Aerocaps are alive and well in China (pickup truck aero shells)

[serialk11r]

Originally Posted by SlideWRX

That can't be true; I know the Jeep Grand Cherokee is sold over there. A very 'not stringent' Fuel economy case. They use a 2.99~ liter engine because anything 3.0 liters or higher has a serious tax penalty. In the US, the smallest gas engine available is 3.6l.

Well aerohead's statement was mostly correct, the fuel economy requirements there are higher. The way around it is to use smaller engines in everything like you mentioned. They have 3.0L engines instead of 3.5L + engines in Mercedes, 2.0L engines instead of 3.0L engines in BMWs, etc.

[aerohead]

Originally Posted by bondo

Thanks Sven7 for the kind words. Coming from someone like you who works in automotive design, that is a compliment indeed.

The influence of the Asian culture always has a bit of flair to it in automotive design. One design aspect of the far east aerocaps is the fact that they recessed the surface of the roof to allow for a space to put the third brake light into. This breaks up the most important surface of an aerocap, the top. Also, by doing this, it diminishes the angle of the rear window which reduces the rear visibility.

Maybe aerohead could chime in and verify that the step down to a recessed top of the Chinese aerocap may hurt the aerodynamics of it. I'd say it probably does. As far as quality of the Chinese aerocaps, I feel they are quality made as Aerohead implies in his earlier post.

Bondo

Yes,you're gonna lose the boundary layer right there,with localized vorticity and turbulence sequestered within the void.
The flow will reattach before it leaves the cap,but you'll pay a little penalty for the chaos inside there.
It should take care of the rear lift issue,which is a great reason for having the cap in the first place,even if mpg doesn't excite you.
Jaguar has gone to the 'aerolid' with their F-Type,I think we'll be seeing more of this roofline.

[aerohead]

Originally Posted by SlideWRX

That can't be true; I know the Jeep Grand Cherokee is sold over there. A very 'not stringent' Fuel economy case. They use a 2.99~ liter engine because anything 3.0 liters or higher has a serious tax penalty. In the US, the smallest gas engine available is 3.6l.

The government simply doesn't allow importing large volumes of vehicles, to encourage local manufacturing. Most of the major automotive companies have set up local factories to produce/sell there.

JEEP has been produced there since the 1980s.And now that they're more effeminate,and with modern powerplants and 9-speeds,they more efficiently fill a niche which has existed for decades.
Some passenger cars don't make the cut.The Chinese 'CAFE' standards are more stringent than the US.We're catching up though.

[aerohead]

Originally Posted by ChazInMT

The only thing I take issue with is the non raidused corners. It looks like the top shape is good. Unless the box has a plan taper, I`m not so sure a plan taper on the cap wouldn`t be a wash in drag reduction. So, if they only radiused the edge, it would be pretty ideal aero wise.

Yes,Koenig Fachsenfeld and Kamm measured a 16.6% drag reduction when the surfaces were softened.
FIAT reported that a fastback wants 40-degrees of tumblehome to be best.

[freebeard]

That right there is The Template in a nutshell.

[Xist]

Not to open up a new can of worms, but China has stricter standards than the United States?

[aerohead]

Originally Posted by Xist

Not to open up a new can of worms, but China has stricter standards than the United States?

Some journalist reported on it years ago.China,as Admiral Mike Mullins of the Joint Chiefs of Staff, was concerned about the geopolitical implications of the reliance on imported energy, and China was just going to leapfrog,going beyond USA standards, to help protect their economy.
Some USA products weren't efficient enough to make it in.

[aerohead]

Originally Posted by freebeard

That right there is The Template in a nutshell.

Here's there side elevation

Plan-view

Together

Here's the evolution of it