Red Bull RB8 Renault

[Tyler]

If the slot is there to channel air to the underside of the car as some are claiming, how could they do this?
I thought there couldn't be any holes in the floor so how would they manage to channel it through the cockpit first of all and then under the floor?
If it is possible then why aren't we seeing more slots in strategic positions to get more air under the car?
It just seems, as least from a laymans perspective, the obvious thing to do.
Surely if everyone is aiming to get as much air under the car as possible Red Bull couldn't be the first to devise something only now?

[ringo]

That's like saying a steel pipe with its end covered with a plastic bag is going to be compromised if you poke a hole in the plastic bag. The tub strength is mostly in the walls, just look back to the pit garage images with all the brake fluid reservoirs electrons steering rack etc. tucked up in the hole in the tub.

Not even close to being a valid example.

I am assuming the chassis are built to a design limit that has been set by the teams. Putting a slot at the top of the bulkhead effectively reduces its exterior dimension and thus its strength. If you want to to get back to your design limit you are going to have to add material to strengthen the bulkhead. So, if you are designing to a limit, not beyond, and wish to maintain that limit, then something is going to need changing. Assuming the chassis is as light as you can make it, any change means more weight. Why add weight ONLY to accommodate driver cooling. We have no indication, from observing other cars, that driver cooling is mandatory on every car.

Brian

I see what you are saying, but i dont think they dug into the wall of the tub when making that hole.
Most of the time these thing are not designed on the limit. Once a human being is involved the safety factor has to be higher than 1. 1 is the limit load.
The FIA have built that into the load tests. The tub is taking more than it will ever experience on track.
That tub can probably take 10 more suspension member holes in it without losing much strength.
Again i refer you to a steel pipe, notching out some of the wall, or boring a hole in the wall of it wont compromise the strength much.

[hardingfv32]

Most of the time these thing are not designed on the limit. Once a human being is involved the safety factor has to be higher...

If I made such a casual statement about an aero feature you would crucify me. While I agree the limit might be a little nebulous, once it is set that is what you design too. If you put a hole somewhere, then by definition you have to compensate for it in the design. If I am the technical director and you make this hole without changing the lay-up, I will question why there was extra strength available in the first place.

Brian

[MIKEY_!]

If the tub passes the FIA tests we can't complain about safety.

[thisisatest]

from a forward crash impact perspective, i dont see the hole reducing the impact strength. volume is reduced, but there is barely any reduction in the amount of wall parallel to the direction of impact. with the vent, there's some overlap of upper horizontal wall, giving extra supporting structure during an impact.

[Owen.C93]

This video is talking about how the RB8 is heating it's tyres with the exhaust. Not that I can really understand it.

[youtube]http://www.youtube.com/watch?v=qsY-AwOO ... AAAAAAAAAA[/youtube]

[hardingfv32]

from a forward crash impact perspective, i dont see the hole reducing the impact strength

I am thinking in terms of chassis twist or flex strength. They set a target and the computer develops the lay-up plan. You make a hole in the chassis, run the program again and you develop a new lay-up plan to get back to the target.

Brian

[hardingfv32]

This video is talking about how the RB8 is heating it's tyres with the exhaust

Am I wrong in assuming that because I see absolutely no heat shielding on the control arms, axles, or hub appendages, that the exhaust flow is just not over heating anything. I assume any form of heat shied would be some color other than black.

Brian

[wesley123]

Where is anyone naming overheating? The vid goes about heating the tires with exhaust gasses, not a problem of overheating

[ringo]

from a forward crash impact perspective, i dont see the hole reducing the impact strength

I am thinking in terms of chassis twist or flex strength. They set a target and the computer develops the lay-up plan. You make a hole in the chassis, run the program again and you develop a new lay-up plan to get back to the target.

Brian

It still wont have a safety factor of one. The loads in those CAD programs are set by the users. They can't account for every single load that may exist. They're not God.
Therefore safety factors are always used. We mustn't think too highly of these guys and their technology; it's still not enough to predict everything.
If human life is involved, i suppose safety factor over 2 is used. Maybe even more because of fatigue, since the tub needs to last a whole season.

In terms of twist, the free end has the least stress. So the notch isn't much of a weakness.

[aral]

In terms of twist, the free end has the least stress. So the notch isn't much of a weakness.

Surely that as the front bulkhead is carrying the front suspension loads, then the stress will actually be quite considerable. Any removal of the web, will reduce the torsional rigidity.

[hardingfv32]

Surely that as the front bulkhead is carrying the front suspension loads, then the stress will actually be quite considerable. Any removal of the web, will reduce the torsional rigidity.

Directly on point. We don't even know which requirement is higher, crash test loads or chassis torsional requirements.

This is very simple. The team develops a limit target for chassis torsional strength. I have no clue how they pick the target, but I do know that you can't proceed with the chassis design without that number. The rest is done by the computer.

Now, if you want to argue that some torsional stiffness is being traded for an aero benefit, that is fine.

For the benefit of our discussion on this forum we have to assume that everything the teams do is on the limit. It is the only way we can baseline some of our technical discussions or analysis trade offs.

Brian

[Owen.C93]

This video is talking about how the RB8 is heating it's tyres with the exhaust

Am I wrong in assuming that because I see absolutely no heat shielding on the control arms, axles, or hub appendages, that the exhaust flow is just not over heating anything. I assume any form of heat shied would be some color other than black.

Brian

If they can get away with black then they will, I mean it will be black by the end of the race anyway right

[hardingfv32]

Where is anyone naming overheating?

Not in the context of the video, but in general with the way the exhaust is being routed. The exhaust seems to flow close to the suspension or axle, yet no apparent shielding. Is it cooling that rapidly?

Brian

[wesley123]

Red Bull uses 95% the same exhaust position as it did with the RB5, which also didnt use any shielding, seems like they do not need any.