Wheel Fenders, Fairings, Skirts, Covers

[NSTG8R]

The explanation at the time the P4 was revealed is that it improved the aerodynamics of the wind flow pattern over the entire vehicle. They actually had some visuals to demonstrate it but it has been so long I don't remember where they are. It might help you look, if you are interested, if you know the P4 was unveiled in January. Z

Now that you mention it Z, I do remember seeing some top-view drawings of various shapes somewhere on one of the Elio sites, but I still can't see how they're getting a laminar flow with a squared off rear...in my mind, tear drop/airfoil shape would be the best. That's why I queried Snick about the venting (I'm assuming that's what he was talking about) the rear fairing, reducing the low pressure (suction if you will) back there.

 

[goofyone]

Now that you mention it Z, I do remember seeing some top-view drawings of various shapes somewhere on one of the Elio sites, but I still can't see how they're getting a laminar flow with a squared off rear...in my mind, tear drop/airfoil shape would be the best. That's why I queried Snick about the venting (I'm assuming that's what he was talking about) the rear fairing, reducing the low pressure (suction if you will) back there.

While the realities of fluid dynamics dictate that a teardrop shape is the ideal aerodynamic form, Kamm found that by cutting off / flattening the streamlined end of the tear at an intermediate point, and bringing that edge down towards the ground, he could gain most of the benefit of the teardrop shape without incurring such a large material, structural, and size problem. The airflow, once given the suggestion of the beginning of a turbulence-eliminating streamlined teardrop tail, tended to flow in an approximation of that manner regardless of the fact that the entire tail was not there. This is called the Kamm effect.

http://en.wikipedia.org/wiki/Kammback

 

[zelio]

Is there any question why I love this place? LOL Ask and the answer appears - usually in a fairly short time and usually with a smile. Z

 

[ehwatt]

Absolutely huge hp to weight ratio Snick. And as for the post before that, are you referring to something like vents in the rear wheel fairing that exit out the back? Really not sure myself why the P4's rear was squared off...I'm sure they had their reasons.

The rear is squared off for the Kamm (back) deal. Take a long taper that is so slippery, then chop it off cleanly with a meat clever right behind the trunk and the airstream doesn't seem to notice that so much surface is missing, well, not for the most part.

 

[NSTG8R]

Thank you Goofyone and ehwatt! Saved me some Googling. I suppose the tear drop shape would look kind of goofy (no offense Goofyone! ), and pretty tough to mount tail lights on without them being out in the airstream. Doubt it's going to stop me from experimenting with a vented rear though (not to mention the hood). If it has little, or no affect, it still might be cool looking!

 

[Chaz]

To me it looks like a Kammtail or Kammback . Which acts just like a airfoil without the need of a true trailing edge. Cycling is using this becuase it's governing body has a rule that a 3:1 length to width ratio of all tubes on the bicycle. So, they have been using this chopped off airfoil shape that improves air flow but still come in under the 3-1 rule.
You can read more about it here

http://en.m.wikipedia.org/wiki/Kammback

 

[JDub]

It affects aero massively. F1 is about brute power and force, not finesse.

It's actually about the rules.

 

[Snick]

Absolutely huge hp to weight ratio Snick. And as for the post before that, are you referring to something like vents in the rear wheel fairing that exit out the back? Really not sure myself why the P4's rear was squared off...I'm sure they had their reasons.

Hi NSTG8R,

My post #358 was in context to the previous fellow's (I quoted him) wheel fairing comment. In my opinion, the roof arch, main body sides, and tail (Kamm back) look "about right". I think a clever person with properly positioned smoke generators and a GoPro camera out on the road at speed could get some pretty good data and idea of how to reduce wheel drag with a more "stylized" baffle. I predict a cottage industry of sorts springing up to give owners more flair. For instance, look over at the lighting thread--some really cool stuff!

 

[evboy]

Why cant the whole car be painted the same color. Is it a cost issue. Seems like a pretty simple thing to do.

 

[wayne kemp]

I think it is like this, Paul calls the shots as it is his product until money has changed hands.