Raised bonnet hinges

[NotoriousREV]

It means I won. Someone lock the thread.

[JLv3.0]

I'm on it.

[Rich B]

It means I won. Someone lock the thread.

but I want more!!

[NotoriousREV]

It means I won. Someone lock the thread.

but I want more!!

No you don’t.

[Rich B]

It means I won. Someone lock the thread.

but I want more!!

No you don’t.

thats the spirit!!

[NotoriousREV]

No it isn’t.

[Beany]

Fuck the aero, can we all agree that it looks fucking stupid?

[Jobbo]

This is an image from GM:



This is another one (with a flush bonnet and no trough) that also shows that the high pressure area is higher up the screen than the trailing edge of the bonnet:

Both of those images show that the bottom of the screen is a high pressure area in general. It is clearly possible to design an small opening in such a way that locally the pressure is not the same as generally in the area (as is the case with the wiper aperture in those images), but you cannot escape from the fact that generally the base of the screen region is obviously a high pressure - even on your own diagrams.

If you open the bonnet an inch or two, the small wiper aperture is no longer working as designed; air will not be isolated from the under bonnet region. So even the tiny blue area on your images will disappear. That leaves a dominant high pressure area at the base of the screen.

[Jobbo]

It means I won. Someone lock the thread.

Nobody responded before because it's obvious from the images you posted that you disproved your own point

[NotoriousREV]

I await your CFD evidence. And Ste's.

[V8Granite]

Unless you know the air pressure under the bonnet though the high pressure area at the base of the screen doesn’t matter. As long as it is a lower pressure than under the bonnet.

Just playing devils advocate.

Dave!

[Simon]

Surely if it was a low pressure area you wouldn't be able to pull air into the HVAC system?

[NotoriousREV]

Surely if it was a low pressure area you wouldn't be able to pull air into the HVAC system?

It's all relative. It'll be higher pressure than the interior of the car.

[nuttinnew]

What about if it's turbo/supercharged?

[JLv3.0]

What if the seats are folded down?

[NotoriousREV]

I'm on it.

I gave you one fucking job.

[Simon]

Is this thread still going? We should definitely stop replying to it and just let it die.

[Rich B]

What? It’s only just got started!

[JLv3.0]

I'm on it.

I gave you one fucking job.

And I did it to my normal level of excellency

[GG.]

Could we have GGs take on this before we ahead into round 2?

Sorry - been out of the country on holiday and in dereliction of my arguing duties on the forum...

I don’t really think this is too hard to rationalise (at least as an aerodynamic layman) to be honest.

Whether or not the car has been designed to have a gulley into which the wipers are inserted to move them out of the airflow and reduce drag, would seem to be irrelevant. If there is a dam of fast moving high pressure air sat on top of that area, where is the hot air that you’ve released from the engine bay going to go? I expect that is going to sit in that area of still relatively low pressure air and just cause more turbulence or perhaps move the high pressure flow of air higher up the screen with adverse aerodynamic effects.

As the speed of the airflow through out the newly created vent is a key determinant of the cooling coefficient, it would stand to reason that propping the trailing edge of the bonnet up letting hot air sit at the base of the windscreen, would be of minimal use re cooling given the lack of throughflow of air.

When added to the fact you’ve almost certainly increased drag by tipping the bonnet up, probably screwing up the smooth flow of air over the windscreen & therefore increasing load on the engine for a given velocity then you’ll surely end up with the reverse effect to what you intended?

Can someone just call Adrian Newey and ask him to resolve and submit his workings? May as well ask him for his two penneth worth on Moles and tank tracks whilst you have him on the line.