External air bags as safety barriers?

[Richard]

autogyro - from a a purely technical perspective, how does a stretch rubberized surface work? No mention of personalities, politics or costs please!

[autogyro]

It is designed for the low pressure under the car to suck the surface up into contact with the floor and to make use of this friction to brake the car.
It would replace graval traps mainly, allowing cars to rejoin after a 'beached' spin and would reduce impact speed by a major amount in crashes like Webers recent one.
Most uncontrolled exits from the track happen with the car in an upright position where this surface design will work well even with cars with wheels missing.
The rarer occasions where cars roll usualy results in the roll itself dissipating energy and reducing the eventual barrier impact speed.

[aral]

I have seen a product, a bit like astroturf, that provides considerable retardation of anything passing over it. I dont remember the name of it, but it has considerable retardation powers.
Protection at barriers should not be tyres as these encourage rebound. Better would be the controlled discharge rubberised plastic water containers.
But nothing can minimise flight, as happened with Webber.

[Tim.Wright]

A vertical rubberised surface?

[ReubenG]

It is designed for the low pressure under the car to suck the surface up into contact with the floor and to make use of this friction to brake the car.

In order to suck the flexible surface upwards, there needs to be sub-atmospheric pressure above the surface, which requires air flow. Once the flexible surface makes contact with the bottom of the car, there is no longer any space for the air to flow through. No air flow means no pressure differential, so no normal force over the area of contact - so no friction.

What am I missing about how this is supposed to work?

[autogyro]

Gilgen, Webbers crash was a flight along the circuit and then the car went off track upright for many yards without retadation before hiting the barriers.
My surface placed on the corner run off would probably have stopped Webber before the barriers.
As to the low pressure area. The material is pulled up forming a venturi between the car floor and the ground. Yes, if it makes contact with the floor the low pressure ceases but soon forms again as the material drops.
It is the build up of material under the car that brakes it.

[aral]

Gilgen, Webbers crash was a flight along the circuit and then the car went off track upright for many yards without retadation before hiting the barriers.
My surface placed on the corner run off would probably have stopped Webber before the barriers.
As to the low pressure area. The material is pulled up forming a venturi between the car floor and the ground. Yes, if it makes contact with the floor the low pressure ceases but soon forms again as the material drops.
It is the build up of material under the car that brakes it.

Yes. it may work, but there would need to be a complete car, on wheels, for that to work. And what would happen on a wet day? There would be no friction and car would not be retarded? Further, for the rubber to lift and create the suction that would be needed, it could not be glued down to the substrata, leading to all sorts of problems. But maybe your idea warrants proper evaluation, whereas I have see both controlled discharge containers, and retardant astroturf in action, under tests.

[autogyro]

I discused the idea with Charlie Whiting a few years ago.
There were moves to allow me to run tests and some F3 cars were to be made available to fire at a test surface.
Unfortunately it was decided the cost would be to high.
Perhaps the cost now might not be such a barrier.

[mep]

This picture doesn't really impress me. The driver might had a very soft and safe impact but it doesn't look like it could handle another crash on the same spot.



The system from autogyro might work but I think you still need big runoff areas.
I don't think they could use it on tracks like Monaco in a effective way.
Runoffs are to short to decelerate a car with it and it significantly changes the street surface. After the race they us the track as normal street the system would be a big problem then. To remove it would take some time and doesn't make it cheaper at all. In the end you would still need some kind of barriers.
Tire barriers might be low sophisticated but as we have seen one more time they work really well.

[Tim.Wright]

Im no fluids expert but I would think you would need a pretty flat surface running close to the rubber to get a good pressure drop due to ground effects. Broken cars tend not to be so well organised. As soon as you have enough pitch or roll angle you loose all suction under the floor.

Also, I would tend to think that a broken F1 car would tear a rubber sheet to pieces.

Tim

[WhiteBlue]

I believe that a lot of research has gone into the TecPro barrier and that it is over all a better solution than tyre stacks. It can never be as good as a wide run off that scrubs off the motion energy. With a tyre stack you can hit it lucky and it does a good job or you hit it unlucky and you dive under it or get exposed to huge shear forces. Webber had a lucky hit but not everybody has that. What saved his life was the strength of the roll over structures and the wide run off that prevented him hitting something at speed. Imagine he had gone airborne i front of a bridge. He would have collided with 300 km/h floor first or top side first. Such impacts are not survivable even in modern F1 cars.

[mep]

I wonder why nobody mentioned the commercial sign he hit while being in the air.
When I saw the crash I was more worried because of the sign than because of the tire barriers. Those signs need some stiffness otherwise we see thinks like in SauPaulo years ago where they fell on track. On the other hand it could have caused real trouble to Webber or a following car.

[aral]

I discused the idea with Charlie Whiting a few years ago.
There were moves to allow me to run tests and some F3 cars were to be made available to fire at a test surface.
Unfortunately it was decided the cost would be to high.
Perhaps the cost now might not be such a barrier.

I had a word with my friend, Bernie, and he says that Charlie never mentioned this "idea" to him. However, if he was able to obtain sponsorship from The London Rubber Co., he might just give it a try.

[autogyro]

I doubt Bernie heard about the idea, it did not get that far.