Aeromodability of a VW Bug?

[kach22i]

Originally Posted by Frank Lee

They are positioned correctly in the pics.

Oh gosh Frank, I'm reading all sorts of things into your comment today, somehow you just came off terse sounding, was that your intent?

All I meant, in an off-colored remark sort of way, is that a wing or spoiler may be of more aerodynamic use above the rear window given the cars shape.

I'll post a few examples now for inspiration.

AWESOME ROOF SPOILER FOR BEETLE! - VW Beetle forum - VolkswagenTalk.com



Now of course, you could go a little crazy and cover all your bases, and why not if it's your car?

Volkswagen Beetle Wings / VW Spoiler/Fiberglass Wing Volkswagen

[Frank Lee]

The spoilers above the window are intended to reduce lift at high speed; IIRC they first showed up on a performance variant? If by chance they reduce drag it would only be because of the reduced lift and lift = drag.

The spoilers below the window are intended to reduce drag and lift; the reason these have a better shot at reducing drag being they promote attached flow across the back window.

The main difference between the two is in the size of the trailing wake. The below window spoiler should be leaving a much smaller trailing wake area at the rear of the car than the above window version.

I think running both is counter-productive; logic dictates that you'd want the above described effect of flow across the back window when running a low spoiler which a top spoiler would ruin. But a good test would be the final judge of that.

I'd run a low one because it should have less drag. I'd imagine the reasons for running a top one would be if lift reduction rather than drag reduction is the top priority, or perhaps for equal lift reduction the top one could be much smaller, or ?

[JMPVW73]

http://www.youtube.com/watch?v=mo7L5...layer_embedded

Here is your inline two seat airplane cock pit car. Good luck finding one.


I’ve been kicking this same can around for some time. I generally keep a long list of fantasy projects in my head but a high MPG air-cooled VW keeps getting pushed closer to the front. I should have chimed in on this discussion a long time ago and some others have mentioned what I will say.

Air-Cooled VW’s are very fun cars to hyper-mile with though I’ve never done it religiously and was just as likely to squeal the tires and chirp 2nd and third gear. For many years I coasted the last .75 mile to my house until they put in speed bumps. VW’s will engine off free wheel for great distances and restarting the engine is very smooth. Rebuild your front end as soon as possible. Fresh ball joints and tie rod ends will help you out a lot with this and make driving a pleasure.

If you have the single port engine the ’69 came with keep it. It is well suited for your project. VW engines have notoriously inefficient air fuel delivery and the later dual port is worse in stock form. Single port tuning has long been forgotten so you will need to find old sources for information and search around for parts.

In an earlier post you mentioned wanting a “Freeway Flier” gear. There is a long standing debate about this being good for mileage or bad for your engine and everywhere in between. I would personally stick to “rubber overdrive” and don’t bother with gear changes but do research and make your own mind on that one. Volkswagen Transaxle Gear Ratios!These sites will tell you what you have.

Stay away from a “Power Pulley”. It reduces the parasitic drag of your cooling fan/generator but more importantly it reduces your cooling. Don’t do it!

I want to see you pull off something great with this car. You will be surprised how far you can go with this and retain ability to revert back to stock.

[JMPVW73]

I highly recommend these sites.
The California Look, Classic Volkswagen Beetle, Street and Drag | Cal-Look.com. This is where the biggest names in VW racing and engine building hang out.
VolksrodsHome This is where you will find the most info on body modifications.
TheSamba.com :: Volkswagen Classifieds, photos, shows, forums, and information This site has the biggest parts swap and I’ve always had good experiences. Don’t trust eBay for old used parts; I have been disappointed more often than not.




Now on to the good stuff starting with what you should see first. A 50+MPG Beetle running on two cylinders!





He has the best engine for hyper milling and a lighter car than yours but I think you can still get there. Volkswagen Greats is the best ACVW magazine that ever existed. I have a copy of this issue and several others with similar cars. One day I will dig them out and make some high quality scans for the forum.

I would suggest lowering the car in addition to or rather than use such a tall faring. I can help you with FREE suspension modifications that will lower the front 3-4in. and rear 1-2in. The front rake generates downforce and lower CoG makes a dramatic improvement to stability at interstate speeds. I don’t know what the change in Cd is but I won’t drive a Beetle that is not set up this way.

Any thing more will require a different method or become counter productive using the same. It will also involve fabrication and/or purchase of parts. The low car in the pp video has severe negative camber and toe-in in the rear but it was done that way because they think it is cool. Doing so increases rolling resistance and eats up tires quickly.

[JMPVW73]

The next step as already mentioned could be reducing the drag created by the fenders and sharp angle flat wind shield. Best displayed in this photo. The car to the far right will be mentioned later.



History Dick Beith's 50th Anniversary Return to Bonneville - THE H.A.M.B. Build photos of car.

I like this idea of minimizing the fenders. A narrowed front beam is a common modification and easy to do. The salt flat car is narrowed in excess of 12”. 2-4” is what most people use for traditional cars. The 6-8” narrowed usually lack shock towers and are used by the extreme lowering or drag racing crowd. All are available for a price or if you have the skill you can do this yourself. The rear is a good bit harder and more expensive to narrow but it has been done up to 6”.

You could also remove the front fenders all together to get the Prowler look you want or all fenders to make a Volksrod.


Low Life vee dub club - Members rides At the bottom of this page is a Prowler type car based off a Super Beetle.

[JMPVW73]

[JMPVW73]

I’m going in the direction of a Formula-Vee car that is a side by side two seater.


History of the formula vee




Formula Vee Brazil: Agosto 2010


Or possibly a wedge type car.

Holden Hurricane Concept Photo Gallery - Autoblog


Both the Sterling and Bradley were wedge shape VW based kit cars also sold in an electric version.
Sterling Sports Cars kit car VW replica
The Bradley GTE - Electric Kit Car History - Kit Car Magazine

[JMPVW73]

[Frank Lee]

WOW, even I (who went through Kirk's program) had never seen the 50/50 mag article before!!! It was seeing the 50/50 at a car show that got me into auto engineering in the first place.

FYI the flat windshield isn't the problem area.

[kach22i]

Originally Posted by JMPVW73

Here is your inline two seat airplane cock pit car. Good luck finding one.

AWESOME!

JMPVW73, very informative posts, a breath of fresh air.

Frank Lee, I'm not going to beat this horse till it's dead. I only ask that you look at the following images and maybe click the link to where the original VW picture is. It takes little imagination and average levels of observation to predict the results of the added horizontal planes, call them wings, spoilers or what ever suits your fancy.

Beetle Aerodynamics / Roofspoiler
Beetle Aerodynamics / Roofspoiler