this is the sort of thing i had in mind
http://img.photobucket.com/albums/v2...1.jpg~original
will just have to try and do it all before the season starts.
cheers rob

Try and do something to the place around the transmission. Its a big gap that engulfs much air...In one of my designs im using a fake bottom and very square wheel wells for the back since rear wheels dont turn and their movement is minimal in a yaw manner.

Chris

yep going for a compleate flat floor pan gentaly rising to the rear leading into a defusser.
cheers rob

In a few hours im flying back home so i could get some measurements. I believe that with "gently" you mean from the rear of the floor pan towards the back... otherwise it will be too low -the front clearence-(if it goes from the front to the rear directly)

Also one of my other considerations is: Would the side skirts be more effective if they have a small lip at a 90 degree angle towards the cetreline of the car? this would improve stractural rigidity and make it a bit more difficult for the side skirt to break if it touches the ground in a small radius u turn with high altitude difference...just a thought

Another thing for you jugie and every other racing: in the case that the regulations permit it... Have you thought of putting ribs on the top-outer end of your wings? (like the K3 935) they are supposed to improve the flow over the end of the wing. (like the small lip that goes on top of the rear window, but on the longitudinal plane) it could improve the airflow to the rear fenders...and any air intake around there

Chris

floor will rise from just behind the front axle line to just behind the rear axle line,or as far back as i can before curveing up to the defusser.rise only needs to be a degree or so.
the wing vanes that you refur to i'm trying to confirm if i can run them or not.regs are prety free as long as the work is below the axle line or does not alter the side profile of the car.
cheers rob

in order to get the best of the ground effects i would go with parallel bottom instead of inclined. See both pics to understand what im saying. Also i would go for the same depth for the venturi and the difuser (side view). From what i understood the rules doesnt give you enough space to play with ground effects... :( so i dont know if the venturi would have enough meaning...

Chris

in hill climbing and the class that i'm in i can pretty much do what i want,apart from fans and the wing angels have to be fixed.also have to have a min of 40mm ground clearance. will be a learning curve in what will and wont work on the humble bug but it will be fun trying.
cheers rob

This thread is awesome!! I have an idea for the street. If you do the mods under the car, subtle vents on fenders, slight front chop & a little rake with both front & rear lowering of the suspension. You could have near sports car aero but still look pretty much stock. Just an idea.

I have picked trhe brain of gavin, he's a mate that is an aerodynamic engineer on the currnt F1 Renault team, yes the ones that are winning :D
he reckons the first thing is the flat pan, second is slice the rear of the front wings so you can see the rear of the front tyres. get the car as low and flat as you can. kill the lift on the front with louvers on the wing tops and even ducts on the bonnet, a bit like the elise.

:)

Hey Jimby,

Ask your mate to look at a Ghia and make a couple recommendations as to improving it's aerodynamics.

Thanks

what about front splitter and spoiler?
took my new rear wing to work today to get it painted,came off a f3 lola and is a duel element.
will start work on the flat floor and front spoiler/splitter at the weekend.have all next week of work to get ready for new season/volksworld show :D
cheers rob

Thanks Gavin! I'm really glad to hear that his recommendations are what I've been thinking about doing. Gives me a little bit more confidence that I'll actually get some results for my efforts.

Jason

i only asked him about what we could do for the aircooled cup cars as we cant run a wing. i didnt ask him about a front splitter device. from what ive overheard its not all bad to have a bit of a bigger gap at the front of the car that tapers down as it goes under as the effect is that the air is squeezed and forced under the car as a faster rate than the air moving over the top of the car, and as faster air has alower pressure it sucks the car down. trying to keep all the air from geting under the front of a car will not create a vacuum but will create turbulent air at a higher pressure than the top of the car and would cause lift (hence the flat pan so you dont get turbulent air gathering under the fuel tank, above the geabox, around the engine and under the wings/running boards. i can find out if he's going to the volksworld show and if your car is there ill get him to cast an eye over it.

cheers :D

Judge, are you going to the volksworld show? I am going for sure. It would be nice to gather up and meet each other. I will post this at the "off topic" as well...

Chris

yes i will be at the show all weekend and so will the race car,inside on display :D got all next week of to get it ready.
shall we say 1 o'clock saturday at my car? any body else up for it?
cheers rob

This is, I think, not correct because an earlier formule 1 team had mounted flaps under there cars for (out my head) 1 year and they were much quicker only because of that. And because of the air that speeds up over the top of the car and got down at the back.. sucked the underside of the car vacuum.
At the end of that year it was immideately forbitten.

Wiebrand (p.s. flattening and flaps are also things I want to do in the future to the underside of my car)

I think this thing is over the top, but I like the front dam idea quite a bit. I'm going to be doing something similar with mine, but more subtle.

http://images.thesamba.com/vw/gallery/pix/263217.jpg

You bet im going to be there... :D :D

That just made my day.

You bet im going to be there... :D :D

That just made my day.

very close to what is going on my car next week.
what you have to remember is for a race car "looks" come second place to function.
cheers rob

For a true street German-style car as well, mind you ;)

Erm, help me out here(I'm with stupid!)..., but why/waht are those little amber lights on all the Bugs?

Cheers!

I would guess turnsignals ;)

this is what i fitted today
cheers rob

Nice touch with exhaust exit. :)

An little bit bigger than mine one.
http://www.keversite.nl/fotoalbum/fo...2003181946.jpg

The "foots" for the wing will be machined new, also the sideplates.

WIebrand

In Perú we use for 110 Mph this 2

bumper and in front the windshield (trasnparent)

http://groups.msn.com/vwclubdelperu/starosamayo2005.msnw?action=ShowPhoto&PhotoID=4517

http://groups.msn.com/vwclubdelperu/starosamayo2005.msnw?action=ShowPhoto&PhotoID=4521

http://groups.msn.com/vwclubdelperu/starosamayo2005.msnw?action=ShowPhoto&PhotoID=4522

http://groups.msn.com/vwclubdelperu/starosamayo2005.msnw?action=ShowPhoto&PhotoID=4525

http://groups.msn.com/vwclubdelperu/starosamayo2005.msnw?action=ShowPhoto&PhotoID=4531

CARLOS PALOMINO

This thread has been dead for a while, but I thought I'd post this picture of airflow over a bug that I found.

Find one of those for a Ghia and we're talkin!;)

Wanted to raise this one from the dead:

Here's my thoughts on aero on a bug:

Green: downforce

Red: lift/resistance

Yellow lift/resistance zones

http://images.thesamba.com/vw/gallery/pix/574423.jpg

Thinking about slotting out this area of my fender:

http://images.thesamba.com/vw/gallery/pix/574420.jpg

How well do either of these work?:

http://images.thesamba.com/vw/gallery/pix/574150.jpg

http://images.thesamba.com/vw/gallery/pix/574421.jpg

Jason

The fender slotting is generally a good idea I think.
The Remmele bug also has extensive holes in the rear apron and rear fenders for letting out hot exhaust radiant heat as well as decreasing rear lift imo.

I suppose any rear roof device works, if only to distort the laminar flow there so lift is reduced.

Look at these race bugs for reference of things you can do. Racing brings out the best developments in people don't you agree? ;)

http://i174.photobucket.com/albums/w...1.jpg~original

http://i174.photobucket.com/albums/w...0.jpg~original

Generally the reason you put vents in the fenders is to let the high pressure air out of the wheel well. Bug and non-bug alike all have this problem where high pressure high builds in the fender wells (because of the wheel openings, tire/air interaction, brake/radiator ducting) causing drag. Louvers on top for the fenders or holes in the back relieve the air pressure and if done right can even add down force or reduce drag.

I'm going to make similar cuts in the backs of my front fenders though possibly higher up. On the rears I haven't decided if or where I'll cut but I've considered hacking 4" off the bottom of the rear fenders so they didn't catch air. One of my sources of inspiration is the 997 turbo, with the larger rear fender vents and I thought about something like that as well

I've been looking for one of those lip spoilers for the top of my car but I'm not sure who has them in stock. I'd like to put one one the race bug and decrease the angle of attack on the wing.

Carbon Joe said he could make a roof lip for me in a little while, should I double the order?

Jason

Has anybody tried this program? I can't remember where I found it, came across it again while sorting through my favourites...

http://www.equationsinmotion.org/equationsinmotion

Jason,

I think you will find that the area at the base of the screen will be a high pressure area (that is where most manufacturers put the cabin air intake) and there will be a high pressure area at the very front of the car with a low pressure area immediately behind it that usually equates to the front quarter of the nose. As regards the flow over the rear window, I did see some years ago a flow path photo that implied that the air hugged the body shape pretty closely. If so, that would not create a low pressure area as you suggest it would be closer to neutral although I am inclined to believe that this is actually a mildly high pressure zone given the shape of the venting immediately under the rear window. This area is where VW expect the engine to take its cooling air from and supply cool air to the carb. If it were low pressure then the fan and the carb would be fighting for breath. This logic is further enhanced by the use of engine cover wings and the siting of intercoolers.

The roof lip spoilers are there under normal circumstances to create a break in the laminar flow to induce a negative (i.e. below atmospheric) pressure bubble at the rear that in a beetle ought to cause lift and poor cooling unless say, air was ducted from below the floor pan to vent into the engine compartment and then into the low pressure air zone.

Whilst I have not seen many aerodynamic assessments/records for the bug I have for the 911 particularly the racing 935s etc, which in many respects is a squashed bug (:rolleyes: forgive the pun) and much of what I have said holds very true. there was some interesting work done on the 911 with regards to the effect of the wings that were hugely extended beyond the main body that was not too dissimilar to the beetle. The aerodynamic findings was that drag was significantly reduced if the tops of the wings were extended rearwards as much as possible - connecting the front and rear wings showed the least drag. The wheel arch areas were indeed high pressure and rear venting was benefcial not least in brake cooling.

Clive

Jason, if you order one, double it for sure and I'll grab it off you. Thanks!

Love to see this topic raised from the dead:)

I would like to correct/ increase definition on some things said before.
*First take a look at the link Rich gave us which is very helpful.
*Consider looking at the right side of a car (ie right is front, left is back) and for the ease of explanation consider the car as 2d (the overall profile on the centreline)
*Stagnation point is a theoretical point ahead of smthng that moves through
and the air starts to split at this point in order for the part to move through the air. WE, OUR CARS move THROUGH the air, not the other way...

1. As we move toward left the car starts to show its profile. our bumper being the foremost point, it has a stagnation point just ahead of it. Since the bumper isn't solid as it moves through air, the air suddenly gets sucked by the rear of the bumper, creating a vacuum effect and spiraling vertices.

2. next is the handle on the front hood. lets say it just splits the air left to right, so it is negligible at this moment(we could use it if talking 3d)

3. next is the profile of the front hood. specifically on the 1303 and less on the older bugs it has a hump facing forward. this has another stagnation point that the spirals from the bumper interfere with.

THERE is the first actual problem area due to the LOW PRESSURE POINT BEHIND the bumper and the HIGH PRESSURE POINT IN FRONT of the hood.

IN GENERAL every clean profile that the air gets to "see" first is a HIGH PRESSURE AREA, analyzed in HIGH PRESSURE POINTS and the opposite is for the LOW PRESSURE/VACUUM AREA/POINTS

Evil, the reason the auto makers put the air intake between the windshield and the hood is that the create a strong vacuum zone by raising the rear lip of the hood (to further promote the effect) so air can be SUCKED in.
Also the fan at the back actually works, because it lays in a low pressure area (engine compartment) that is connected to the "laminar" air flow at the rear with the grills below the rear window.

Don't confuse ram air that can work with carbs, efi with the actual fan
that is if we could put a big hose supplying air directly into the fan the fan would spin, but there would be no air flow.

same applies to turboprop engines in aircraft where u have a turbine spinning and a gearbox actually a huge reduction box that the prop is connected on to. if the ratio of turbine/prop was 1:1 the prop would go supersonic and the effect will be the same as spinning the same prop in space at zero pressure
this a real example from the cessna super cargomaster caravan aircraft where the turbine runs at 33000rpm @ 75% thrust and the prop at a mere 1750rpm.this is why u cannot go supersonic with a prop and only with a jet

sorry for the non germanlook example, it was the most recent i had from a personal experience


Chris

So, from all this knowledge/experience above, what would you suggest to be the first/best action to do on our little bugs Chris?

I will reply as soon as i get home.iphone isnt very easy on writting emails.what im going to do is get a rake on my 1303, get some kind of spoiler @ front to reduce the air gioing under and try to evac as much air as possible from wings.
Chris