Porsche 918 the Prius from hell

[Hobbs04]

Considering the wealth of knowledge on this site I'm surprised no one has brought this up.
Good read and hopefully this kind of tech pushes Porsche/VW to get back into F1.

http://www.motortrend.com/roadtests/alt ... ide/?ti=v3

[Websta]

check the off-topic chat, probably mentioned in there with the other non-F1 related stuff.

[DaveKillens]

It's a cool car, but the technology is interesting. The hybrid technology was plucked off the Porsche 997 GT3 R Hybrid, which use the Williams flywheel KERS technology.

Porsche gets cool hybrid technology from Williams, Williams use the money from Porsche towards their Formula One team. It's one of many reasons why Williams have come back from such a dismal season in 2011.

[Hobbs04]

check the off-topic chat, probably mentioned in there with the other non-F1 related stuff.

Will do.

[Hobbs04]

It's the real world application of technologies that keep cars fast and cool. Check out the exhaust exits.

[Hobbs04]

On YouTube show "Drive" they mentioned the crankshaft was "flat planed." I've never heard that term.

[mx_tifoso]

http://en.wikipedia.org/wiki/V8_engine# ... aft_design

[DaveKillens]

Flat-plane crankshaft



Cross-plane crankshaft



The alteration of the crankshaft throws alters the torque delivery and vibration characteristics of the engine. Wow, I said it in one sentence, but we can spend thousands of words describing the differences, advantages, and disadvantages of each configuration. But to do that we have to learn about the big bang engine, primary and secondary vibrations just to get started.

[tok-tokkie]

From the link:

Also in an effort to reduce drag, the side vents in the front fascia are able to open and close depending on cooling needs. In most conditions they will remain closed to push air around the car rather than through it. But the designers insisted they open when the car is at rest for aesthetic reasons.

I don't understand what they are talking about:
1. Are they referring to the two INLETS each side of the number plate? (Vents are what air comes out of, not what air flows into). It seems to fit in with the staement that the air is deflected around the car rather than through it.
2. If they are referring to those inlets how do they open & close? Is is a black flap or louvre system? If so how does that affect the aesthetics?
3. There is also some air inlet(?) behind the door but they are surely not referring to that.
4. I am also surprised that deflecting air around the car is more efficient than letting it flow through the car. Basically allowing it through the car reduces the frontal area. Seems like that reduced area is more than offset by the friction of the air flowing through the car. Not what I would have expected.

[matt21]

4. I am also surprised that deflecting air around the car is more efficient than letting it flow through the car. Basically allowing it through the car reduces the frontal area. Seems like that reduced area is more than offset by the friction of the air flowing through the car. Not what I would have expected.

How is the frontal area reduced by letting air flow through the car?
up to now I always thought the frontal area is more or less just a projection of the car to a vertical wall.

Every aerodynamist wants as less airflow through the car as possible to reduce drag and gain advantages, as you can see if you look on the F1-side pods.

[Hobbs04]

From the link:

Also in an effort to reduce drag, the side vents in the front fascia are able to open and close depending on cooling needs. In most conditions they will remain closed to push air around the car rather than through it. But the designers insisted they open when the car is at rest for aesthetic reasons.

I don't understand what they are talking about:
1. Are they referring to the two INLETS each side of the number plate? (Vents are what air comes out of, not what air flows into). It seems to fit in with the staement that the air is deflected around the car rather than through it.
2. If they are referring to those inlets how do they open & close? Is is a black flap or louvre system? If so how does that affect the aesthetics?
3. There is also some air inlet(?) behind the door but they are surely not referring to that.
4. I am also surprised that deflecting air around the car is more efficient than letting it flow through the car. Basically allowing it through the car reduces the frontal area. Seems like that reduced area is more than offset by the friction of the air flowing through the car. Not what I would have expected.

1. They inlets are the ones under each headlight.
2. It operates like your traditional window blinds.
3. The side inlets don't have the same aero penalty as the two fronts.
4. It appears it has 3 modes, fuel efficient, track, top speed. The flaps in the front can do 3 different modes. Open, closed, and tilted down to feed air down to gain rear downforce thru diffuser.

[tok-tokkie]

Thanks for the explanation. So a 'vent' in the article is actually an inlet.

If air can flow through a car then the effective frontal area is diminished because less air is deflected than the full frontal area would deflect. If there was a straight open pipe from front to back then the area of the pipe would not form part of the frontal area. The Britten motorcycle was rather like that.

[matt21]

If there was a straight open pipe from front to back then the area of the pipe would not form part of the frontal area.

But where do you have this on a car? I think to have air flow through the car would only be done for aerodynamic reasons like the Ferrari nose hole in 2008.