Optimum nose shape

[aerohead]

Originally Posted by Otto

The Porsche Carrerra GT, the Boxster, and the Cayman S all have virtually semi-circular nose planforms.

In profile, the Carrera GT and Boxster noses both have upper edges with a ~4-6" radius curve, the Cayman somewhat less.

Such shapes should not be too difficult to duplicate. Well-rounded and with gentle curvature, presumably they are efficient aerodynamic shapes.

Otto,if you could do a movable front airdam like Volvo had for awhile and Ford did with Probe-IV you'd have best of both worlds.
She wouldn't get knocked off in town( Corvette,New Beetle,Camaro/Firebird,Chevy HHR,etc.. ) and then, when safely out of town,she drops to give lower drag where it really matters.
The T-100 is getting one of these.It's never had a proper nose either.And it's got to move,as with the racing tires and lowered ground clearance now,she has some real clearance issues!

[Otto]

Originally Posted by aerohead

Otto,if you could do a movable front airdam like Volvo had for awhile and Ford did with Probe-IV you'd have best of both worlds.
She wouldn't get knocked off in town( Corvette,New Beetle,Camaro/Firebird,Chevy HHR,etc.. ) and then, when safely out of town,she drops to give lower drag where it really matters.
The T-100 is getting one of these.It's never had a proper nose either.And it's got to move,as with the racing tires and lowered ground clearance now,she has some real clearance issues!

Got pics of the Volvo or Probe IV airdam? I'm not familiar, so will Google for those. Thanks.

For around town driveability and speed bump/curb issues, I've wondered about inflatable or ramair actuated devices, including splitter or air dam, side skirts, etc.. That way, no deployment until highway speed. A simple electromagnetic deployment would work, if you do not forget to retract.

[aerohead]

Originally Posted by Otto

Got pics of the Volvo or Probe IV airdam? I'm not familiar, so will Google for those. Thanks.

For around town driveability and speed bump/curb issues, I've wondered about inflatable or ramair actuated devices, including splitter or air dam, side skirts, etc.. That way, no deployment until highway speed. A simple electromagnetic deployment would work, if you do not forget to retract.

Otto,I think I've got images of both,but it may be Saturday before I can get Al to post them.I'm months behind on images.
On the deployment issue,seems like any cruise-control logic/sensor technology would dovetail right in.
A 'speed' preset enables or disables a solenoid,air ram,hydraulic ram,servo motor cable winch,ad infinitum,to lower and raise the unit.
Also,electronic ranging,as on any digital camera system could be hijacked to provide a 'forward-looking' hazard avoidance provision,should you drive up onto road debris,road-kill,etc.,especially after dark,when the event-horizon is really brief before 'contact.'
Something else to consider,and I think we kicked this one around before,is that whatever you construct,make it really low mass so if it has to 'move in a hurry' it won't get bogged down with inertial forces.This is where carbon composite would shine.Model airplane technology would give the low mass,but stone-toss from a car ahead could spell doom for the light skin.
An inflated structure might have to have vacuum available for quick-collapsing.

[Frank Lee]

carlos made a deployable air dam but i haven't heard anything about how it's working out lately.

[Rokeby]

And then again, maybe not.

[Otto]

Originally Posted by Rokeby

And then again, maybe not.

Well, to tell the complete truth, I've given thought to putting Great Stuff expanding insulation foam on the nose, then sculpting it to shape, and/or using smooth plexiglass as a curved form to hold the foam in place until it sets up, just like using plywood forms to pour a concrete building foundation.

Best method is probably to glue foam blocks onto the naked (stock nose cover off) front of the car, and sculpt that to shape as a male master for a female mold. On homebuilt airplanes, most guys use this foam glued to engine method to make engine cowlings. Gasoline fumes will destroy the foam, leaving little powdery residue.

[aerohead]

Otto,I found a better photo of the Volvo than mine.I GOOGLED :Volvo Concept Car 1980 and got:
http://www.swedespeed.com/news/uploads/features/vcc.jpg

[aerohead]

GOOGLE has a bunch of pics of the Probe IV.And cgg83 has a thread for the controls at: cfg83-albums-car-styling

[Otto]

Originally Posted by aerohead

Otto,I found a better photo of the Volvo than mine.I GOOGLED :Volvo Concept Car 1980 and got:
http://www.swedespeed.com/news/uploads/features/vcc.jpg

I'll bet that spoiler would work even better if instead of a bulldozer blade shape, it were semi-circular or elliptical in planform, shedding air laterally out and past the front tires.

[aerohead]

Originally Posted by Otto

I'll bet that spoiler would work even better if instead of a bulldozer blade shape, it were semi-circular or elliptical in planform, shedding air laterally out and past the front tires.

Yeah,that would be my take on it.I suspect that they made the best of a bad situation without altering the Volvo's front end.Cheap and quick!
Volvo's more modern designs are getting the organic shapes and Cds will reflect that.
The semicircular airdam might require more of a vertical,guillotine type motion rather than a simple hinged/swinging motion in order not to bind during articulation unless the hinge is way rearward,close to the tire face.