Limitless Limitless front splitter leveling

[joshjosh]

Hello fellow RCholics! I have this buried in my build thread, but I thought it worthy of sharing. I pre-ordered my Limitless, and I got it at release. Shortly after I had a daughter, so I didn’t get much time to play, so I’ve only driven it twice so far. I did a lot of studying aerodynamics to design my 3D parts during this time though. At some point Arrma changed the front bumper to have a more downward angle. Attached is a picture of the two bumpers. On the right is my original bumper, and in the left is the new style. If you zoom in you can clearly see the angle change.

However, even with this change the front splitter has an upward angle. This is in part due to the design of the chassis. I was able to place 4mm of spacers and achieve an almost level splitter angle. If I give myself a little bit of rake I should be able achieve a level splitter angle, and possibly even achieve an aerodynamically desirable downward angle.

I’ve seen posts on here about Limitless doing backflips (like this One), and also people not able to run without the front aero wings. This is due to the upward angle of the front splitter generating lift. Even if the splitter is level when you are sitting still, the front end lifts and the rear squats during acceleration, which would still cause the splitter to have an upward angle. Here’s a good Video that explains why you really want to achieve a downward angle with your splitter. I’ve also attached a picture of the splitter angle when the chassis is level with 4mm of spacing added.

On the right is the original, on the left is the new design.

With the 4mm of spacing added, you can see the front splitter only has a slight upward angle when the chassis is level.

 

[parcou]

Thx for the post

I never thought much about the splitter, but I am bashing no speed runs for me. But I do compensate for the rear squat with the chassis racked lower in the front and changed to next level-up stiffer springs and shock coil adjustments. I also reduced the body post so the tires sit closer to the chassis with the least about of fender space without rubbing.

Me, I hated to see the front lifting higher than the rear....so now on take-off and hard bashes it rides level under power without the nose in the air.

Sure speed runners have to be a bit more dialed than me because I am over the top for bash'in but it looks better running with my setup.

 

[joshjosh]

Thx for the post

I never thought much about the splitter, but I am bashing no speed runs for me. But I do compensate for the rear squat with the chassis racked lower in the front and changed to next level-up stiffer springs and shock coil adjustments. I also reduced the body post so the tires sit closer to the chassis with the least about of fender space without rubbing.

Me, I hated to see the front lifting higher than the rear....so now on take-off and hard bashes it rides level under power without the nose in the air.

Sure speed runners have to be a bit more dialed than me because I am over the top for bash'in but it looks better running with my setup.

Thanks for the response! It sounds like you’ve done a great job at dialing your vehicle in.

My main goal is also bashing, so my goal is to have the front splitter sit level. That way the front splitter doesn’t get tore up catching on the ground or debris. As you mentioned, speed runners would need to pay closer attention this than us.

One thing I really enjoy are the ScorchedRC titanium splitter screws. They act as a buffer to keep the splitter from hitting the ground, and shoot out marvelous sparks when they hit!

I’ve seen a lot of speed runners rely on rake to get the front splitter at the correct angle, but this has many drawbacks. First it raises the center of gravity in the rear, which can affect the way the car reacts to slight steering adjustments at high speeds. Secondly, it can create a Venturi effect, where the air has high pressure at the front, moving very quickly, but then slows down once it reaches the low pressure zone presented by the large rake. Lastly, with a large amount of rake the body becomes a large source of downforce. This downforce is hard to control and predict, which leads to more downforce than intended when trying for higher speeds.

With this mod you can control the downforce predictably with the front and rear wings, because the chassis will be close to level. Also allowing for the front and rear to have a similar center of gravity, making turns better and more predictable.