Force transmitted through steering wheels in crashes

[tommylommykins]

Just a quick question for someone in the know, or someone with the mechanical knowlege to find an answer:

There is obviously a direct link between the front wheels and an F1 driver's hands through the steering wheel. That link must be strong enough to keep the wheels pointing sideways when turning corners, presumably a rather large force in any car, but especially so in formula one. Does anyone know if there are safety systems in place to make sure that any enormous force transmitted through the steering linkage in a crash does not make it all the way back up into the steering wheel, where it could break the driver's wrists?

If there is a deliberate weak-point in the steering system, would the power steering be the key to providing an adequate weak-spot or other passive mechanism for preventing injury: between the steering wheel and the power steering device, the forces transmitted must be very low, providing somewhere to add a reasonable breakpoint?

[autogyro]

I do not think the amount of movement lock to lock would be sufficient to cause serious injury.
In anycase, with a power steering system it is not possible to transfer much in the way of energy from a suddenly jerked road wheel to the steering wheel. The hydraulic system will act as a damper.

[scarbs]

As the steering system is only hydraulic assisted, there is still a direct mechanical link from the road wheel through to the steering wheel; via the wheel, upright, track rod, rack and column.
There is a chance a steering wheel could flick back and injure the drivers hands (thumbs being common injury), there is no such mechanism to protect him.

IIRC Hamiltons trip into the tyre barriers a few years ago, had the steering wheel aggressively spin left and right, no injury was caused but the movement would have been enough to injure wrists or thumbs had been holding on.

[xpensive]

I do not think the amount of movement lock to lock would be sufficient to cause serious injury.
In anycase, with a power steering system it is not possible to transfer much in the way of energy from a suddenly jerked road wheel to the steering wheel. The hydraulic system will act as a damper.

Hydraulics a damper? You don't have the vaguest idea of what you are talking about gyro, do you now?

[tommylommykins]

I do not think the amount of movement lock to lock would be sufficient to cause serious injury.
In anycase, with a power steering system it is not possible to transfer much in the way of energy from a suddenly jerked road wheel to the steering wheel. The hydraulic system will act as a damper.

Hydraulics a damper? You don't have the vaguest idea of what you are talking about gyro, do you now?

Would someone care to elaborate, for someone unititiated, like me?

Regardless of the fact that there must be a direct mechanical link from the wheels to the wheels, any hydraulic system also attached must also have an effect?

I'm not in any way versed in hydraulics, but I make the assumption that trying to force a liquid really fast through a small hole would represent a resistance to velocity, and therefore would be damping..

[Tim.Wright]

The power steering will act as a damper because if the rack is forced to move, the hydraulic piston will be forced to follow it, displacing hydraulic fluid in the process.

I'm not in any way versed in hydraulics, but I make the assumption that trying to force a liquid really fast through a small hole would represent a resistance to velocity, and therefore would be damping..

Exactly right

Regardless, I think with such a high speed impact force, the steering arms will fail before a large force is transmitted through to the driver.

Tim

[mep]

.........force feed back guys.
I think even on a normal road car you can manage to break your thumb or wrist in a crash.

[autogyro]

.........force feed back guys.
I think even on a normal road car you can manage to break your thumb or wrist in a crash.

Yes but the steering wheel rotation on an F1 car is far less than on a road car.

[vonk]

In drivers school they teach:
1) Don’t ever hold on to the steering wheel.
2) Let go of the steering wheel when impact is unavoidable
3) Steering power assist is required precisely because the low steering ratio results in high force feedback from the wheels.

As for hydraulic damping of sudden high force rate feed-back, I believe this might interfere with driver control while riding over curbs, where high frequency feed-back shocks are encountered.

[010010011010]

Yeah I heard martin brundell talking about this when Hamilton had his crash at the nurburgring a few years ago. Vonk is right, theres no safety feature, you simply let go of it usually.

Even so alot of drivers dont (such as hamilton in 2007) and they dont suffer any great damage most of the time.

[spinmastermic]

In oval racing its essential to let go of the wheel in a crash, as it will break your wrist. But thats because the speed (high) and the angle of impact are generally the same on ovals.

Your instinct is to drive out of any problem though. I mean, fair play to Buemi trying to avoid the barriers after both wheels came off in China.

[autogyro]

In short oval racing the steering is relatively low geared or standard road ratio.
With a conventional steering wheel it is the thumbs that take the force.
The force is magnified by the low ratio and the much larger number of turns lock to lock than an F1 car. Power steering is also unusual in short oval racing as steering feel is everything. So there is no hydraulic back feed damping.
Forced feed back from steering would not be a good idea on any racing car.

[vonk]

Steering feel derives from force feedback. Force feedback depends on the steering ratio. F1 cars have very low ratios, which would produce excessive force feedback to the steering wheel. Some (not all) of that feedback is absorbed by the hydraulic steering assist.

[autogyro]

We are at crossed purposes vonk.
I totaly agree that feed back is designed into the steering geometry on any performance vehicle to increase the feel for the driver.
I was describing power steering feed back, which is counter (in most cases) to improved driver feel and would increase the force returned to the steering wheel in a crash.

[DaveKillens]

As stated, the safety device used in a crash is the driver's head, by instructing the arms and hands to let go of the wheel and pull back.