back home...
well, the best for me, even for a daily is to get a flat bottom for the pan. this would extend forward under the head (1303 talking) and expand toward the sides of the car, leaving exposed the wheel wells and the control arm mounts on the head. at the back it should stop at the torsion bar housing, leaving the rear exposed.

the even more extreme solution would be to conseal the tranny as well (bottom) and sides, trying to form two wells for the rear wheels. In order to cool the tranny, i would use naca ducts starting at the torsion housing and blowing through two eclipses at the sides of the tranny box towards the axle mounts.although there will be a need for a means of cooling the bottom and getting access to the drain plug and fill plug of the tranny.

That's where differencies start, depending on rear tire size, offset and engine/exhaust configuration, the size of the rear wheel wells will have to vary for the rest of items to fit.

best would be to fabricate a diffuser at the back, keeping the tire and part of the suspension to the outside of each side of the car, tranny in the middle, but narrowing both diffuser paths (extending away from the centreline) for the engine/exhaust combo to fit.

Depending on the angle of the diffuser the fender/rear apron/fender combo will have to be chopped in order to for a bit of a proper profile for the 2 diffuser paths.

This only some idea, based on physics, NOT calculations. it also provides a means of "hiding" all enhancements from others, and not increasing drag the biggest aero prob of the bug imo is the rear, where we got an engine aft of a huge well ( where the tranny sits) and two wings that perform in a "parachute way" for the car

In the end it comes to the owner to decide which way and how far to go...

Chris

Just wanted to add this link for searches:

Bug Aerodynamics

Jason

Thanx Jason for posting the link here!

I made my own Roof Spoiler that's attached to the rear window rubber:
http://www.gerrelt.nl/roofspoiler/beta1.jpg

http://www.gerrelt.nl/roofspoiler/beta2.jpg

http://www.gerrelt.nl/roofspoiler/beta3.jpg

See this article on how I made it: Creating a Roof Spoiler.

That turned out great, that was my first choice as it is very subtle. I decided to go with the roof spoiler however because I fear that by that far back on a bug the lift is already quite considerable, the roof spoiler breaks up the laminar flow about 8 inches more toward the front.

How did you come up with the angle of the lip?

Jason

Thanks, Jason,

A guy who was into gliding (airplanes without engine), told me that everything above 12 degrees becomes an obstruction, while 12 degrees and lower is a deflector.

I don't know if it also applies to cars, but it turned out to be a nice angle.

Regarding roofspoiler placement:
I think a small roofspoiler further up front equals a bigger spoiler further back.
But it also depends on the speed you drive, the faster you go, the bigger the spoiler must be.
But I am no aerodynamics engineer... :)

Greetings,
Gerrelt.

Nice rear spoiler Gerrelt.
I also had the same idea as Gerrelt, but never finished it. It was slightly bigger with the same mounting concept.
http://i24.photobucket.com/albums/c4...2.jpg~original

Thanx Oldskool1303!

Yours would have been great too. It's got a more race-track look, more extreme.

If you could incorporate a third brake light would be something!

Yes! I thought about that, that would be excellent.

But.. I haven't found a nice way to get a wire to the inside of the car...
Maybe it could be led through the window rubber, but I don't really like that.
And drilling the glass is probably a big no-no... :cool:

Any ideas?

I really like this, it would probably work pretty well, especially for how unobtrusively mounted it is. It makes a lot of sense to me not to bolt through unless you have to.

Jason

nice... can we get some close up shots of it PLEASE... :)

Chris.

Gerrelt,

I too like your very discreet spoiler. Well done! One question - how did you fix it in position? Is it just held under the window rubber with some sticky pads on the end sections? My query there would be if there was any water ingress around the rubber as it will be stretched wider and the spoiler is not quite so smooth as the glass?

You have got to market this idea.

Clive

Hi Clive,

Thanx!

I've put some tape on the sides of the spoiler, on the inside. I didn't want to loose the spoiler after all that work. :lmao:
But it's held on pretty good by the window rubber alone. But, for assurance, a piece of tape or some sealant on the inside would be best.

I've been driving with the spoiler since June last year. I have driven through the rain, and I haven't seen a leak. The window is still resting on the rubber, making a good seal.

I have almost finished a mold. With this mold I plan to make more of these spoilers. Do you want me to inform you when they come available?

Greetings,
Gerrelt.

Hi Gerrelt,

It sounds as though its well proven then.
Please let me know when they become available either here or on my e-mail address - clive.williams@bwdltd.com

Many thanks:cheers:

Clive

Hi

I was driving my sons 1303 on a freeway today and I was thinking of this subject, is that weird?

Anyway I wondered what the affect would be on the "Parachute" area when you run a non air cooled motor, Subaru etc which has no sealing around the engine to body area, the otherwise trapped air would be able to escape through vents in the engine lid or the under rear window vents.

Steve