You're on the right track. Aluminum would be fine, use 5052 16 gauge so it'll be easier to bend.

 

I would prefer some sort of plastic just bolted directly to the side, the plastic will be able to flex when bottoming/high centering and will spring back unlike the aluminum. The stiffness of your plastic will have to be experimented with soft enough to flex without upsetting the car, stiff enough to not flex in due to aero pressure. I'm thinking ballistic nylon might be a good choice since it will be lower wear but you'll need to experiment with the thickness to get the right stiffness.

 

you could try this plastic?

Colored Plastic Rolls, 10 Ft. - Speedway Motors, America's Oldest Speed Shop

 

Yeah that would be the stuff to prototype with. Its polyethylene IIRC, super cheap and also awesome for air dams and ducting. I think that its going to be in the stiffness range you want.

 

I use it for my air dam. works pretty good. im sure theres better stuff out there but it suites my needs.

 

I use Circle Track wear strip material, its pretty much just thin abs plastic. Its very durable I daily drive with it on the front scraping things everywhere and its still all together in one peice. Im working on sideskirts myself with the same material, using alumalite extensions with the abs seal.

 

I've seen them done on a very hard-core 911 out of sheet aluminium much like you are thinking, but with fasteners (Duz?) to allow realtively easy removal to access the jacking points.

Thomas

 

My original thoughts included dzus tabs 90 degrees to the rockers for fastening. They need to be removable for me to be able to get it on and off the trailer at a minimum.

 

I'd rather run quick latches on them. The skirts are going to be consumables that you replace and its easier to swap the quick latch buttons to the new skirt than the dzus. BUT if you tear a skirt completely off and dont recover it, you're out $25 x however many quick latches you put on it, vs $5 x however many dzus fasteners. Though, in theory you should still be able to drive onto the trailer with these because they should flex.

 

That's if you use the spring loaded dzus heads, rather than the unsprung button head type. With the latter, you only need to drill a hole.

 

Rear wheel spats. Are they worth a drag reduction over bare tire?
I made these out of clear lexan, so they are incredibly hard to get pictures of. My phone couldn't focus on them, so please excuse the blur and glare.

 

I would think that you want the rear open to help air flow out of the wheel well.. and you want something to deflect air around the front of the tire.

In my opinion all that is doing is acting as rock/mud guards to protect your paint and disturbing airflow behind it so the air down the side of your car is more turbulent and unattached

 

I think they are in front of the wheels and not behind.

 

yeah my bad, I just glanced at it and thought that it was the front fender with the blue door being aft

 

I would put them in front of the tires and try to ease the air flow to the side of the car. The tire is the worst when it comes to aerodynamics, so trying to get the air flow to go around them as much as possible.

 

I just noticed, after going back to page 1 and looking over some of the old stuff, that we've completely lost the structure Emilio originally intended for posts.

 

That's why I started Aerodynamic Discussion to keep his design of good info going. Aerodynamic Discussion was to talk about anything aero from Miata's to Formula's to Tractor Trailers.

 

Keeping to a format makes the thread more compact and easier to search. Unless I patrol it, these threads derail pretty quickly.

1993ka24det's separate discussion thread works but now we have two threads discussing the same topic. It would take a mod a few hours to clean up, move posts, splice, merge or whatever.

 

Borderline in terms of "aero" but it deals with airflow so I'll throw it in to get the thread back on it's original format/focus:

Dollars spent: $0 at time of construction (used materials laying around)
Hours spent: 5
How effective: Will find out this weekend
*update*: worked great, brakes performed great and never overheated
Materials used: Aluminum sheet, 2" aluminum intercooler piping, rivets
Tracks tested on: Going to Spring Mountain Motorsport Ranch this weekend
Race/TT class built for: Miata Challenge & Super Miata

I wanted to get the brakes ducted before the next event, but not enough time to order ducting for the airdam and get it here in time...

Originally thought of making these out of a composite but then discovered that I was out of resin. So looks like I'm making it out of aluminum! Scrounged around, found a sheet of a thickness I liked for this, and also some spare 2" intercooler piping. That'll do.

Got a concept worked up in my head, made a template out of construction paper:



Transfer to aluminum, then get to cuttin':



Next, brush up on my origami:



After a riveting time with the rivet gun:



Trimmed the front of them to the same contour as the airdam and then riveted to the sides of the radiator ducting:



It would have been easier/faster to make these attach to the airdam, but the whole point of all the dzus fasteners on the airdam is for it to be able to be pulled off in 10 seconds to check/repair stuff. This way, the airdam still comes off like usual - the whole brake ducting system is fixed behind it:



Cut el airdamo, and voila!:

 

I'm slightly confused by the cutouts on the bumper skin.
Why are they smaller than the ducts?

Moti