Interesting read

[Mitch Wright]

https://www.linkedin.com/pulse/how-d...rk-willem-toet

[Pearldrummer7]

Very interesting read on diffusers. I'd love to try to recreate those under-body flow diagrams for our cars at different heights and with different defusers

[skullandbones]

I found that interesting too. Funny about the comment below the article about diffuser efficiency in a "yaw" state. I would think a driver of a formula car would be interested in survival if their car isn't running a pretty straight line. Though theoretically interesting, drivers would consider that a real "oh sh**" moment.

Thanks,

WEK.

[Duke]

Another great link/read for aerodynamic information:

http://www.lateral-g.net/forums/showthread.php4?t=48400

[Santiago]

Very nice read - thanks Mitch for sharing it.

One thing that always throws up a caution flag for me though is that for many folks at our level, we just need to get some basics down first before delving into the much more advanced analysis and techniques.

To me, regarding diffusers, that means thinking seriously about:

1. How and where you transition from the forward floor to the angled part(s) of the diffuser itself - the "how" should be unbroken planes (which means no gaps, holes, etc.), and the "where" should be based on where you want the lowest area of pressure to sit (i.o.w. it's a strategic design decision)

2. Using fences to line the diffuser its full length (front to rear)

3. Using the entire width of the available space between tires (or control arms)

The FFR supplied piece makes most of this a challenge. The 818 chassis itself with the way the engine sits makes some of it difficult. With the right exhaust you should be able to see a main angle of 7-9 deg without interference, but if you're committed to a particular exhaust, you may be tempted to cut a hole near the leading edge of the diffuser (which is so-not-a-good-idea). Also, nothing says a diffuser has to have a only one angle; they can have multiple floor-segments each with their own angles and even continuously variable ones (i.e. curved upwards). As the article shows, all of these are going to give the diffuser different performance characteristics. I'm just really surprised at how much wider the performance envelope is for the higher angle diffusers. The low-angle ones are so much more peaky! That's really intriguing, esp. since most every 818 is going to have a fairly high ride height ("high" being relative to the world of ground-effect cars).

Anyway, once you get the basics squared away with a solid design, you can start fine tuning it...start figuring out ways to feed it. =)

Best,
-j

[Santiago]

My favorite quote from the comments to the article:

"As Aeros, particularly when working in F1, we will spread bull**** to people so that they are misled because the other teams are listening."

Makes you get real cautions when it comes to seeing stuff on the web...
I am glad to see him promote Katz's book a few times - really good read.

[Pearldrummer7]

Duke- I read the link you posted. It sounds like pretty good stuff to me. Lot to learn here! This quote sticks out to me

"Deck lid surface lower than fenders or concave shape."

Our deck lids seem slightly convex to me. And certainly no lower than the fenders. I have a lot of space under the deck lid, too. I wonder if a concave deck lid would be worth considering