Rear wing downforce comparison sheet

[Lennart]

Yes, Simscale does a CFD simulation of any 3d model you want. But you should follow the CFD tutorial on their website, otherwise you won't figure out how to start a simulation.
-You can simulate rotating wheels
-Measure the aero on the whole car
-Additionally measure the rear wing on its own and other parts
-The free version has 10 simulations
But I am sure Simscale is not the only free CFD program out there.

Before I found out about the CFD stuff I made some aero parts for my senton 2wd which used to just take off over 80kmh.
I think my last part was a front suspension mounted wing which completely held the car on the ground, even over bumps. And it weighted just 22grams so it was not the ballast but the aero doing the work.

Playing around in the virtual wind tunnel helps you get a better understanding of aero. You wont be able to predict the airflow but you will get a better idea of what parts might work or what's "just for the looks".

Your car look quite brutal, nice.

 

[LibertyMKiii]

I'm curious as to whether or not the program you are using only measures the aerodynamics of wings or can it be applied to a car?
Back when I first took to speed running I always said it was my goal to get my build to go as fast as possible with its proper body. And we all know that the Senton body has aerodynamics that match a brick. Yet when I stuck the Limitless front end on it, I saw potential with another idea. One I will try this year. Was trying to keep it under wraps as I may even try to go for a ROTM with it when I do a new body. But I VERY curious if what I did will actually beat my stock body PB of 104mph. Except the build changed so much that I'm pretty much guaranteed to top it now regardless of this addition simply because I have a better esc and motor, along with other tweaks done.
Man, I used to have alot pride that I had alot of practical knowledge as opposed to the "useless computer crap". And lately with stuff like the program you're using and CNC, just to name two, has me lacking and wanting...Weird how that turned out.View attachment 355796View attachment 355797View attachment 355798

One of the interesting things about aerodynamics is that you are pushing the air around the car. The push has a direct relationship with loads on the car depending how and where you direct the air.

The question I have for you would be do you want more front downforce? If so the current wedge type idea you are showing will be great.
The alternative option would be to make the air directed towards the side of the truck instead of over top by adding some curve to the front end.

Example here with some poorly drawn red tracers

This is a flow simulation of my 200+ build. As you can see everything was streamlined for low drag.

 

[Greengaunja]

One of the interesting things about aerodynamics is that you are pushing the air around the car. The push has a direct relationship with loads on the car depending how and where you direct the air.

The question I have for you would be do you want more front downforce? If so the current wedge type idea you are showing will be great.
The alternative option would be to make the air directed towards the side of the truck instead of over top by adding some curve to the front end.

Example here with some poorly drawn red tracers
View attachment 355804


This is a flow simulation of my 200+ build. As you can see everything was streamlined for low drag.
View attachment 355805
View attachment 355806

Not too concerned about front end downforce as keeping the front down I figured out with the first build,using gearing and differential fluids(slow acceleration and distribute power between rear and front better). What I was attempting to do was eliminate the drag created by the front end.
Like I do know there is zero aerodynamic gain with that body. It's more a throwback to how I got into speedrunning after some posts by K-BASH and his Senton 8s. Not ready to call it a day on that yet.
There is little doubt that this, combined with the Scorched wheel wells, creates a ton of drag slowing the truck down.

Yes, Simscale does a CFD simulation of any 3d model you want. But you should follow the CFD tutorial on their website, otherwise you won't figure out how to start a simulation.
-You can simulate rotating wheels
-Measure the aero on the whole car
-Additionally measure the rear wing on its own and other parts
-The free version has 10 simulations
But I am sure Simscale is not the only free CFD program out there.

I may need to try and task my son with this. For incentives, of course lol. Seriously, I once brought my laptop back for refund because there wasn't an off/on switch or button only to feel like a fool after being shown the "sensor switch".

 

[LibertyMKiii]

Not too concerned about front end downforce as keeping the front down I figured out with the first build,using gearing and differential fluids(slow acceleration and distribute power between rear and front better). What I was attempting to do was eliminate the drag created by the front end.
Like I do know there is zero aerodynamic gain with that body. It's more a throwback to how I got into speedrunning after some posts by K-BASH and his Senton 8s. Not ready to call it a day on that yet.

Agreed, often you try to design for multiple bennefits. You can certainly help keep the front end down by using the air. At the same time you can reduce drag with a good design.

You may want to look at the delta plastiks thunder truck for some design ideas. It has the more rounded front I mentioned. James McCoy took that truck body to 170 mph. Fastest RC truck that I am aware of.

 

[bigbristv]

I'm in the middle of a very scientific* project involving a front splitter, rear winglets and such. So far I have seen a steady gain of 1mph with 82.3mph being top speed at this point.

Circumstances:
1st run, no splitter, winglets- 77.1mph
2nd run, no splitter, winglets- 81.1mph
1st run, with splitter & winglets- 78.2mph
2nd run, with splitter & winglets- 82.3mph

Clearly gained about 1mph with added aero.



*extremely ghetto

 

[dure16]

Circumstances:
1st run, no splitter, winglets- 77.1mph
2nd run, no splitter, winglets- 81.1mph
1st run, with splitter & winglets- 78.2mph
2nd run, with splitter & winglets- 82.3mph

I wonder why your second runs are faster? Were they traveling the same direction as your first runs?

 

[bigbristv]

I wonder why your second runs are faster? Were they traveling the same direction as your first runs?

I believe it's due to warming up of the battery.