Teardrop aerodynamics... in reverse!

[niky]

Safety regulations, ergonomics, cost.

Having an engine compartment in front gives you a crush zone that's useful for something other than being crushed. While you could put a windshield further forward over the engine, that still doesn't help visibility all that much (and move it too far forward and you'll have to wrap it into the roof so drivers can see overhead traffic lights), with the engine there... and it gives you much more cabin to build and an unusually large greenhouse, which means bad things for the AC. This all puts a practical limit on how far forward you can move it.



Move the engine to the back and you can design a better front end.



But a lot of people "don't feel safe" with a blunt-nosed car. Hence, even small cars today need massive proboscises to convince people they'll survive smashing head on into an eighteen-wheeler at 120 mph.

And whatever happens up front, the rear end will always suffer due to the need for rear passenger space and/or/maybe? cargo.

[jamesqf]

Originally Posted by niky

But a lot of people "don't feel safe" with a blunt-nosed car. Hence, even small cars today need massive proboscises to convince people they'll survive smashing head on into an eighteen-wheeler at 120 mph.

It's not that, or at least not just that. If you have a blunt-nosed car, like your blue example, the people in the front seats are forced to sit in an uncomfortable (at least to me) bolt-upright posture, instead of a comfortable semi-reclining one with legs stretched out in front, as with the red one. And that also forces the car to be much taller than it needs to be, so that any improvement in Cd is negated by the increased A.

[oldtamiyaphile]

Originally Posted by Cd

I remember reading that Ferrari mounted their mirrors high on the Testarossa to reduce A pillar drag.
I guess it didn't help much, since I have never seen that configuration again.

The Toyota TS020 did similar, and a few of today's hyper cars have very long mirror stalks. Putting mirrors at the A pillar is about the worst place for them in aero terms, but of course, there are other reasons why that's the favored location. Remember that 90% of the reason for buying a Ferrari is the styling.

[Hersbird]

A teardrop is a good shape but a taper both front and rear is even better. So keep the front end like they are today, just also then taper the rear end as well. Keep the seating position low and reclined as well to reduce frontal aera.

[niky]

Originally Posted by jamesqf

It's not that, or at least not just that. If you have a blunt-nosed car, like your blue example, the people in the front seats are forced to sit in an uncomfortable (at least to me) bolt-upright posture, instead of a comfortable semi-reclining one with legs stretched out in front, as with the red one. And that also forces the car to be much taller than it needs to be, so that any improvement in Cd is negated by the increased A.

Well, a lot of cars on the road already force me to sit more upright than I like to see over the hood. But then again, I'm only one Tom Cruise high, so I may just be an outlier...

[aerohead]

Originally Posted by Hersbird

A teardrop is a good shape but a taper both front and rear is even better. So keep the front end like they are today, just also then taper the rear end as well. Keep the seating position low and reclined as well to reduce frontal aera.

The 'double-ended' body is elliptical.It has identical drag characteristics as the teardrop'd streamline body of revolution.It has no advantage.
The trouble with the ellipse,is that the windshields have impossible angles,as far as outward visibility is concerned.You simply cannot see out of the car.
The 'teardrop',with it's bulbous nose,is ideal,aerodynamically,up to around 250-mph.And the vision is ideal also.

" Aero is more about the rear of the car than the front.
Freeman Thomas,Director,Strategic Design,Ford Motor Company,Los Angeles Auto Show,2008

[jamesqf]

Originally Posted by niky

Well, a lot of cars on the road already force me to sit more upright than I like to see over the hood.

The obvious solution to that is to make the hood lower :-)

But then again, I'm only one Tom Cruise high, so I may just be an outlier...

OK, I give up. Use the @#%$ metric system :-)

[aerohead]

Originally Posted by jamesqf

The obvious solution to that is to make the hood lower :-)



OK, I give up. Use the @#%$ metric system :-)

Federal pedestrian safety regulations are driving higher cowl heights to protect potential victims from striking engine hard points under the hood,as well as the wiper motor.
This law won't be going away and automakers will have to design accordingly.
Here,in this X-RAY image of the new Mustang,you can see how close underhood structures are in relationship to the hood

[freebeard]

The Loach was always my favorite. They buzz instead of flapping.

Cowl height is among the first parameters set and it's hard to change. Consider the Mustang/Probe kerfluffle in the 80-90s.

"This time, we were in on the project earlier," Ford designer Mark Kelly told us. All along, we had thought the Ford-Mazda partnership that produced the Probe and MX-6 front-drive two-plus-twos had been an even-Steven deal from day one, so we wondered: had Ford just been tagging along when these cars first appeared in 1988?

Kelly and product development chief Neil Ressler explained that the first time around, they were handed an existing Mazda platform, that of the 626 sedan. For their half of the joint sports-coupe project, they could only restyle the skin and fiddle with chassis tuning. All the "hard points" had to remain fixed in space. Cowl height, suspension locations, wheelbase, track—the key mechanical-architecture cards had already been dealt before Ford walked into the room.

For the second-generation, 1993 models, however, Ford engineers were able to spec out the new platform the way they wanted it. They started with a considerably bigger and more stable footprint by stretching the wheelbase almost four inches and pushing out the track, front and rear, more than two inches. Dropping the cowl height a dramatic three inches and pulling the windshield base forward nearly four inches provided the canvas on which a lean, long, contemporary shape could be drawn.

http://www.caranddriver.com/reviews/1993-ford-probe-gt-archived-test-review

Let's hear it for the boxer-motor.