Aerodynamics of a bug

[beetle1303]

Originally Posted by thelazerviking

you can reverse the whole thing for the back of the front fender to create better airflow and vent out that fender too indstead of those louver ideas and junk tghat probably won't work so well

I was thinking of making the front wings as the 935 K3 car. Flat on top following the curve of the front (side view) merging to the front quarter panels (where the 1303 has the fat trim piece) and being open (view from the back)

Chris

[thelazerviking]

the bug is like a giant airfoil, especially with it's flat bottom. put a front spoiler on it and lower the car then instead of high pressure under the car it should be a lower pressure. i think the reason the rear end feels so light at high speeds is because of how rounded out the back end it, there's probably a very great area of low pressure there, pulling the rear end up. if the front is lower than the rear that should help keep the rear end down too because it creates low pressure in the rear of the car, that's basically what a spoiler does though. check out how airplane winds work with airfoils.

[bean_8044]

this reminds me of something i was working on in Japan.
http://www.asahi-net.or.jp/~ge8w-ngk.../mente272.html
Its in japanese, but you can see the schematics which is all you really need. No, that wasnt my car, but i was trying to make it work on mine

[PJL54Oval]

HotRod Magazine just did an article on this subject. Some simple things to do are the front air dam, Lower the front of the car sightly more than the rear (accelerates the air under the car), Add side skirts to prevent air from entering the bottom from the sides and Spoil the air off the back of the car. Spoiling the air actually accomplishes two things. It decreases lift especialy with the shape of the beetle and also reduces drag by eliminating the low pressure at the back of the car.

Now on a completely different line of thought, has anyone here ever seen the Chaparral 2J? It was nick named the "sucker car" and had two fans mounted on the back of the car to literally suck the air from under the car. If you are running an air cooled engine you could draw some of the air from under the car (like some of you do) and this actually helps! Here's a link that shows the two snowmobile engine driven fans on the 2J car. http://www.petroleummuseum.org/Chaparral/Tour4Indy.html

I doubt that this will help us much but it was really cool to see.

Jim Hall was a pioneer in Ground effects and dominated road racing. He won indy his first year (Johnny Rutherford driving) by channeling the air under the car to create down force.

[judgie]

have plans this winter for the race car.
front spoiler and spliter leading to a flat floor pan into a rising rear diffuser,deep side skirts to stop air going into the low presure area under the car.
vented wings,grills on top of the fronts and holes in the bottom rear edge of the rears.
there will be 2 naca ducts in the floor pan to feed cold air to the bottom of the engine, header and gearbox.also two vents in rear 1/4 like remmele style ones to feed the air boxes on each carb.
to fiinish it all of i have a f3000 lola bi-plane rear wing which will be mounted as high and far back as the regs will let me.highest piont of the wing can not be higher than the roof line and rear most part can not over hang the rear of the car by 400mm.
this the car at the moment

will post pics when this work is compleat and let you all know if it works.
cheers rob

[lazylongboarder]

I'm impressed so far...Keep us posted on the improvements.

[beetle1303]

Very good choices i must admit. One issue for me though ( im going the same way for my street 1303)

The position of the front ing vents
A: the J-sports racing bug has 2 cuts on the back side of the wings

B: F40 used a huge vent on the back plane(vertical) of the front wings

C: DTM Audis and 935 have vents on top of their front wings. From what i have read on the DTM cars is that the vents on top of the wing help the above the wing ( low pressure) get filled with the vented air from the wheel wells...

D: the best i believe would be the 911 gt1 design


I also agree with the front bottom closing every posible gap (air trap)

Chris