill carbon fiber skin.

I had designed a F1-style nose for the Limitless bu never actually made one.

I had sculpted a new nose that would direct air around the tires and shock tower better.

My latest project "Aero Max" has wings for the A-arms

 

[Tex Koder]

I love what you are doing here. Swan necks are more efficient, but only if they are strong enough.

My main concern would be that if the swan neck flexes, then your wing AOA will be off and creating lift instead. I think for small scale like our RCs you will likely need to make the wing held up by the end plates.

This was one I made for a guy in FL.
3D printed core with twill carbon fiber skin.

View attachment 257851

View attachment 257852

I had designed a F1-style nose for the Limitless bu never actually made one.
View attachment 257853

I had sculpted a new nose that would direct air around the tires and shock tower better.
View attachment 257854

My latest project "Aero Max" has wings for the A-arms

View attachment 257855

Liberty.
I don't believe I've ever seen those other wing & F1 nose designs of yours!
What else are you hiding

 

[LibertyMKiii]

Liberty.
I don't believe I've ever seen those other wing & F1 nose designs of yours!
What else are you hiding

Lots of things
Most are old projects that I abandoned to chase something new a shiny.

 

[Lennart]

Dang some nice feedback
I try to answer chronologically.

I use Fusion 360 for CAD models and Simscale for CFD. For now, I can use them for free. But Simscale lately introduced a maximum of 10 simulations, so I will have to look into a different program at some point.

I print with petg, which has a little flex and is not as brittle as PLA. BTW my battery "trays" are printed with tpu, which is fine for normal driving, probably only until I crash .

For the project I first want as much downforce as possible so that it becomes noticeable at lower speeds. Don't want to send the car into a corner at 200kmh.

The 1717 kevlar wrap just got me worried.... In case it fails, is it covered by the castle warranty?

The wing changed the angle of attack by 0.5 degrees when I put 4kg weights on top (middle of the wing). I actually did a cfd run with those two airfoils and a -5 degree aoa. According to cfd it had like 70% of the regular downforce and only like 60% of the drag. Cant remember the exact values but it actually got more efficient, which I did not understand. I actually planned to do a flexi wing for less drag at higher speeds, but it flexes less than I expected. How far the sides will flex downwards or if the whole wing gets obliterated can only be shown in the next drive. The wing including the 17 screws weights 121grams.

And the wing is 3 way adjustable with -3° 0° and 3°. And despite a lot of sanding the surface is pretty rough, so I will cover it with smooth tape.

Making something out of carbon fiber like Diem Turner or Liberty ...is beyond my skillset and toolset at the moment.
And I went through all the bigger build and project posts on this forum which really motivated me.
Now I have written way too much.....................................................................

 

[rotauq]

Making something out of carbon fiber like Diem Turner or Liberty ...is beyond my skillset and toolset at the moment.

You know how to draw and print, i'd say get yourself a forged carbon starters kit:
https://www.arrmaforum.com/threads/forged-carbon-parts.46733/

 

[Diem Turner]

Dang some nice feedback
I try to answer chronologically.

I use Fusion 360 for CAD models and Simscale for CFD. For now, I can use them for free. But Simscale lately introduced a maximum of 10 simulations, so I will have to look into a different program at some point.

I print with petg, which has a little flex and is not as brittle as PLA. BTW my battery "trays" are printed with tpu, which is fine for normal driving, probably only until I crash .

For the project I first want as much downforce as possible so that it becomes noticeable at lower speeds. Don't want to send the car into a corner at 200kmh.

The 1717 kevlar wrap just got me worried.... In case it fails, is it covered by the castle warranty?

The wing changed the angle of attack by 0.5 degrees when I put 4kg weights on top (middle of the wing). I actually did a cfd run with those two airfoils and a -5 degree aoa. According to cfd it had like 70% of the regular downforce and only like 60% of the drag. Cant remember the exact values but it actually got more efficient, which I did not understand. I actually planned to do a flexi wing for less drag at higher speeds, but it flexes less than I expected. How far the sides will flex downwards or if the whole wing gets obliterated can only be shown in the next drive. The wing including the 17 screws weights 121grams.

And the wing is 3 way adjustable with -3° 0° and 3°. And despite a lot of sanding the surface is pretty rough, so I will cover it with smooth tape.View attachment 257878

Making something out of carbon fiber like Diem Turner or Liberty ...is beyond my skillset and toolset at the moment.
And I went through all the bigger build and project posts on this forum which really motivated me.
Now I have written way too much.....................................................................

The wing I made is nothing complicated. I just took some Styrofoam sheet and cut some spars in the same shape and glued them to the top plate. Then I took some 0.2mm carbon fiber sheet and glued it to the spars. It's a really simple construction. The aluminum frame took a little time to get the leading edge hammered out and some filing to make it all interconnect, but it was just a matter of taking the time to make everything fit right. I just freestyled it. I didn't make any plans or templates. I just got the material and started working. I did make an initial mockup out of cardboard just as a proof of concept, but it was basically just made using intuition.

 

[Diem Turner]

Hey look! I found a video of my cardboard mockup. I took a screencap.

 

[Tex Koder]

Hey look! I found a video of my cardboard mockup. I took a screencap.
View attachment 257891

I am seriously going to KopyKat your design for one of my projects!!

 

[Diem Turner]

I am seriously going to KopyKat your design for one of my projects!!

Coming from you, that's about as high as praise gets in my book. Thank you and I look forward to seeing what you're working on

If you have any questions or want any measurements or anything else, PM me. I'll be happy to provide any information I can. But judging by what all else you construct, I'm sure you got this.

 

[Tex Koder]

Coming from you, that's about as high as praise gets in my book. Thank you and I look forward to seeing what you're working on

If you have any questions or want any measurements or anything else, PM me. I'll be happy to provide any information I can. But judging by what all else you construct, I'm sure you got this.

I'm just a humble student in all this.. Trying to catch up..
You guys have already brought the ideas/concepts into Reality and Operational.

 

[Diem Turner]

You are humble indeed good sir.

I just fly by the seat of my pants when making stuff. If you've ever watched Mythbusters (who hasn't?), Jamie would make intricate and detailed plans before starting anything. Adam would just peruse the workshop, grab materials off the shelf, just start cutting up stuff and working something out. I work the same way Adam does.

 

[Lennart]

Short simulation update. Aerodynamics is f*****g annoying sometimes. Overall downforce went slightly down because the front wing is not working at all.
Version 2 updates:
-swan neck-mounted rear wing (works better, behind the old mount you can see a pressure increase)
-rear diffuser (does not create much downforce, the middle sections kickup point is too aggressive, blue line)
-wing to keep dirty air from the front shock tower away from the rear wing
-a limitless lookalike bodyshell (maybe this blocks the air and decreases front wing performance big time)

In version 1 the front wing works good, but the rear wing centre section has dirty air from the front shock tower.

In version 2 the front wing is not working good anymore
Here I solved the center section problem. But now the outer section is hit by dirty air from the front wing and front wheel. Maybe the bodyshell pushes
this air upwards to the wing.
In case you wonder: the outer section of the rear diffuser is not blue, because the rear wheel wake and some of the front wheel wake are entering.

From now on I will just build the front wing and diffuser and not waste all my time on Simulations

 

[Diem Turner]

Short simulation update. Aerodynamics is f*****g annoying sometimes. Overall downforce went slightly down because the front wing is not working at all.
Version 2 updates:
-swan neck-mounted rear wing (works better, behind the old mount you can see a pressure increase)
-rear diffuser (does not create much downforce, the middle sections kickup point is too aggressive, blue line)
-wing to keep dirty air from the front shock tower away from the rear wing
-a limitless lookalike bodyshell (maybe this blocks the air and decreases front wing performance big time)
View attachment 258278
In version 1 the front wing works good In version 2 the front wing is not working good anymore
The rear wing center section has dirty air from the front shock tower Here I solved the center section problem. But now the outer section is hit by
dirty air from the front wing and front wheel. Maybe the bodyshell pushes
this air upwards to the wing.
In case you wonder: the outer section of the rear diffuser is not blue
because the rear wheel wake and some of the front wheel wake are entering.

From now on I will just build the front wing and diffuser and not waste all my time on Simulations

Fascinating stuff man. It seems like aerodynamics has some similarities with elementary particle physics or Quantum Electrodynamics. Just when you think you have a handle on what's happening, you try something out and the results are the inversion of what you expected. I admire your ambition

 

[Lennart]

Fascinating stuff man. It seems like aerodynamics has some similarities with elementary particle physics or Quantum Electrodynamics. Just when you think you have a handle on what's happening, you try something out and the results are the inversion of what you expected. I admire your ambition

Yes totally.
I think there is a reason why F1 teams can spend millions on aerodynamics. Optimizing can do much but the time you would have to spend on it is just too much. So I will just live with the extra drag my unoptimized aero is creating .
And between the two versions, I changed too much stuff, so I don't know really what is causing what. Like a completely new car.

 

[Tex Koder]

Yes totally.
I think there is a reason why F1 teams can spend millions on aerodynamics. Optimizing can do much but the time you would have to spend on it is just too much. So I will just live with the extra drag my unoptimized aero is creating .
And between the two versions, I changed too much stuff, so I don't know really what is causing what. Like a completely new car.

That's a whole other Time Consuming thing... trying to Document all the little changes you make to your designs in the attempt to optimize it....

You should see the sheer amount of 3D iterations I have made just for a silly ESC fan adaptor
or front splitters for the 6S...

And, here's showing 1/5 of the Changes/Tweaks to my custom QUAD Fans Mount/Motor Brace (with all the dimensions turned off)

 

[LibertyMKiii]

Yes totally.
I think there is a reason why F1 teams can spend millions on aerodynamics. Optimizing can do much but the time you would have to spend on it is just too much. So I will just live with the extra drag my unoptimized aero is creating .
And between the two versions, I changed too much stuff, so I don't know really what is causing what. Like a completely new car.

Totally agree.
Designing for a certain speed is another challenge also.

I had designed some good shapes for RC bodies, but forgot to consider that in speed runs we get about 8 seconds to go from Zero to insane speeds.